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RV and Camper Rooftop Air Conditioner Maintenance, Troubleshooting, and Repair

Updated on May 20, 2017
Randy Godwin profile image

Randy is a lifelong lover of the outdoors and especially camping. This article is intended to help the RVer save money and time on repairs.

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Camper Trailer and Motorhome RV AC Servicing

Since the majority of motor homes, camper trailer, or RV A/C systems are used during the hottest time of the year, it is a must to keep them in good operating order. Merely cleaning and replacing the filter is not good enough to maintain your RV AC in tip-top condition.

There are certain procedures for guaranteeing the maximum efficiency of your motorhome or camper trailer A/C unit. These steps are not as difficult to perform as you might think and will save you money and inconvenience as well.

Cleaning the condenser and evaporator annually will make a huge difference in the cooling ability of the motorhome or camper trailer RV unit. Lubricating the A/C fan motor may help extend the life and performance of the unit itself.

You will also learn a little about how these RV cooling units differ from regular household units by following the tips in this article. Be sure and check the many actual questions and answers in the comments at the bottom of this page to find a problem similar to yours if the info in not found in the main text.

Gaining Access To The RV AC Unit

Removing the shroud from a Coleman rooftop AC.
Removing the shroud from a Coleman rooftop AC. | Source

Keeping Your AC Cool

Airstream Sovereign With Coleman Mach Rooftop AC
Airstream Sovereign With Coleman Mach Rooftop AC

Brands and Models of Rooftop RV AC Units

There are several main producers of rooftop units. Coleman RV air conditioners are common on many of the best equipped motorhomes and camper trailers. The same can be said for Carrier AC units, as well as Duo Therm A/Cs. Dometic made one of the first rooftop air conditioners, as well as, camper refrigerators and ice machines.

Thankfully, all of these units are similar in function and design. Some of these cooling units may even be identical under the shroud.. Being familiar with household AC units will aid you greatly in servicing and repairing your air condition system, but there are a few differences as you will see.

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Troubleshooting RV AC Units

Before beginning any repair or maintenance step, it is helpful to familiarize yourself with the main components of the rooftop AC unit itself. A fan motor circulates the air from the interior of the motorhome or camper trailer through the RV AC unit where it is cooled and then returned into the RV interior.

The compressor performs the job of circulating the Freon through the condenser and evaporator coils cooling fins and the cycle is repeated as the thermostat setting deems it necessary.

Both the compressor and the fan motor use capacitors to provide a high voltage charge to get them moving and a lesser charge to keep them running.

Often, only one capacitor is used for both fan and compressor. It the capacitor goes bad, neither the fan nor the compressor will start. This part is easily replaced and is not very expensive to purchase in most cases.

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Rooftop A/C Shroud

The AC shroud showing retaining screw holes
The AC shroud showing retaining screw holes

Rooftop RV AC Shroud Removal

In order to clean or repair the RV AC unit, it is necessary to remove the shroud from atop the unit. Ordinarily this is a simple job requiring only a Phillips screwdriver or small wrench. Remove the four screws or nuts from the AC shroud and carefully slide it up off of the unit.

If the shroud is old, it may be cracked around the retaining screws or the vent holes on the sides and back. Now is the time to repair the bad spots before replacing the shroud.

A good quality epoxy cement, or other glue made for plastic repairs, should be used to reinforce the weak or broken place before replacing the shroud. It is also advisable to use wider washers on the shroud retaining screws to prevent further cracking.

If the damage seems too bad to repair, a new RV shroud may be the only option. A broken RV A/C shroud will decrease cooling efficiency plus pose a danger of flying off while the camper is in transit .

Accessing the Fan Motor and Fans

The Coleman Mach  A/C Fan Motor made by Fasco
The Coleman Mach A/C Fan Motor made by Fasco
The rooftop unit With Condenser Cover removed
The rooftop unit With Condenser Cover removed

Servicing and Repairing the RV A/C Fan Motor

With the shroud removed, it is easy to inspect the fan motor for any repairs or maintenance needed. Before doing any repairs or maintenance to the rooftop RV AC be sure to turn the electrical breaker off or unplug the motorhome or camper trailer from the electrical power source. The starting capacitor may be still charged with high voltage, so be sure not to touch it with the bare hands.

The fan should spin easily when turned by hand. Even so, it is a good idea to oil the bearings and clean the accumulated debris from both front and rear fan blades. It may be necessary to loosen the fan motor from its mountings to fully access both ends of the motor bearings.

If the RV fan motor has oil tubes to lubricate the fan, then simply put a few drops of machine oil in the tubes on either end of the motor. If the motor has sleeves instead of ball bearings, you may still dribble a small amount of oil on the sleeves where they contact the fan motor shafts. Even a small amount of oil will do wonders for these types of fan motors.

If the AC fan motor still seems to start slowly or needs a nudge to start working, it is recommended that you replace it with a new one. If the fan motor has oil tubes evident on each end of the motor, it may be rebuilt and replaced for much less than buying a new one. It all depends on the particular unit on your camper.

If either the fan motor or compressor fails to start a new starting capacitor may solve the problem. Be sure to order the right size and voltage for your rooftop unit. These capacitors may be found at your local AC parts dealer or you may find them online for greater savings. Be careful when handling these capacitors as they may still hold some electrical charge.

This Condenser Needs Cleaning

Spray cleaner and a shop-vac will do the job.
Spray cleaner and a shop-vac will do the job.

Cleaning the RV AC Condenser and Evaporator

It is recommended that you clean the condenser and evaporator fins every couple of years to maintain the efficiency of your RV air conditioner. Eventually, the cooling fins on these units will become clogged with dirt and dust.

Use a good spray or foaming cleaner, such as those shown here, to loosen the debris and then use a wet/dry shop vac to remove the loosened dirt and dust. Be sure to cover the vent leading down into the interior to keep the grime from seeping down inside.

Be careful not to bend these fine fins as they will bend easily. A special fin comb tool made just for straightening these fins may be purchased from an RV AC parts dealer or through links on this page. Once again, be careful when performing this maintenance procedure.

Bent fins inhibit the flow of air through the unit, so be sure to keep them as straight as possible using the fin comb. You may need to use a fin straightening tool to align any bent fins in the evaporator or condenser coils.

Oh No! Not A Bad Compressor

A bad capacitor is often the problem if the compressor won't start.
A bad capacitor is often the problem if the compressor won't start.

RV AC Compressor Repair or Replacement

The most costly and difficult part of an RV AC unit to replace or repair is the compressor. In many cases it is advisable to simply replace the unit instead of trying to replace the compressor. With a new unit costing about $500 to $600, spending $300 to $400 dollars for compressor replacement doesn’t make much sense.

The labor involved, plus the prohibitive cost of the compressor, can almost pay for a new RV rooftop unit. These units are very easily replaced and will have a new warranty to cover future repairs for a few years. This is usually the correct option when the compressor goes bad.

The alternative is to find a used compressor. Unless you are skilled in replacing the compressor and are able to recharge the unit with freon, this is not advisable. This step is entirely up to your skills and pocketbook. There are used RV A/C parts available online and locally in some cases.

FAQS about RV AC Repairs

Be sure and check the many questions and answers in the comment section below. Feel free to ask a question if you don't see a similar question and answer, or simply ask the question if you don't have time to peruse all of the comments.

If you've encountered a strange problem and/or solution, please leave a comment below so others may learn from it. Thanks for any advice you may have to offer too! Thanks for relating any odd problem with your camper A/C and or the solution.

Now, Enjoy Your Camping Trip

If properly maintained and serviced, your motorhome or camper trailer A/C will last for many years of camping excursions. Most maintenance can be performed by the owners if they have basic mechanical skills. Understanding how an AC unit works may just save that camping trip you have been looking forward to for so long.

Be careful and take photos of the unit before removing any parts which may cause confusion during reassembly. Be sure to protect the roof of your RV while servicing your rooftop unit. Good luck with your repairs and maintenance.

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    • profile image

      bill 7 years ago

      my 2000 honda generator will start up my ac unit fine and run well on the initial start-up period. but, once the thermostat kicks the compressor off and the trailer warms so the compressor will have to kick back on, this is when the geenerator will not kick the compressor on again and will trip the breaker. it's an old 88 featherlite camper with and old air conditioner. is ther anything that will assist the compressor once it tries to restart???

    • Randy Godwin profile image
      Author

      Randy Godwin 7 years ago from Southern Georgia

      It sounds like the compressor is getting hot, Bill. This makes it harder to start back up when the thermostat kicks it on. It's possible the capacitor is not giving the compressor enough of a charge to kick it on, but this is unlikely if it starts fine when cold.

      You might try a new capacitor to see if it is the cause of the problem. Most of these units use the same capacitor to start both the compressor and the fan.

      I hope this helps!

    • profile image

      Vicki Thomas 7 years ago

      The air conditioner in our 2008 Arista motorhome has never cooled very well. There is barely any air coming out of the vents, albeit cool air! The dealer ways there is nothing wrong with the A/C. Are there are some things we can try on our own? Perhaps the vents are blocked somehow. How would we check that? Any suggestions are welcome, as we live and travel in Texas which is very hot in the summer!

    • Randy Godwin profile image
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      Randy Godwin 7 years ago from Southern Georgia

      This sound like the coils in your unit are clogged up. Remove the shroud and clean the coils with a strong cleaner such as 409 or a coil cleaning solution found by clicking on the Amazon ads on this page. If the coils are dirty it can inhibit the flow of air through the coils thus making the airflow less than it should be.

      Thanks for reading!

    • profile image

      msviere 7 years ago

      i have a boliy 3600 geni and i just bought a new(used) camper with a 15k btu a/c unit in it. it ran my 13.5 just fine and i put in a separate capactor and it still doesn't run it i don't know if it was the right one i have a buddy that does hvac and he gave it to me to try the generator is rated for 3300 watts wich i thought should be plenty to run it. it runs for about 2 min and then kicks the overload out on the geni. it seems like the a/c is bogging in those 2 min. any ideas? thanks

    • Randy Godwin profile image
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      Randy Godwin 7 years ago from Southern Georgia

      The capacitor doesn't seem to be your problem. It is only for starting the compressor and fan motor. It is either the fan motor but more likely the compressor. Use an amp meter to check the LRA (Lock Rotor Amps) on the compressor which should match the numbers on the compressor label. This will tell you if the compressor is overloading. The same for the fan motor. Hope this helps!

    • profile image

      Tom Percuoco 7 years ago

      When camper AC reaches thermostat setting it shuts off as expected and then comes back on and off repeatedly and keeps triggering until I lower the thermostat and it stars all over again! Is there something wrong with the thermostat or something with the sensor/sending unit?

    • Randy Godwin profile image
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      Randy Godwin 7 years ago from Southern Georgia

      This sounds like a thermostat problem, Tom! Check the thermostat sensor which should be in the area where the filter is placed. Sometimes these get bent and do not let the thermostat swing properly.

      Also check the thermostat connections for loose wires. Hope this helps you out! Thanks for your time!

    • profile image

      Cindy Maes 6 years ago

      I have a 2007 5th wheel rv. In the past 1 and 1/2 years the compressor keeps going out in my Carrier 15,000 unit. Is this caused by electrical surges? I've already replaced it twice and Carrier says they will not warranty it again. It started kicking the breaker off again last night and the fan will run but the compressor kicks the breaker

    • Randy Godwin profile image
      Author

      Randy Godwin 6 years ago from Southern Georgia

      This sounds like you have low voltage Cindy! If you are using the same hookup all the time, this may be the case. Low voltage/and or amperage may cause the compressor to go bad if the AC unit operates for long periods of time.

      If the lights dim when the compressor kicks on, it indicates insufficient electrical power to operate both fan motor and compressor efficiently.

      Be sure your AC unit is not icing up by checking under the air filter for ice blocking the coil. Running the thermostat too high will cause the ice to form and once it blocks the airflow the compressor may run until it kicks the breaker off.

      Electrical surges could possibly affect the compressor but this would be a long shot unless you live in an area with poor electrical service. Good luck!

    • profile image

      Cindy Maes 6 years ago

      I talked to a tech a carrier and was told if the fan motor is going bad it will cause the compressor to blow the fuse when it gets too hot. We took the cover off today and stsrted the fan by hand and the compressor did not kick out the fuse. I turned it off and tried to restart with out the help of spinning the fan and had to turn off the unit before it blew. Capacitor bad?? They said the fan spun easy when they turned it

    • Randy Godwin profile image
      Author

      Randy Godwin 6 years ago from Southern Georgia

      Yes, this sounds like a bad capacitor, Cindy! The capacitor is used to give a boost to both the compressor and fan motor during the start up and is probably not giving enough charge to start both.

      Changing the capacitor is easy and relatively inexpensive. I hope this solves your problem with kicking the breaker or fuse!

    • profile image

      Keith Donaldson 6 years ago

      I have a rooftop unit on a Travelstar 23RBS. The unit quit blowing cold air last week. The blower runs great, but it is blowing hot air (it's in the 90's here). In the evening when it cools a little, I can put it on very low cool and the compressor doesn't cut in. Then when I turn the temp down I can hear the compressor cut on, but it still doesn't pump cool air.

      Ideas?

    • Randy Godwin profile image
      Author

      Randy Godwin 6 years ago from Southern Georgia

      Your RV AC unit appears to be low on freon or else the compressor may be malfunctioning. It could possibly be a relay but probably not. Sorry, but without seeing it run this is the best suggestions I can give. Good luck!

    • profile image

      Cindy Maes 6 years ago

      I want to thank you for your help...after reading this web page I got on the right track in getting my AC fixed. The new capacitor did the trick!!

    • Randy Godwin profile image
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      Randy Godwin 6 years ago from Southern Georgia

      Wonderful news Cindy! So glad you were able to get your AC going again! Thanks for letting me know about your success and for reading my article. Good luck and enjoy your camping trips!

    • profile image

      Ben 6 years ago

      Hello Randy, to get started, our RV Air-conditioner isn't functioning properly, it WAS functioning perfectly fine last year... Problem: After turning it on, it will blow cool air for @ 1 minute, then something happens and it gets quieter, and the cool air gets warm, then it starts getting hotter than outside air. The coils are clean and the fan does blow perfectly fine without problems. It's hooked up to a 30A fuse all by itself so it's getting enough electricity (I can run the microwave and TV at the same time without a problem). It's a Coleman Mach (I don't know the exact model # or anything like that).

      Please help with any input you can provide!

      < Thanks >

    • Randy Godwin profile image
      Author

      Randy Godwin 6 years ago from Southern Georgia

      Hi Ben! The reason the AC gets quieter and blows hot air is because the compressor is overloading and kicking off. After it cools down the compressor resets and it will run again for a while.

      While my diagnosis is not a sure thing, it sounds as if the compressor is bad and is locking down after it gets too hot. If you know someone with an amp meter you can check to see if the compressor is drawing more amps than it is supposed to.

      The amperage it normally requires to operate normally should be listed on the compressor or on the AC chassis itself. Not good news, as installing a new compressor may be cost prohibitive. Please let me know what you find out if I am wrong in my suggestions.

      Thanks for checking out my article and good luck with your AC!

    • profile image

      toni 6 years ago

      Our Carrier RV A/C is putting out foul smelling air, like Dirty Sock Syndrome in a house A/C; it still cools fine but it just smells bad. We don't smoke, don't have pets in it and clean the filters; we do the majority of our cooking outside as far as "absorbed odors" go. Anyone have any suggestions, thoughts?

    • Randy Godwin profile image
      Author

      Randy Godwin 6 years ago from Southern Georgia

      Hello Toni! This sounds as if the coils in your AC are very dirty and are letting condensation form, therefore causing the air flowing across the evaporator coil pick up the odor and blow it down inside of the RV.

      If your RV AC has a drain it may be blocked, causing water to stand inside of the AC unit and also causing a bad smell to be blown down inside of the RV.

      Cleaning the coil is a fairly simple job and will probably solve your problem. Follow the instructions in this article and clean the drain if it has one.

      Hope this gets rid of your bad odor. Thanks for checking out my articles.

    • profile image

      Robert 6 years ago

      Have a 13,500 coleman a/c unit. It work for about 10 to 15 minutes then kick the braker off. In that time it cool the camper from 100 down to 75. I can keep it running by turn the fan on for about three minutes. The problem I have is after the temperature out side drops to 99 the unit will run all night long as it should. It when the temperature is above 100 it will not run right.

      No ice, coils cleaned. What do you think

    • Randy Godwin profile image
      Author

      Randy Godwin 6 years ago from Southern Georgia

      It does sound strange for your RV AC to trip the breaker this way, Robert! It is possible the breaker is faulty or is not providing enough amps to run both the fan and compressor until the outside temperature drops enough to cycle the compressor on and off.

      However, the compressor itself may be drawing too many amps of electrical power which will eventually cause the breaker to trip off. The only way to find out if your compressor is drawing too many amps is to use an amp meter.

      If it draws more amps than indicated by the specs given on the label, you will know the compressor is the culprit. Changing the breaker to a slightly higher amperage may solve the problem, but the compressor may be getting worse and this will only prolong the eventual demise of the unit.

      I will study your problem and check my sources for another cause for your problem. I will post anything new here. Please let me know if you find out if something else is causing the problem. It helps others who read these posts with their own RV AC problems.

      Thanks for your time!

      Randy Godwin

    • profile image

      Robert 6 years ago

      Have changed the breaker to a house unit 20 amps. Line straight to plug cord. It been doing it for a year. Have even tried to put cover over unit with wood with space for a flow. Am about to shoot water on compressor. It is on a truck camper larson. I'am a drag racer and only need it to work during the heat of the day. Did put a low amp started a year ago and help get it to run by run the fan for the three minutes. thank for the information

      it has me stumped.

    • Randy Godwin profile image
      Author

      Randy Godwin 6 years ago from Southern Georgia

      Me too, so far, Robert! I consulted another AC guy and he can't figure it out either. He did ask if you could check the temperature of the air when the compressor is running. Sometimes the air will be very cold when the freon level is getting low.

      For the AC to cool the air from 100 down to 75 in only 10 to 15 minutes seems rather quick. So check the air temp first!

      Is the compressor getting really hot? Perhaps running the fan cools the compressor down enough to let it continue working. If so, this is not good news!

      Randy

    • profile image

      Robert 6 years ago

      I found a splice in electrial line. It seen work better. I know it cool down fast but truck camp maybe 36 sq feet with bunk over truck shut off. Will know this weekend.

      Thanks

      Robert

    • Randy Godwin profile image
      Author

      Randy Godwin 6 years ago from Southern Georgia

      Keeping my fingers crossed, Robert! Hope this solves your problem! Thanks for the update!

      Randy

    • profile image

      tom 6 years ago

      when I turn off my ac the compressor keeps running, I turned it in fan only and it still blew cold until it froze up. the only way I could git the compressor to go off was to throw the breaker

    • Randy Godwin profile image
      Author

      Randy Godwin 6 years ago from Southern Georgia

      This appears to be a switch problem, Tom! Depending on the make and model of your RV AC, the switch may be shorted out and is allowing the elec current to be supplied to the compressor at all times.

      The inability to shut off power to the compressor using the off setting on the switch is an indication of a shorted switch! If you are familiar with using a multimeter you can check the switch before buying a new one! Order one online to save a bundle of money!

      Thanks for reading!

    • Randy Godwin profile image
      Author

      Randy Godwin 6 years ago from Southern Georgia

      Webb White asks : "How do you test a roof mounted RV A/c Capacitor? Mine won't kick on with the Generator running. Tries but won't run."

      No links WW, sorry!

      Use an ohm meter and use a high setting. Unplug connections and check the multimeter readout. The ohms should go up high and then drop to 0. Reverse the multimeter leads and check again. If the results are the same, the capacitor is good!

      Sorry about the link!

    • profile image

      clyde Williams 6 years ago

      Hi Randy, I'm a new at this, my problem is #1 ac fan start but the compressor kick on and off every 10 sec., we have good voltage all coils and fins inside and outside are clean. Model 15000 Colman w/hp rv 06 country coach. Any help would be grateful, thank

    • Randy Godwin profile image
      Author

      Randy Godwin 6 years ago from Southern Georgia

      Hello Clyde! After discussing your problem with another AC troubleshooter, we decided the problem is probably the capacitor! It is apparently trying to start the compressor while running the fan and doesn't have enough of a boost to run the compressor! Therefore the compressor kicks on but fails to run and repeats this cycle.

      My response to the question right above yours tells how the capacitor may be checked with an ohm meter(multimeter). If the capacitor turns out to be good, the problem might be the thermostat! I would check the capacitor first because it is a fairly inexpensive and easy replacement in most cases.

      If this doesn't solve the problem, please let me know!

      Thanks,

      Randy

    • Randy Godwin profile image
      Author

      Randy Godwin 6 years ago from Southern Georgia

      A common problem with rooftop RV A/C units, Don! Depending on how old your ac unit is, it may or may not have a drain line! If it does have one, you should be able to see it leading down from the bottom of the unit.

      But many of the newer AC units do not have a drain and depend on the fan motor to spray it out through the back of the unit! If the coils are very dirty or clogged, the water cannot be ejected and will pool up until it has nowhere to go but down through the vent.

      This is usually the problem with the newer models! A good coil cleaning should solve the problem! Follow the instructions in the above article to do this! Otherwise, make sure the drain line is clear if your unit has one!

      I hope this will remedy the problem! Thanks for reading!

    • profile image

      Jim 6 years ago

      I have a Duo therm roof top ac unit. This problem just started happening. Everything works fine and the ac cools good during the cycle but when the thermostat cuts the system off the compressor will keep running and you have to cut the breaker off to stop it. I have 7.5 volts at the red wire at the thermostat. Is there a way to bypass on the thermostat to test if the thermostat is the problem ? I have checked everywhere on the net and can't find a specific solution to this problem.

    • Randy Godwin profile image
      Author

      Randy Godwin 6 years ago from Southern Georgia

      Yes there is Jim, but I will have to research a bit to give you the proper method of doing so! But the thermostat may not be your problem as this sounds more like a relay problem.

      I don't have much time right now because of the Thanksgiving festivities but will try and back to you as soon as possible! Please check back and comment if I haven't responded by tomorrow!

      Thanks!

      Randy

    • profile image

      Jim 6 years ago

      Randy, Where would the relay be at ? All I have been able to find is the two capacitors in the metal box. This is on my RV. I didn't think that the duo therm had a starting relay. That was my first thought that the starting relay was bad and sticking but someone told me that they didn't use a start relay. I'm not sure. Thank you. Hope you didn't eat too much Turkey. Well, Dallas Cowboys got beat. ( again )

    • Randy Godwin profile image
      Author

      Randy Godwin 6 years ago from Southern Georgia

      Hello again Jim! I am not very familiar with the Duo-Therm AC unit but I assume they are similar to the Coleman units! I will check with my expert and see what I can find out! I will come back and tell you what I found!

      Randy

    • Randy Godwin profile image
      Author

      Randy Godwin 6 years ago from Southern Georgia

      @Jim-Back again, Jim! My fellow AC advisor seems to think the problem is in the switch! It does make sense as to why the power to the compressor is not being cut off.

      Barring this, it can only be in a relay or the thermostat! You can check the switch with a multimeter to see if the circuit is broken when the switch is off! Hope this helps you out!

    • profile image

      JIm 6 years ago

      Thanks Randy for all your help on this site. I will check it out.

    • Randy Godwin profile image
      Author

      Randy Godwin 6 years ago from Southern Georgia

      You're welcome, Jim! I think this will be a simple fix if you can isolate the problem. Let me know what you find out, if you don't mind! This may help others to repair their own AC units.

      Thanks for stopping in!

      Randy

    • profile image

      Jim 6 years ago

      Randy, when you say switch or you talking about the starting relay ? I found what I guess is the starting relay. It is a small electronic box attached to the terminals of the smaller black capacitor. It is labled motor starter on the side. It is only about one and half inches by one and a half inches by approx 3/8 thick or a little less. Can you tell me off hand how I would check the electronic relay with a multimeter ? or can you check it with a multimeter since it is electronic ? It has got to be the thermostat or the relay but I'm not sure about how to troubleshoot either one. I wish they would stick with the old mechanical relays instead of the cheap made in china throw away and replace electronic parts that don't hold up. Thank you.

    • Randy Godwin profile image
      Author

      Randy Godwin 6 years ago from Southern Georgia

      No, Jim! I am referring to the control switch which furnishes power to both fan and compressor! The compressor should not run with the switch in the off position! A short in the switch would enable the results you are experiencing! Here is a link to a wiring schematic probably similar to yours.

      http://www.dometic.com/bbc46421-3d0f-4be1-b388-c00...

    • Randy Godwin profile image
      Author

      Randy Godwin 6 years ago from Southern Georgia

      Click the parts list on the right side of the page to access the wiring schematic, Jim!

      Randy

    • profile image

      Jim 6 years ago

      Ok Randy, I think I have the problem fixed. I took the thermostat off and I had some non conductive electrical contact parts cleaner and I sprayed the off switch good with the cleaner and worked the slide switch back and forth a few times. I connected the thermostat back up and ran it thru a cycle and when it cut off the compressor cut off with it. How so simple. Wished I got paid by the hour to fix my own stuff ! One problem in my RV that I suspect could have led to the problem is that the factory mounted the thermostat above the kitchen sink where the steam and humidity from washing dishes probably resulted in the slide swith becoming corroded and/or attracting dust over time even though it is sealed pretty good. This might be something that other people might run across and one for your books !

      Another solution as crazy as it sounds relates to the ac not draining the water properly when the unit cuts off on a hot day. I live in East Texas and during the summmer we can go a long time without rain. My unit wasn't draining properly and got on top of the rv and took the cover off of the unit and ran a stiff wire all the way thru the drain channel to see if it had an obstruction. A Rain frog came out of the channel. He was making himself a home in the wet drain channel since it was so dry and no rain for a long time. They are bad about getting in my unit in the summer time. A simple thing as a rain frog in your drain channel can cause a problem. Thank you very much for your help. It's nice to know that people are willing to help each other in this world today.

    • Randy Godwin profile image
      Author

      Randy Godwin 6 years ago from Southern Georgia

      Great news Jim, and thanks for relating the fix! It is often a simple problem which causes us the most grief! Your helpful comments and suggestions will certainly aid others having a similar rooftop AC unit problem!

      Yes, the older RV AC units have these drains and the little tree frogs (we call them rain frogs here too) may seek out such a damp place in dry weather!

      It IS good to know that most people are very glad to help others! Thank you for the info!

      Good Luck and stop by again!

      Randy Godwin

    • fruby59 profile image

      fruby59 6 years ago

      where is the capacitor located generally on these rooftop units? i have a duo-therm and after reading all the inputs on your page i think my problem may be with thecapacitor or servicing. dont know if they can be serciced so will try the capcitor first.

    • Randy Godwin profile image
      Author

      Randy Godwin 6 years ago from Southern Georgia

      Hello fruby59. I thought I had a photo of a capacitor on this article but I was wrong. I will try and put one on this and my other related A/C repair articles.

      But until I do so, the capacitor is usually located in the area behind the control panel. It resembles a dry cell battery in appearance with two connection points on top.

      Be sure not to touch the connections as the capacitor may be charged. Hope this helps you out.

      Thanks for reading!

      Randy

    • fruby59 profile image

      fruby59 6 years ago

      thankyou so much, so it must be accessed for the inside. i appreciate it and will let you know how it works out. this is an awsome sight you have and i will be frequenting it a lot.

    • Randy Godwin profile image
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      Randy Godwin 6 years ago from Southern Georgia

      @fruby59-Just remove the shroud and a cover is easily removed on the top area of the unit. I mistakenly said behind the control panel because I was thinking of a wall unit.

      On occasion, the capacitor will be in plain view, but in many new units it is beneath the cover where the electrical wires lead to the fan motor and compressor.

      Still looking for a good photo and may have to take one to display this info. Thanks for letting me know I need a photo illustrating the capacitor's location. And good luck on your repairs.

      Randy

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      Heath 6 years ago

      My ac runs for awhile and it will start leaking in the trailer what causes this.

    • Randy Godwin profile image
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      Randy Godwin 6 years ago from Southern Georgia

      A common problem, Heath. If the rooftop RV AC unit is an older model it may have a drain which can become clogged. Newer models disperse the excess moisture back into the air.

      In either case, the unit needs a thorough cleaning. When the coils become clogged with dirt the moisture cannot be dispelled through the fins and into the air.

      The water collection area on the bottom of your RV AC unit eventually becomes full and leaks water down through the vent into the RV.

      Remove the shroud and clean the coils with a good coil cleaning product. Be sure to clean the debris and dirt from the bottom of the unit too. Be sure the power to the AC is off while doing this maintenance. If your unit has a drain, you will see it while cleaning. Make sure it is clear and your problem is solved.

      Good luck and thanks for reading!

      Randy

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      Matthew C 6 years ago

      my ac run for 4mins and stop only to start up in 20mins again.i've changed the 20uf capacitor in it to 30uf but the proplem is still unsolved ,i've set the thermostart to many level but there's no changes; is it a compresor problem pls help me it is a mobil ac

    • Randy Godwin profile image
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      Randy Godwin 6 years ago from Southern Georgia

      Hello Matthew! It sounds like your compressor is kicking the overload and when it cools it works for the 4 minutes until it gets hot again. If the fan starts easily, the compressor is suspect. Sorry, I cannot offer you a better diagnosis with so little info!

      Randy

    • Randy Godwin profile image
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      Randy Godwin 6 years ago from Southern Georgia

      It may be the compressor overloading after it runs a short time, Ononenyi. When it cools down it will run for another short period. An amp meter is needed to check to see if the compressor is pulling more amps than is required to run it normally.

      Since the fan is still running properly it appears it is not the problem. A bad compressor is not usually worth replacing because of the expense. Good luck and feel free to ask further if you need more info.

      Thanks for reading my RV repair hubs.

      Randy

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      Matt 6 years ago

      I too have a roof-top duo therm that has stopped working. I can hear a faint clicking from the unit when the thermostat is switched on. It's only a couple of years old. Ideas? Thanks

    • Randy Godwin profile image
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      Randy Godwin 6 years ago from Southern Georgia

      @Matt-Does the unit work at all? By this I mean, does the fan run or does the unit do nothing at all when turned on? More info would assist me in helping you find the problem.

      Randy

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      Matt 6 years ago

      it does nothing just the clicking when you first flip the thermostat

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      Matt 6 years ago

      or its a single click i should say

    • Randy Godwin profile image
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      Randy Godwin 6 years ago from Southern Georgia

      @Matt-The clicking is normal and is caused by the thermostat attempting to activate the compressor to come on. Since neither the fan nor compressor runs when the switch is turned on, then it appears as if the electrical power is not getting to the RV AC unit.

      Check the breaker panel to be sure the power is going through the breaker and on to the AC unit first. In some cases the breaker will appear to be good but is not allowing the electrical power to pass through.

      It is possible for the electrical connections in the ceiling panel assembly to be loose or the wire nuts may not be tight enough. If all of these connections seem okay the control switch itself may be shorted out.

      A multimeter is very useful for checking the connections and switches for proper functioning. If you still cannot trace down the problem, please feel free to ask for further info.

      Randy

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      David 6 years ago

      I have a rooftop rv ac.

      It started to run with both fan and compressor on fine during the first cycle. But when it reaches the proper temp the fan shuts off but the compressor keeps running until the breaker kicks trips. Any ideas what might be wrong?

    • Randy Godwin profile image
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      Randy Godwin 6 years ago from Southern Georgia

      @David--The fan motor should not stop running unless it is a special energy saving option particular to your RV AC unit.

      If the fan motor bearings are worn or in need of oiling, the motor will eventually overheat and stop turning. This adds extra load to the electrical supply which causes the compressor to kick the breaker.

      You may be able to oil the sleeves or bearings on your fan motor and try running it again. If this isn't your problem, please feel free to ask for further info on your problem.

      Thanks for reading!

      Randy

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      Jayme 6 years ago

      I have a 1991 fleetwood prowler that my husband got about for months ago and the ac unit worked great and now it doesn't wasn't to work. It sounds like it wants to kick on but then it stops. Is there anything I can do to get it started again and I'm also very sure its the original ac.

    • Randy Godwin profile image
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      Randy Godwin 6 years ago from Southern Georgia

      Hey Jayme, it sounds like the fan motor is stuck or the capacitor may be bad. Try removing the ceiling cover where the filter is located and give the fan a spin and turn the unit on "high cool". If the fan doesn't spin easily when turned by hand the bearings need oiling on the fan motor. If the unit operates normally after spinning the fan and the fan spins easily by hand, a new starting capacitor is probably the culprit. An easy an inexpensive item to replace,

      Have you tried running the unit in the "fan" mode only? If so, did the fan operate at all? Try the above suggested procedure and tell me what happened!

      Thanks for the question and for reading my article.

      Randy

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      Jayme 6 years ago

      Thank you I will try that. Also does everything in the trailer needed to be of before I try this?

    • Randy Godwin profile image
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      Randy Godwin 6 years ago from Southern Georgia

      No, Jayme. Just be sure your hand is not still on the fan after spinning it when you turn the unit on. Give it a brisk spin to keep it turning until the unit is switched on.

      Randy

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      Jayme 6 years ago

      Ok I took the cover of where the filter is and I don't not see a fan at all. Is there more things that need to be takin off for me to get to it.my husband works alot and doesn't have time to look at it when he does come home.

    • Randy Godwin profile image
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      Randy Godwin 6 years ago from Southern Georgia

      The fan is a "squirrel cage" type fan, Jayme. Not a typical propeller type such as in a window fan. You will have to reach up inside of the air duct leading down through the roof until you fell the edges of the blade fins on the fan. If the bearings are fine, you should be able to easily spin the fan with little effort.

      In some cases there are several screws which have to be removed from the ceiling assembly and the knobs pulled off to access the fan vent.

      This link will show you pictures which may help you understand better what i am referring to.

      https://hubpages.com/sports/Where-To-Buy-And-How-T...

      Try this and get back to me.

      Randy

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      Jayme 6 years ago

      Ok so I did spin the fan and turned it on high cool like you said but there was still nothing and the fan did spin easy.

    • Randy Godwin profile image
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      Randy Godwin 6 years ago from Southern Georgia

      Let me consult with a fellow AC troubleshooter and get back to you Jayme! What make AC unit do you have in your RV? And does it kick the breaker if left on or just stop sounding as if the compressor is trying to run?

      Randy

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      Jayme 6 years ago

      The breaker has cut off a few time when it was working and the make is a coleman.

    • Randy Godwin profile image
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      Randy Godwin 6 years ago from Southern Georgia

      Thanks Jayme, I suspected as much. If you don't see my answer here tomorrow, please post another comment here and remind me. I am swamped with questions on many of my RV repair articles and I tend to forget to respond when it is this busy.

      I have a hunch what your problem is but haven't received an answer from my fellow RV AC troubleshooter. Don't give up yet! LOL!

      Randy

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      Jayme 6 years ago

      I understand I'm in no hurry its been broke for the past two months.we are living in it right now but its not to hot out just yet we living in it for the time being we have the windows open all day long with a fan running.don't get yourself wore out you have a life to live as well.thank you so much for helping.

    • Randy Godwin profile image
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      Randy Godwin 6 years ago from Southern Georgia

      I wish I could actually examine your AC, Jayme. It could be a capacitor or a relay which is causing you problems but I don't know if you would be able to check the items yourself.

      Do you have ant friends capable of using a multimeter to test these electric parts? I am still checking into other possibilities, so don't give up yet!

      Randy

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      Dave 6 years ago

      I have a Coleman 15000 unit that is about 12 years old. It worked good through last Fall, but recently tried to use it and it does not cool. I can get the fan to come on. However, when I try to turn on the a/c I get a clicking sound from the relays on the control board in the plenum box. The thermostat will then cycle periodically trying to turn on the a/c but you can here the relays just clicking. I have checked the voltage and get about 119volts, and when the thermostat tries to start the compressor it drops to about 116volts. I was thinking it could be the capacity on the compressor, but per you other feedback, this might not be the case since the fan works, or could it just not be strong enough to start the compressor? Or could it be the control board in the plenum where the relays are and that needs to be replaced? Would appreciate you guidance.

    • Randy Godwin profile image
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      Randy Godwin 6 years ago from Southern Georgia

      Hello Dave,

      Since the Coleman unit is fairly old, I would suggest you check the amount of amps being pulled by the compressor when it is attempting to start. On the compressor itself, or on a separate plate, there will be information which gives the amount of amps needed to start and the amount needed to run.

      It will be listed as START AMPS and RUN AMPS. You will need an amp meter to check the amperage for when the compressor is trying to start up. If more is being drawn than indicated, the compressor is bad.

      I doubt it is the capacitor but you can check it with a regular multimeter. Set the meter on ohms and place the probes on the separate poles of the capacitor. If the random numbers start high and gradually become lower when you check this and then when the probes are reversed, the capacitor shows to be fine.

      It's possible a relay is bad, but they sound like they are doing their job. I hope it isn't the compressor, but with the age of your unit it sounds as if it may be the culprit.

      Good luck and please tell me what you find out.

      Thanks for your question and feel free to ask for more info if needed.

      Randy Godwin

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      joelwilcox06 6 years ago

      I have a 2008 puma and the a/c has been working fine. went and set it up a couple of days ago and noticed today that the unit is cooling but is making a loud noise. it was so loud I turned it off and we had to come back to the house tonight because of the heat. Any tips on what it could be? thanks

    • Randy Godwin profile image
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      Randy Godwin 6 years ago from Southern Georgia

      Well Joel, it is probably the compressor or the fan making the noise as these are the only moving parts. I would suggest you remove the shroud and have a look while the unit is running.

      It may be the fan blades striking the side of the metal shroud or the compressor could be going bad. Let me know what you find out when you remove the shroud and I"ll try to help.

    • profile image

      Dave 6 years ago

      Randy, Per your advise last week, I checked the unit and the compressor was bad. I replaced it with a new Coleman 15k btu unit today and got it running, cooled nicely. A question, I got it working and it cooled when I set the thermostat on low fan, but when I set it on high fan, I got a buzzing sound in the thermostat and it stayed on low fan and kept cooling. What could this be?

    • Randy Godwin profile image
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      Randy Godwin 6 years ago from Southern Georgia

      Hello again, Dave. I was afraid the problem was your compressor, but was hoping for a different result. Let me ask my go-to guy about your problem and I'll get back to you. This is a new one on me!

      Randy

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      debugs 6 years ago from Odessey777, Umbris

      Hey Randy, useful hub yah got... How about telling me if roof insulators make the AC cooler?

    • Randy Godwin profile image
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      Randy Godwin 6 years ago from Southern Georgia

      Yo, debugs! Any type of insulation on the roof will help the AC perform more efficiently! This is especially true for an RV sitting out in the direct sunlight.

      Thanks for stopping by and for the question!

      Randy

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      Andy 6 years ago

      So I have a 2003 Ford E450. It has a carrier roof unit with 3 fans. The fans work, but the air is not cold. I adjust the thermostat up front and it makes a clicking noise. I think this could be the switch to the compressor to turn on, but not sure. What do you think would be the 1st step in evaluating this a/c unit? Recharge? Listen to the actual a/c unit for the compressor kicking on? Sorry this is a newb question. Thanks in advance.

    • Randy Godwin profile image
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      Randy Godwin 6 years ago from Southern Georgia

      Yes Andy, the clicking in the thermostat is the signal for the compressor to start running. The best way to check the compressor is with a clamp-on amp meter.

      The meter will tell you how many amps the compressor is pulling when it is trying to start. The start/run amps normally required for your unit will be indicated on the compressor or some other plate on the unit.

      If it pulls more amps than the displayed specs indicate is needed, the compressor is bad. It could also be a relay but you will not know until the voltage to the compressor is checked.

      I hope this helps you find your problem. Any other info you can give me might help find the problem. Feel free to ask for further info.

      Randy Godwin

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      Andy 6 years ago

      Thanks. So there isn't a port where you can just check the charge of a/c? I was surprised that the e-450 didn't have regular a/c and only used the roof one... I will look into the voltage. Thanks again for the recommendations.

    • Randy Godwin profile image
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      Randy Godwin 6 years ago from Southern Georgia

      These units use a sealed system unlike an A/C unit in a car or truck, Andy. A piercing valve is usually necessary to recharge these type RV rooftop AC/ systems.

      Good luck with your repairs and thanks again for checking out my RV repair articles.

      Randy

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      Christina 6 years ago

      we have a duo therm unit, it doesn't shut off when thermostat reaches temp. What could this be??

    • Randy Godwin profile image
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      Randy Godwin 6 years ago from Southern Georgia

      Hello Christina, it will be either a malfunctioning thermostat or a relay. I would suspect the thermostat is the problem as it determines when the compressor runs or not.

      It is simple and relatively inexpensive to replace the thermostat in your particular Duo Therm unit. I would try this first.

      Thanks for the query,

      Randy Godwin

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      Jim 6 years ago

      I have a good one for you, I have a 13500 Dometic, Duo Therm Brisk Air. New unit as of last year. Air was functioning properly last year. I moved the RV to a new location and was too far from the electrical service so I had to extend the trailers power cord. I did this properly using 25' of 10/3 wire. Everything in the unit is working fine, all circuits have been checked from end to end. They all show correct. The air conditioner is cooling fine......except.....the fan inside is running backwards, it is blowing out of the return, and sucking air in through the vents. HELP

    • Randy Godwin profile image
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      Randy Godwin 6 years ago from Southern Georgia

      Hello Jim. The only thing I can think of which may have a bearing on your problem is you may have reversed the polarity by crossing the wires in your extension cord.

      Some electric motors will run backwards if the polarity of the wire connections are reversed. But a good multimeter should show this if indeed this is the problem. Let met know what you find out!

      Thanks,

      Randy

    • jsdiver316 profile image

      jsdiver316 6 years ago

      I had people tell me that on 110v that it didn't matter, I reversed it anyway...... nothing. Thanks for listening. I'll let you know when I finally figure it out

    • Randy Godwin profile image
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      Randy Godwin 6 years ago from Southern Georgia

      Thanks jsdiver! I didn't really think it was the problem either. I did want to eliminate the possibility since you mentioned the extension cord.

      You also didn't say if you had tried it at the original plug in again to see if it had made a difference. Thanks for the question and please do tell us what you find out.

      Randy

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      Kevin 6 years ago

      I have a Duo-Therm brisk air 13,500 btu roof unit. Yesterday it was running fine, I left and went to the store and when I returned home the unit was making a humming noise, was not blowing air and was hot inside. I turned it off and waited about 5 minutes and turned it back on, now the fan will only turn when its on fan high or ac high and it turns slow. I can feel cold air from the vent but it is barley moving. I removed the cover on top and opened the box to look at the capacitor and both the capacitor and the other part in there are leaking a fluid. Does this mean they are bad, and what is the name of the other part. I have not checked with the multimeter yet as I am new to this and am going from what I am learning here and I did not see anything about leaking. Any help would be great.

    • profile image

      Kevin 6 years ago

      Just to update. I checked the capacitor with the multimeter and it started high then went down. Same when reversed. I think the other pars is a motor run capacitor. Is their a way to test it?

    • Randy Godwin profile image
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      Randy Godwin 6 years ago from Southern Georgia

      Hello Kevin! Some units use two capacitors, one for the compressor and the other for the compressor. Both are tested in the same manner you used to see if they are good.

      Otherwise, your fan motor may be the culprit. Try spinning the fan motor by hand before switching the unit on high fan to see if it will start turning faster.

      If it is hard to turn by hand, it is the fan bearings getting hot and causing the motor to stall. Any leaking fluid is a bad sign, whether coming from the capacitors or the compressor.

    • profile image

      Kevin 6 years ago

      I spun the fan and it turns easy. I spun it then started the fan on high and it still runs the same speed. I checked the motor run capacitor and it looked good too but they were both wired still when i checked them, so i unplugged both of them and neither one shows anything on the meter now. The compressor is still coming on so are they suppose to hold the charge when they are unplugged? Something tells me it has to be a capacitor so i am going to go to the RV dealer today and have them checked. I think the leaking fluid was not a leak at all but some kind of gel or something the capacitors set in. If you have any other suggestions let me know please, and i will update later what i find out at the dealer.

    • Randy Godwin profile image
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      Randy Godwin 6 years ago from Southern Georgia

      @Kevin-The capacitor must be holding a charge if the compressor starts up easily as does the fan. There may be a relay which is not allowing the fan to run at different speeds or the fan switch itself may be the problem.

      Let me know what the dealer says about the capacitors as this is something of an enigma to me!

      Thanks for relating your problem as others may benefit from your experience with your RV AC repairs.

      Randy

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      Raider1975 6 years ago

      I have a coleman ac top unit. I turn it on and it runs fine for 10 minutes. After that it trips the breaker. Well today it was tripping the breaker in the house. I am about to beat it with a sledge. I bought the rv in 2004. I never used the ac 1 time. So naturally now that i want to use it in the summer it wont work lol.

    • Randy Godwin profile image
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      Randy Godwin 6 years ago from Southern Georgia

      Yo Raider! Are you using an extension cord to supply power to the AC? What size breaker is in the house? Is the compressor cycling on and off as it should? A little more info is needed!

      Randy Godwin

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      Raider1975 6 years ago

      No extention cord. It comes on as it should and runs about 10 minutes. Then it kicks the breaker. I went and bought another breaker switch of the same kind. Still same problem. I had tried it at a campground plugged directley in and would not work.

    • Randy Godwin profile image
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      Randy Godwin 6 years ago from Southern Georgia

      Too bad, Raider! The only thing I can suggest is to check the compressor with an amp meter to see if it is drawing too much power. The run/start amps should be listed on the compressor or on a small plate inside the unit.

      I suspect the compressor is pulling too many amps which causes one of the breakers-either in the camper or in the house- to eventually trip. If you have any 110 volt lights they will probably dim when the unit runs. Can you tell if the compressor is cycling on and off as it should?

      Randy

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      Raider1975 6 years ago

      WOW i cant believe a ac unit i only tried to use 1 other time is bad lol. Its still like new lol. I cant really tell if its cycling. The air gets cold but it dont run long.

    • Randy Godwin profile image
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      Randy Godwin 6 years ago from Southern Georgia

      I'm hoping I am wrong, Raider. But sometimes not using an AC very much is worse than using them often. Things have a way of going bad when they sit idle. But don't panic yet as it could be something else causing the problem. I'm just trying to get the most common problems accounted for. The amp test will tell for sure!

      Randy

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      Raider1975 6 years ago

      Well i have no one to test the amps for me.

    • Randy Godwin profile image
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      Randy Godwin 6 years ago from Southern Georgia

      I thought so, because not everyone has an amp meter. If there is a rental place near you it may be possible to rent one for a short while. Otherwise, an AC serviceman or friend with an amp meter is your only choice. I wish I could suggest an easier solution but it is what it is.

      I will check with my go-to-guy and see if there is an alternative method you can use to test the compressor in the meantime. Check back tomorrow!

      You might try turning the thermostat down low and see if it makes a difference in the breaker not tripping as quick.

      Randy

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      Raider1975 6 years ago

      Ok thanks alot. I am scheduled to take it in monday to get looked at.

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      vbnny13502 6 years ago

      RE: roof top carrier ducted rv a/c Unit runs and blows cold air only to the rear outlets. we get no air flow the front outlets where do we start looking. Have already looked in ducts, no obstruction seen.

    • profile image

      Kevin 6 years ago

      Turns out it was the capacitor. Got a new one for $39 out the door, installed it yesterday and it works great. Thank you for all your help.

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      jsdiver316 (Jim) 6 years ago

      Hi Randy, I posted on here 5 days ago about the fan in my ac running backwards........ I fixed it. Since I told you I would let you know here it is..........When I took the unit up to replace the gasket(it was leaking) I put the unit back down backwards. It was fine the whole time, just facing the wrong direction. Hope you get a smile out of this, I did and so did evry single one of my buddies

      Take Care

      Jim

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      Raider1975 6 years ago

      Well i ran the ac today and it ran for 15 minutes. When it cycled and tried to start back up it just hummed and tripped the breaker.

    • profile image

      Raider1975 6 years ago

      Oh and if i catch it while its humming i can turn the thermostat to warm for about 3 minutes then turn it back to cold and it works just fine.

    • Randy Godwin profile image
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      Randy Godwin 6 years ago from Southern Georgia

      @VBnny--I'm not sure how the ducts are arranged on your RV, VBnny. There has to be a split in the duct system if both front and rear vents are supplied by one unit.

      You might look beneath the A/C shroud to see if there is a baffle controlling the flow. In the meantime I will see what I can find out for you.

      Thanks,

      Randy

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      Raider1975 6 years ago

      Its kind of like shutting off ac then turning it right back on. Its like the compressor has too much pressure and it wont turn over. Sorry trying to explain the best i can.

    • profile image

      Raider1975 6 years ago

      And i tried you suggestion. I turned down the thermostat to low cool and not as cold. Its running fine. But as soon as i turn it up it trips breaker.

    • Randy Godwin profile image
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      Randy Godwin 6 years ago from Southern Georgia

      @Kevin--Wonderful news, Kevin! Glad you were able to run down the problem. Thanks for your input and for stopping in! Please drop by again!

      Thanks again,

      Randy

    • Randy Godwin profile image
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      Randy Godwin 6 years ago from Southern Georgia

      @JSDiver--LOL, JS! I didn't realize you had removed the unit when you asked me about your problem. Sounds like something I would do, so don't feel to bad!

      I have a smile on my face because you solved your problem without having to spend a lot of money. I imagine you are a bit relieved yourself.

      Thanks for the smile and for the intriguing, if somewhat confusing, question and stop in agin when you get the chance.

      Randy

    • Randy Godwin profile image
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      Randy Godwin 6 years ago from Southern Georgia

      @Raider--Wow! This sounds more and more like the compressor is at fault, Raider. When the compressor is malfunctioning it pulls excess amps which usually gets worse as the compressor gets hot. I wish I could help you more but checking the amps on the compressor is usually the next step if the fan motor seems to be operating correctly.

      Please let me know what you find out if you have to take it in for repairs. Usually, replacing a compressor will cost so much it's better to buy a new rooftop AC.

      Thanks for the questions and your input!

      Randy

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      Laura 6 years ago

      We have a 2004 fleetwood prowler with a Coleman ac that is not working. It turns on, but does not blow. I read similar post trying to troubleshoot the problem. I removed the ceiling cover and tried to spin the fan by hand -- it does not move. What now?

    • Randy Godwin profile image
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      Randy Godwin 6 years ago from Southern Georgia

      Hello Laura! The fan motor bearings are probably worn and have become stuck. If they have oil ports on the bearings, you may be able to fill them with machine oil and eventually get them to turn freely.

      But some of today's RV AC units use sleeve type bearings which cannot be repaired requiring the fan motor to be replaced. Sometimes even these sleeve type bearings can be oiled enough to get them going again.

      Otherwise, you may have to replace the fan motor with one such as advertised in the ads in the above article.

      Good luck with your repairs and thanks for the question.

      Randy Godwin

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      James 6 years ago

      Randy, couple of things. One is I came home today to find that my power cord to the meter outside was fried on the bottom right post of a thirty amp connector. The owners daughter proceeded to tell me it was my power cord and all i had to do was ask her electrician. Yes as a matter of fact we are in New Jersey, how did you know lol. I don't care what it was. I want to know how to avoid it in the future. Obviously a surge protector. So what does tht have to do with the price of rice in China? I have also noticed that the 12 volt lights will change in intensity sometimes. The air conditioner stays on a lot longer than it used to and seems more like a swamp cooler now. Worked with engineers most of my life and a common sense person but it seems as though there might be some inter mingling. I read all of your postings and understand to clean the coils and other stuff for the cooling. I can't figure outthe power fluctuation but now think it has something to do with the meltdown. Just curious on your thoughts. 2005 Fleetwood Gearbox 34 ft toy hauler. Onan 5500 gold Marquis. The lights fluctuated with the generator running also. Thanks for any insight. I thought I was smart?

    • Randy Godwin profile image
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      Randy Godwin 6 years ago from Southern Georgia

      Hello James. I've found out I'm never smart enough! LOL! The 12 volt lights dimming or increasing in intensity is likely the power converter recharging the batteries when they get below a certain amount of voltage.

      The converter doesn't constantly charge the batteries and will cycle on and off.The power cord may have had something to do with the AC but it may be the unit itself. It's possible your AC has lost a bit of freon over the years and has to run longer to achieve the desired temperature.

      If your problem was a power surge it seems like the breaker would have tripped before melting the plug. Might just be a bad receptacle.

      Sorry I can't be more helpful with your problems!

      Randy

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      scott 6 years ago

      Hi. Last season we couldn't get our fan to spin on our Coleman Mack unless we did it manually. So we were told to replace the motor capacitors, one 7.5 MFD and the other is 45 MFD, both 370VAC, Oval. Now that we did the cooling compressor won't kick on to cool the unit. It worked last year even when we had to manually spin the fan, any suggestions?

    • Randy Godwin profile image
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      Randy Godwin 6 years ago from Southern Georgia

      I would try putting the old compressor capacitor back in to see if the new one is any good, Scott. If the compressor was running last year then the old capacitor was working fine.

      It is not unheard of for a new capacitor to be bad. Also, check the connections to the new capacitor to be sure they are making good contact.

      Does the compressor seem to try to start at all?

      Randy

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      Scott 6 years ago

      Randy thanks for responding. I did put the old compressor capacitor back on and tried it but it didn't work. The a/c place had tested it for me and told me it was good so now I have tried both old and new and neither works. It doesn't seem to try to start at all. The guy at the a/c place said it didn't matter how i attached the 3 wires, do you agree with that? also I noticed the compressor seemed really warm while i was trying to test it...

    • Randy Godwin profile image
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      Randy Godwin 6 years ago from Southern Georgia

      Doesn't sound good, Scott! The only thing left to do is to check to see how many amps the compressor is pulling when trying to start. The start/run amps should be listed on the compressor or on a plate nearby.

      Unless you have an amp meter, you will have to either rent one or carry the unit to a serviceman for this check. There should be a wiring diagram indicating the correct capacitor connections if you are concerned with the proper wiring. I hope the compressor is not a goner.

      Thanks for your question and please let me know what you found out about your RV AC unit!

      Randy

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      Scott 6 years ago

      I will do as you recommend and let you know what happens. It amy take a few weeks before I complete this!! Thanks!

    • Randy Godwin profile image
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      Randy Godwin 6 years ago from Southern Georgia

      Thanks Scott! I will keep my fingers crossed hoping it's not the compressor!

      Randy

    • Wesman Todd Shaw profile image

      Wesman Todd Shaw 6 years ago from Kaufman, Texas

      Hey Randy, GREAT ARTICLE! I've been in my working career, either a salesman for various and sundry things - or an hvac service mechanic.

      I actually live in an RV, a Dutchman "Sport" travel trailer. It's just me, and my folk's house is next door - so I've got everything I own and need right around here pretty close.

      All good advice, and I couldn't see anything to think otherwise about.

      I'm almost ashamed - I'm in Texas, and have had my hands on so many residential and light commercial air conditioning systems that there's no way I'd ever recall even one percent of them. . . .but I have no idea what brand the little package unit is on my trailer! I guess that's because I've not had to ever give it a look though, and that's a good thing!

    • Randy Godwin profile image
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      Randy Godwin 6 years ago from Southern Georgia

      That is a good thing, WTS! If it ain't broke.....! This article has made me quite a bit of money both in Adsense and Amazon sales, so I suppose it is well received. I sure get lots of questions and comments on it, as well as, a few lucrative AC sales occasionally.

      Thanks for the input and wishing you continued good luck with your RV AC.

      Randy

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      Charlotte 6 years ago

      Our air conditioner comes on fine, but does not turn off. We have to manually turn the thermostat down. It is either icy or not on. Do we need to replace the thermostat? Thanks.

    • Randy Godwin profile image
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      Randy Godwin 6 years ago from Southern Georgia

      Hello Charlotte,

      The thermostat is probably the culprit in your case, although the fan selector switch or a relay could also be at fault. Replacing the thermostat is a fairly simple job.

      Good luck and ask for more info if you need to. Thanks for reading and the question!

      Randy Godwin

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      Scott 6 years ago

      Hello Randy, we spoke last week and we wanted to tell you what the AC doctor who came out told us about our Coleman Mack. We had replaced both capacitors but then the compressor wouldn't kick on. AC Doc checked it out and said it was pulling 14.1 amps and it should only be pulling 11 so he recommended to replace it with a brand new a/c since he didn't have access to a used one. Also when asked to check the freon he said he is not a licensed freon guy - I always thought if you worked on a/c's you were licensed on it all but guess not. Anyway quick question if it is low/out of freon would that make the compressor not cool and just run hot? Thanks!!

    • Randy Godwin profile image
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      Randy Godwin 6 years ago from Southern Georgia

      Hello again, Scott! Not everyone who works on A/Cs are licensed to use freon because there are other aspects of the units which do not require recharging the closed freon system.

      This is especially true in the case of many roof mounted RV AC units. As for your last question concerning the compressor merely being low on freon-it is possible this is the case, but since the compressor is pulling more amps than required, this indicates a malfunction in the compressor.

      I will consult with another AC guy concerning the low freon possibility and post my findings here, hopefully today at some point.

      Thanks again for your findings and check back later.

      Randy

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      Scott 6 years ago

      Thanks again Randy, look forward to your response and thanks for the info on the license too!

    • Randy Godwin profile image
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      Randy Godwin 6 years ago from Southern Georgia

      Update for Scott! From what I can gather, a low freon charge would not necessarily cause the compressor to draw more amps nor get really hot while in operation.

      I know this isn't what you wanted to hear, Scott. But it is what it is. I'm sorry I cannot offer you better news or a better solution to your problem.

      Thanks for your questions and comments and good luck with your future repairs. Please feel free to ask for any further info if you think I may be of service.

      Randy

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      Scott 6 years ago

      Randy thanks so much - at least we now know the correct answer - need a/c has been ordered!! Thanks for all of your information!!!

      Take care.

      Scott

    • Randy Godwin profile image
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      Randy Godwin 6 years ago from Southern Georgia

      Enjoy the camping season, Scott! If you need info for installing your new AC then check out this article I wrote especially for the replacement procedure. Thanks!

      Randy

      https://axleaddict.com/rvs/How-To-Replace-An-RV-Or...

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      Danimal1024 6 years ago

      I have a 2004 Four Winds travel trailer with a DuoTherm rooftop unit. I'm in Arizona so we use the AC when we're loading up before our trips. I have proper 30 amp shore power at my house so everything runs fine. We went camping this weekend and borrowed a generator in case we needed the AC. The generator is a Yamaha 6600 with a 30amp recep. It was pretty warm so we decided to run the AC. Generator handled it fine but for what ever reason the generator quit running. (I'm guessing due to the altitude in northern Arizona). I got it running again but it was fluctuating all while the AC was running. I finally shut it off concerned with possible damage to the AC. When we got home I plugged it in so we could run the AC while we unloaded. AC cools just fine but it seems the compressor is making a rattling noise. Ran without shutting off for a couple hours so I know it works fine. I'm just curious if there is possible damage to the compressor due to the fluctuation in voltage with the generator. After reading all the previous posts I know I need to check the amp draw (I have an amp meter as I am an electrician). Any ideas or other advice?

    • Randy Godwin profile image
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      Randy Godwin 6 years ago from Southern Georgia

      Hello Danimal, I'm not sure if there is any damage to your RV AC because of the voltage fluctuation you experienced on your trip. I have a friend who recently had his unit act in a similar manner when he went on a camping trip.

      Normally the unit would trip a breaker if it wasn't getting enough amps to run the compressor, but using the generator may have made a difference in this safety precaution.

      Sorry I cannot give you any more pertinent info at this time. Checking the amp draw seems to be the only option at this point. An interesting question for this article but with no good answer at this time.

      I would like to know the results of your amp test when it is done, if you would be so kind as to notify me.

      Thanks for the question and for your time.

      Randy Godwin

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      Danimal1024 6 years ago

      Thanks for the quick response! I won't be able to check it for a few days as I'm working out of town for the week but I will let you know when I get the chance! Thanks again!

    • Randy Godwin profile image
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      Randy Godwin 6 years ago from Southern Georgia

      Thanks Danimal! In the meantime I will see if I can find more info for you to consider concerning your problem. Perhaps your findings will assist others with similar RV AC malfunctioning.

      Randy

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      Lawrence 6 years ago

      Getting the camper ready for the summer and when I turned the AC on, I could hear the unit start on top but fan doesn't come on. When I climb on top what should I be looking for?

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      Danimal1024 6 years ago

      Do you suppose that starting and stopping the generator with the AC on without giving the AC proper amount of time between start/stop could have caused a problem? What happens if you don't give an AC unit an ample amount of time between start/stop?

      Thanks

    • Randy Godwin profile image
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      Randy Godwin 6 years ago from Southern Georgia

      @Lawrence-Try removing the ceiling filter cover to access the squirrel cage type fan. With the unit switched off, give the fan a spin to see if it turns easily. If so, spin the fan hard and switch the unit on to see if the fan starts running on its on.

      If it does indeed begin working it is probably a bad fan capacitor.

      If the fan doesn't spin easily it is probably because the fan bearings are rusty or stuck. There may be oil tubes expressly for lubricating these bearings on each end of the fan motor. If not, spraying with a good lubricant may buy you more time till you replace the fan motor.

      Thanks for the query and good luck with your repairs.

      Randy Godwin

    • Randy Godwin profile image
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      Randy Godwin 6 years ago from Southern Georgia

      @Danimal-In a normal 110 volt plug in situation the breaker would likely trip if the compressor didn't have enough time to recycle between starts. I assume the AC was still plugged into the RV power supply furnished by the generator, so the breaker would have likely still tripped if too many amps were drawn by the compressor.

      I also am assuming there were other electrical devices in your RV being powered by the generator too.

      Randy

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      mike 6 years ago

      hello i have a 2005 tahoe toy box with a duo therm ac unit. it keeps kicking the breaker in the coach. i had the power checked at the post ,it was 110 volts. i ran it last night and it seemed fine,it cools great,but early in the am it seemed to cycle fairly quickly.like the compresser was starting then stoping. everything lookes clean and i dont see any ice. any help would be great thanks

    • Randy Godwin profile image
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      Randy Godwin 6 years ago from Southern Georgia

      Hi Mike. This sounds like the freon charge may be a bit low which causes the compressor to recycle frequently. I suggest you get someone to check the run/start amps being drawn by the compressor to see if it is at fault.

      If not, having the unit recharged may solve your problem. P;ease let me know what you eventually find out.

      Thanks for the query and for your time.

      Randy Godwin

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      Alex 6 years ago

      Hello, I have an older brisk aire unit. It has worked fine since I bought the rv. I am on my fist camping trip and the AC is giving me trouble. The AC was working fine but all of a sudden the compressor quit. The fan worked though. Then the fan quit but I could here the compressor working. After turning it off for awhile the fan will work and the compressor tries to work but doesn't fully come on. I can see the lights dim in the rv when it tries to come on. I am using a 25 foot 30 amp extension cord.

    • Randy Godwin profile image
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      Randy Godwin 6 years ago from Southern Georgia

      Hi Alex, this sounds like a bad starting capacitor which operates both fan motor and compressor. Both require an extra boost of energy to get them going and the capacitor is supposed to furnish this to keep from tripping a breaker when both try to start at once.

      This is a simple repair job only requiring the removal of the AC shroud to gain access to the capacitor. I hope this is indeed your problem as a capacitor is relatively inexpensive.

      Randy

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      Neva 6 years ago

      Randy we have a 2007 out back sydney the a/c has always worked fine except for occasions where compressor would make a loud roaring sound kinda like it wouldn't kick which the dealership said was normal for hot days... However lately when ac is running which we only run on auto between 63-68 degrees it's making a rattling noise. What could this be?

    • Randy Godwin profile image
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      Randy Godwin 6 years ago from Southern Georgia

      Hi Neva, I'm not quite sure about what the the dealer told you as the AC should not make a roaring sound occasionally and sometimes not. Did you buy this RV new?

      However, there are several reasons why the unit could make a rattling noise. It's possible there is some debris which may have gotten inside the unit and is obstructing the fan, or else fan may be striking the edge of the cover surrounding it.

      The worst possible scenario is the compressor starting to malfunction and the noise is coming from it. This may require removing the shroud-a simple procedure which only requires removing 4 nuts-to discover where the noise is coming from.

      I hope it is something simple but it does sound like the compressor may be at fault. Feel free to contact me again when you find the problem and I will attempt to help you further.

      Thanks for the question and your time.

      Randy Godwin

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      Neva 6 years ago

      Thank you soon as this heat wave moves by we will take the shroud off and take a look.. Yes we did buy this camper bran new actaully just a wk after it became available on the dealership lot from factory. The rattling sound has gotten better

    • Randy Godwin profile image
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      Randy Godwin 6 years ago from Southern Georgia

      @Neva-Great, let me know if you discover the cause of the noise. This has my curiosity aroused. Also, if you have more questions, please feel free to ask here again.

      Randy

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      Neva 6 years ago

      Randy, will do early in morning before this heat gets very hot we are going to check shroud I cleaned vents today and took flash light looked up looks dusty but that's all.. Noise isn't as bad but it just doesn't feel cool in the camper..had ac on auto 63 and it never kicked on and off but then again it was. Heat index of 100 today by soon as find out will let you know

    • Randy Godwin profile image
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      Randy Godwin 6 years ago from Southern Georgia

      @Neva-It doesn't sound good at this point, Neva. It could possibly be a low freon charge as this may cause some added noise from the compressor. Let me know what you find out when the shroud is removed.

      Randy

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      Gregg 6 years ago

      Hi Randy,

      What a great page! I read the whole thing and I have a new topic for ya... I recently purchased a new to me travel trailer with a ducted Duo-Therm. The guy said to run it on hi when it's hot or it might freeze up. I thought ok, it probably takes Hi to cool this 29' monster so I did. It ran for a couple hours and eventually kicked the breaker. I was in the house when it happened so I didn't hear or notice anything prior to that other than the camper vibrating. My old camper had a 20yr old Coleman that I worked on last year (new capacitor!) but I didn't give the vibration too much thought. Today I took the shroud off and checked the fan blades. The unit is very similar to the old coleman from the top looking down, i.e. one motor with a fan on each end (blower and cooling). With the shroud and cover off, I turned on the fan on high and the whole thing was shaking like a paint mixer. I turned it off. The blades were clean, and the fans rotate freely and the shaft seems firm in the motor. However the blower squirrel cage has one of the little tines about 1/2 missing. I suppose this is the cause of the vibration. There is the big styrofoam block surrounding the blower where the motor mounts. It looks like I may have to take the whole unit off and turn it up-side down to replace the squirrel cage...does that sound right? I can't see any other way it might come out. Please tell me there is an easier way...please :)

      Going to click and order some of that cleaner and a fin comb. :)

    • Randy Godwin profile image
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      Randy Godwin 6 years ago from Southern Georgia

      Hi Greg, and thanks for the compliment you given me concerning this article. I'm glad it's helped a few folks with their RV AC problems.

      On some of the Coleman model AC units it is easier to remove the fan motor from the squirrel cage than the SC from the motor. It may be necessary to remove the exhaust fan from the motor shaft first to give you room for withdrawing the shaft from the SC fan.

      It may also be necessary to loosen the allen screw from the SC fan to remove it. You get the idea, it depends on the particular model. Some require removal of the metal SC compartment. It should be no major problem. I hope this helps you out and ask for more info if needed.

      Thanks for you question, Gregg!

      Randy Godwin

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      David 6 years ago

      I have a 2006 Outback 28RSS. It has a carrier 13.500 AC unit. I bought the rv new and the AC has always cooled perfectly. This past week we went camping and during the day the unit could not keep up and it would reach 84 degrees in the Rv with the outside temp at 92 to 94. The air blowing from the vents was 64 degrees during the day and 55 degrees during the night. The camper would cool to 65 degrees at night but quickly climb back up during the morning. Since I cannot check or add freon what should I do?

    • Randy Godwin profile image
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      Randy Godwin 6 years ago from Southern Georgia

      Hi David, I would remove the shroud-only 4 retaining nuts in most cases-and check to see if the coils are dirty. This is a common problem with RV AC units which aren't cooling as well as they should.

      Use a good coil cleaner such as found on this page if they appear to need cleaning. These coils not only allow the cold air to be transferred to the RV interior, but allow the hot air to be dispelled from the rooftop AC unit.

      I hope this fixes your RV AC problem and that you enjoy the next camping trip. Thanks for reading and good luck on your repairs.

      Randy Godwin

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      David 6 years ago

      Cleaned the coils. Minorly dirty, not very. They look shiney and clean now with zero dirt. Outside temp now at 79 degrees with 87% humidity. Overcast with no direct sun. A/C was on all night long and temp inside rv was 65degrees when I checked it at 7:30 a.m. With air off while I cleaned coils the inside air went to 79 degrees and after turning it back on it has dropped to 75 degrees while blowing 54 degrees from the vents. My buddy has the exact same rv as me and his blows at 44 degrees from vents. Never checked mine until it started not cooling as well this week so I don't know how cold it blew before. I would expect that it should be the same as his since they are identical rv's with the exact same a/c.

    • Randy Godwin profile image
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      Randy Godwin 6 years ago from Southern Georgia

      @David-44 degrees sounds about right. You probably have a very small freon leak which has eventually caused the system to be low enough to affect the cooling process.

      Recharging the system may be the only option for you, David. Although it is not a difficult process, I hesitate to suggest you do it yourself. At any rate, it would cost less than replacing the unit.

      Sorry I cannot be of more help to you. Good luck and thanks for your input and questions.

      Randy

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      S Simon 6 years ago

      I have a 1997 gulf stream seahawk with a 15,000 btu coleman. The only way to shut the compessor of is to turn off breaker. You can put thermostat in any position and ac compressor will still run. Was 90 in camper yesterday and ac was putting out 59 degree air. Unit will eventually freeze up. do you have any ideas?

    • Randy Godwin profile image
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      Randy Godwin 6 years ago from Southern Georgia

      Sounds like you need to replace the thermostat, S. Simon. You may access it by removing the ceiling assembly. It's easy to replace and relatively inexpensive. You may find a replacement through the parts links on this page.

      Good luck and thanks for the question.

      Randy Godwin

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      S Simon 6 years ago

      The thermostate is located on the wall, I neglected to say it is ducted air system. I remoed rhe thermostat and when I turned the breaker on the compressor still came on

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      S Simon 6 years ago

      I unplugged power from relay board and plugged it back in and unit started working correctly. Could this have reset the themostat or do u think I should pue\rchase a new relay board

    • Randy Godwin profile image
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      Randy Godwin 6 years ago from Southern Georgia

      I wondered if the thermostat was on the unit or not, S Simon. I would try it a bit before purchasing a new board. Perhaps the thermostat did indeed reset.

      Randy

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      jake 6 years ago

      Hello, i have the same prob. as ( jim 6 weeks ago) acept I have not changed a thing. The fan blows fine alone but as soon as you switch it to one of the cool settings the fan slows to a stop and then starts in the wrong direction. I un hooked the thermostat , and went through all settings and it works properly as long as the compresser is not on.?????? any ideas ,thanks jake

    • Randy Godwin profile image
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      Randy Godwin 6 years ago from Southern Georgia

      Hello Jake, Why not simply turn the unit around backwards, like Jim did? LOL! Just joking, of course.:)

      This may be a problem with the switch, Jake. Or it may be a screwy capacitor which starts the compressor. You really need to do an amp check on the compressor if it doesn't run at all. You didn't mention if the compressor ever started or not.

      Perhaps a little more info could help me narrow down the problem.

      Randy Godwin

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      Jake  6 years ago

      Thanks for the fast reply. Yes the compressor seems to work as it should ( cools to 50 or so )In fact every thing seems to be fine .Just cant figure out why the blower switches direction when the compressor is running. thanks ,jake

    • Randy Godwin profile image
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      Randy Godwin 6 years ago from Southern Georgia

      That is a puzzler, Jake. Since the fan is running backwards, it would mean the air blowing through the coils would be reversed also and not cool properly. Does this unit have 1 or 2 capacitors?

      Randy

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      jake  6 years ago

      2, one little and one bigger.

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      jake 6 years ago

      Got it , new capacitor and good as new. Thanks for your time.

    • Randy Godwin profile image
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      Randy Godwin 6 years ago from Southern Georgia

      Sorry to take so long responding, Jake. I'm on vacation in Jamaica and just checked my comments.

      Glad you found the problem and thanks for your question and the solution as it may help other RV owners with similar problems.

      Thanks again for visiting my articles.

      Randy

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      Rushell 6 years ago

      Hi Randy. Hoping you can help me out with our problem. Our camper is an older Coachmen, probably a '74 or so. Went camping earlier this week and while camping and running the ac, we lost all power, tripped a breaker. Turned the breaker back on and ran find for 2 days. On our last night there, in the middle of the night, we lost all power to the ac unit. Lights and tv, etc. all still work, but when you go to turn the ac on, it's like there is no power to it at all. We've checked the breakers and it's not that. We've switched outlets that the extension cord is plugged into but that didn't help. Checked the fan, it moves freely. Don't know what else to do. If you could point us in any direction, we would be grateful, thank you.

    • Randy Godwin profile image
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      Randy Godwin 6 years ago from Southern Georgia

      Rushell, you may have an A/C unit with only one starting capacitor for both fan motor and compressor. This sounds like your problem. Check this first before going any further as this is a common problem.

      Randy Godwin

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      Del 6 years ago

      Randy I have a 1984 Allegro MH. When I run the 2 A/C units

      (Duo therm) from the generator they both work find. When I am parked and run and A/C from the house or RV parks only the front unit works. Checking A/C at the rear units and find none, Is this correct from manufacture?. It has been this way sense I have owned it, 1992.

    • Randy Godwin profile image
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      Randy Godwin 6 years ago from Southern Georgia

      Hello Del, I assume the home and RV park hook ups are 50 amp rated and not the standard 30 amp campsite outlets.

      The reason I ask is 2 units will probably pull more amperage than a standard home or RV campsite hook up.

      Otherwise, it sounds as if you have 2 different line connections for the land and generator operations. Can you give me more info?

      Randy

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      Mike 6 years ago

      Hello Randy, I'm diagnosing my coleman Mach RV A/C unit.

      Problem #1: Firstly, I'm pretty sure I have a thermostat problem. It is inconsistent at putting 12Vdc on yellow when I switch it to cool. I can handle that one.

      Problem #2: In the ceiling unit's control box, I have no evidence of the compressor relay switching. Even when I jumper 12V to the yellow wire and verify it is present at the control board level, the 110Vac is not passing through the compressor relay to the purple wire.

      Problem #3: I installed a switch (service & troubleshooting use only) in place of the control unit's compressor relay. The compressor will start & run, but it the evap will not cool down. I have shop-vac'd the evap coil and during my testing, I have my hand right on the evap coil when the compressor's running. I can not discern any change in temp. This is the issue I am most concerned with. In my mind this is a ref charge issue; likely no charge. Thoughts, ideas?

    • Randy Godwin profile image
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      Randy Godwin 6 years ago from Southern Georgia

      You are probably right, Mike. It sounds as if you need to recharge the unit as everything else seems normal. The relay is likely pressure activated and this also indicates low freon charge.

      I hope the recharge gets you going again and thanks for the detailed description of your troubleshooting steps.

      Randy

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      Gregg 6 years ago

      From above: blower replacement.

      Well I replaced the blower and both squirel cage and exhaust fan blades. Only when I picked up the original exhause blade did I notice the large mass of mud-dobber nest on the hub of the blade!! I had checked the blades themselves, but did not reach behind to feel what I couldn't see was about a fistful of dried mud. This mass makes way more sense in throwing the motor off balance than a small piece of plastic missing from the SQ blade. I was irritated to say the least. The good part though is that the new motor spins smooth and quiet. And with the exhaust blade out of the way, I was able to give the coils a good cleaning. Maybe someone's future internet search for vibrating blower fan will point to this post and remind them to feel behind the blade where you can't see for mud dobbers :)

      Peace!

      Gregg

    • Randy Godwin profile image
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      Randy Godwin 6 years ago from Southern Georgia

      Gregg, sorry you didn't find the mud dobber nest before going to all the trouble of replacing the fans. But I will certainly suggest this possibility to any future similar problems an RV owner may have.

      Thanks for relating your experience and the solution to your problem. I'm sure it will help others in the future.

      Randy

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      Dennis 5 years ago

      Sorry about the misspelled words,I'm posting this with my new,first, smart phone and it "corrects" my spelling. We "purchased" the camper.

      Dennis

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      Danny Simpson 5 years ago

      What should the low side freon presure be on a duro thurm brisk air ac.

    • Randy Godwin profile image
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      Randy Godwin 5 years ago from Southern Georgia

      @Danny-This should be listed on the compressor or on a plate on the AC itself. The pressure will vary depending on how the unit is cycling and will be the same on both high and low sides when the unit has been turned off for awhile.

      For a more concise reading you will have to consult a manual for your unit. I do not have this info at hand.

      Randy

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      Danny 5 years ago

      Thanks Randy it is working ok now. It was run without a filter so I had to clean the coils and I added three ounces of freon.

    • Randy Godwin profile image
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      Randy Godwin 5 years ago from Southern Georgia

      Great Danny! Dirty coils are a common RV AC problem. Enjoy a nice cool camping trip now. Thanks for your input and questions.

      Randy

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      Dennis 5 years ago

      Randy, We just purchased a 2003 Gulf Stream Innsbruck camper. When the air conditioner is set past about the half way point on the coolness knob there is a large load put on the curcuit for about 1 to 2 seconds about 15 seconds into the non-compressor portion of the cycle. On "high cool" and the coldest setting, the compressor runs about 90 seconds and than shuts off for about 60 second during which the high load happens. I haven't put an amp meter on it yet but it is enough to make a 4000watt/5000starting generator about jump out of my pickup than die when it happens. I put a 6500watt generator on it and it heavily loads it but it doesn't kill it. You can also tell there is the same high load put on it when the camper is plugged into 110v. Is it a capacitor loading or what? Any ideas?

      Dennis

    • Randy Godwin profile image
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      Randy Godwin 5 years ago from Southern Georgia

      Dennis, if you check the capacitor ohms with a multimeter you should get a descending, random number if the capacitor is good. In other words-198-197-196 the longer the leads are attached. The numbers are important to the test as long as they descend in value.

      The amp meter should tell the tale on the compressor if the capacitors are good.

      Randy

      Randy

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      Steve Lasko 5 years ago

      Hi Randy, we recently had one of our A/C's replaced in our '96 Newmar Mountain Aire. Since then we've been doing some long term camping in Texas and Florida and the electric costs have been astronomical! $245/month! Anyway, the only thing I could think of checking was to see if the installers might have inadvertently re-wired the units to 110 rather than 220. So, I checked the breakers and had the proper amperage (13+ on rear and 14+ on front), but each was all on just one leg of the 220 circuit. The other leg of each circuit was essentially zero. Is this normal? I thought that with 220 I'd read amperage off each of the two wires for the circuit.

    • Randy Godwin profile image
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      Randy Godwin 5 years ago from Southern Georgia

      Hello Steve. Are you positive your RV operates on 220 volts? Most RV AC rooftop units operate on 110 volts. If you have a 220 volt hookup-probably at least 50 amps- it would indeed seem as if they would operate on separate legs of the 220 volt supply. But one thermostat might require the same power supply for both.

      Randy

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      Steve 5 years ago

      The RV is the typical 50 amp service. The circuit breaker for each A/C has two wires and the (single) breaker is the type that has two switches on it; one red and one blue. In other words, each A/C has two wires, which, I assume is for two 120v wires. Given this, I'm pretty sure that, although the coach has 120 supply, it is split as needed inside. Now I'm going to see if I can find the manual to verify! Oh yeah, there is a single thermostat for both zones. It's a central type system.

    • profile image

      Steve 5 years ago

      Randy - It just dawned on me that the second wire is likely for the heat strips. I doubt that the compressor and heat strip run off the same wire. Whatdayathink?

    • Randy Godwin profile image
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      Randy Godwin 5 years ago from Southern Georgia

      Apparently the AC system uses one leg of the 220 volt service to supply the entire cooling system, Steve. The single thermostat would likely require a single 110 volt circuit for activating both units.

      I believe your units are installed correctly. Thanks for the question and for reading my articles.

      Randy

    • Randy Godwin profile image
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      Randy Godwin 5 years ago from Southern Georgia

      @Steve-Not sure about the heat strips in your system. Most rooftop AC units I've dealt with use the same circuit to operate both AC and heat strips since they do not pull amps at the same time. You could be correct though.

      Randy

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      Steve 5 years ago

      Thank you for your info. Nice web page. It has been a nice way to get information.

    • Randy Godwin profile image
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      Randy Godwin 5 years ago from Southern Georgia

      Always glad to hear my articles have worth, Steve. Please check out my other RV repair articles if you ever need them.

      Thanks again for stopping by.

      Randy

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      Bruce G 5 years ago

      I have a duo therm that does not blow cold. Investigation revealed a broken copper tube that routes from the compressor to the cooling fins. Line severed vertically about a 1/2" from 1st cooling fin. Is there a way to re-couple the line? and then have someone charge the system? or is it replace time ?

      Bruce G

    • Randy Godwin profile image
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      Randy Godwin 5 years ago from Southern Georgia

      Hi Bruce. Yes, the line may be repaired and the unit recharged if the broken line is the only problem. Check with an AC repair service or an RV dealer. Thanks for stopping by and good luck on the repairs!

      Randy

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      Mike 5 years ago

      MI rooftop A/C unit is freezing up. After a while it stops blowing cold. When I go up on top and look in the vents there is a coating of ice on all the tubes. Ideas?

    • Randy Godwin profile image
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      Randy Godwin 5 years ago from Southern Georgia

      Hi Mike. There are several things which will cause the coils to freeze over in a rooftop RV AC unit. The most common cause is running the thermostat too high in hot humid weather.

      Also, if the coils are really dirty, the air cannot pass through the fins easily and transfer the cold to the air intended for cooling your RV.

      Usually a good cleaning of the coils will remedy this problem. Use a good coil cleaner, such as found in the ads on this page, and this should solve your problem.

      The most serious problem which may cause your unit to ice up is a low freon charge. Just before an ac unit runs out of freon it will get really cold and cause the icing. If the other remedies do not work, a recharge is in order. In this case, you have a leak somewhere in the system.

      I hope this info helps you find the problem. Thanks for the question and for reading my articles.

      Randy Godwin

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      Bruce G 5 years ago

      Can the line repair be a DIY I am pretty good at these things, but would need a direction as to soldering a union or utilize a threaded coupling or . . . .

      Thank you

    • Randy Godwin profile image
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      Randy Godwin 5 years ago from Southern Georgia

      @Bruce-Yes it can, Bruce. Depending on where the line is broken, a copper coupling may be used to repair the line for recharging.

      A vacuum must be pulled on the unit before recharging and a piercing valve used to enable recharging the unit with freon. Pulling the vacuum will also tell whether there are any more leaks in the system which need repairing.

      Good luck and I hope you have no problem with the repairs.

      Randy

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      AE 5 years ago

      I have a travel trailer that has a rooftop air conditioner. About a week ago it quit cooling. The air conditoner runs but it blows hot air. What could be the problem?

    • Randy Godwin profile image
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      Randy Godwin 5 years ago from Southern Georgia

      Hello AE. First you must see if the compressor is working. If so, the system may be low on freon. If not, it is probably a bad starting capacitor or at worst, a bad compressor. Let me know what you find for further advice.

      Randy Godwin

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      james 5 years ago

      my ac unit blows cold air at night but as soon as the suns starts to rise it dosent cool very well. trying to repair it myself what do u think the prob is. thanks

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      Terry Wright 5 years ago

      I was usning my Dometic Heat Pump in the a/c mode when my son inadvertantly pushed a camping chair into the breaker switch that controls the a/c unit. Of course the unti immediately shut down. I can't get it to come back on. In laymans terms I think I blew a fuse. Is that a possibility or did something more drastic happen?

      thanks. My email address is terrence.wright@kcc.usda.gov

    • Randy Godwin profile image
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      Randy Godwin 5 years ago from Southern Georgia

      Hi James! I would try giving both coils a good thorough cleaning to see if restricted airflow through them may be causing your problems. Otherwise, your unit may be low on freon and needs recharging.

      Feel free to ask for more info if needed and thanks for dropping in and reading my articles.

      Randy Godwin

    • Randy Godwin profile image
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      Randy Godwin 5 years ago from Southern Georgia

      Hello Terry, unless you can check the breaker switch with a multimeter there is no way to see if the breaker itself is the culprit.

      You may also see if power is getting to the breaker switch itself using the same tester or multimeter. It isn't uncommon for these breakers to malfunction. Be sure to check the on board breakers in the 110 volt AC panel box to insure the A/C breaker there is not tripped also.

      Ask for more info if needed and thanks for reading my articles.

      Randy Godwin

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      Big E Fan 5 years ago

      Randy, Great Ideas. I am new to this type of thing so my question is: I have a 1989 Mobil Villa & was wondering if the freon used on most trailers was R-12 or R-22? I am a certified auto tech, but this is my 1st travel trailer. Thanks.

    • Randy Godwin profile image
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      Randy Godwin 5 years ago from Southern Georgia

      I'm really not sure about the type of freon used on your particular model RV AC, Big E Fan. It should be marked appropriately somewhere on the unit itself. I would thin it would be R-22, but this is just a guess on my part.

      Thanks for the question and I will see if I can find further info for you.

      Randy

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      Big E Fan 5 years ago

      Thanks Randy, I thought it may be 22 but wasn't sure. I will look when I get my rv back home (is stored @ a friends house for now).

    • Randy Godwin profile image
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      Randy Godwin 5 years ago from Southern Georgia

      No problem, Big E Fan. You should find the freon type listed on the unit. Thanks for stopping by.

      Randy

    • Randy Godwin profile image
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      Randy Godwin 5 years ago from Southern Georgia

      Hi David! It does indeed sound like you have a thermostat problem since both units are affected. It could be a relay problem only if both A/C units are controlled with one relay which is not normally the case.

      I would try a new thermostat first or check the present one with a multimeter to see if there is voltage going to the units with the switch in the cool or fan positions.

      I'd like to hear what you find out when you isolate the problem. Thanks for the questions and for checking out my article.

      Randy Godwin

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      Holly 5 years ago

      Wondering if anyone knows of a wall thermostat I could use with my Coleman Mach unit that will allow for a remote sensor and has auto heat/cool. All I can find are residental wall thermostats that operate on 24v and I obviously need a 12v. I have been able to use a regular Honeywell wall thermostat that is millivolt to 24v and that works, BUT I can't attach a remote thermostat (really important) nor does it have an auto heat/cool capacity.

      thanks for ANY assistance!!!

    • Randy Godwin profile image
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      Randy Godwin 5 years ago from Southern Georgia

      Holly, is your Mach already equipped to be changed to a remote? It makes a difference, you know!

      Randy

    • profile image

      Holly 5 years ago

      Hi Randy

      My Mach is set up for a wall thermostat, I have had a regular household "Filtrete" brand thermostat on there and has worked fine for both heating and cooling for the last 8 months (I have to manually change from heat to cool with this unit, I have a heat strip on my Mach) Let me give the reason I am looking for a remote sensor/thermostat.(wired remote is fine) The Mach is mounted on the top of an insulated cargo container that is being used as a growing room for animal fodder, think an enclosed greenhouse.(completely legal! LOL growing barley seed) There is LOTS of moisture, and the reason that the Filtrete wall thermostat needs to be replaced, is that it was constantly getting wet! duh! and has now stopped working. So, I want to be able to get a thermostat that has a remote (waterproof!) sensor I can mount on the inside of the unit, and mount the the actual thermostat control through the wall of the container on the outside, where it is dry. I can find thermostats that are 24v that can have a remote sensor attached, and are automatic heat/cool )but I can't find anything like that that operates on a 12v, or a millivolt to 24v system. Even one that isn't an auto changeover to heat and cool, as long as it can have a remote sensor attached.

      So, does that help a bit?

    • Randy Godwin profile image
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      Randy Godwin 5 years ago from Southern Georgia

      Sorry Holly, I was half asleep when i responded to your previous post. Yes, I understand what you are trying to do and indeed the thermostat itself only has to have a remote operated sensor.

      I'll look around for more info on this option!

      Randy

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      Holly 5 years ago

      Thanks Randy! I REALLY appreciate any assistance you can give me to find something that will work! :)

    • profile image

      Holly 5 years ago

      Hi Randy,

      Any luck finding a 12V or millivolt to 24V thermostat that can take a remote (waterproof) sensor?

    • Randy Godwin profile image
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      Randy Godwin 5 years ago from Southern Georgia

      Sorry Holly, check with the maker of your particular RV AC as I don't have any special access to these manufacturers.

      I will check further, though!

    • Wesman Todd Shaw profile image

      Wesman Todd Shaw 5 years ago from Kaufman, Texas

      WOAH!!!!!!!!!!!! This thang here still gets some good looking over!

      Seems obvious now (having looked at the previous comment I left) that the danged old a/c on this little home of mine is a Coleman.

      I haven't messed with it much other than washing the indoor coil with some super duper alkaline coil cleaner....but the other day I ran the a/c a little bit.

      Pretty mild Winter over here!

      I think I've either got a wire loose or a burnt winding...thing ran in low and high (the fan) but not the speed in the middle!!!

    • Randy Godwin profile image
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      Randy Godwin 5 years ago from Southern Georgia

      Yo, Wesman! A very mild winter here in southern GA too! Some have already been cutting their lawns the last few weeks or so as not much frost has burned the grass this year.

      Sounds like you've got a bad fan switch in your AC or else a bad relay in the fan motor, Wesman! Thanks for stopping by!

      SSSSS

    • Wesman Todd Shaw profile image

      Wesman Todd Shaw 5 years ago from Kaufman, Texas

      I'd like it to be the switch!

      I never really used "medium" anyway.

      I know one thing....my tstat is about gone. It's about to where it's just calling for a/c or it ain't, and all that space in between is nothing but dead space.

      Probably I'm going to have to get me a replacement part OEM style or a good universal one.

    • Randy Godwin profile image
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      Randy Godwin 5 years ago from Southern Georgia

      More than likely it is the switch, Wesman. An easy and not too expensive fix for you. Yep, sounds like you are overdue for a new thermostat too! Better get ready for the hot stuff!

      SSSSS

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      Doyle Smith 5 years ago

      I have a 1987 Executive RV. It has the Dometic under floor split system A/C unites 3,500 BTU 125v 14 amps running. The evap runs on the 12v, condenser 125v.. The front unit runs off the Gen. or the power cord. The rear unit which was fine when last operated will not start up now. Not trying to run both at the same time. You can hear the Gen pull down each time the unit attempts to start. I can hear what I think is the power relay clicking (strongly) when you demand cooling. However the unit will not start. A idea's? Thanks

    • profile image

      Doyle Smith 5 years ago

      PS: Sorry, I left out one piece of info. The indoor 12v runs the evap fan and the 125 volt condenser fan run when cooling is demanded.

    • Randy Godwin profile image
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      Randy Godwin 5 years ago from Southern Georgia

      Hello Doyle! Sorry to take so long to answer your question, but a man has to go fishing sometimes! LOL! Have checked the fan to see if it will turn freely if spun by hand? Often these fans have sleeves instead of ball bearings and they tend to stick if not used in a while.

      If the compressor is bad it will pull more amps than what is listed on the label. Check the start/run amps to see if it is pulling more than required. If I have misunderstood your question, or you need more info, then please feel free to ask.

      Randy

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      noelnelson76 5 years ago

      Hi Randy,

      I experienced a power surge on my duotherm hp 59516.331 roof top rv ac on 1998 cardinal 5th wheel. The ac was running fine before the surge. Now the ac will not do anything. the heat side on the manual wall mounted tstat works fine. I replaced the hard start capacitor. Still no change

    • Randy Godwin profile image
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      Randy Godwin 5 years ago from Southern Georgia

      Yo Noel! Perhaps the surge may have damaged a relay on your unit. You mentioned the heat side of the wall mount thermostat working but didn't say if the A/C used the same thermostat or if your unit is a combination heat/cool unit. If so, it's possible the thermostat may be faulty on the A/C side. Check the voltage on this side to see if it is sending current to the unit. If so, you may have to check at the other end--in the ceiling assembly possibly-to see if a relay is at fault.

      If I'm not understanding your unit correctly, then feel free to ask for more info.

    • profile image

      NOEL NELSON 5 years ago

      Yo Randy,

      Thanks for the information! To be clear the ac and heat use the same single mount Duotherm manual thermostat. The gas heat unit is located underneath the kitchen counter next to the hot water heater and is working fine. Will that relay in ceiling assembly be part of the control circuit board?

      Thanks Again

      Noel

    • Randy Godwin profile image
      Author

      Randy Godwin 5 years ago from Southern Georgia

      Okay Noel, I wondered if the A/C unit also had a heat strip, but now I understand you have two separate heat and cool sources. Still, the thermostat may be at fault so you might check the voltage supposed to be going to the AC unit when the thermostat for the cool side clicks on.

      You may have an 18 volt charge but I'm not sure of the thermostat in your RV. If this checks out fine you must find where the thermostat wires end up in the AC unit itself. Not sure on your model but you may be able to find a wiring diagram online.

      Using a multimeter, you should be able to tell where the current from the thermostat goes to and therefore what the problem is. I hope this helps you a bit more but check back if necessary.

      Randy

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      Jimmy Mac 5 years ago

      Randy, I have a 2007 Outback with a 15,000 BTU Carrier A/C I have noticed that the noise level of the unit has increased over the years and recently the start ups have been really noisy. I can sometimes bump the unit from below and the noise subsides and it seems that the longer it runs the noise eventually decreases. any suggestions would be appreciated. thanks.

    • Randy Godwin profile image
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      Randy Godwin 5 years ago from Southern Georgia

      Hey Jimmy Mac! It's possible the shock absorbers on the compressor may be worn or even loose on your unit or perhaps there is something which is making the fan be out of balance such as a mud dobber nest stuck to the fan blade. I've seen this happen several times before.

      I would suggest removing the cowling from the unit and checking for such obstructions or loose rubber shock absorbers on the compressor. It may be necessary to watch the unit while someone else starts it up to observe the noise problem.

      Feel free to ask for more info if this advice doesn't help. Sometimes the compressor will make noise when it first starts up if it is very old or beginning to go bad. Thanks for your question and for checking out my articles.

      Randy

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      Ron 5 years ago

      Hi, I have a Coleman model 8333-876 rooftop on my 5th wheel, The Compressor won't run at all. The fan will run but... it runs slow on "fast" and fast on "slow"!I replaced the fan, hard start, and run caps on the unit. I hear no relay click, or and sign of a compressor hum/noise. The only thing that works is the fan although it runs different/backwards of the fan settings on the wall thermostat!!!No one has changed any wires, or worked on the unit. It ran good about a week ago. any ideas? Thanks.....

    • Randy Godwin profile image
      Author

      Randy Godwin 5 years ago from Southern Georgia

      hello Ron! Have you checked the thermostat to see if it is operating correctly? You didn't indicate whether or not the thermostat also controlled the furnace in your RV, but for now I'll assume it does.

      It seems you've eliminated almost everything else which could cause the problem, so checking the voltage going from the thermostat to the rooftop AC would be the next logical step. In fact, you may have gone to a lot of unnecessary trouble and expense already, but we aren't sure of that yet.

      Since I'm not sure what type of thermostat is in your RV I can't tell you what the multimeter should read as far as voltage is concerned. This info should be listed somewhere on the thermostat itself.

      It is possible there are 2 separate control features on the thermostat with the AC side being inoperable. It may not be sending the correct signal to the compressor to start up or run. I would check this out before doing anything else. A new thermostat is usually very inexpensive and quite easy to replace if you find it is the culprit.

      This is only a suggestion so feel free to ask for more info if needed. Thanks for the question and please let me know if my suggestions helped or not. Thanks again for checking out my RV repair articles. Good luck on your repairs!

      Randy Godwin

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      Ron 5 years ago

      Hi Randy,

      I have a stock coleman rv thermostat that came with the unit. It is a heat cool type that runs both the rooftop and furnace. It has heat/ cool, fan auto, and high and low fan speeds. I checked the fuse in it... but I wasn't lucky, its good! I suspect the thermostat but at 80 dollars I wanted to be sure before replacing that also!It worked great about a week ago, now for some reason the fan hi, and low setting are reversed! and the compressor will not hum, click, buzz... just sorta sets there laughing at me. I thought maybe a wire burned off the compressor but they are all solid and good...only thing that works is the fan. well kinda, the setting for high and low are working backwards. I was wondering how to check the relays in the metal box located in the plenum. Thank you for such a fast response!

    • Randy Godwin profile image
      Author

      Randy Godwin 5 years ago from Southern Georgia

      I doubt seriously the compressor is at fault, Ron. And you know it isn't the fan if you've replaced it. You should be able to check the thermostat wires where they enter the unit to see if voltage is present. The relay should be nearby also. You can also check the voltage at the thermostat itself where the wire leads to the A/C. Not sure what voltage is required for normal operation on your unit.

      But if you fail to get voltage, it is probably the thermostat,. No, or low voltage, and a relay is more than likely the culprit. Sorry I can't be of more assistance at this time, but I don't have a schematic for your unit. You can perhaps find one online if you need to know the location of the relays. Please check back if you think I can help you further.

      Randy

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      karen 5 years ago

      my a/c worked fine last yr. this yr. took it out, turned on the a/c and it started vibrating the whole camper and was very loud. can you tell me what it could be. thanks.

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      karen 5 years ago

      oh yea thought I better tell you its a 1999 coachman

    • Randy Godwin profile image
      Author

      Randy Godwin 5 years ago from Southern Georgia

      Hi Karen! The most common problem when an A/C starts vibrating after being idle for awhile is when a mud dauber builds a nest on one of the air conditioner fan blades. This throws the motor out of balance and creates the vibrations you are describing.

      The only other cause in most cases is from a bad compressor or either bad bearings in the fan motor, But check out the fan blades on both the squirrel cage type fan and the regular bladed fan on either ends of the fan motor shaft for nests first.

      You didn't mention whether the unit was cooling or not. Ask for more info if needed.

      Thanks for the question and for reading!

      Randy

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      karen 5 years ago

      Thanks Randy: We are going to check the a/c out today. And for the cooling, it does blow air out, but didn't leave it on long enough to see because was to scared to leave it on to long with it making that noise. Was scared it would really mess things up. I'm hoping its mud daubers.

    • Randy Godwin profile image
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      Randy Godwin 5 years ago from Southern Georgia

      I am too, Karen. Once you remove the cowling from the unit you may switch it on for a short time and hopefully see what is vibrating in the unit. It is also possible the compressor's rubber shock absorbers may be deteriorated and are allowing it to shake while running.

      Please tell me what you find out so I may help others with a similar problem. A word of advice, though! It is often difficult to see inside the squirrel cage fan--this one blows air into the RV--to detect a mud dauber nest or other object.

      If this is the case--hopefully--clean the nest out thoroughly because the slightest weight will create an imbalance and therefore vibrations in the unit.

      Thanks again I'm keeping my fingers crossed for your success.

      Randy

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      karen 5 years ago

      Well Randy you were right. It was a mud daubers nest: Works like a charm. Thanks again for all your help.

    • Randy Godwin profile image
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      Randy Godwin 5 years ago from Southern Georgia

      I love it when a plan comes together, Karen! LOL! Thanks for coming back and letting me know what the problem was. I also have repair articles on almost any other RV problem you may encounter, so next time you have a problem please check out those too! Have a great camping season!

      Randy SSSSS

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      karen 5 years ago

      If I have anymore problems you will be the first I will contact. And for camping season love it. Thanks again

    • Randy Godwin profile image
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      Randy Godwin 5 years ago from Southern Georgia

      I'd really appreciate it, Karen. Glad to be of service!

      Randy

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      ryan 5 years ago

      my furnace or ac unit is not workin.. I have no power to the high voltage caps that are on the roof. I also do not have the 12v power to the termostat. all fuses are good and there are not breakers tripped. I have the 110vac to the control circuit board that is on the inside of the ac unit.. If i bypass the 110volt relay on the board i can get it to turn on.. does the 12v from the thermstate come from this board? what do u think

    • Randy Godwin profile image
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      Randy Godwin 5 years ago from Southern Georgia

      Yes, if the thermostat is bad, or is not being furnished power by the converter, the unit will not run. This is probably your problem. Are all of the other 12 volt DC items working properly? If so, the thermostat is likely the culprit.

      Ask for more info if needed!

      Randy SSSSS

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      Karen 5 years ago

      Hey Randy: I have another problem, which I noticed last yr. when ever the a/c is running and even goes off water runs threw the return vent and the vents. There is no drain hose that we can see. Can you help me.

    • Randy Godwin profile image
      Author

      Randy Godwin 5 years ago from Southern Georgia

      Hello again, Karen! This is a common problem when the coils get dirty or almost stopped up with some type of debris or simply dirt collected over the years.

      There some older units with drains which may get clogged, but most new ones simply disperse the moisture into the air in a fine spray.

      There are coil cleaners especially for this task sold on this page, but you might get by using some 409 or similar such household cleaner if you wet the coils and soak them for a bit.

      This job is rather messy so it is important to protect the top of your RV from the gunk removed by quickly washing the spills away with a water hose or spray. A wet/dry vacuum is really a good thing to have for this maintenance job. Be sure to disconnect the unit from the elec. power, or turn the breaker off until the unit is dry to prevent damage to it or yourself.

      I'll bet your unit stops leaking if you clean both coils well. I know your unit will cool much better without working so hard too!

      Thanks for the question and ask again for more info.

      Randy

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      Karen 5 years ago

      Hey Randy: My husband states that he cleaned them real good when we had the problem with the mud daubers.

    • Randy Godwin profile image
      Author

      Randy Godwin 5 years ago from Southern Georgia

      Well, it appears you DO have a drain in your unit then, Karen. If both the front and rear coils are clean, then I can see no other reason for moisture to be leaking down through the vents unless the gasket is bad between the unit and the roof.

      If debris or dirt is layering the inside bottom of the unit the drain may not be visible. Let me know what you find out of ask for more info if needed.

    • profile image

      Doug Benes 5 years ago

      Does the air conditioner the wilderness need 220 volts to operate?

    • Randy Godwin profile image
      Author

      Randy Godwin 5 years ago from Southern Georgia

      Hi Doug! No, the normal voltage used on most RV AC systems is usually 110 volts. If you have two AC units you may have to have a 50 amp service hookup instead of the typical 30 amp supply used at most RV parks.

      Randy

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      Shannon 5 years ago

      I have a Coleman roof air on my 1992 motorhome. The air conditioner always seem to run normally, accepting sometimes icing up, but this Spring when I tried to start the air conditioner it bogs down. The compressor doesn't start. With the generator it will start to run slow when I try to turn on the air conditioner. The fan blows, but compressor does not start. How can I tell if it's to compressor, or a capacitor?

    • Randy Godwin profile image
      Author

      Randy Godwin 5 years ago from Southern Georgia

      Hi Shannon. Some RV A/C units have 2 capacitors, one for the compressor and one for the fan. The only way to check a capacitor is to use a multimeter on the OHM setting which should be checked with the unit off. You should get random numbers which decrease slowly if the capacitor is good.

      Unless you can have an amp meter to check the run/start amps listed on the compressor, it is difficult to tell if it is bad. Since capacitors are relatively inexpensive, I hope this is your problem and not the compressor. Icing problems often indicate low freon pressure too! Ask for more info if needed and thanks for the question.

      Randy

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      rocketman 5 years ago

      My 2004 Duo-therm 13,500 won't run the compressor. The fan will turn on and off with use of the thermostat, and the blower fan also functions. I suspect the capaciter could be bad, but wouldn't that make the compressor motor humm from trying to turn on? Because it's not making any noise.

    • Randy Godwin profile image
      Author

      Randy Godwin 5 years ago from Southern Georgia

      Hey rocketman! Is your AC controlled by a wall mounted thermostat or one on the unit itself? It could possibly be a thermostat problem. A relay could also result in the same problem. Have you checked to see if power is going to the compressor or if the thermostat is sending a signal to the compressor?

      Randy

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      Rocketman 5 years ago

      It is a wall mounted control, but the condenser cooling fan does turn on and off when I increase/decrease the temp on the thermostat. So I was assuming that it was getting the signal. I'm going rooftop in a little while, and will check the power to the condensor. thanks for your help.

    • Randy Godwin profile image
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      Randy Godwin 5 years ago from Southern Georgia

      Rocketman--Since you are going on top you can check the power to the compressor when it should be running. Using the Ohm meter you can check the capacitor too. If it only has one the compressor should at least try to run when first starting up. If it has two, the one for the compressor may be bad. The ohms should start out at a random number and then start dropping if the capacitor is good. If you get no reading it is bad in most cases.

      Let me know what you find out or if you need more info.

      Thanks again for stopping by!

      Randy

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      Rocketman 5 years ago

      Randy - no power to the compressor, checked the relays inside, and all 3 seem to be working ( can hear a click )There are two capaciters, I checked ohms, on the starter cap.,and it was 25ish for both directions, it held steady. Not sure what to think about that. Checked the voltage on the thermostat,the voltage would drop to 0 for the AC circuit when I switched it on. I'm thinking that is correct.

      I'm still leaning towards the starter capaciter.

      Thanks again for your help

    • Randy Godwin profile image
      Author

      Randy Godwin 5 years ago from Southern Georgia

      Yes, it sounds like the capacitor, Rocketman. Normally you get random numbers which decrease, not a steady number display. If the capacitors are the same you might try swapping them or the wires to see if indeed the capacitor is bad. At any rate, a bad capacitor would be the least expensive fix in most cases.

      Glad to help and feel free to ask for more info.

    • profile image

      Rocketman 5 years ago

      Randy,

      The capacitor didn't do the trick, now I'm really confused. I double checked the power coming out of the box inside it's 120V, but there is nothing at the compressor.

    • Randy Godwin profile image
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      Randy Godwin 5 years ago from Southern Georgia

      Yo again, Rocketman! Well actually, this is good news as the compressor is the most expensive repair part in your A/C and it appears it isn't at fault.

      Next I would suggest you check the thermostat to see if it is sending a start signal to the relay which controls the compressor. This is a common problem when a wall mounted thermostat is implemented. I Hope this is indeed the problem as it is a relatively inexpensive part to replace.

      You many be able to jump the wires in the thermostat to see if it is indeed the culprit. I just noticed where you said the voltage dropped to 0 when activated and this sounds like it might not be activating the relay to start the compressor. I hope this will solve your problem but let me know what you find out.

      Randy

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      Jennifer 5 years ago

      Hello I have a dometic thermo ac unit and its a got ducts throught out the camper ever since I bought the camper the ac would work great until the next morning when the unit would freez up and blow low not so cold air so we would usallly turn it off and then a few hr later be able to turn it back on and it would work fine till the next moring then all over same process well this last weekend when i went to turn it back on nothing happends u can hear a click but no fan or nothing happends ? So I am woundering what happened? Did the motor maybe lock up or do I need a new compressor and advice would be great thanks for your time.

    • Randy Godwin profile image
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      Randy Godwin 5 years ago from Southern Georgia

      Hi Jennifer. Usually when a unit freezes up it is low on freon. This may also happen if it is operated with the thermostat turned down so low the compressor never shuts off. But this shouldn't prevent the unit from coming on at all.

      If your unit only has one capacitor to start both fan and compressor it may be bad. There is also a possibility the thermostat is malfunctioning and not sending an electrical signal for the unit to come on.

      The only way to check if the compressor is trying to start is to check the power in the unit with the thermostat set in the run mode. Someone with a multimeter can do this for you as well as the thermostat.

      Ask more questions if necessary. Thanks for the question!

      Randy

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      Rocketman 5 years ago

      Randy,

      Finally figured out it was the board that was bad, one of the three relays won't cycle on.

      thanks for your help

    • Randy Godwin profile image
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      Randy Godwin 5 years ago from Southern Georgia

      Glad you found the trouble, Rocketman! Thanks for telling me what the problem was, it may help other RVer's with their RV AC troubleshooting attempts.

      Randy

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      Steve 5 years ago

      Randy,

      I have an old Coleman rooftop unit in an 88 Gulfstream. The AC works fine, blows cold, and cycles as it should, but at way too high a temperature. With the built in thermostat turned all the way down, it cycles at around 78-80 degrees, so the coach never cools to a comfortable temperature. Do the thermostats fail in a way that just changes the ambient temperature of their trigger point? Is there an adjustment that I can make?

    • Randy Godwin profile image
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      Randy Godwin 5 years ago from Southern Georgia

      Hi Steve. This does indeed sound like a thermostat problem. I don't believe a built-in thermostat can be adjusted, but I may be wrong about that. It is a fairly simple replacement procedure in most cases with the cost of a new thermo usually pretty reasonable. You can look online for your particular Coleman model and get an idea of the price.

      Thanks for the question and feel free to ask for more info if needed.

      Randy

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      Rick 5 years ago

      I have an a/c unit in my camper turns on with just a hum ,no blower or air coming out . Reset the breaker still same any ideas?? Thanks Rick

    • Randy Godwin profile image
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      Randy Godwin 5 years ago from Southern Georgia

      Hi Rick! I suspect the starting capacitor--which gives a voltage boost to both compressor and fan until they get started--is bad. A relative easy and cheap fix to replace. I hope this solves your problem but if not, feel free to ask for more advice.

      Thanks for the question and for reading.

      Randy

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      Merle 5 years ago

      I have a older rooftop Coleman Mach in which I thought the fan motor shaft needed lubed so I did so. The shaft seems to spin freely while the unit is off. When the unit is turned on to the fan speeds, it always spins on high, most of the time on low also. When turned to cool, the compressor kicks on and everything seems OK. The problem occurs when the thrmostat cycles, either by itself or manually. When the compressor tries to kick back on, the fan motor slow down and eventually locks up tight, hums and gets quite hot. As soon as the unit is shut off, the fan shaft is free again. What do you think this could be? Thanks so much!

    • Randy Godwin profile image
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      Randy Godwin 5 years ago from Southern Georgia

      Hello Merle, sorry to take long to respond but I lot my internet connection last night. After consulting another AC repairman we believe either the capacitor(s) is bad or the winding inyour motor may be at fault. If you have a digital you multimeter you can use the ohm setting to check the capacitor.

      It should start out giving random numbers at first which should begin to slowly drop if the capacitor is good. You many have 2 capacitors, one for the fan and the other for the compressor.

      It' also possible the windings in the fan motor are shorting out and causing resistance to the motor, making it lock down when it gets hot. One more question, does the fan turn easily immediately after seizing up when you hut the AC down?

      It may be tonight before I get my home internet service fixed so it may be then before I can respond if you need more info.

      Thank for the question and for reading.

      Randy

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      Merle 5 years ago

      Hi Randy,

      Thanks so much for the response. Hope your internet comes back OK!

      This unit has three caps; one for the fan motor and one each for the Start and Run circuits on the compressor. It also uses a Positive Temperature Coefficient Resistor in series with the compressor Start cap. I have both digital and analog meters so I will check those capacitors and the PTCR resistor as well. Any idea what it should measure or is it variable? Looking at the schematic it seems to me that the problem almost certainly has to be with either the fan motor or its cap. There's really nothing else in that circuit except the speed selector switch. My problem is that I don't fully understand what is happening when the compressor kicks on that would cause the fan motor to lock up. Unless the compressor is drawing so much current that it's slowing down the fan motor to the point that it can't recover due to it having bad windings or its cap is bad, as you suggested. Does that sound feasible? When the fan locks up, it stays that way until you turn the A/C to OFF, and then immediately the shaft is free again. As long as the unit stays ON, that shaft is locked up. I may not get around to checking things out until sometime over the weekend but thank you for getting back to me. I actually don't need this running until mid-July but figured I better get moving on it before then!

      Thanks again,

      Merle

    • Randy Godwin profile image
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      Randy Godwin 5 years ago from Southern Georgia

      I'm still without internet, Merle! Sitting at a McDonalds now. LOL! The numbers should begin to decrease as you watch if the caps are good. Hope to be back online tonight if you need more info. Thanks for responding and ask for more help if you need it.

      Randy

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      Mike 5 years ago

      Hi Randy. Your site is great!

      I have a 22' Hi-Lo with a Duo-Therm roof AC. The air conditioner runs cold for hours on end when the temperature is in the 80s. However, in really hot weather it will run cold for about 30 minutes, and then suddenly will not.

      The blower itself keeps blowing, but no cold air comes out. The filter and fins are clean, and even if I try turning down the thermostat it still doesn't blow cold air.

      There is a lot of condensation run off that occurs -- but that seems normal on a hot day. Do you have any idea what I should be checking?

      Thanks for your help.

      Mike

    • Randy Godwin profile image
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      Randy Godwin 5 years ago from Southern Georgia

      This sounds like a lack of freon, Mike. As long as the temperature is not too high the unit can cycle with low freon pressure, but when it gets a bit higher the unit has trouble keeping up.

      these units normally do not have an port to check the pressure with and requires a bullet piercing valve to add more freon. to the low pressure side. This is something an experienced AC guy usually does unless you are familiar with the process.

      Thanks for the question and for visiting my RV repair articles.

      Randy

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      Linda 5 years ago

      have 1998 Chiefton. Had no power. replaced automatic transfer switch. had power to all but rear a/c. replaced energy management unit. have rear air on shore power but not on generator. wonder if new energy management unit will not allow rear a/c on generator but it is a 6500 onan so should have plenty of power to run rear a/c.

    • Randy Godwin profile image
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      Randy Godwin 5 years ago from Southern Georgia

      Hello Linda. I'm not sure how many amps the 6500 watt generator is rated for, but it is possible the energy management unit could be preventing the rear ac to operate if the amperage is not rated high enough. According to what I can find out the amperage may be a bit low for two A/C units.

      It looks like you generator is rated around 10 amps according to the online specs. I'm not sure how many amps your units pull but believe they would require a bigger generator for both of them to operate at the same time.

      I hope I'm wrong though! Thanks for visiting and for the question.

      Randy

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      Linda 5 years ago

      its a 50 amp generator and both a/c's worked before on the generator. The energy management will cut out the rear a/c if too many appliances are running and it gets too high on the amperage. That's the design. But the rear a/c is showing NO power to it on the meter when on generator. all runs fine on shore power.

    • Randy Godwin profile image
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      Randy Godwin 5 years ago from Southern Georgia

      Okay, thanks for the amp rating, Linda. I couldn't find this info while searching for your model generator. Yes, 50 amps is plenty as this is the most you can get at an RV park.

      Not being familiar with the energy management device or how your particular RV is wired makes it difficult for me to offer a solution. I assume you wired the new generator in correctly so I am stumped at this point! Sorry! I will check further for a possible solution though.

      Randy

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      Linda 5 years ago

      Randy, We have new transfer switch and new energy management system but not a new generator. Thanks for your help. I think we still have a wire crossed or loose in the ATS but we have a troubleshooting guide from Winnebago to go through.

    • Randy Godwin profile image
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      Randy Godwin 5 years ago from Southern Georgia

      Okay Linda. You might check the amps being created by your generator if it is an older model. It may not be operating correctly which could affect the output. Good luck on finding the culprit and thanks again!.

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      David 5 years ago

      Ihave duo thermo 13.5 roof ac cleaned evap and condensor low switch does not work med and high does work compressor makes a humming noise not sure if ti is on or not can hear it very good on low setting since fan does not blow on low. AC blow hot air

    • Randy Godwin profile image
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      Randy Godwin 5 years ago from Southern Georgia

      Hi David. In order to see if the compressor is working properly you will need an amp meter to check the amperage it is pulling. The start/run amps is listed either on the compressor or on a plate located on the unit inside of the shroud. Are you sure the freon is okay in the unit or that the capacitor is okay? If the capacitor is bad it may not be giving the compressor enough voltage to start it running. Any more questions you may have can be asked here if you need more advice.

      Thanks for reading.

      Randy

    • Melanie Matthews profile image

      Melanie Matthews 5 years ago

      Randy,

      I have been reading your posts. Wonderful stuff. I have a 92 motorhome with a Dometic ac only roof cooler and am relatively new in the rv world. When I turn the thermostat on to cool and the setting to auto, the fan immediately kicks on. After a couple of minutes the compressor also kicks on and runs for about 10 min. Then both the fan AND the compressor suddenly kick off and stay off even though the thermostat is demanding cool. The thermostat lights remain on but no fan power and no compressor. It is not tripping any breaker and if I turn the switch to off and back on to cool, the fan will immediately restart, but no compressor. After waiting several hours/a day, I can repeat the same process and get the same result. I have followed your advice to others and tested the capacitor. It tests normal. I have cleaned the coils. I have felt for air leaks in the return air opening that might cause a short cycle. Do you have any advice on what to do next? I'd really appreciate anything you could share.

      Thanks,

      Chris

    • Randy Godwin profile image
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      Randy Godwin 5 years ago from Southern Georgia

      Hello Melanie, sorry i took so long to respond but your comment was caught by HP's spam filter and I just found it.

      This could be a thermostat problem, Melanie. Everything else seems to be okay. it is also possible the freon charge may be low causing the short cycle. Let me check with my main AC guy and get back to you. I'll try to do this tomorrow.

      Randy

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      Phil 5 years ago

      I just bought a new fleetwood discovery with three units. All work fine on generator when we are parked. But the back two units do not cool while we are travelling in the heat of the day.

    • Randy Godwin profile image
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      Randy Godwin 5 years ago from Southern Georgia

      Hi Phil! I assume you are referencing a motorhome instead of a tow behind RV. I'm sorry, but I cannot advise you on this problem because I have no way of knowing about your particular 3-unit system. It may be some sort of energy control coming into play in your RV. Obviously, if the units work while parked using the generator they should do so while en route. I'd really like to know what you find out about this if you'd be so kind as to tell me.

      Randy

    • Melanie Matthews profile image

      Melanie Matthews 5 years ago

      Randy,

      Thank you for the help. I will move in the direction of the thermostat. If you can get any additional info to share from your main AC guy, that would be greatly appreciated. I'll let you know if it's the thermometer

      Chris

    • Randy Godwin profile image
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      Randy Godwin 5 years ago from Southern Georgia

      Will do, Chris :)

      Randy

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      Gladys 5 years ago

      Hi where can i take my Air O Space BED for repair

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      CGB 5 years ago

      I had a question regarding a Coleman 13,500 roof top A/C unit. I just paid to have the thing serviced (i.e. clean the coils, filter, etc.). I just got it back and now it keeps tripping the breaker. It never did this before the A/C service. The guys that performed the service said the unit was from the late 1980s. When I took it in the volt meter would read between 110 and 120 volts. When the compressor kicks in the voltage drops to below 100 volts. So I thought maybe cleaning the coils and air filter would help, but it seemed to make matters worse. As a side note it was around 103 degrees out today when it started tripping the breaker. I am dredding that it is the compressor going bad. It does cool fine or at least fair until the circuit breaker trips.

    • Randy Godwin profile image
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      Randy Godwin 5 years ago from Southern Georgia

      Hello CGB. You probably need to use an amp meter to check the start/run amps on the compressor to rule it being the culprit completely out.

      It does sound as if it may be the problem though since the coils are clean and the air flow over them is good. And the high temps you're experiencing is making the unit run extra hard so it does sound like a struggling compressor. But check the amps to be sure before giving up on the old unit.

    • profile image

      CGB 5 years ago

      Thank you once again for an extremely prompt response and.assistance.

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      James 5 years ago

      Randy,

      I have a Savoy SL, about 6 yrs old. AC is Coleman Mach. It was working fine yesterday. Preparing to go to Galveston in the AM. This morning, AC would make a one click noise and not come on. I changed the batteries in remote, but nothing. Have never serviced the AC. Any ideas? This happened one other time when I set up at a camping spot. I pushed the Emergency AC button on the unit inside camper and it started. Of course, it appears that this button just by passes the remote. Thanks for any suggestions.

    • Randy Godwin profile image
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      Randy Godwin 5 years ago from Southern Georgia

      Good morning James! Did the Emergency AC button work this time? If so, it may be the remote or the sensor but then, if the unit made a click it would appear the remote is still operative. Usually if the start capacitor is at fault the compressor and/or the fan will at least hum and try to start. Another question--does your AC unit have a wall mount thermostat?

      Randy

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      James 5 years ago

      Thanks for a quick reply! Still does not work. I do not hear any humming noise. I only have a hand held remote. Correction, it is a Carrier unit. I live just east of Dallas and it has been in te 100s, past 2 days 105. Camper is in my new barn. Had AC on to pack 3 days ago and was working fine. Then about 2 days ago turned it up to 90 just to keep it from getting too hot. Last night decided to turn it off. Then, this AM is when it would not come on. Just took off the cover on roof. Only unusual thing, two small tubes appeared to have a hard rubber coated and it had melted a table spoon off of the tube. Fan turned freely and made no noise. Coils where clean. Thanks.

    • Randy Godwin profile image
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      Randy Godwin 5 years ago from Southern Georgia

      Hopefully it is a bad start capacitor(s), James. Even if the compressor is bad the fan should try to turn. Are you sure you are getting power to the unit? It isn't uncommon for a breaker to go bad. There could be a bad relay or thermostat which will not allow the power to reach the unit. As you can see, there are several possibilities to consider.

      An amp meter is needed to check the compressor if you can round up one. I hope this helps.

      Randy

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      jparker66 5 years ago

      Thanks. I will do more checking.

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      Mike 5 years ago

      We have a new to us 1997 Montana Class C. Took it to a state park and all seemed fine. Then we noticed that every time we turned on a light the A/C would turn off. Even if we opened the door to the fridge the A/C turns off. Any ideas where I could begin? After a few minutes the air would come on again and then we would have to be careful not to turn on a light again. Thanks, Mike

    • Randy Godwin profile image
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      Randy Godwin 5 years ago from Southern Georgia

      Hey Mike. If you have a wall mount thermostat which controls the A/C it operates on 12 volts DC, the same as your lights, fridge, vent fans, etc.

      It's possible the power converter is not keeping the battery(s) charged enough so that when you turn on a light or open the fridge door it is affecting the voltage to the AC thermostat enough to cause it to stop operating correctly.

      Check the fluid level in the battery(s) and the voltage produced by the converter to determine which is at fault. The converter should produce at least 13 volts when a 12 volt light or some other 12 volt item is in operation. Also, it is possible the battery(s) are old and not capable of storing a full charge any longer. I hope this gives you an idea of what to check for. Thanks for reading and for the question.

      As always, feel free to ask for more advice if needed.

      Randy

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      jparker66 5 years ago

      Randy,

      Feel foolish. Breaker was tripped! Now I wonder, Why? Do these units require the freon to be checked? Does Carrier still make units for RVs? If I change the AC unit out, what do you recommend? Appreciate the answers and help. JP

    • Randy Godwin profile image
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      Randy Godwin 5 years ago from Southern Georgia

      Ha JP! This is good news so don't feel bad. Yes, Carrier still makes AC units for RVs, but actually the Coleman units are the best for the money and will fit right back in place of your Carrier unit.

      There isn't any way to check the freon level without installing a piercing valve but you can usually tell when the freon is low when the unit stops cooling efficiently. Here is an article telling how to intall such a unit.

      http://hub.me/a5JqJ

      I hope this helps you out.

      Randy

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      GTD 4 years ago

      I have a carrier vented system with wall remote with the a/c running the furnance also started running at the same time could this be a failed circuit board in the a/c?

    • Randy Godwin profile image
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      Randy Godwin 4 years ago from Southern Georgia

      GTD--This sounds more like a bad thermostat than the circuit board. You didn't say if the AC and furnace were two separate units or if the AC has a heat strip to furnish the heat. If it has a heat strip it may be a bad control switch. More info would be helpful.

      Randy

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      GTD 4 years ago

      The a/c and the furnace are two separate units which are controlled by the same remote . The a/c works fine but with the temp outside inthe 90's the furnace came on and both systems were running at the same time, I had to remove the fuse to shut down both a/c and heat.

    • Randy Godwin profile image
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      Randy Godwin 4 years ago from Southern Georgia

      This still sounds like a thermostat problem, GTD. The thermostat should control both units and not the remote which only sends a signal to it. Is there a wall mounted thermostat? If so, I would check it. Especially if it has a manual setting. The thermostat should not allow both units work simultaneously.

    • profile image

      GTD 4 years ago

      there is no wall thermostat only a hand held remote to set your temp and select fan, a/c, or furnace modes. I guess the thermostat is in the ceiling mounted a/c unit.

    • Randy Godwin profile image
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      Randy Godwin 4 years ago from Southern Georgia

      Sorry I cannot be of more help, GTD. It could be the remote if it controls both units. Without being there to check the unit I cannot be more specific.

      Randy

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      Byron 4 years ago

      I have a 2004 Jatco Flight. The A/C is coming on, fan and pump. The pump will start, run for a few seconds then shut off. 30-45 seconds later it will cycle again. I can feel a copper line get cold when the comp. cycles. I checked the capacitor as you have instructed. Reading is high then goes down but not sequentially. It goes right from high to low and the same when reversing the leads. I also watched the lights and they do not dim when the pump cycles on. Mine has a start up capacitor and a run capacitor. I'm thinking the run one is bad. Any thoughts?

    • Randy Godwin profile image
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      Randy Godwin 4 years ago from Southern Georgia

      Hey Byron! Yes, this does sound as if the RUN capacitor may be bad. Either that or you are low on freon. I favor the bad cap. though. Hope this is indeed the case as it's an easy fix. :) Thjanks for reading and the question.

      Randy Godwin

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      B.K. Powell 4 years ago

      I have a 2005 mountaineer camper, I cannot run the air and microwave at the same time without tripping the breaker. It is the same with a hairdryer and air . This happens on my private lot and campgrounds, you think a weak breaker is the problem

    • Randy Godwin profile image
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      Randy Godwin 4 years ago from Southern Georgia

      Hello B.K.--Yes, apparently the microwave and hair dryer are pulling on the same breaker as the AC. You may wish to change the breaker to a slightly higher amperage to prevent it from tripping so easily or else put the AC on a circuit by itself if it isn't already.

      Randy

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      John 4 years ago

      Randy, I have a 2008 Montana fifth wheel. The a/c fan kicks on when you turn the thermostat to a lower temp, but the compressor doesn't kick on and no cold air comes out the vents. The thermostat is digital and runs the furnace and the a/c. The conection in the thermostat is like a phone line connection. When you unplug it, the fan turns off. Last year it worked fine. Not sure where to go.

    • Randy Godwin profile image
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      Randy Godwin 4 years ago from Southern Georgia

      Hi John. There are several possibilities as to the problem you are encountering with your unit. The simplest and most inexpensive fix is the compressor starting capacitor being at fault. You can check it with a digital multimeter as explained in the answers above. A bad thermostat is also a possible problem as is a bad relay. I'd suggest checking the capacitor first and then go from there. Hopefully the compressor is not at fault. Ask for more info if needed and thanks for the question.

      Randy

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      John 4 years ago

      Thanks Randy, any idea where the capacitor is located? On top of the roof or can it be reached from inside the trailer?

      Thanks Randy

    • Randy Godwin profile image
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      Randy Godwin 4 years ago from Southern Georgia

      Sure John. The shroud covering the unit removes easily and will give you access to the capacitor. The heavy wires leading from the compressor should lead you right to the caps. With the multimeter set on OHMS the caps should post high random numbers which quickly descend in value if they are working correctly. Good luck!

      Randy

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      John 4 years ago

      Thanks again Randy, I'll give it a try.

    • Randy Godwin profile image
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      Randy Godwin 4 years ago from Southern Georgia

      Glad to help, John. If you need more info feel free to ask. :)

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      YumaDune 4 years ago

      I have a 2003 Fleetwood with two Coleman Mach AC's. One works fine and the doesn't. I pulled the inside grille and the fan turned hard. I replaced the fan motor and now the fan blows fine. The compressor does not start. I checked for power at the compressor..nothing. I replaced the start and run capacitors and still no compressor start. I checked the schematic and it shows no relay?? I'm stumped!

    • Randy Godwin profile image
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      Randy Godwin 4 years ago from Southern Georgia

      Hello YumaDune. Do you have a wall mount thermostat which controls both rooftop AC units? Is it possible the A/C signal is not getting from the thermostat to the malfunctioning unit?

      Randy

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      YumaDune 4 years ago

      Found the problem...stupid is as stupid does... wire off on the PC Board!!

    • Randy Godwin profile image
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      Randy Godwin 4 years ago from Southern Georgia

      Ha Yuma! Better a stupid mistake with an easy fix than an expensive problem any day. LOL! I'm guilty of many of these as are most of us. Glad you found the problem and thanks for the question and for telling us what you found out. I'll keep this is mind on similar questions in the future. :)

      Randy

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      watash1 4 years ago

      Hi Randy, My rear heat pump on my m.h. only blows cold air not matter what the temp. and unit has been cleaned. Could this be the reversing value and how do I check.

      Or any other suggestions

      Thanks watash

    • Randy Godwin profile image
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      Randy Godwin 4 years ago from Southern Georgia

      Sorry watash, I'm not really familiar with heat pump systems on RVs.

      Randy

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      Davenash 4 years ago

      Hello,

      Very good information here. I have a question and hopefully you can help. I have a Coleman Mach unit about three years old. It has a heat strip in it too. The compressor will start and run for 8 to 10 minutes then shuts down and won't restart for hours on end, the fan runs fine.

      I've noticed when this happens the heat strip no longer works as well. You can usually hear it kick in and out while turning the thermostat on the a/c unit but nothing until the compressor starts working again. The compressor gets warm while running but not hot by any means, one refrigerant line warm/hot and the other cold. Filters and condensor are clean. The controls are mounted on the unit. A couple times even though the breaker wasn't tripped (fan ran) I turned it off and then back on and the problem repeated, compressor runs 8 to 10 mins. on then off however this doesn't reset it at all times, sometimes you just have to wait it out. I'm confused, any help would be appreciated. Thank you.

    • Randy Godwin profile image
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      Randy Godwin 4 years ago from Southern Georgia

      Hi Dave! It sounds as though the compressor may be overloading and tripping a relay which may also affect your heat strip power. I hope I'm wrong but the only way to really eliminate this possibility is to check the START/RUN amps on the compressor with an amp meter.

      However, I will check with my go-to man for other possibilities in the meantime. I'll try to post what I find here as soon as possible. thanks for the question and for your time.

      Randy

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      Davenash 4 years ago

      Randy,

      Thanks for the quick response. I know I have a volt/ohm meter but not sure about an amp meter, I'll have to check. Where might this relay be located? Could it possibly be weak or bad? When you check with your go-to man any information would be great and thanks a lot for your time.

    • Randy Godwin profile image
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      Randy Godwin 4 years ago from Southern Georgia

      You may have to borrow or "rent" an amp meter to check the compressor, Dave, Have you checked the capacitor(s) on the unit? Sometimes they get too hot and won't allow the compressor to start or continue to operate correctly. I'll get back to you!

      SSSSS

    • profile image

      Davenash 4 years ago

      Capacitors not bulged or leaking, the start capacitor was warm but not hot, the run capacitor cool. I think I can round up a meter if needed for sure, either rent or possibly barrow. Thanks again Randy.

    • Randy Godwin profile image
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      Randy Godwin 4 years ago from Southern Georgia

      Good luck Dave, and I'll see what else I can come up with.

    • profile image

      Davenash 4 years ago

      Perhaps I could replace both the start and run capacitors (not too expensive) and if it still has the problem condemn the compressor through process of elimination? I'll have the cost of renting the amp meter anyway. Thanks for all the info, I'll check back in tomorrow.

    • profile image

      yelnats69 4 years ago

      Hi Randy,

      I have a coleman Mach unit that everything seems ok but it simply does blow cold, The RV is in England, and Air Con is rare there, I think it may be just low on freon?? what type of freon does it use?

      where can I get instructions on how to recharge/top up unit?

      I was considering installing valves into the system to make service easier, I have accss to brazing/welding /soldering tools . In England you do not a need a license to work on A/C and feon.

    • Randy Godwin profile image
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      Randy Godwin 4 years ago from Southern Georgia

      Hello yelnats69--If you are sure the compressor is working correctly you can purchase what is know as a piercing valve. This easy to use--and very inexpensive--little item is installed on the low-pressure line from the compressor by attaching it using the two screws to force a hollow needle which pierces the line and has a twist valve to allow freon to be introduced to the system.

      After charging the system the valve can be left for future charging or soldered closed. I'm nor sure what type freon you have access to but it should be easy to find out. Thanks for the question and good luck with your repairs. :)

      Randy

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      Davenash 4 years ago

      Randy,

      Problem solved. Manual heat/cool thermostat issue located on ceiling mount. Bad thermocoupler. One for the record books.

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      Randy Godwin 4 years ago from Southern Georgia

      Great news, Dave. Glad you found the problem and thanks for relating the solution. Perhaps it will aid others with the same RV AC problem. Thanks for your input on this.

      Randy

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      HRPapaD 4 years ago

      Hello Randy,

      I have an HR MH with two Duo-Therm Penguins. My wife and I spend our vacations in hot climates. My issue is the front AC is working fine and the rear AC runs fine in the daytime but during the night at some point the set temp is satisfied the fan will come on and then the compresser will kick in and run for maybe 10-15 seconds then kick back off. A little bit later it comes on again, 10-15 sec. This will continue through the night. Once the sun comes up it runs fine again. I can reset the thermastat to colder and it will run until satisfied once and the process starts over again. Any sugesstions on how to proceed?

      HRPapaD

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      Randy Godwin 4 years ago from Southern Georgia

      @HRPapaD--It is possible a low freon charge is the culprit, but it seems strange the unit will perform normally during the daylight hours. Are both units operating on the same thermostat or do they have separate controls?

      I'll consult with my go-to guy on your problem as I'm curious about the actions of the unit myself. I'll report back what I find out shortly. Thanks for the question and for reading! :)

      Randy

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      HRPapaD 4 years ago

      Randy,

      Thanks for the fast response. Both AC's work from one Thermostat with a setting for each i.e. AC1 and AC2. This has accured on two vacations so it seems to eliminate an aberration. It seems, if it was low on freon the second vacation it would be so low it would not even work. Don't get me wrong, adding freon is a simple fix if the leak can be located and repaired easy. I thought maybe it was freezing during the night. Which could be possible, I guess, if it is low on freon.

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      Randy Godwin 4 years ago from Southern Georgia

      Perhaps you are correct about the low freon suggestion, Papa! I'll get back to you probably tonight after I consult with my guy. Thanks for your patience. :)

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      HRPapaD 4 years ago

      Randy

      Thanks for all your assistance on trouble shooting my AC. Were you able to find out anything more on my daytime/nighttime issue?

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      Randy Godwin 4 years ago from Southern Georgia

      Sorry to take so long, HRPapaD. I'm supposed to hear from my man tonite as I just got hold of him.

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      HRPapaD 4 years ago

      Hello Randy, did you ever get any suggestions on my AC issues?

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      Randy Godwin 4 years ago from Southern Georgia

      Not yet and I am indeed sorry about that, HRPapa. I called the guy right after we last communicated and, believe it or not, he was night hunting for wild hogs. I briefly told him your situation but he has yet to get back to me. I'll certainly remind him today. Again, my apologies for taking so long!

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      HTPapaD 4 years ago

      Thanks Randy, I do appreciate your help as I am currently stumped on this issue.

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      Randy Godwin 4 years ago from Southern Georgia

      @HRPapa--Finally heard from my guy. He said if the coils are clean on your A/C then it is more than likely a low freon charge causing the problem. Have you noticed if the coils are freezing up at night when the temps are cooler?

      I hope this info helps, but if not, let me know. I'd like to find out what's causing the problem myself. :)

      --RG

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      HRPapaD 4 years ago

      Thanks for your response. I have not taken the cover off as yet but I will and check the coils for cleanliness. I certainly hope that is the issue. I will respond when I learn more.

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      Randy Godwin 4 years ago from Southern Georgia

      Great, HRPappa! I hope a simple cleaning solves the problem and it certainly wouldn't hurt the unit's efficiency. Please let me know what you find out. Thanks!

      --RG

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      jerry 4 years ago

      replacing Duo Thermo analog thermostat with a Coleman Mac Digital thermostat. Most wires match to what is on the analog except Blue on Coleman is for -12 volts and the red is for +12 volts. duo thermo has red +7.5 and green gnd. Can I replace the analog thermostat with the Coleman digital.

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      Randy Godwin 4 years ago from Southern Georgia

      Hi Jerry. I'm afraid I cannot give you an answer for this question without consulting with my go-to guy. I'm puzzled by the 7.5 numbers as most RV thermostats operate on 12 volts. I'll try to find out for you though. Thanks for the question and for reading, Jerry! :)

      Randy

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      jbothjx 4 years ago

      Thanks for the reply Randy I'll check back in a couple of days.

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      Randy Godwin 4 years ago from Southern Georgia

      Fine Jerry, I'll see what I can find out for you. :)

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      HRPapaD 4 years ago

      Hey Randy, just wanted to let you know, I cleaned both condensers and they were not that bad considering the MH is an 05 and they had never been cleaned. Both AC's came on after the cleaning, but, unfortunately the temp here is not warm enough to test the night time condition of not starting the next cycle after about 15 seconds.

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      Randy Godwin 4 years ago from Southern Georgia

      Hello again, HRPapa! I'm glad it wasn't a difficult job to clean the coils and I hope this will solve your problem. If not, please let me know and we'll check other options.

      Randy

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      jbothjx 4 years ago

      Randy any information on switching the Duo Thermo analog with the Coleman digital Thermostat? Just checking

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      Randy Godwin 4 years ago from Southern Georgia

      Sorry jbothjx, I'd forgot about checking for you. It's been a rough few days around here. I'll get right on it! :)

      --RG

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      Ian 4 years ago

      I have a 2006 Gulfstream Cavalier. It is an emergency living unit with a rooftop A/C. This morning, after running perfectly for a couple of days, it turned on and immediately and repeatedly kicked on and off. I turned off the unit not to "burn it up". After about an hour, I turned it back on and it ran correctly for the first cycle. When it turned on the second time the problem started again. The compressor turns on and it blows cold......any ideas on what it could be?

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      Randy Godwin 4 years ago from Southern Georgia

      Hello Ian, this sounds like your AC unit is low on freon. Right before an AC unit runs out of freon it will blow really cold air. A low charged unit will often cycle on and off as you describe yours doing. I hope this info helps you out.

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      Brian Conley 4 years ago

      I live between Savannah GA and Statesboro GA. I love this area.

      Last year when I got to my campsite, I tried turning on my Carrier Air V AC unit. It would run for about 2 or 3 minutes, then shut off and have a green light blinking 5 times. I was told that it was the compressor.

      Fast forward to today, I just received me new Dometic roof top unit. (I was told by camping World to call them, so I called and they told me the correct Roof unit to work with my interior Air V unit, and also a conversion kit). I installed it today. Very easy to do once I got it on the roof. But now I am having the same problem. The unit will come on, run for 2 or 3 minutes, then shut off and blink 5 times.

      I can run just the fan without any issues, but as soon and I turn on COOL, it starts messing up. Any ideas?

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      Randy Godwin 4 years ago from Southern Georgia

      Hello Brian. Just off the top of my head I would guess it is a voltage or a thermostat problem. Is this a single AC unit operating on a wall mounted thermostat, or is the controls located on the AC itself?

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      Brian Conley 4 years ago

      It is neither. The Carrier unit I have uses a wireless remote to turn it on and off and set the temp. I installed new batteries in the remote and it seems to work fine.

      There is a small yellow thing on the interior AC unit portion that is called a "Thermistor". That is the correct spelling.

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      Randy Godwin 4 years ago from Southern Georgia

      The controls are located inside the unit then, Brian. First I would consult with the Carrier people before doing anything to void the warranty. They should be able to tell you what the problem is. Sorry I cannot be of more help to you at this time.

      Randy

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      Ian 4 years ago

      Thanks Randy,

      I friend of mine mentioned a low pressure switch, so that goes right along with your suggestion of freon. Thanks again!

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      Randy Godwin 4 years ago from Southern Georgia

      No problem Ian, I hope recharging the unit solves the problem. :)

      --RG

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      Brian 4 years ago

      Randy, carrier no longer supports these units and will not talk to anyone about them.

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      Randy Godwin 4 years ago from Southern Georgia

      Wow, Brian. Will not talk to anyone about them? Let me ask around to see if I can find out something for you. Never heard of this problem.

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      Brian 4 years ago

      I am planning on taking my camper to Camping World tomorrow. I called Dometic and they told me to take it in there so they could cover any warranty work, if needed.

      So I suppose I will have to bite the bullet and pay someone else to fix it.

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      Randy Godwin 4 years ago from Southern Georgia

      Sorry Brian, I haven't found out anything new about your problem. I agree with Dometic that they need to cover the warranty work. Let me know if you find out what the problem is and I can pass it on to others. My bet is that it's something in the thermostat.

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      jbothjx 4 years ago

      checking back in Randy, any news concerning the thermostats/

      thanks

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      Randy Godwin 4 years ago from Southern Georgia

      No, I'm afraid I've come up with a dead end on this one so far, jbothjx. I have one more place to check though.

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      jbothjx 4 years ago

      ok, I'll check back in a couple of days

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      Keith Higgs 4 years ago

      In your experience can Coleman Roof top sealed units be successfully recharged using either piercing valves? I have had some tell me they will always leak? The RV service guy said with the cost of Freon and the labor you might as well buy a new AC unit! Ouch, hoping to be able to charge the unit.

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      Randy Godwin 4 years ago from Southern Georgia

      Hello, Keith. It depends on where and how much the unit is leaking. A piercing valve is relatively cheap and easy to install but I do know RV service people tend to be very overpriced.

      Have you inspected the unit with the shroud removed to see if there is a tell-tale oil stain where the leak occurred? If not it may be worth it to shoot a little freon containing dye into the AC to see how bad and where the leak is.

      No, they don't always leak.

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      Keith Higgs 4 years ago

      Thanks for the quick response Randy. I am going over to the lake this afternoon to do some troubleshooting and I will pull the shroud and see if I see anything. I was going to check the see if I can hear the compressor kick in and try to check the amp draw as well. Any other suggestions to check would be appreciated.

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      Randy Godwin 4 years ago from Southern Georgia

      Okay Keith, might as well check the capacitors while you have the shroud removed. If you have two capacitors--one each for the fan and compressor--the compressor capacitor may not be starting it up properly.

      To check the caps, simply remove the wires--careful they may be charged--and check them with a multimeter. If they are working properly you will read random numbers which should slowly decrease when touching the probes to the terminals.

      Let me know what you find out if you need more info. Thanks for the questions!

      RG

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      jbothjx 4 years ago

      Just to let you know I found out that the Duo Thermo sends ground to all points, ( fan, air, heat) the coleman mac sends voltages so they are not compatible with that given information.

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      Keith Higgs 4 years ago

      Well I found the problem without even having to get my multimeter out. I turned on the unit, heard the compressor kick on but no cold air. So I pulled the inside return grate which by the way had no filter(previous owner did not put one in) and I could see that the condensor coils were about 3/4 blocked with dust and dirt. It was so thick you could peel it off like a sheet of paper in places. I cleaned the coils real good with a tooth brush (that's all I had) turned the unit on and the compressor kicked in, within a minute the air began getting cooler and the longer it ran the colder it got. So problem solved. Picking up some filters today and should be good for the summer. Thanks for the help.

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      Randy Godwin 4 years ago from Southern Georgia

      Hey Keith. So pleased you fixed the problem without too much trouble. There are some real effective coil cleaners just for AC condensers and coils. I recommend cleaning them good every other year because the filters doesn't catch all of the dust during camping season.

      I've other RV repair articles on this too if you need anything else. Thanks for the question and for your time relating what the problem was.

      RG

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      Randy 4 years ago

      Hi, we recently purchased a 1998 Camplite Damon pop up camper. It has a ceiling ac unit. We hooked the power up by extension cord at the house to test everything. All works except the ac unit wont even turn on at all. Any ideas?

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      Jaymie 4 years ago

      We have a brand new coachmen catalina... This is our 3rd time using it have never had to use the air. We tried it today and it doesn't kick on, no noise or anything when we turn it to auto with the temp all the way down. The fan does work thought. We have it hooked up to electricity and everything else works fine. Any idea what it wrong with it?

      Thanks

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      Randy Godwin 4 years ago from Southern Georgia

      @the 1998 Camplite Damon--a bit more info would help me decide what the problem is. Have you checked the breakers to see if power is actually getting to the unit? Does it make any sound at all as if it is trying to start up?

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      Randy Godwin 4 years ago from Southern Georgia

      Hi Jayme. It is possible the capacitor which starts up the compressor may have gone bad. Some units use a separate cap for the fan motor and the compressor. I think I listed the way to check capacitors in this article. Anything else you can tell me about the unit?

      __RG

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      Randy 4 years ago

      No it doesn't make a sound or do anything. We have checked to make sure the breakers aren't threw and they appeared fine. There are also 4 fuses beside the breakers. Would they have anything to do with it?

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      Randy Godwin 4 years ago from Southern Georgia

      @Randy--If they are glass fuses they probably control the 12 volt lights and fans in the camper. There is a possibility there is a bad connection in the junction box located inside of the ceiling assembly. You can also check to see if power is reaching the unit in the junction box. You really need to use a multimeter or test light to be sure if the breakers are good also.

      If you have a wall mount thermostat the fuses would control it and possibly keep the signal from getting to the unit if a fuse is bad. Checking the power in the junction box is the simplest way to ascertain the unit is at fault.

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      Randy 4 years ago

      Ok thanks! Would the junction box be located on the inside ceiling part of the camper or the outside roof?

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      Randy Godwin 4 years ago from Southern Georgia

      Usually the juntion box is located in the inside ceiling assembly which can be accessed by removing four screws. There will a cover which hides where the unit is connected to the line going to the breaker. Be careful as always if the line is hot.

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      Randy 4 years ago

      Thanks so much for your help! We'll try that

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      Randy Godwin 4 years ago from Southern Georgia

      No problem! Feel free to ask for more info if you need it. It just seems strange that neither the fan motor or compressor won't start, but it is possible. Please let me know what you find if you don't mind.

      Randy

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      Randy 4 years ago

      Took the cover off and checked the 2 cords in the junction box with a volt meter. It's not registering any power on the volt meter with touching it to the cords.

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      Randy Godwin 4 years ago from Southern Georgia

      I suspected as much because usually if power is getting to the AC unit either fan or compressor will try to run. Go back to the ac breaker and test both sides of it to see if power is getting through it or to it. You should trace down the problem in this manner, but if you need more help please ask.

      --RG

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      Randy 4 years ago

      Ok will do. Is it more likely to be the cord bad or the breaker?

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      Randy Godwin 4 years ago from Southern Georgia

      If you're not getting power to the junction box then I would suspect the breaker which supplies electricity to the AC unit. I assume the thermostat is mounted on the unit itself and not on the wall. If it is a wall mount then check the 12 volt breakers or fuses since the thermostat may be controlled by the 12 volt system.

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      Randy 4 years ago

      The thermostat is on the actual unit. I'm gonna give the breaker a try and i'll let you know something. Thanks for all your help!

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      Jaymie 4 years ago

      Thanks for your input! I don't really know anything about campers or air conditioners. We have it parked on a lot by the river so we only go out on the weekends. We're trying to get some one from the place we got it to come look at it. Thanks again! Great page!

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      Randy Godwin 4 years ago from Southern Georgia

      Sorry I can't help you if you don't know how to check the breaker, Jaymie. Thanks for the question anyway! :)

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      Chris 4 years ago

      Hello! I have a 1996 Coachmen camper. We took it out for the first time this weekend and the air worked great; however, when it got cool enough I would turn it off only to find out that when I turned it back on all I could hear was a faint hum. no fan blowing.. after a few tries it would cut on and work great... until I cut it back off :( I have tried to spin the fan and it is very hard to spin with my hand even after soaking it down with oil. Does it sound like I need a new fan motor. I would assume, but people keep telling me that my capacitor would be the reason my fan motor would not work??? So, fan motor or fan motor and capacitor?? Also, there's no nests in the fan. THANK YOU!!

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      Randy Godwin 4 years ago from Southern Georgia

      Hello Chris. The fan should spin easily if you try and turn it when off. It does indeed sound as if the fan bearings are worn and are getting hot after running it for a bit. A capacitor is relatively inexpensive if you wish to try that first as sometimes they do affect the starting up procedure.

      It seems odd that the fan would be that hard to start just sometimes. If you have two caps you may swap them out and determine if it is the capacitor or the fan motor before getting a new fan motor. Hope this helps. You may also check the cap with a ohm meter. Unplug the wires and check it with the meter set on high ohms. You should get a random number which decreases in value if the cap is good.

      Thanks for the question!

      RG

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      Randy 4 years ago

      To follow up on my campers ac not working. We wasn't aware that it actually plugged into an outlet inside the camper. Can't find the power cord anywhere to plug in, any idea where to get a replacement?

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      Randy Godwin 4 years ago from Southern Georgia

      No power cord? Are you sure is isn't wired into the junction box beneath the ceiling assembly? You can simply make your own cord as this is 110-120 volt AC. I wonder how the former owner had it rigged?

      Have you checked to see if an electrical source is available in the roof of if you can snake a line to the AC? A cord on a small home 110 volt window AC if you can find an old one somewhere.

      Let me know the outcome if you will.

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      Randy 4 years ago

      Unless its tucked up in there. We're gonna have to take it back apart one day when the rain stops. There is a ceiling outlet close to the unit.

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      Randy Godwin 4 years ago from Southern Georgia

      Either the line or the cord will hook to the AC in the junction box reached by merely removing the screws from the ceiling assembly inside the RV. It won't leak around the unit simply checking the junction box.

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      Randy 4 years ago

      I guess I'm just confused, of course I don't know anything about them but I can't figure out why we got no voltage wjen we checked the junction box with a meter?

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      Randy Godwin 4 years ago from Southern Georgia

      Are there wire nuts--little colored twist-on connectors- hooking 2 wires together in the junction box? If there are only 3 wires--a black wire and a white wire, along with green ground connected the box--then you may indeed require a power cord. If there are wire nut connections then the power is possibly off in the breaker panel on the breaker supplying power to the AC. This breaker could be bad or tripped. Re-trip all of the breakers if you haven't tried this yet. I just haven't heard of a plug in roof mounted AC so far. Could be, though!

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      Randy 4 years ago

      Yeah we have tried all resetting all the breakers and still no power. After taking the cover off, there is a wire running over to the outlet on the ceiling from the air conditioner. Also there is a matching outlet down near the breaker box. Some one suggested that may have to run a cord between the 2 outlets to power the unit. Also in the junction box there are 3 cords in wire nuts and I do believe there is a ground.

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      Randy Godwin 4 years ago from Southern Georgia

      I wish I could the way it is wired as it sounds interesting. If the outlet is dead then you could try running a cord between the outlets but the cord would have to have male connectors on each of the cord. I can't recommend this without seeing it though.

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      dgiroirects 4 years ago

      Have a Cougar 5th wheel with a Dometic AC Unit. The unit runs but it trips the breaker during the hotter parts of the day. It will run all night fine but sometime between 2 and 5 pm it trips breaker. I changed the breaker and it worked for about a week and started again. Any thoughts on what to check next.

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      Randy Godwin 4 years ago from Southern Georgia

      @dgiroirects--Have you cleaned the coils yet? Sometimes dirty coils will cause the breaker to trip when the unit is working too hard to keep the air cool.

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      robert 4 years ago

      just replacteed fan motor on my coleman ac unit ran a extensoin cord to see if it works . everything ran fine .but it dosent seem to get as cold as it did. wondering if the extension cord would not make it get as cold as it did

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      Randy Godwin 4 years ago from Southern Georgia

      You must have a heavy duty extension cord to keep the compressor operating efficiently Robert. This could well be the problem. The compressor may not be getting enough amps for it to cycle long enough. I assume you checked the coils when replacing the fan motor to see if they were clean? I'd bet it is the extension cord. Thanks for the question and ask for additional info if needed.

      Randy

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      cory 4 years ago

      Hi...i have a colman mach on my travel trailer and i cleaned the coils and now i turn the unit on and it cools until it reaches where the termostat is set and i never comes back on...i have to reset breaker and it will come back on..it never did this until i cleaned the coils...when it shuts off it kills the blower and all fuctions of the ac..please help

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      Randy Godwin 4 years ago from Southern Georgia

      Hello Cory, I've never heard of cleaning the coils causing any such problems as you've described, but then, I learn new things every day I haven't heard of before. Let me get in touch with my go-to guy and I'll get back to you tomorrow. This problem is intriguing to me. Thanks for the question.

      Randy

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      CONSTRUCK 4 years ago

      Randy , I have about the same problem that Malanie had except I have no wall thermostat, only the controls on the ceiling part of the unit. I have an older Duo Therm Briskaire and my problem is I turn it on and it runs fine for 45 minutes to an hour, then it shuts down. I can hear the compressor humming. I switch the unit off and wait 15-20 minutes and turn it back on and everything runs fine for another 45 minutes . Any ideas?

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      Randy Godwin 4 years ago from Southern Georgia

      Hey CONSTRUCK, if you have access to an amp meter you can check the start/run amps listed either on the compressor, or on a plate close by. It sounds as if the compressor is overloading for some reason.

      While you have the shroud removed you can examine the coils and clean them if they need it. It is possible the fan is at fault also as older model RV AC units are not used frequently and sometimes the bearings will seize up after running long enough to get hot.

      You can also check the capacitor(s) with a muli-timeter set on ohms. I think the procedure is related several times in the text and the comments. If you only have one capacitor to start and run both compressor and fan, that may be the problem.

      Sorry I can't narrow it down any better but there are several things which may cause the problem. Please ask for more info if you need it and thanks for the question.

      Randy

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      CONSTRUCK 4 years ago

      Thanks Randy..It uses 2 capacitors, both are 10mfd. The motor is from another rv which is free spinning and not that old. I have not cleaned the coils as yet, so I will give that a try and also check the amps on the compressor. I am thinking I checked the ohms on the capacitors last year but will check them again also. Oh and it does not trip the breaker, just shuts off and I can hear humming when it does so. Don`t know whether it is the fan motor or the compressor humming.

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      Randy Godwin 4 years ago from Southern Georgia

      Let me know what you find out, CONSTRUCK. I'll be interested to know what you find .

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      Chad 4 years ago

      I have a 2007 Palomino Sabre 5th wheel camper and I was wondering if the A/C unit ever needs to be re-charged with freon?

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      Randy Godwin 4 years ago from Southern Georgia

      Hi Chad, it depends on the unit itself whether it ever needs to be recharged with freon. Some units never develop leaks but most of them will eventually have to be recharged some time or another.

      If your RV AC isn't cooling properly and everything seems to operating correctly, you may need to have it recharged. Hope this helps!

      Randy

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      Randy 4 years ago

      Just an update on the Camplite Damon air conditioner with no power. Turns out we needed the cord to run between the 2 outlets and now it works great. Thanks for all your help. I have one last question, we are going to purchase a generator to run the ac and outlets while camping. Will a 2,000 watt generator run it ok?

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      Randy Godwin 4 years ago from Southern Georgia

      Thanks for returning and telling me what you found, Randy. I've never heard of this type connection, but then, I run into all sorts of weird set-ups in RVs.

      I don't believe a 2000 watt generator will handle the AC and outlets well enough to prevent damage to the AC unit compressor or fan motor. Not enough amps. Pleased you found out the problem with the AC though.

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      Randy 4 years ago

      What watt would you recommend?

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      Randy Godwin 4 years ago from Southern Georgia

      At least 3000 watts to pull the AC with no strain, but 4000 watts would be even better.

      --RG

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      Randy 4 years ago

      Thanks so much for your help with all of this. We purchased a 3500 watt generator with a 4000 watt start up.

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      Randy Godwin 4 years ago from Southern Georgia

      Hope you have great luck with the new generator, Randy. Have a great camping season and pleas ask if you need any more help with your RV.

      Randy :)

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      Garon Horton 4 years ago

      The fan motor in my rooftop RV ac started wobbling. It still runs but is clearly out of balance. Any insight on whether that is the motor or something on the fan blade? Also, not sure it is cooling this year but it did last year. Any easy checks I can do to see if it is something I could fix?

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      Randy Godwin 4 years ago from Southern Georgia

      Hello Garon, and thanks for the question. Often a mud dauber will build a nest on the fan blades making it out of balance and causing the wobbling you describe. Remove the AC shroud and you will be able to check for this or other causes for the unbalanced fan.

      While you are at it you will be able to see if the bearings are worn simply by seeing if the fan motor shaft will move around inside the bearings. It is also a good time to clean the fins in both the coils which could cause a lack of airflow and cooling efficiency.

      I hope this helps you find the problem. :)

      Randy

    • profile image

      Randy 4 years ago

      Thanks again for all your help sir!

    • Randy Godwin profile image
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      Randy Godwin 4 years ago from Southern Georgia

      My pleasure, Randy. Please check out my other RV repair articles if you ever need more assistance. Thanks for your input.

      Randy :)

    • Skip Kreiner profile image

      Skip Kreiner 4 years ago

      Randy, I've read almost all your posts, could not find an answer to my Prob. Sept 2012 bought a new Brisk Air, used it very little. This year it will start and run fine for about 10 mins then fan stops - comp still runs. Measured temp on fan motor 210 degrees. 3 wires to control box for fan -red yellow black. yellow not hooked up but all three show 120 volts. Would cap be prob or fan. it does spin free.

    • Randy Godwin profile image
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      Randy Godwin 4 years ago from Southern Georgia

      Hello, Skip. It may indeed be the capacitor causing the trouble. Do you have one each for the compressor and the fan motor? They are easy to check with multi-meter set for ohms. Remove the wires--being careful not touch the terminals--and set the ohms on high. You should get a random number decreasing in value if the capacitor is good. Hope this helps. :)

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      Lisa 4 years ago

      Hi Randy, I have a rooftop coleman air cond. that was working but leaking inside the trailer. Hose was cleaned and leaves etc. the air was still working but then started to leak inside again after two days of running the air. Very humid days. Can you suggest what the problem can be? it is a deluxe 6757mach1 rotary series, model d... 1990 thanks Lisa

    • Randy Godwin profile image
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      Randy Godwin 4 years ago from Southern Georgia

      Hey Lisa. Unless you have a drain in your RV to remove excess water from the ac during very humid days, more than likely the coils inside the AC need to be cleaned. There are products on this page made especially for getting the grime out with the least effort, but any good cleaner, such as 409, will do the job if you can use a bit of water pressure to loosen the accumulated crud from the fins.

      If you do have a clogged drain you'll still have remove the shroud to clear it as well as clean the coils. Clean coils will allow the fan to disperse the water into the outside air and not allow it to gather and leak down into the interior through the vent.

      I hope you have luck with either task. Thanks for the question and feel free to ask for more info.

      --RG

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      Rv lady 4 years ago

      Hi

      Few questions.....

      Removed the rooftop ac-but don't want to put a vent or skylight in.

      We would like to close up the hole. What is the best way to do that and have it flush with the ceiling? How do you attach it so that no nails or screws show? Lastly, what is best to use/do so there will be NO leaks! :)

      Thank you so so much for your assistance!!

    • Randy Godwin profile image
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      Randy Godwin 4 years ago from Southern Georgia

      Hello RV lady. There are several choices to replace or cover the vent in your RV. You may find them here:

      http://www.amazon.com/s?ie=UTF8&field-keywords...

      As far as covering the vent completely up, I'm sorry, but to prevent leaks it would be simpler and cheaper to just install a vent cover in the opening. Trying to waterproof the vent opening may cause leaks and other water damage.

      --RG

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      Gordon Elliott 4 years ago

      I bought a 1993 Prowler with the original A/C unit on it. The unit cycles on fan but the compressor doesn't kick in. The fan runs on High but the compressor doesn't kick in. The fans runs on low the compressor kicks in. Once started it cools but will not shut off. Gets really cold. I have to manually turn it down. I did have to oil the fan because it was sticking a little. Still need to blow out the coils. It does trip the house breaker on 20 amp but in camp ground it runs without kicking 30 amp breaker. May be because of poor 100 ft. extention cord to home. Should I clean all the wire connections? Give this think a good cleaning. Could it possibly be the thermostat? Making it not cut out on low fan and not start on high fan or could it be the capacitor? I think this thing sat for a while.

    • Randy Godwin profile image
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      Randy Godwin 4 years ago from Southern Georgia

      Hi Gordon, a long extension cord may make the unit trip a breaker and may not carry enough amps to run the compressor and the fan on high speed. This is especially so on a 20 amp breaker. Does the AC still act up while on a 30 amp campground breaker? When you say you "have to manually turn it down" are you referring to the thermostat?

      Also does your unit have two capacitors, one each for the fan and compressor? A bit more info may help me advise you.

      Randy

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      Ge3311 4 years ago

      The A/C still acts up on 30 Amp. But does not kick breaker. The Compressor will not start on High Fan but will start on Low fan. Yes I have to manually turn down the thermostat. I don't know yet if it has two capacitors or one. I haven't checked it yet. I don't know if the capacitors on the inside ceiling our under the shroud on the roof. I did notice the compressor will start on low fan and then hesitate like its drawing power and then go on running properly but will not kick out but this is only on low fan. I can't run on auto at all fan will kick in but compressor will not.

    • Randy Godwin profile image
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      Randy Godwin 4 years ago from Southern Georgia

      The capacitor(s) are located underneath the shroud, probably near the electrical junction box, but can see them easily is most cases. If you only have one capacitor starting and running both fan motor and compressor, it's possible it may not be furnishing enough amps to operate both compressor and high fan. I suggest you start by checking the capacitors.

      The worse case scenario is if the compressor is drawing too many amps, and therefore causing your problems. The only way to check the compressor is with an amp meter if you can locate one. The start/run amps are found listed on or near the compressor in most cases. Hope this helps. :)

    • profile image

      daronha 4 years ago

      I have two Dometic Duo-therm, ducted, combo roof AC/Heat pumps in my motor home. The rear unit was replaced about 6 years ago and is operating fine. In the front unit (13 years old), the heat pump works for extended periods with no problem. However, when I set the thermostat to "cool", the AC cools for about 15 minutes then the fan continues but the compressor quits. If I shut it down and wait awhile, then turn it back on, it blows cold for a while then quits again. This happens at high ambient temps when we need AC the most! An RV technician advised me that the motor is running too hot due to the refrigerant level being too low. Then, the thermal switch opens the circuit and shuts the compressor down."

      But, he said, "It is a sealed unit..too complicated to re-charge, only a few people are certified to pierce, refill and re-seal." Who will do this for me? How can I find a dependable tech? I am camping in the Seattle area for the next three weeks. Is it worth messing with? a new unit will cost about $1,400. Any suggestions?

    • Randy Godwin profile image
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      Randy Godwin 4 years ago from Southern Georgia

      Hello, Daronha. I'd get another opinion as to recharging the freon in your unit. It's not a particularly complicated task to recharge the system in most cases. have you considered installing a non-ducted unit in your RV instead? This will cost you around $800 give or take a few bucks.

      Another option is buying a portable AC unit to help cool down the interior. These are quite reasonably priced in most cases and don't require permanent installation.

    • profile image

      daronha 4 years ago

      Hi Randy. Thanks for your rapid response. I will consult another RV tech as soon as I can find an expert. They all seem to be very busy right now. I forgot to mention that with the shroud off my simple clamp ammeter read way higher amps than the Dometic standard 12 amp draw. The amps on the black wire to the compressor climbed gradually to a reading of 17 amps before I manually shut the unit down. It does not look good to me! Thanks for you cost saving tips but, I think I would like to stay with the ducted combo AC/heat pump system. If I need a new unit I guess I will have to pay the price! Meanwhile, I want to exhaust all of the possibilities for repair of my existing AC. Question: If the original diagnosis that I need to add refrigerant is verified, can I purchase the piercing valve at a refrigeration supplier or on line? Are they allowed to sell to a DIY lay person or to only licensed techs? If allowed then I could purchase freon and do it myself... or should I consult an AC tech? Is the piercing valve a regular shrader valve as found on auto systems? Once I determine the type of refrigerant, can I use the correct type of auto freon refill canisters? Assuming all of the above is allowed, how do I determine the proper line to pierce? Is it necessary to vacuum the old refrigerant out before refilling? How is this done? Sorry for the long note.

      BTW, Randy, my compliments on a great informative web page. I have learned a lot from your responses and also some of your users. Thanks for being there for us!

    • Randy Godwin profile image
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      Randy Godwin 4 years ago from Southern Georgia

      Yes, you should be able to find a piercing valve online, Daronha. I've bought a few from a local AC supply company. You can probably tell where the low pressure line has been sealed after charging by looking for short stub on the end of the line. Not sure if you buy the type of freon you need without a license in your area, though.

      The start/run amps will be different amps with the start amps being higher to kick start the compressor when first starting. The start/run amps should be found on the compressor or on plate close by.

      I hope the compressor isn't going bad on you because then recharging the system will be all for naught. Good luck and thanks for the kind words and for reading my article. Check out my other RV articles if you have other problems with your camper.

      Randy:)

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      callie 4 years ago

      i have a duo therm roof top unit started and ran fine but shut down like it was cycling off at temperature but never came back on. i turned off the generator and waited and restarted but the AC never kicks back on, i dont hear anythign at all it was running fine so not sure if i tripped a breaker or a blown fuse? just got the RV and was using it for the first time is that a good place to start?

    • Randy Godwin profile image
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      Randy Godwin 4 years ago from Southern Georgia

      Yes Callie, check the breakers or fuses first to make sure they haven't tripped. If so, something may be causing the unit to overload by pulling too many amps. It could be the compressor or fan motor.

    • profile image

      gnorman 4 years ago

      we brougth a 2013 crossroads camper back in feburary. we have used it 4 times this summer,each time,the air just blows very slow out of the vents what could it be?

    • Randy Godwin profile image
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      Randy Godwin 4 years ago from Southern Georgia

      Is this a ducted AC system, gnorman? That is, are there several vents coming from one rooftop AC? If so, there may be an obstruction in the vent system.

    • profile image

      Amanda 4 years ago

      My ac sounds like it tries to kick on but can't just is loud sound switched it to fan and still makes same sound. It worked 30 min ago and it blowed cold but sound was getting louder like lugging down still blew cold so I switched it off. Now wont come on. It's 100 and will have to fix before heat of day. What could this be?

    • Randy Godwin profile image
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      Randy Godwin 4 years ago from Southern Georgia

      Hello Amanda, it must be the fan if it continued to make noise when switched to fan. It could be a bad fan motor or else something causing the fan to be out of balance. You might remove the shroud and have a a look to see if a mud dauber has attached a nest to the fan blades and throwing it out of balance.

    • profile image

      saltyfish80 4 years ago

      Hi Randy,

      I have a coleman mach 15000. It runs for about 10 minutes and then flips the breaker. Then you have to wait about 5 minutes and turns back on for about 5 min then trips it again. I had a friend that works on residential ac look at it amd said he thinks there is a leak and best to buy a new unit. But he has not worked on rv ac. I'm wondering if he is right or if I should get another opinion. We have checked the power and it is not an amp problem. Any advice would be apprieciated.

    • Randy Godwin profile image
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      Randy Godwin 4 years ago from Southern Georgia

      Hi Saltyfish! Sorry to take so long responding to your query but I'm presently out of the country on vacation in place with undependable internet service.

      You need to use an amp meter to see if the start/run amps are over the standard usage rates. They should be listed on or near the compressor. If the compressor is pulling over the listed amps then yes, you'd probably be better off replacing the ac with a new one.

    • profile image

      Kip 4 years ago

      I have a 2008 Fleetwood excursion. The rooftop AC units drain directly on the roof. Is this normal or are there drain holes that the water should be draining into?

    • Randy Godwin profile image
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      Randy Godwin 4 years ago from Southern Georgia

      Unfortunately most of the newer AC units don't drains and usually disperse the moisture out into the air, Kip. More than likely the coils are very dirty and the fan cannot keep the unit drained enough to keep it from leaking out onto the roof or down through the ceiling assembly.

      A good cleaning of the coils will prevent this from happening and also make your AC operate more efficiently. An easy job in most cases. Thanks for the question, Kip.

      Randy:)

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      mike 4 years ago

      got a 2012 skyline nomad 40 ft air works but during night starts makin loud vibrating sound like it has a heart beat every other 5 seconds any suggestions

    • Randy Godwin profile image
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      Randy Godwin 4 years ago from Southern Georgia

      Hi Mike. I'd check the fan to see if it is out of balance in some way. Perhaps a mud dauber has attached a nest onto the fan blade. This, or either the compressor is going to the bad.

    • profile image

      CONSTRUK 4 years ago

      Hi Randy, I had a problem 6 weeks ago with my duo-therm Briskaire that ran for an hour and shut down. Well it still does that on high cool, but I found it will run normal and forever on medium and low cool. Weird.

    • profile image

      Amanda 4 years ago

      Hi so we checked the fan and ended up being the fan motor needed replacing. Now after replacing that and replacing new breakers. The ac isn't blowing as cold as it use to and now after the compressor (I guess is the sound) kicks off about 3 second later it trips the breaker the fan blows the entire time and is hot outside so really shouldn't be kicking off I don't think but almost like when the compressor tries to come back on it trips. Just seems like it can't restart

    • profile image

      Daryl cap 4 years ago

      This past weekend I was camping in ny, it was around 100 everyday. Upon arrival I hooked to my 30amp service and turned on the ac. About 45 minutes later breaker tripped and outside plug was so hot had to remove with a glove. I later let the plug cool and plugged it back in this time he ac would not cool. Comp and fan both engaged. Upon arrival at home I again tried to run the ac and again cord heated and the comp and the fan ran, but would not cool. Any ideas?

    • Randy Godwin profile image
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      Randy Godwin 4 years ago from Southern Georgia

      Hello Daryl. You need to check the start/run amps against what they should be as stated on the compressor. I suspect the compressor is at fault.

    • profile image

      Ken 4 years ago

      I have a Coleman roof air on my 2004 RV. Fans work but no compressor. Checking voltage, 12 volts on yellow wire from thermostat at roof air. 12ov to relay for compressor on 120v wire side but relay to 120v side to compressor never closes, so no voltage to compressor. Don't have circuit for board, but appears 12 volt relay coil is open, but again, I don't have schematics for the board, just logical troubleshooting. Suggestions on where I could get a schematic for A-1 Components PC0104 Rev A board? mfg date 1/20/03

    • Randy Godwin profile image
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      Randy Godwin 4 years ago from Southern Georgia

      Sorry Ken, I don't have access to the schematics for your unit. Try checking online or with the mfg.

    • profile image

      ken 4 years ago

      I think I found it. On the board I mentioned, it's the control board on the roof top unit, I can measure 12 volts at the coil of the relay when the compressor is suppose to go on, but the relay never closes, the 120v never gets to the compressor. It's a simple SPST relay, so guessing the coil is open because I through my volt/ohm meter on it and it does read open. Great, a $4.00 part to hopefully get the air going again. I'll check back if you post a comment on my issue.

    • profile image

      ken 4 years ago

      Just to close this. I de- soldered the relay off the board, still open on coil. Put 12 volt source across coil, as I thought, the coil is open. There is 12v on the circuit board to the coil, so my issue will be resolved when I receive the new relay, at about $4.00. Not sure if a repair shop would have sold me the board or just replaced the entire roof unit, either way, I'm happy and I thank you for your sight that helped me troubleshoot this by past posts. Best to you.

    • Randy Godwin profile image
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      Randy Godwin 4 years ago from Southern Georgia

      Thanks for your input, Ken. Glad you found the relay you needed for such a reasonable price. I suspect some repair shops do take advantage of those who don't know anything about an AC unit, and thus the main reason for my writing these RV repair articles. I hate to see people being taken advantage of and I hope my articles give a bit of know-how to the readers to prevent them from ripped off.

      Thanks again for your time. :)

    • Scott Hoover profile image

      Scott Hoover 4 years ago from Evansville, Indiana

      Randy, I just bought a complete advant ac unit (heat strip,upper/lower and new thermostat) to replace my ducted 15,000 btu duo therm. Hooked everything up and air blows cold, heat strip works but furnace will not work. The duo therm had 2 blue wires that ran from furnace and hooked into a 2 wire t-stat wire (red and white), that ran to lower unit. then the blue wires went to the upper unit. and everything worked great furnace and ac until ac went out. Now that I have replaced the complete unit with a advant unit I can not get the thermostat to operate the furnace. If I tie the red and white wire together that comes up from the furnace the furnace will turn on and run. I only have 1 wire left from the control unit which is a brown and white wire. http://www.advent-air.com/media/technical%20docs/A... Here is a schematic of the ac.

    • Randy Godwin profile image
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      Randy Godwin 4 years ago from Southern Georgia

      Hello Scott, I'm afraid I can't help you with your thermostat problem if it doesn't hook up the same way as your old one. I'm out of the country at the moment but will consult with my go-to guy when I get home in a few days. Check back in a few days if you don't figure out the problem.

    • profile image

      Tom Elwood 3 years ago

      Hi Ken I have a 2003 Breckenridge Park Model 844. In the bathroom there is ceiling vent that discharges the air into the bathroom. When the air is running some water drips from the opening. All the other vents which there are four others are OK. I called Breckenridge service and they said it might be the insulation has failed in that section. The unit is a Colman 13,500. Also this is the first time this has happened. We have used the air every year. We live full time in this unit and it does not go on the road. If you or anyone can help us that would be great.

      Thanks

    • Randy Godwin profile image
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      Randy Godwin 3 years ago from Southern Georgia

      Hi Tom. The coils in your AC unit probably need a good cleaning. When they get clogged with dirt and grime the fan cannot blow the excess moisture into the outside air as it is supposed to and some may leak down into the vents. I hope this info helps.

      Randy

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      Tom Elwoo 3 years ago

      Randy Thanks so much for the quick reply. I will try to get up on the roof as soon as I can. Do you have any suggestions as to what I should use for a cleaner?

      Tom

    • Randy Godwin profile image
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      Randy Godwin 3 years ago from Southern Georgia

      There are several good cleaners advertised on this page Tom, and even more choices through the Amazon ads. Some of the coil cleaners don't require any clean up after spraying the coils but others need to be shop-vacuumed after application.

      Any strong spray cleaner will work to some extent but may leave residue if not rinsed thoroughly after application. Hope this solves your problem, Tom.

      Randy

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      Nic 3 years ago

      Randy, I replaced the fan motor on the AC and I suspect the new motor runs backwards. Should the fan blow air through the fins or suck air?

    • Randy Godwin profile image
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      Randy Godwin 3 years ago from Southern Georgia

      Hello Nic. It depends on which coil you are referring to. The fan motor should pull air up through the filter which covers one coil while blowing the hot air out the rear of the AC unit.

    • profile image

      Nic 3 years ago

      Randy, Thank you very much! It is correct then!. Should the fan be totally inside the filter? From the pictures it looks like its about halfway out. * The fan that looks like a fan in a car.

      Thank you so much for responding, it is much appreciated!

    • profile image

      Tom Elwood 3 years ago

      Hi Again I haven't had a chance to get up on the roof yet to check the coils, but I ordered the foam cleaner that you suggested from Amazon. Will let you know the outcome. Thanks Again for the quick reply.

    • Randy Godwin profile image
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      Randy Godwin 3 years ago from Southern Georgia

      Nic--Just an optical illusion I suppose as the fan is inside the filter compartment. Good luck with your new fan and thanks for reading.

      --RG

    • Randy Godwin profile image
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      Randy Godwin 3 years ago from Southern Georgia

      Thanks Tom, and hope the cleaner does the job for you. Please do let me know how it works out for you. :)

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      Froelke 3 years ago

      Randy, I have a rear roof ac unit that works well when turned on in a constant mode, however, when put on "auto" it will cool until it reaches the set point, turn off, but then won't come back on again by itself until the bedroom gets very warm. Inside, I have found a lengthy curled up wire in a white sheath with an exposed metal end, when if I touch it, then it will turn back on again for a few minutes, then turn back off again, only not to turn on again until I mess with the end of the wire. In the meantime, the front ac will cycle on and off normally, maintaining a comfortable temp, while the bedroom gets too warm. Do you have any idea where I should be looking for the problem? Thanks for any help you might be able to offer.

    • Randy Godwin profile image
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      Randy Godwin 3 years ago from Southern Georgia

      Hello Froelke. The wire you've found is obviously part of the thermostat which controls the rear unit. I assume one thermostat operates both front and rear units and this wire is probably shorting out the system. A new thermostat will perhaps solve the problem your are experiencing with the rear unit. Sorry, this is all the advice I can offer without a schematic of the thermostat to look at.

      --RG

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      chris 3 years ago

      dometic 59516.531 brisk air

      hooked up power and a/c worked great for a few days.

      then when you turn it on the fan motor/ blower does not come on.

      you can hear the a/c "kick on" but nothing from fan.

      i have replaced the "start" and "run" capacitors.

      replaced the fan motor, both fans, and a "new run" capacitor add on

      that came with motor.3 capacitors total.

      i replaced wire nuts ,stripped, and re twisted the 120v hook up in

      the control box.

      i looked at the 3amp fuse in the control box and it looked

      "dark" but not blown, i only had a 5amp new fuse

      so i tried it with same results.

      it came with a 110v battery charger it is hooked up to battery.

      it is set on start and begins to blink after a few min.not sure

      if this is even relavent. i found a loose white wire that is bolted to frame

      i assume for a ground rod, i havn't installed a rod yet.

      all lights and circuits seem to work fine. no other blown fuses,

      or tripped breakers.

      any help troubleshooting this?

    • Randy Godwin profile image
      Author

      Randy Godwin 3 years ago from Southern Georgia

      Hi Chris. Seems odd alright since the unit operated fine to start with. Unless there is a relay malfunctioning somewhere I cannot figure what the problem could be. When you say it came with a battery charger, what do you mean by "it". I'll try to contact a friend of mine who usually is my go-to guy when these type problems arise but it may take a day or so. Sorry for the wait!

      Randy

    • profile image

      chris 3 years ago

      thanks for fast response and great page!

      the "it" (camper) came with the charger, it is a 2005 cavalier. the man who sold it to us had 120v extension cord hooked to dc "trickle"charger that hooks to battery. i thought it was odd that it was set to sart, but it seems that is working. i hooked a 12v light to the battery lines and it shines bright, also all the interior lighting is 12v.

      the place that sold us the new parts says may be control board?

    • Randy Godwin profile image
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      Randy Godwin 3 years ago from Southern Georgia

      I had a similar question a while back and it turned out also to be a control board problem, Chris. Sounds about right.

      __RG

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      jason 3 years ago

      i have a domestic ac unit, it is blowing hot air the compressor has 115 volts i put a new capacitor kit on it and when i turn it on it sound like its on but it isnt blowing cold air out the fan runs fine everything seems to be running fine but there is no cold air. were do i go from here.

    • Randy Godwin profile image
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      Randy Godwin 3 years ago from Southern Georgia

      Jason--It sounds as though the freon is low in your unit. Check the start/run amps on the compressor to make sure it is operating at all.

      Randy

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      Froelke 3 years ago

      Thank you Randy. I appreciate your response, and your advice.

    • profile image

      jason 3 years ago

      randy- if the freon is low do i have to buy a new ac unit or can someone put freon in it since it is a sealed unit and if they could isnt that just putting a bandaid on it. if i have to put a new unit on my camper are all the units pritty much the same or do i have to but the exact one that i have on there.

    • Randy Godwin profile image
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      Randy Godwin 3 years ago from Southern Georgia

      Hello again, Jason. Yes, a qualified AC repairman can recharge your unit with freon and patch the leak if this is what caused your unit to malfunction. I cannot say how long the fix will last but it should be okay if the other components of the AC are okay.

      All RV AC units are made to fit a standard 14"x 14" ceiling vent hole so the model and brand is not important as long as it is large enough to cool your RV.

      I hope this info helps you out.

      Randy

    • profile image

      chris 3 years ago

      just put in a new control board and now it doesn't even kick the compressor on???

      i can hear it click now ( in the control box when i turn the therm. to fan & when i turn it to cool.

      nothing from the compressor or fan???

      i checked all breakers, do you think it could be the DC side, but i thought the compressor was AC????

    • Randy Godwin profile image
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      Randy Godwin 3 years ago from Southern Georgia

      Yes Chris, the compressor is AC. Have you checked the voltage to the compressor while the unit is on to see if electrical power is flowing to it?

    • profile image

      chris 3 years ago

      i didn't check this evening... it just doesn't make sense. the compressor was kicking on before i installed the control board. the board itself was simple unplug/replug wires, i can't see where anything would get installed wrong.

      what are your thoughts on using the battery charger to run the DC side. it was set (and i'm sure the previous owner told me) on START.

    • Randy Godwin profile image
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      Randy Godwin 3 years ago from Southern Georgia

      Can't hurt to try, Chris. I assume the charger is replacing the power converter so it's worth a try. Sometimes previous owners have rigged the system in a manner different from usual.

    • profile image

      chris 3 years ago

      wife called in a pro today-

      the problem from the start was that i got carried away cleaning the unit

      with a shop-vac, i must have jarred the wiring pretty good. 3 wires from the thermostat

      where broken. man do i feel dumb!

      so i replaced:

      start cap

      run cap.

      motor

      x2 fans

      control board

      trying to save some money, by doing it myself !

      now i KNOW what folks mean when they say

      " spent a dollar trying to save a dime"

      i basically paid for a new unit :(

      thanks again for your help

    • Randy Godwin profile image
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      Randy Godwin 3 years ago from Southern Georgia

      Sorry you had such a problem with your unit, Chris. Sometimes it is better to get an expert's opinion at the very start. Don't feel bad as many of us have experienced that dumb feeling while trying to fix some type of machine or other. I know I have!

      You have learned a bit about AC units which will probably help you in the future though. Good luck on your future repairs. :)

    • profile image

      Gojoalta 3 years ago

      Just installed new Coleman Mach3 w/heat coil - and added hard start kit for generator - and new analog heat/cool thermostat. When firing up for first time the relay clicks and it clicks at thermostat approx every 2 sec's. Fan works fine - but unit will not fire up. All brand new parts. All wires connected and tight. Any suggestions would be greatly appreciated.

    • Randy Godwin profile image
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      Randy Godwin 3 years ago from Southern Georgia

      Hello Gojoalta. This is indeed a puzzle but are you sure the thermostat is wired properly? I don't understand why the thermostat would click every 2 sec's unless it is wired wrong. Have you checked to see if voltage is reaching the compressor?

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      matt1776 3 years ago

      I have a dometic sl135r-b. I need a blower motor. can you tell me what the new part number is? the manual says m15050 but i cant find it. also do you know if this one has bearings that can be lubed? I am going to pop the shroud off to take a look tomorrow. it has the original motor from 1986.

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      Randy Godwin 3 years ago from Southern Georgia

      Sorry Matt, I can't help you there. You should be able to find a universal fan motor and mount which you may need to cut the shaft(s) off to the correct length. Get the info from the old motor when you remove the shroud and then consult with some electric motor companies. The amazon links on this page may help you find a substitute.

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      Jean 3 years ago

      I have a Duo Therm thermostat

      by Dometic that comes on for 20 to 30 minutes then goes off

      and comes back on again in 2 to

      3 minutes. And if the temp is set below 75 it comes on but doesn't go off.

    • Randy Godwin profile image
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      Randy Godwin 3 years ago from Southern Georgia

      What temperature do have the thermostat set when the unit runs 20-30 minutes and then starts again in 2-3 minutes, Jean? And also, how hot are the temperatures where you live? Just an estimation, of course.

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      Tom elwood 3 years ago

      Hello Again. We talked a week or so ago about water leaking down into the bathroom duct work when the air condition was running. I finally got to it this morning. Checked the coil and it was in very god shape no clogging that I could see. Some one told me that there are two drain holes that should be checked but can't seem to locate them. Do I have to remove any covers to locate them?

    • Randy Godwin profile image
      Author

      Randy Godwin 3 years ago from Southern Georgia

      Yes Tom, they are located beneath the shroud and accessed from the roof if your unit has them. There are 2 coils in your unit, by the way.

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      chris 3 years ago

      randy,

      sorry if this isn't ok here. i still have "old" fan motor/2 capicitors/control board that i removed. they were not the problem, so i assume they are still good. should i sell on ebay or keep for spares?

      edwardsrinker@earthlink.net if you are interested.

      you did help me learn a lot about camper AC and i apreciate it!

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