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How To Troubleshoot, Service, and Repair a Motorhome or Camper Travel Trailer Rooftop RV Air Conditioner AC. FAQs

A new Coleman 13,500 BTU A/C unit ready to install.
A new Coleman 13,500 BTU A/C unit ready to install. | Source

The Importance of RV AC Maintenance

The rooftop air conditioners used on motorhomes are made to give many years of dependable cooling efficiency. But in order for the AC to operate dependably each season, it is necessary to keep the rooftop AC unit on your motorhome clean and properly maintained.

Occasionally the motorhome rooftop AC needs repairing and this article will assist you in knowing which parts of your RV AC to replace or service.These repair and maintenance tips are very simple to follow, even for those with less than good hands-on experience.

If you are unfamiliar with how a motorhome air conditioning system works, this article will help you understand which parts of the motorhome rooftop air conditioner unit to check, service, and repair.

Accessing the AC coils

Removing the RV AC Shroud retaining bolts
Removing the RV AC Shroud retaining bolts

Condenser and Evaporator Coil Maintenance

Roof air conditioning units are the same as ones used on other types of RV campers such as travel trailers and pop-up campers. Your motorhome AC system may have one or two units to help keep the camper cold, or warm if the RV AC units have optional heat elements. These repair and maintenance procedures are identical for all types of the aforementioned campers.

After a few seasons of use, it isn’t unusual for the AC unit(s) to not cool the motorhome as quickly or as efficiently as it once did. Even though you have kept the filters clean on a regular basis, the evaporator and condenser coils will eventually become coated with dirt and grime which inhibits airflow and cooling efficiency.

Before attempting any maintenance or repairs on the rooftop AC unit be sure to switch off the electrical supply to the unit, either by tripping the breaker or by unplugging the motorhome from the electrical receptacle. You are now ready to remove the RV AC shroud by unscrewing the four bolts securing it to the RV AC unit itself.

Cleaning The Coils

This coil is badly in need of cleaning
This coil is badly in need of cleaning

Cleaning Your RV AC Coils

How To Clean The RV AC Coils

After removing the AC shroud you will be able to see the evaporator and condenser coils on either end of the RV AC unit.

If they appear similar to those in the photos at the right then they need a thorough cleaning. to allow unrestricted airflow through them.

A good wet/dry Shop Vac will help to keep you from making a big mess during the cleaning regimen.

Although regular household cleaners may clean the coils to a certain extent, AC coil cleaners made especially for the purpose will remove the grime build-up much more efficiently and will not harm the coils themselves. Several types of these fine products may be found on this page.

Follow the instructions carefully for the best results and use the Shop-Vac to remove any excess cleaner or grime from the RV AC unit. Use a coil fin comb to straighten any bent fins because they too will keep the airflow from moving through the AC coils efficiently.

These fin combs are very inexpensive and may be used many times in the future on both RV and home AC coil fins.

RV AC fan motor

Sleeved bearing RV AC fan motor
Sleeved bearing RV AC fan motor
Model and serial numbers on RV AC fan motor
Model and serial numbers on RV AC fan motor

Replacement RV Rooftop AC

RV AC Fan Motor maintenance

While the RV AC shroud is removed, it is a good time to service the fan motor and clean the fans themselves. Whether your RV AC unit is made by Coleman, Carrier, Duotherm, or Dometic, it will have one fan motor which turns both the squirrel cage fan and the heat exhausting fan.

This motor should be oiled at this time.

If your RV AC fan motor has regular bearings in it there will be oiling ports at each end of the motor. It may be necessary to remove the top metal sheeting from over the fan motor to access the bearing oiling ports.

A few sheet metal screws will have to be removed to allow you access to the bearing ports add oil to the bearings.

If no oil ports are evident, then your rooftop AC unit has sleeves instead of bearings. You may still oil the shaft at the point where the sleeves are contained in the fan motor housing. The oil will seep inside and help the fan motor last much longer.

A fan motor with sleeves cannot be rebuilt economically, as can the bearing models, and must be replaced with a new one. Check the ads below to find the right fan motor for your RV AC.

Removing and Replacing the Fan Motor

RV AC fan motor with retaining screws removed from AC chassis.  Your RV AC model may be different.
RV AC fan motor with retaining screws removed from AC chassis. Your RV AC model may be different.

Replacement RV AC Fan Motors

How To Replace A Motorhome AC Fan Motor

If your AC fan motor is slow to start even after oiling, or needs a nudge to get it going, it will need rebuilding or replacement with a new one.

As stated previously, a bearing model fan motor may be rebuilt fairly cheaply and will last for many more years. But not so a sleeved bearing AC fan motor.

If your unit seems to be in pretty good shape a new AC fan motor may be ordered to fit your particular RV AC unit.

Check out the links on this page to find the type of fan motor you need to replace your model Click on the ads to look further on the Amazon site if you do not see your model of fan motor. There are many sizes and models to choose from.

Replacement of the AC fan motor is a simple job with only a few tools required for the project. Mark the wire colors before removing the fan motor if the connection isn’t a simple plug-in type electrical connection.

Test the new RV AC fan motor before replacing the AC shroud to check for proper alignment and fan clearance.

RV AC Capacitor Replacement

If the fan or compressor fails to start and the AC unit merely hums or trips a breaker, it is possible the starting capacitor is malfunctioning.  The capacitor stores electricity to give both the fan motor and the compressor an extra boost when the RV AC unit first starts.  It is not unusual for this item to go bad.

The capacitor is easily replaced in the event it has gone bad.  Note the wiring before removing the old AC capacitor and install the new capacitor in the same manner.  Your AC unit should now start and run fine.  Check the required voltage and model numbers on the new AC capacitor when ordering a new one.


The RV AC Compressor

A/C Coil Fin Comb

Air Conditioner Fin Comb
Air Conditioner Fin Comb

Straighten out those bent coil fins and increase the efficiency of your A/C unit.

 

RV AC Compressor Problems

If, after determining the switches, capacitor, and relays are not at fault, the RV AC compressor fails to operate correctly it is usually better to just junk the unit and buy a new one.

Unless you have access to a used compressor and have the means to replace it and recharge the system yourself, it will be too expensive to repair in most cases. Under normal circumstances the compressor will last much longer than the warranty covers.

The thermostat and switches may be purchased online by finding the correct model and serial numbers before ordering the new parts. These items w\are very easily replaced in most cases. Pay attention to the wiring connections as always when replacing these electrical components.


Protect Your Motorhome AC Unit In The Off Season

Your motorhome AC unit should give you many seasons of dependable operation if serviced annually. The use of a cover for the RV AC unit is highly recommended during the times when the motorhome is not in use.

These inexpensive RV AC covers protect the unit from being exposed to moisture, extreme cold or hot temperatures, and debris from storms, birds and insects. They will more than pay for their cost over time.

If your RV AC unit needs replacing, please see my article on how to install a new rooftop RV AC unit. Replacing your old unit with a more efficient RV AC unit is a very simple and quick procedure you can do yourself. Don’t be afraid to try these service tips yourself. You will learn much about these wonderful RV air conditioners.

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Comments 434 comments

Dave Kelly 6 years ago

I am looking for a small roof top A/C for a small 1964 14 ft Shasta camp trailer. I currently have a 12 volt roof fan in a 14" X 14" opening. I don't need a large one. 5,000 BTU's or less. Any ideas.


Randy Godwin profile image

Randy Godwin 6 years ago from Southern Georgia Author

The 14" X 14" opening is standard size for most all rooftop RV AC units, Dave! You will be hard pressed to find one of these in anything as small as a 5000 BTU rooftop AC.

Of course, you can always turn the thermostat down to keep it from being too cool. You might consider buying a regular 5000 BTU window unit and installing it in a window on the front of your Shasta. I have one in my 14 ft. camper trailer and it works great. Less than 200 bucks too!

Just make sure the AC unit has enough slant to allow the water to drain outside of the camper. Hope you figure out which type would suit you best. Thanks for reading!


Randy Godwin profile image

Randy Godwin 6 years ago from Southern Georgia Author

@ Jack B. Sorry I cannot include your question Jack, but the link in your name raises a warning from my server. However I will answer your question which was

"where is the capacitor located ? Under the rooftop housing , or accessed from the inside of the trailer ?"

The capacitor is located under the shroud it has wires coming from both the compressor and fan motor and is usually gray in color. I will try to add a capacitor photo onto this article to help the DIY campers understand what a capacitor looks like.

Thanks!


Randy Godwin profile image

Randy Godwin 6 years ago from Southern Georgia Author

The oil port is shown in the photo on this page showing the model and serial number of the fan motor, MikeD! The oil port is the tube in the center of the photo. The end of the tube is broken off, as you can tell.

If no tube or port is evident, then you have a sealed bearing, as in the photo above the previously mentioned one. Drop oil at the spot on the shaft where the red washer is. Oil both ends of the fan motor.

Sorry, I cannot allow your linked name on these comments!


edgarjme@msn.com 5 years ago

I have purchased my 1st motorhome and the forward cabin ac unit will start then slow down and trip breaker.Any sugestions?thank you


Randy Godwin profile image

Randy Godwin 5 years ago from Southern Georgia Author

It appears your fan motor bearings are getting hot and causing the breaker to trip. You can check by trying to turn the fan by hand after the breaker trips by removing the AC filter inside the RV and trying to turn the fan by hand.

If the fan turns easily it is fine. It should spin without any dragging at all. If not, the compressor could be the problem. Hope this helps, Edgar.

Thanks for stopping by!

Randy


Jessika Jones 5 years ago

hey, this is a great article. I will show my husband. He is wanting to replace the coils in our roof air in our pop up. The were smashed a little. The air works great at night but has a hard time keeping up during the heat of the day which I think is normal but he seems to think the coils being smashed has something to do with it. Let me know what u think. If you think they do need replacing, where would I get replacement coils and how much are they? thanks.


Randy Godwin profile image

Randy Godwin 5 years ago from Southern Georgia Author

Hello Jessica,

Your husband may only need to order a coil fin comb to straighten those in your RV AC coil. They are sold on this page in a section above.

Thanks for reading and for your comments.

Randy Godwin


steve and kristi 5 years ago

Hello, we heve a 15000 roof top ac on our 2005 5th wheel,it is freezing up. The cooling side has about one quarter inch of frost. After its turned off she starts and cools great and a few hours later freezes again. What do you think it is? Thanking you in advance.


Randy Godwin profile image

Randy Godwin 5 years ago from Southern Georgia Author

There are several possible reasons for your RV AC unit to freeze up, Steve and Kristi. The most common cause is keeping the thermostat at too high a setting.

In this case, the air flowing through the coils cannot remove enough of the cold to prevent it from icing up. Simply lowering the thermostat setting will remedy this problem.

Another possible problem is if the coils are clogged with dust and debris thus preventing the air from properly transferring the cold from the coils to the air circulating through your RV. Using a good coil cleaner will fix this problem.

The last possibility is a low freon charge. If your unit has a slow leak in the closed system, it will get get really cold right before the freon charge is totally depleted because of the leak.

In this scenario a freon recharge is in order. I hope this helps you find the problem. Thanks for the question and for reading my RV repair articles.

Randy Godwin


mrfullerton 5 years ago

Hi Randy,

My 5th Wheel AC/HEat just simply isn't going on. I replace the Dometic thermostat and the electrical board right under the vent inside the trailer. But still nothing. Any thoughts?


Randy Godwin profile image

Randy Godwin 5 years ago from Southern Georgia Author

Hi mrfullerton! I would suggest you start at the 110 volt breaker and the 12 volt breaker in the power panels first.

The 12 volt breaker will power the thermostat and the 110 volt breaker the power to the AC/heat unit. If both of these check out then go from there. You should have power to the fan/on/off switch.

It sometimes may be tough to find out where the circuit is broken. Any other info you can give me will help me narrow down your problem. Let me know what you find when you check these items.

Randy


billie andrews 4 years ago

to randy godwin,how do i recharge my brisk air unit it does not have a service port,it is a 1986 model how can i add one,and what type of freon is it?


Randy Godwin profile image

Randy Godwin 4 years ago from Southern Georgia Author

In order to recharge your unit you must install a piercing valve which should be no problem to find at a local AC supply business, Billy.

Not sure about your freon type but it is possible to convert the old type to the 314a freon and save quite a bit of cash in the process. The piercing valve will enable you to connect the recharging device with a quick-connect fitting. Good luck with your repairs and thanks for the question!

Randy


Bob 4 years ago

AC comes on and the fan comes on and I can hear the compresor come 0n, but it does not cool. Help Thank You


Randy Godwin profile image

Randy Godwin 4 years ago from Southern Georgia Author

Probably a low freon charge, Bob! If the compressor is running this indicates a lack of freon as the most obvious problem. Ask for more info if you need it.

Randy


Mr Oswald 4 years ago

Our 2005 Damon Intruder Motor Home rear AC squeaks. Does that mean a bearing is going out, just needs oiling or does it mean the motor is going bad? Can I do some repair myself or does this require a technician?


Randy Godwin profile image

Randy Godwin 4 years ago from Southern Georgia Author

Hello Mr. Oswald! If your A/C fan has grease fittings you can simply grease it, but most newer units have sealed bearings which do not have grease fittings. However, you can shoot some spray lubricant, or even some from a small applicator type oil can around both front and rear motor bearings to lubricate the fan enough in some cases.

Otherwise, you may have to replace the fan motor. It's usually not a very difficult job for someone with basic repair skills. Ask for more advice and help if you need it. Thanks for the question and for visiting my articles.

Randy


Brad 4 years ago

My roof top carrier want work on cool setting but will work on fan setting it was working when I bought a week ago


Randy Godwin profile image

Randy Godwin 4 years ago from Southern Georgia Author

Hi Brad. Does the unit blow cool air on the fan setting or just regular air? I'm not sure I understand your question correctly.

Randy


Brad 4 years ago

It only blows regular air when on the fan setting when I put it on the cool setting the fan or compresser nothing works the air conditioner want do anything but only when I put on fan


Randy Godwin profile image

Randy Godwin 4 years ago from Southern Georgia Author

Brad--It could be several things causing the problem. A bad selector switch, bad thermostat, bad remote--if you have one-even a bad capacitor, though since the fan will run on "fan" this seems unlikely. Anything else you can tell me to narrow it down, Brad?


Brad 4 years ago

I turned it on cool and it stayed on for minutes and cut off. It did this several times. And it was very hot in the trailer so I know it didn't hit the set temperature on the thermostat now when I set it on cool it does nothing I even push the emergency cool button on the roof and it does nothing


Randy Godwin profile image

Randy Godwin 4 years ago from Southern Georgia Author

This still sounds like a thermostat problem and hope it is as this might be the simplest fix, Brad. You didn't say whether it uses a wall mount thermo or not.


Brad 4 years ago

It's a wireless remote


Randy Godwin profile image

Randy Godwin 4 years ago from Southern Georgia Author

I just had a similar question involving a unit with a wireless remote on another A/C repair article, Brad. I still haven't heard what the reader found out yet. His remote was running the A/C and furnace at the same time. Perhaps a problem with the remote thermo not working correctly.


Brad 4 years ago

I will keep checking back with you. Thanks for all your help. Thermostat was my first guess but I'm no a/c man. Again thanks for your help


Randy Godwin profile image

Randy Godwin 4 years ago from Southern Georgia Author

Thanks Brad. Sorry I can't be of more help but please come back and tell me what you found out as this seems to be a fairly new problem with remote operated units. I can then pass on the info to others like yourself.

Randy


Brad 4 years ago

Randy I figured it out. There is a little glass fuse (barrel fuse) in the ceiling. I took the fuse out for a minute and put it back in it resets the a/c it works fine now. A rv tech told me about it. I hope this will help someone because I was ready to take mine to shop to get looked at. I really like your site.


Randy Godwin profile image

Randy Godwin 4 years ago from Southern Georgia Author

Thanks so much for the solution, Brad. I didn't know about the fuse in the ceiling. I'm sure this info will come in handy sooner rather than later here. Drop back by anytime you have a problem or another solution and thanks for your time. :)

Randy


nora 3 years ago

my air conditioner was working fine, and all of a sudden, it kept tripping the breaker. i would turn it back on and the breaker kept tripping, till finally it wont turn on. the heat works but all you hear is the clicking of the thermostat when you put the ac on. does anyone know what this could be


Randy Godwin profile image

Randy Godwin 3 years ago from Southern Georgia Author

Hello, Nora. You neglected to state whether the fan would run or not. I suspect either the fan motor or the compressor is overloading the circuit causing it to trip a breaker. If the fan works then I suspect a bad compressor. A bit more info may help me in advising you as to repairs.

Randy :)


Anton 3 years ago

Hello, I have just about the same unit as in this article and I've done all the maintenance described. However I'm noticing lately in temperatures over 100-105 that the compressor will cycle off for 5-15 minutes every hour or so.

Can someone tell me if this is normal? Or maybe there is a service I can preform to prevent this? I'm primary concerned this may be a sign of bad things to come.

I should also mention that I replaced the thermostat last year so I doubt that has anything to do with it.

Thank you in advance for any help!


Randy Godwin profile image

Randy Godwin 3 years ago from Southern Georgia Author

Hello Anton, and I'm sorry to be so late in responding to your question, but for some reason your comment was caught by the HP spam filter and I just found it.

What temp do you have the thermostat set at on these 100+ degree days? Does the unit keep the RV comfortable or are you having a problem getting the air cool enough? A little more info may help me advise you better. :)

--RG


Anton 3 years ago

Hello Randy,

It has a knob with no numbers so I'm not sure exactly what the temp is set at but it's close to maxed out and as long as the compressor doesn't shut off then it's plenty comfortable with an extra fan moving air around.

I believe the unit is overheating as I've tried misting some water over it the past couple days during the hottest hours and the compressor has stayed on fine. But this obviously isn't a practical long term solution. I've also tested voltage into the unit and it's a clean 116V.

Thanks again!


Randy Godwin profile image

Randy Godwin 3 years ago from Southern Georgia Author

@Anton--It does sound as if the unit is having to work very hard to keep the air comfortable. Is the A/C an older unit? If so, you may be bit low on freon, but more than likely the compressor is having to work too hard. Have you considered using one of the new portable AC's which are great for the hottest times of the year? The high temps you are describing actually calls for either a larger AC or either multiple units if your camper is very large.

If you have access to an amp meter you test the start/run amps on the compressor and get a better idea of the shape it is in. I hope this info helps you some way.

--RG


erniegjack profile image

erniegjack 3 years ago from Springfield, Missouri

WE have 99 Fleetwood Flair class A camper, with a 8,000 series Rooftop A/C unit. The unit stopped & we had a tech come out and he cleaned the coils and the unit. The unit was restarted using the breaker on the panel and the compressor now runs 24/7 unless we trip the breaker. He told us that it would only be a matter of time before we need another A/C unit. The units using this systems works fine. Any suggestions would be greatly appreciated.


Randy Godwin profile image

Randy Godwin 3 years ago from Southern Georgia Author

Hi, Ernie. Is it necessary for the unit to run 24/7 to keep the camper cool? If not, I wonder why the thermostat isn't cutting the compressor off when it reaches the desired temp.

Ifindeed the AC is required to run all of the time, then you have a problem. Is this the only ac unit used in your camper?


Anton 3 years ago

Thanks Randy

I'll find time to run a test on the compressor.

Just out of curiosity... I've seen the overheat switch which attaches at the top of the compressor at the wiring. When this fails, does it just give out or does it maybe become more sensitive before hand?

My AC is an older 67 series and as well as it works, parts have been replaced over the years so I'm wondering if the sensor might be something worth adding to the list.

Thanks again :)


S Bring 3 years ago

Dometic 520315.701E. Blows cold air but shuts off before the desired temperature is reached. Not connected to a wall thermostat. Runs for about two minutes then shuts off regardless of outside temp.


Randy Godwin profile image

Randy Godwin 3 years ago from Southern Georgia Author

Hello again, Anton. I'm not sure about the possibility of the overload switch getting weaker as time goes on. Testing the compressor start/run amps should give you a clue if this is indeed a possibility. I haven't heard of this switch failing very often, though. Let me know what you find out if possible. Now I'm curious if this could be the problem.


Randy Godwin profile image

Randy Godwin 3 years ago from Southern Georgia Author

S Bring--Does the fan and the compressor cut off or just the compressor? You still have a thermostat mounted in the unit so it could be faulty and causing the problem. I suspect the compressor is overloading if the unit shuts completely down, but I need more info to say for sure.

Randy


S Bring 3 years ago

Thanks, Randy, for your speedy reply. Both the compressor and the fan shut off. I agree that it's probably a thermostat. Now to see if I can find where it is! Hope my husband can do this repair.


Randy Godwin profile image

Randy Godwin 3 years ago from Southern Georgia Author

@S Bring--It may not be the thermostat if both fan and compressor are shutting down. The thermostat is the knob on the AC which you turn to set the temperature. It is easy to replace but unless you have an energy saver on the unit it shouldn't turn off the fan.

I suspect the compressor is drawing too many amps and tripping the overload. I hope this isn't the case.


S Bring 3 years ago

Glad to keep reading this thread. If the compressor is drawing too many amps, what's the cause? What's the fix?


Randy Godwin profile image

Randy Godwin 3 years ago from Southern Georgia Author

S Bring--The compressor is the most important part of the AC and if it's drawing too many amps it is probably worn out or damaged in some manner.

Unless you can find a replacement compressor cheap and someone to install and recharge it with freon, it's usually better to simply replace the whole ac unit. In other words, it is normally cost prohibitive to replace the compressor.

Many feel it is not worth the cost as you still have an old unit with other parts which may give out at any time. I hope it isn't the compressor in your case. If you can have someone test the start/run amps--usually listed on the compressor itself--this will tell you if the compressor is indeed bad.

An amp meter is required to test the compressor if your husband has access to one. It may be possible to rent one at a local rental business. let me know if can be of further assistance.

--RG


Larry 3 years ago

I have 2000 Damon Daybreak , That I purchased 3 years ago . Everything has been working fine till today . The rooftop AC unit was working fine all week-end . On our way home today had the generator on and the AC running off from that . And the AC stopped completely . When got home , plugged it into a 110 electrical outlet , but still will not start up . Does absolutely nothing . Any suggestions ????


Randy Godwin profile image

Randy Godwin 3 years ago from Southern Georgia Author

Hello Larry,

Does the AC make any noise at all? Will the fan try and start or does the unit do nothing? Is the thermostat mounted on the wall or on the AC itself? Perhaps a little more info will help me narrow the problem down a bit.

--RG


john a 3 years ago

how do i put freon in a roof top ac on a camper??i don't find any service ports to put freon in


Randy Godwin profile image

Randy Godwin 3 years ago from Southern Georgia Author

Hi John, you must install a piercing valve on the low pressure side of the compressor to add more freon to the system. You can find one at any AC or refrigeration parts supply. Thanks for the question. :)


Daronha 3 years ago

Hi Randy,

Its me, Daron again (still).

Re: Installing a piercing valve and re-charging with R22 Freon.

I found several types of piercing valves available online for various prices. However, do I need to have special gauges and fittings to refill Freon to proper pressure? I am having a problem finding an RV tech who is certified to refill Freon. The residential home AC techs have the equipment and access to Freon but say that they only do home units, not RVs.

Can this be done with a simple refill hose kit from an auto parts store? Do I need to purge the old Freon with a vacuum pump before I refill?

Daron


Randy Godwin profile image

Randy Godwin 3 years ago from Southern Georgia Author

It's better to pull a vacuum on the system if you can Daron, but recharging the system without doing so may still work if you can't borrow the gauges or correct tools. It's up to you whether to risk it or not.


Chris Gollihar profile image

Chris Gollihar 3 years ago

hey randy: I have a RV with dual DUO THERM A/C units. I was plugged in to 3o amp, and made mistake of trying to turn on rear A/C also. It would not come on. I tried later to use the generator, and still nothing. No fan, and no compressor. Front A/C works good. The rear A/C worked great last time it was used. I got on roof and pulled cover. everything looks connected. The motor spun freely, also the blower wheel. Could the start or run capacitors have gone bad?? I'm not sure which is which. There is one on the left front, and one on right front next to looks like a relay. Any help I'd appreciate.. Chris


Chris Gollihar profile image

Chris Gollihar 3 years ago

hey randy, I also forgot, I reset the breaker and checked the wiring plugs. They were all tight. Chris


Randy Godwin profile image

Randy Godwin 3 years ago from Southern Georgia Author

Hey Chris. This is a puzzle alright. Apparently trying to run both units on the 30 amp hook-up has created the problem you are experiencing now. I wouldn't think both capacitors would be bad at the same time but it is indeed possible. Have you checked the thermostat to see if it is sending a signal to the rear unit to start up?


Chris Gollihar profile image

Chris Gollihar 3 years ago

hey randy, thanks for the reply. My a/c's have the dials on the a/c unit. How do I check the thermostat with voltmeter?? I want to replace both a/c's, but at $650-700 each, lotta money. They are 26 years old.


Randy Godwin profile image

Randy Godwin 3 years ago from Southern Georgia Author

Chris--The dial type thermostats should have an audible clicking sound when they are adjusted to the point of the compressor kicking on. You should be able to check the thermostat with a voltmeter where the wires connect to the rear of it. When the thermostat is adjusted for cooler temps you should get voltage to the compressor when the click is audible. If this isn't the problem we'll go from there.

Even though the units are 26 years old, I'd still go the repair route rather than replace with new ones until you have to. Let me know what you find if you don't mind, Chris. It may help others with a similar problem.

Thanks for the question and your time,

Randy


Chris Gollihar profile image

Chris Gollihar 3 years ago

hi randy: I checked it today. I used a compressor to clean everything out, a little maintenance. I checked for AC voltage at the breaker, with the generator on, it shows 124volts. so, it's getting power. Wife told me it turned on once, and I haven't got it started since. I checked the two plugs, and they are tight. So to get at the back of thermostat, I need to remove the small cover from the thing?? Then, am I checking for battery voltage or AC voltage?? which terminals do I check?? Do wires have to be removed first?? Thank You, Chris


Randy Godwin profile image

Randy Godwin 3 years ago from Southern Georgia Author

Hello again, Chris. I think the voltage coming from the thermostat on your model should be AC. Some remotely mounted thermostats use DC voltage supplied by the on board converter but you indicated this one was on the ceiling assembly itself. If you have a good multimeter you will be able to tell for sure, but I'm pretty sure it will be AC.

No, the wires do not have to be disconnected, but as usual, don't touch the probes or terminals without disconnecting the power or the main breaker. Not sure how many wires there are and you may have to experiment a bit to find which ones run to the stat. There may be only two on your AC. You should be able to tell the difference in voltage being present when turning the thermostat up or down. The stat should a signal to the compressor when it is needed to run. This still doesn't explain why the fan won't run, however.

Will consult another AC guy this evening as I'm wondering about the control board being at fault.


Chris Gollihar profile image

Chris Gollihar 3 years ago

thanks for the response randy. I have a good meter, Ill check it out tomorrow . thanks for your help, chris


Randy Godwin profile image

Randy Godwin 3 years ago from Southern Georgia Author

No problem, Chris. I'll keep thinkin' on it in the meantime. lol!


Chris Gollihar profile image

Chris Gollihar 3 years ago

hey randy, well I checked it out today. I checked the power wires that go to thermostat, I got like 19Volts. So, meter shows 124Volts at the breaker, and around 19, where the hot wires go to the thermostat. Does this mean the thermostat is bad?? I didn't see any loose connections. This is with genny running. I tried ground in different spots, same issue.

Chris


Randy Godwin profile image

Randy Godwin 3 years ago from Southern Georgia Author

I believe the thermostat sends an 18 volt signal to the compressor Chris, so this would be okay at 19 volts. Still, I'll have to check to be sure about that. Give me a chance to check with my go-to guy tomorrow as he has been ill for the last few days.


Chris Gollihar profile image

Chris Gollihar 3 years ago

Thanks randy, i appreciate it.. Chris


John Jewell 3 years ago

I have a Dometic Duo Therm 57915.622 AC Unit. It works well for almost 15 years old. The trouble is that after it shuts off from reaching the temp setting, it tries to start again in only 20-30 seconds and trips the circuit breaker. If I turn it off manually and let it rest for about a minute it starts easily. I've already replaced the capacitor to no avail. Is this a problem with the thermostat or the control box?


Randy Godwin profile image

Randy Godwin 3 years ago from Southern Georgia Author

Yes, it could be the thermostat. It could also be a low freon problem, John. This is especially so because of the age of the unit. If you can get your hands on an amp meter you can check the start/run amps on the compressor to rule out a bad compressor.


cs0155 3 years ago

Hey Randy, I have a Duo Therm AC unit on my fifth wheel(2006) . It doesn't run at all, the remote works, there is 120v going into the main circuit board and 12v,no power on the fan wires into the fan relay,(low/high speeds). In between there is a "selector box " for cooling or heat modes that attaches into to the main board by a telephone cable( a single electronic card, no way to test it). Box is located in the wall. Not lights are "coming on" on either modes when selected. There is power into the unit(120v) , no noise, no hummin, all fuses ok

Your comments are appreciated..tks cs


Randy Godwin profile image

Randy Godwin 3 years ago from Southern Georgia Author

@cs0155--I assume there are no manual controls on the unit so how do you know the remote is operating properly? Does the AC unit utilize a wall mounted thermostat or is it located on the unit itself and controlled by the remote? just trying to narrow the problem down a bit. Thanks for the question.

--RG


cs0155 3 years ago

Thank You for your prompt response, there is no manual control or thermostat on the wall,besides the "Selector Box" for cooling or heating. The remote allows for temp setting, fan speed and other parameters. I will look for it again, just bought the fifth wheel. I found very little information regarding the ac in the manuals. Hoping you can help..carlos


Randy Godwin profile image

Randy Godwin 3 years ago from Southern Georgia Author

Sorry to be so little assistance, cso155. I don't have any info for your particular unit, but feel free to ask for more info if you think I may help.


Jane 3 years ago

Today I went outside to check my coachmen rv and heard a humming sound coming from within before I opened the door. When I got inside it had stopped, so I waited to see if it would sound again. It did. My a/c would hum about 5 seconds and cutoff. I went to the wall mounded thermostat to make sure it was off...and it was! I turned on the heater and it worked fine BUT every 3 minutes the a/c would try to come on too. What in the world could it be??


Randy Godwin profile image

Randy Godwin 3 years ago from Southern Georgia Author

Sounds very strange Jane, unless there is a problem with the thermostat which is sending a mixed signal to the AC unit itself. This isn't entirely impossible, by the way. Anything else you can tell me to help you out? Have you had any problem with the 12 volt DC system, other than the thermostat that is? Lights, fans, or refrigerator thermostat?


cs0155 2 years ago

Randy, I have solved my ac problem. I eliminated all the fancy circuit boards and remote control; by replacing it with a basic wall thermostat, using a 120V /24v transformer (similar to the ones used in a doorbell) for the low control voltage, a sequencer (relay) (similar to those used in straight cool split residential ac systems) turns on/off the compressor and the fan. I also installed a 5 amp fuse to protect the transformer in series in the 24v control circuit. The power(120v), is supplied via connection block. The thermostat senses the temp sending a 24v signal to the sequencer relay using the yellow wire (green could be used instead off yellow)turning the ac on/off as required. So far so good..... Regards. cs0155


DaveM 2 years ago

Can the roof AC cover be left on the exterior AC unit when traveling? I want to keep dirt and insects from impacting the coil and unit exterior. Can it be left on when traveling?


Randy Godwin profile image

Randy Godwin 2 years ago from Southern Georgia Author

I assume you are speaking of the AC shroud, Dave? If so, then yes, the shroud is meant to protect the coils and interior components in the unit from being damaged when traveling. If you're still concerned then I suggest you purchase an RV AC cover to cover your unit while on the road. Thanks for the question.

Randy


Kitty Prince profile image

Kitty Prince 2 years ago from Mobile, Alabama

Randy, Thank goodness I found you. We put in a Coleman motor to replace the Fasco motor. The noise is deafening and the vibration is bad enough to shake the camper. It seems to be wired correctly. What's next? Summer is on it's way in Lower Alabama. Thanks in advance.


Randy Godwin profile image

Randy Godwin 2 years ago from Southern Georgia Author

Hello Kitty, and thanks for the question. The new fan motor is obviously out of balance in some manner. Either the motor shaft itself is bent, or the fans--both squirrel cage and bladed-- are bent or have some obstruction stuck to them causing them to be out of balance.

Both the noise and vibrations are caused by the imbalance caused by either the above mentioned problems. You should be able to discern what is causing the problem, but feel free to ask for more info if needed.

Randy :)


Kitty Prince profile image

Kitty Prince 2 years ago from Mobile, Alabama

Could the weight of bolts throw off the balance? If the fan blade clamp screw is not centered on the flat spot of the shaft, would that throw it off?You must pardon my ignorance on this subject but trying to get this resolved. Again, many thanks.


Randy Godwin profile image

Randy Godwin 2 years ago from Southern Georgia Author

Yes Kitty, any type of imbalance can cause bad vibrations and/or noise when the fan is turning at a high rate of speed.

Using different types of bolts to re-affix either of the fans to the shaft of the fan motor itself can alter the balance of the blades which can and will cause bad vibrations and noise when the unit is operating. Be sure the anti-vibration rubber mounting bolts are firmly seated to the unit as they will often affect the balance also.

It isn't uncommon for a fan motor to get out of balance in the off season when mud daubers build their nests inside or on the blades of the fan. Hope you find the problem as the new fan motor should have fixed the problem. As always, feel free to ask for more info if needed.

Randy


Kitty Prince profile image

Kitty Prince 2 years ago from Mobile, Alabama

Dude, you are the best. I narrowed it down to a faulty fan blade. Whoop, whoop. You are an r/v genius. Thank you.


Randy Godwin profile image

Randy Godwin 2 years ago from Southern Georgia Author

I'm so glad you found the problem, Kitty! Just in time for the camping season too. It always makes me feel good to have helped my readers solve a problem with little or no cost to themselves. I hope you'll check out my other RV articles if you ever have any more problems in the future. Thanks again for the question, Kitty! :)

Randy


Doug 2 years ago

Have a 2008 5th wheel camper with the following AC problem. The unit/fan will not run when you turn it on. It will run after you spin the fan with your hand and run fine, then when it has to kick on by itself again the fan will not turn. Where should I start to trouble shoot this problem? Thanks. Sorry but I hate to pay dealer tech prices if I can do it my self.


Randy Godwin profile image

Randy Godwin 2 years ago from Southern Georgia Author

Hello Doug, your problem is more than likely the start/run capacitor which controls the fan. It is relatively inexpensive to replace and easy to change out. Having to start the fan with your hand is a good indicator the capacitor is bad. Thanks for the question and if you need more help please feel free to ask for more info. :)

Randy


Doug 2 years ago

Thanks Randy, I will try and take a look at that this weekend and get the part ordered before spring break time. I will let you know if that fixed the problem. Love this information site.


Randy Godwin profile image

Randy Godwin 2 years ago from Southern Georgia Author

Thanks for visiting, Doug! Good luck and please do let me know if the new capacitor solves the problem. Check out my other RV repair articles for any other problems which may arise.


Doug 2 years ago

Hey Randy, got the numbers off the AC unit on Sunday and took pictures of them. Now looking on EBay for the correct parts I need. My unit is a CSC model # 833508564 serial # 060712278. I had 2 capacitor's on my unit. One is a 2 prong ( short oval) and one is a 3 prong (round). Which one is the run start capacitor. Or just change both while doing it. I am guessing a RV parts store has them or can order them but would probably be higher than on eBay . Thanks for you help Doug


Randy Godwin profile image

Randy Godwin 2 years ago from Southern Georgia Author

Doug--If you have a digital multimeter--or have access to one--you can check the capacitors to see which one is bad. Set the meter to OHMs and touch the terminals with the probes being careful not to touch them with your fingers.

The meter should show a random number which gradually decreases in value if the capacitor is bad. I believe the fan capacitor would be the two-prong one, but I'm not sure on your unit.

Randy


Doug 2 years ago

Hey Randy, sorry it took me a few days to get back with you. Got the parts ( it was the short oval capacitor with 2 wires , fan capacitor )took the old one off , put the new one on ( plug and play ) turned the AC on and it started running . Thanks for all your information, it saved me a RV repair Tech cost. This is a very helpful site. Also buys your parts off the internet, much cheaper than RV store. Thanks again for your help. Doug in Georgia


Randy Godwin profile image

Randy Godwin 2 years ago from Southern Georgia Author

Good to hear , Doug! So pleased you found my article helpful and I'm sure you saved a few bucks repairing your AC yourself. Check out my other RV repair articles by going to my profile if you need any other RV repairs in the future.

And thanks for getting back to me with the good news. :)

Randy


James 2 years ago

Hey Randy, I have an older model coleman 13,500 btu unit. It comes on and runs for about 5 minutes then the fan cuts off and I can hear the compressor still running. If I just leave it on the breaker will flip in about a minute. You can cut it off for about 15 minutes and do it all over again. I checked up top and it seamed that the fan motor was getting really hot so I replaced it and the fan capacitor and it still does the same thing. What else could be causing this?


Mike 2 years ago

Randy, I am having the exact same problem that James is referring to on my Coleman Mach series unit. Any ideas on what could be causing this would be greatly appreciated. I guess I'm glad I haven't replaced the fan motor yet. But it's getting hot in Texas! Thanks in advance!


Randy Godwin profile image

Randy Godwin 2 years ago from Southern Georgia Author

@ James and Mike--I suspect the fan motor at first glance guys, but then James has replaced his already with apparently no improvement. I suggest both of you guys use an amp meter--borrow or rent if you don't have one--and check the start/run amps being pulled by the compressor. The correct start/run amps should be listed either on the compressor or on a plate nearby. This will tell you if the compressor is causing the problem or not.


Worrell 2 years ago

I have a 2000 coachmen rv with 2 duo therm roof units. I started the generator to operate the ac everything ran fine, and decided to convert the power over to 110, but now the ac and fan will not run. I have checked the breakers fuses and capacitors. My thermostat shows 12 volts at the furnace but not at the fan or ac. What would you suggest for me to check next?


Randy Godwin profile image

Randy Godwin 2 years ago from Southern Georgia Author

@Worrell--This sounds like a problem with the selector switch which changes the power from Generator to shore power. Have you checked out this switch yet?

Randy


worrell 2 years ago

where is the transfer switch located for a 2000 coachmen rv? How can I check the switch to verify that if its good?


Randy Godwin profile image

Randy Godwin 2 years ago from Southern Georgia Author

It you are referring to the switch controlling the shore power from generator power I'm not sure where it's locate on your RV. Wherever it is, I'm sure you can test it with a digital multimeter.


hoff 2 years ago

I have a 1992 Monaco crown royale with twin duo therm roof a/c units ( separate thermostats ) I ran the a/c on the gen a couple of weeks ago with no issues. I tried to run it over the weekend on the gen and now it will not work on gen or on the land line. The thermostats won't light up. I have voltage at 120v circuit breakers (separate per unit). I removed the cover on the rear roof top unit and I have no power. I am not sure if one unit powers the other ? I haven't looked at the front unit yet. Looking for any ideas

Thanks,


Randy Godwin profile image

Randy Godwin 2 years ago from Southern Georgia Author

Hello Hoff, if you have two circuit breakers then one unit doesn't power the other. This may be a thermostat problem as you have separate controls. Am I correct in understanding that neither AC unit will operate?

Randy


Hoff 2 years ago

Randy,

yes you are correct neither will operate. It seem crazy that both would fail at the same time ? Do you know where I could find a wiring schematic on this system? It almost would seem that both problems would have to be connected somewhere. Are thermostats a common failure ? I have a 91 Jayco with the exact same one and have never had any issues. Thanks for the prompt response.


Randy Godwin profile image

Randy Godwin 2 years ago from Southern Georgia Author

Unless you can contact a factory representative, I don't know where you could get a wiring diagram, Hoff. Have you tried using shore power rather the generator? It probably isn't the thermostats after all. More likely a bad ground somewhere. Have you checked the transfer switch which controls the generator/shore power? Often these are a problem on some RVs.


randy 2 years ago

Both power sources have the same problem. The land line and the gen.

How could I test the transfer switch ?

Thanks,


Randy Godwin profile image

Randy Godwin 2 years ago from Southern Georgia Author

You should be able to check the transfer switch with a digital multimeter.


randy 2 years ago

That's not a problem, but what am I looking for and how does the transfer switch work ?

Thanks,


Randy Godwin profile image

Randy Godwin 2 years ago from Southern Georgia Author

When switching from the shore power to the generator the transfer switch controls which electrical power the RV uses. Yours may be fully automated but some RVs have a manual switch.


hoff 2 years ago

Randy ,

I spent about 3 hrs tonight looking at the issue I have. I have power at both roof top units, I can jump the power and get all fan speeds and the compressor to kick on but I still have no power at thermostats. I even removed my thermostat from my jayco and swapped them out and it made no difference. I am leaning toward the circuit boards on the rooftop units. Just thrown how both units could fail at the same time. Thinking possible power surge from gen or shoreline? Are these common for failures that you are aware of?

Thanks,


Randy Godwin profile image

Randy Godwin 2 years ago from Southern Georgia Author

Yes Hoff, power surges and lightning strikes could very well affect the circuit boards in your AC units as well as from the generator.


hoff 2 years ago

FYI I did replace the board with one from my jayco and it eliminated the problem

all works fine , just can't find a board replacement

Thanks,


Randy Godwin profile image

Randy Godwin 2 years ago from Southern Georgia Author

Thanks for reporting that the circuit board was the problem, Hoff. Good luck finding replacements and I hope you do so for a reasonable price.

Randy


Ruth 2 years ago

Hi. We have a 2012 Lacrosse and the AC quit. An error code of E1 is showing on the thermostat. We have had the AC checked and the person said the AC unit is fine. We have replaced the thermostat and checked the breakers. All this and no fix. I know the error code means loss of communication between the thermostat and the AC unit. We are at a loss on what is wrong. Please help!


Randy Godwin profile image

Randy Godwin 2 years ago from Southern Georgia Author

Who checked the AC out for you, Ruth? Did they check the capacitor(s) out too?

Randy


Tish 2 years ago

Hi' hope u can help me I have 2014 wildwood rv trailer and for some reason my ac is blowing hot air can you tell me what I need to do please . Greatly appreciated . Thanks


Randy Godwin profile image

Randy Godwin 2 years ago from Southern Georgia Author

Can you tell if the compressor is kicking on or not when you turn the thermostat up and down, Trish?

Randy


Jim 2 years ago

RV Roof top AC not even trying to turn on. Thermostat works for the separate Propane furnace. Thermostat also has a switch for "fan only/ hi/low" BUT... I did not check if the fan works ala this switch on the Thermostat. (83 miles away right now). If the fan works via that switch, then does that mean that power is also also getting to the AC mode in general? Then, could it be a relay? Circuit breaker is OK (on). Is there some sort of lock out? DuoTherm. Thank you thank you thank you.....


Randy Godwin profile image

Randy Godwin 2 years ago from Southern Georgia Author

Hi Jim,

Just had a question similar to yours and it turned out to be the control circuit board. The thermostat sends a signal to this board which then activates the AC unit. Let me know if the fan works when you get a chance. I may have more questions for you to narrow the problem down.

Randy


Natalie 2 years ago

Hi have a dometic 2600 the light on the unit inside the van is not lighting up and the unit is not responding to remote control the fan is working ok and the compresser works for a few minutes then cuts out I can't turn matchine off has button on unit is not working and has I said it's not responding to remote control ?


Randy Godwin profile image

Randy Godwin 2 years ago from Southern Georgia Author

May be a control circuit board problem, Natalie. I've had a bunch of problems lately with this circuit board failing to operate the AC properly. Anything else you can tell me?

Randy


Bill 2 years ago

Hi we have a roof top ac. The fan would come on but no cold air. We bought a new ac and we are still having the same problem. What could be the problem?


Randy Godwin profile image

Randy Godwin 2 years ago from Southern Georgia Author

Hello Bill,

Does your AC have wall mounted thermostat or are all of the controls on the unit itself? It sounds like a thermostat problem at this point. More info may help me advise you.

Randy


Bill 2 years ago

Yes, it is a wall mounted thermostat.


Randy Godwin profile image

Randy Godwin 2 years ago from Southern Georgia Author

That could be the problem if the new unit is performing like the old one.


dennis 2 years ago

i have a travel trailer and ehe I turn the ac on manuall, it will bog down, cool for 30 sec or so and then kick off blowing cold air and it appears the fsn kiks on. the fan setting work just fine. any suggestions?


Randy Godwin profile image

Randy Godwin 2 years ago from Southern Georgia Author

This sounds like the compressor is pulling too many amps, Dennis. If you have access to an amp meter you can check if the compressor is going bad or is already having problems. Anything else you can tell me?

Randy


Anne 2 years ago

Hi, we have a coachmen rv freedom express 2012 and it didn't come with a manual for the ac. My son was turning the unit on and off and now it runs in an energy save mode when on cool. Meaning, the fan shuts off in between when the compressor is not running. It used to blow air all the time even when he compressor wasn't running, which is the setting we need. Any ideas? Thanks.


Randy Godwin profile image

Randy Godwin 2 years ago from Southern Georgia Author

Hello Anne, there should be a 'continuous fan' setting on the thermostat you can set the unit to. Otherwise, I'd suspect the thermostat as being the culprit causing the problem.

Randy


Anne 2 years ago

HiRandy, the continuous fan setting doesn't cool, just blows air. I'm looking for the cool air to run continuously while cooling with compressor on and also in between when temperature is reached but compressor is off.


Randy Godwin profile image

Randy Godwin 2 years ago from Southern Georgia Author

@Anne-Is there an 'energy saving' mode on the thermostat as well as a normal mode? If so, I still suspect the thermostat of being at fault. Did the AC unit run the fan all of the time in the past when cooling?


Derrek 2 years ago

Hi Randy,

Just purchased a 2012 Keystone Raptor 4014LEV Toy hauler about 2 months back. The I have two roof mounted a/c's and a portable a/c in the garage in the back. I have tried cleaning the coils on the back of the unit and that helped some, but last night when I got home (we are full time rv'ers) the a/c wasn't blowing cool air at all. At 10 PM last night the temperature on the thermostat was reading 75 degrees with all 3 a/c units running. The portable unit in the garage area is an 8,000 BTU, the main unit in the Living Room/Kitchen area is a ducted Coleman Mach 15,000 BTU, and the A/C in the bedroom area is a 13,500 BTU. The A/C in the garage blows ice cold and the 13,500 BTU blows ice cold. What do you think this problem could be? As well the filter is clean on the unit that is giving me trouble, but I have read a little bit in here about the evaporator coils possibly needing to be cleaned? Can you get the coil cleaner at like Lowe's? I should also mention that when you open the vents on the main unit to let air drop directly down it blows hard, but is still not cold; and when you close them to use the ducts you can feel very little air blowing throughout the ducted vents. Even the vent that is very close to the main unit is barely getting any air and it seems that the unit is bogging down a bit. Have been fighting this issue in the Texas heat this summer, and trying to get the temperature down from 85-90 degrees inside the trailer down during the heat of the day. Any help that you may be able to provide is greatly appreciated. Thank you SO much and I'm sure my fiancé and son will thank you too!


Randy Godwin profile image

Randy Godwin 2 years ago from Southern Georgia Author

Hello Derrek. I hope I can help you figure out the problem as I can idntify with you during the heat of the day here in south Georgia. Yes, the evaporator and condensing coils need to cleaned occasionally as the filter doesn't always capture all of the dust and debris with some collecting on the coils eventually. There should be some inexpensive coil cleaner sold on this page, but in a pinch you can use any household cleaner such as 409 or similar solvents. Make sure they are approved for aluminum before you use them. Let me know if this helps anything and for more advice if you need it.

Randy


Anne 2 years ago

Hi Randy, the three options on the temp control pad are 'fan' 'cool' and 'heat". Yes the ac unit ran the fan continuously in the past when set to cool. When temp was reached you could hear the compressor shut off but the fan still blew, and then when the temp rose again you could hear the compressor kick in, but always there was air blowing. My son was cycling the unit through the three options the other day (he is three) and now it stops blowing in between cooling. On another note, we also have to always shut off the fuse to the air to run the heat otherwise the air continues to blow in addition to the heat. But that has always been since we bought the camper (haven't had a chance to fix that yet bc we don't have the manual).


Randy Godwin profile image

Randy Godwin 2 years ago from Southern Georgia Author

Anne, this narrows the problem down to the probability of it being either the thermostat or the control circuit board in the AC itself. I'd try replacing the thermostat--or finding someone to check it out--before replacing the more expensive circuit board. I'm just guessing at this point though, so take my advice with a grain of salt if you will. Electrical problems are sometimes a trial and error thing. :)


Derrek 2 years ago

Randy,

I cleaned the evaporator and condenser coils last night, and put some more of the reflective insulation in the massive windows that are on that trailer. As I was going through and installing the insulation in various windows I thought about the big skylight in the bathroom. I took it down and put a piece of the reflective bubble wrap insulation. A flash of light caught the corner of my eye, and I think I have found what my problem may be with the air flow. On each of the ducted vents the manufacturer, Keystone, only put reflective tape between the duct and the vents, and the vents are leaking air into the roof between the paneling and the rubber roof. Talk about cool when I pulled that skylight down. So as you can imagine I felt like a dummy. I'm going to try to cut this story short. I have air escaping into the "attic space" on my fifth wheel. Do you know of something that could better insulate/connect the ducts to the holes in the roof where the vents are? Thanks so much, and as an update, it was a brisk 68 degrees in there this morning when I got up; but still not very much air flow through the ducted vents. Thanks again for any info you may be able to provide.


Randy Godwin profile image

Randy Godwin 2 years ago from Southern Georgia Author

Hey Derrek, I neglected to address the airflow issue in your last post. My fault as I didn't re-read your comment so I missed it. Ordinary duct tape should seal up the leaking vents if you can get to them. These ducts are notorious for leaking and, in some cases, collapsing in on themselves and restricting the airflow from the AC unit.

Please let me know if and when you get the problem solved so I can pass on the fix to other RV owners. Thanks!

Randy


Rob Hunter profile image

Rob Hunter 2 years ago from De Soto, Kansas

Randy, I have a 1992 coleman popup, the other day i tried turning on the rooftop a/c, and it sounded like the compressor was havinghaving problems starting, it was shaking and sounded like it was chugging. The fan worked fine and didn't vibrate or anything. A couple days later it seemed to turn on fine. Last weekend the fan runs, but it sounds like the compressor will not turn on, and will not cool. But like I said, I'm not sure the compressor might be on, but I dont think so. Plshelp! Thank you

Rob


Randy Godwin profile image

Randy Godwin 2 years ago from Southern Georgia Author

Hello Rob, you probably need to use an amp meter to check the compressor to see how many amps it's pulling. If it's using more start/run amps than is listed on the compressor or on a plate nearby it is either going bad or is already bad. You may try replacing the capacitor which starts the compressor if it isn't starting right up when you first turn the AC on.

Randy


Rob Hunter profile image

Rob Hunter 2 years ago from De Soto, Kansas

Thank you randy. I will give it a try.


Trevor 2 years ago

Hi randy. I have a 2005 coachman trailer. I took it out for are first weekend camping and the air works great but after 3 to 4 hours it freezes up? One thing I noticed was there is no " click" sound on the thermostat when setting the temp. Also the compresser never seems to shut off? Any thoughts?


Randy Godwin profile image

Randy Godwin 2 years ago from Southern Georgia Author

Hello Trevor, you may have a bad thermostat. Is it wall mounted or on the AC itself?

Randy


Trev 2 years ago

Wall mounted. I also forgot to mention that it will not shut off now? Just keeps running? I have to use the breaker to turn it off.


Randy Godwin profile image

Randy Godwin 2 years ago from Southern Georgia Author

Sorry to take so long to respond Trevor, but I had to be offline for awhile. I suspect the thermostat at this point, but it could also be the control board causing the problem. I lean towards the thermostat because you stated it didn't 'click' when you were setting it. Replacing the thermostat is the most economical of the two components at any rate.


Trevor 2 years ago

Thx Randy I will give it a try. Can I use a normal house thermostat ? Or does it have to be a RV pacific thermostat?


Randy Godwin profile image

Randy Godwin 2 years ago from Southern Georgia Author

I'm not sure about using a house type thermostat, Trevor. You can check the present one, but I'm sure it uses a 12 volt DC power supply to control it.


Trevor 2 years ago

Ok thx Randy. I will let you know how I made out.


Trevor 2 years ago

Well I got the new thermostat in but as soon as I turned the breaker back on the air came on. Even thou it was in the off position. So next step is a new control board I guess? Is that something I can do or is that a dealer project ?


Randy Godwin profile image

Randy Godwin 2 years ago from Southern Georgia Author

Please do, Trevor. It may help others with the same problem. :)


Randy Godwin profile image

Randy Godwin 2 years ago from Southern Georgia Author

Sorry that didn't fix the problem, Trevor. Depending on the type AC you have it's usually a plug in component. Amazon sells these parts as I've sold a few from the links on this page. I hope a new one fixes the problem as it has for others in the past. Good luck!


Trevor 2 years ago

Well thx again for all your help Randy. I will try a new board and let you know how I made out!

Trevor. Ontario , Canada


Jeff 2 years ago

Hi Randy, I have been experiencing similar problem where compressor keeps running, and I have to use the breaker to shut it down. Where is the control board located? on the roof? or inside? It is a Duotherm/Dometic.

Thanks


Randy Godwin profile image

Randy Godwin 2 years ago from Southern Georgia Author

Hi Jeff, not positive on your model but I'd think it would be accessible from the inside of the RV.


scott 2 years ago

OK sir,I have a 95 winning dual air. Conditiioners was driving with both air's on started to smell wire burning so I couldn't stop for a little when I did could not find anything we are in Phx with dogs. Anyway my wife set the airs at 70 which I've learned in the past not very good for the generater . well then all of a sudden the front unit smokes the board what would cause this ,the high voltage side of the board is all that burnt any suggestions would be appreciated .


Randy Godwin profile image

Randy Godwin 2 years ago from Southern Georgia Author

Hello Scott, It's possible the generator wasn't furnishing enough amps to fully power both AC's with the thermostat set at 70 degrees. Can you run the units individually or are they both controlled by one thermostat?


Scott Alexander 2 years ago

I have an Airxcel RV roof unit (mod 8333D876) with a compressor that will not shut off, freezing us out overnight. I just replaced the thermostat, but still no cutoff. Various sites around the web seem to point to the relay, but according to the manufacturer's diagrams I have a "PTCR Device" instead. Should this be my next attempt?


Randy Godwin profile image

Randy Godwin 2 years ago from Southern Georgia Author

Hi Scott, you may have a control board problem as I've encountered a lot of them lately. Relays were once used in older AC's but now most are incorporated in a circuit board which is relatively easy to replace in most models. Not cheap in most cases though. A low freon charge will also make the coils ice up right before the charge is depleted completely. Probably not your problem though.


Trevor 2 years ago

Hi Randy. It's Trevor again with the 2005 coachmen. To make a long story short I got the new control board however they have discontinued my board and gave me a newer board. The original pt# was 3107541.009. New up dated one is 3313379.000. On the new board there is one plug missing the original had . However it does have one other type of plug on it my original does not have on it? I am at a bit of lose as what to do now? Any ideas?


Randy Godwin profile image

Randy Godwin 2 years ago from Southern Georgia Author

Wow Trevor, I'm at a loss as to what to tell you about this problem. The place you got the new board from couldn't advise you as to how it should be adapted? There may be a simple adapter plug made just for your application available if you just know where and who to ask. I'm sorry to say that person is not me. I will try to find out something tomorrow if I get the chance. Surely others have had the same problem.

Randy


Trevor 2 years ago

Ok thx Randy


john 2 years ago

hi all, i have a 1995 coleman 7330-720 roof a/c and it seems the compressor is on all the time. when i turn off the unit i can hear the compressor still running and have to turn off the breaker for it to stop. i removed the inside cover and removed the compressor relay yellow wire and it stops the compressor. does it sound like the relay needs to be replaced. when i get the part i know i need to turn off the circuit breaker but to i need to watch out for the capacitor wires or will i get a shock removing the wires. they are larger purple wires and i think its a capacitor but dont know if i could get a jolt from them.


Randy Godwin profile image

Randy Godwin 2 years ago from Southern Georgia Author

Hey John, does your unit operate from a wall mount thermostat rather than one on the unit? And yes, you may have a bad relay causing the problem but it also could be a bad control board depending on the model.

Yes, the capacitor stays charged and can shock you if you use uninsulated pliers to remove the connections. Please ask if you have more questions and I'll try and help you narrow the problem down.

Randy


Ashley Morris 2 years ago

I have a Duo Therm rooftop AC on my 99 Holiday Rambler. A few things are happening:

1. The front unit will make a clicking noise in the control box even when the thermostat is off.

2. The unit will start when using the generator, but more often than not the front unit tends to kick the breaker after start up.

I don't know if these two things are related, but I would like your opinion. It seems as if I could be looking at a capacitor going bad???


Randy Godwin profile image

Randy Godwin 2 years ago from Southern Georgia Author

It is possible the capacitor is to weak to get the compressor started and this may be causing the breaker to trip, Ashley. Anyway, it may be worth a try to to test the capacitor with a meter set on OHMs. It should register a random number which decreases in value if it is good. Worst case scenario is a compressor going bad.

Randy


DENNY JOHNSTON 2 years ago

I have a 1997 22' Fleetwood Class C with one Coleman rooftop A/C that is still cooling OK, but at times, will not cycle off, leaving us very cold inside. I replaced the thermostat, but nothing changed. It works and cycles OK about half of the time. Is it just the really hot weather I am experiencing while going through the desert SW ?


Randy Godwin profile image

Randy Godwin 2 years ago from Southern Georgia Author

Hi Denny,

It could be the weather but it also could be dirty coils or a malfunctioning control board since you've already replaced the thermostat. Dirty coils can make the compressor overheat and may cause it to run longer than normal. If the coils are clean I lean towards the control board being the problem. Is there anything else you can tell me? Sometimes a low freon charge can cause the AC to put out ultra-cold air before it totally stops cooling at all.

Randy


Rick 2 years ago

I have a 98 Coachman Roof top A/C that the fan will run, but there is a low hum and the lights will dim in the camper for about 2 seconds and then the hum kicks off and fan keeps running. It will keep "trying" to kick on but will never get the compressor running to cool. The thermostat is on the unit itself.


Randy Godwin profile image

Randy Godwin 2 years ago from Southern Georgia Author

The capacitor which starts the compressor running may be bad, Rick. It's easy to replace and not very expensive in most cases. There;s usually 2 capacitors, one to start the fan and one to start the compressor.

Randy


Charles Duer 2 years ago

Would hot weather have an effect on A/C on a class c motor home rooftop unit. My problem is the a/c will run for a time, then it trip the breaker. And that is with the genrator or 30 amp goundline.


Randy Godwin profile image

Randy Godwin 2 years ago from Southern Georgia Author

Hello Charles, if the coils are very dirty it will cause the compressor to overheat and kick a breaker. Sorry so long to respond but I'm away from home and my computer is on the blink.

RG


willie king 2 years ago

hello randy my ac unit in my camper trailer was tripping the breaker every now and then but now when you put the thermostat on cool it just makes a clicking sound in the ceiling


Randy Godwin profile image

Randy Godwin 2 years ago from Southern Georgia Author

Sounds like you may have compressor problems, Willie. You may try a new starting capacitor before going to the expense of changing to a new unit. Have you checked the start/run amps on the compressor yet to see if it's pulling too many amps? This a sure sign of a bad compressor. I hope this isn't the case. :(

Randy


Debra 2 years ago

We just bought a Coachman cadet and the air condition runs for about 3 min. and then shuts off. The filters are clean. the coolent refilled. Not sure what is wrong.


Randy Godwin profile image

Randy Godwin 2 years ago from Southern Georgia Author

Debra, the coils may be dirty and causing the AC to overheat.


Ben Macias profile image

Ben Macias 2 years ago from Mount Calm, Texas

Randy, our a/c unit in our rv has suddenly started vibrating making it really loud and annoying. my husband went on top the roof to investigate and discovered that the rubber washers in the motor mounts were worn and broken. He replace them with metal washers and broke a bracket in the process. What can we do to fix this hiccup?

its a 2012 dometic duo therm


Randy Godwin profile image

Randy Godwin 2 years ago from Southern Georgia Author

Hi Ben, or Mrs. Ben. Is the broken bracket the main problem, or is the problem both a broke bracket and the worn rubber grommets used to keep the vibrations down?

There is a universal bracket kit sold for replacing an outdated motor with one of a different model or make. Usually they are found at an electric motor supplier or one which repairs them. You may also find some replacement rubber washers at such a place. Try googling for them as I don't have any info as to where to look for them either.


Paetyn Vaughn 2 years ago

The AC on my RV only runs on fan mode. When it is turned on to just fan, the fan spins and it blows air. When I switch it to AC, or cool mode, the ac just makes a humming noise and no air blows out. Fan works on all settings, high and low. AC just makes the humming noise on all the settings, high and low, and no air blows out at all. Thank you!


Randy Godwin profile image

Randy Godwin 2 years ago from Southern Georgia Author

Hello Paety, this could be a bad capacitor as some AC units use only one capacitor to start both fan and compressor. The shroud has to be removed to get access to the capacitors but you may need some help as they hold an electrical charge and you could be shocked by touching them with your bare hands. I hope this info helps a bit but there could be other causes for the problem.

--RG


thomas 2 years ago

I have 1986 jayco rooftop ac runs for about an hour then fan quits running an ihear a humming .I shut it off for five min and it works for awile then dose the same thing


Randy Godwin profile image

Randy Godwin 2 years ago from Southern Georgia Author

Hi Thomas, does the fan have oil ports for the bearings? If not, I'd try oiling the sleeves on each side of the motor to see if they are getting hot and causing the problem.

Randy


Marie Fay 2 years ago

Hi

We have a 2014 Cedar Creek and the air conditioner is dripping around the output in the bathroom. What can we do?


Randy Godwin profile image

Randy Godwin 2 years ago from Southern Georgia Author

Hey Marie, you simply need to clean both coils in your AC. It's an easy chore if you use a special coil cleaner or a bit harder using a household cleaner such as 409. There is an expensive coil cleaner on this page but if you use that ad there are some other more affordable coil cleaners listed.

A good wet/dry shop-vac makes the job much easier and less of a mess to deal with. When you get the coils clean the dripping should stop. Thanks for the question. :)


Paetyn Vaughn 2 years ago

Hey randy, I really appreciate the advice you gave me a couple of days ago. We replaced the capacitor (it was bad) and the AC ran for a couple of minutes then it stopped again. The fan still works, the air does not blow when AC is turned to cool. Do you have any other suggestions?


Paetyn Vaughn 2 years ago

Randy, we got it working! Thank you so much for the advice. You have saved us hundreds of dollars!


Randy Godwin profile image

Randy Godwin 2 years ago from Southern Georgia Author

I'm so pleased to hear that, Paetyn! I'm always glad to help RVers save money and time. Thanks for coming back and telling me how your problem turned out. :)

Randy


Jessie 2 years ago

Hello Randy! MY boyfriend and i just bought a trailer and are living in it year round. We live in the valley where it is quite hot and depend on our ac. The other day i took off the cover to clean the filter that recirculates the air through the trailer because one of our three ducts was not blowing out cold air very hard. The other three ducts were blowing out cold air strong but the one close to the unit itself was very weak. After cleaning the filter i restored it and now none of the ducts are blowing out cold air. I dont know if this is because there is a leak or because i caused a problem after cleaning the filter. When we take the filter off and turn it on, all the ducts blow air again but very lightly, any ideas as too what the issue is? Thanks!!


Randy Godwin profile image

Randy Godwin 2 years ago from Southern Georgia Author

Hello Jessie,

I can't imagine what you could have done to cause the problem to get worse by cleaning the filter. I had a reader tell me he found out his ducts were leaking cold air into the space between the roof and ceiling because the duct tape used to join the ducting together had deteriorated, This can happen when the ducting is in the floor also.

Another thing causing low airflow is dirty coils. When they get clogged with dirt and gunk--no filter catches all of the grime--the efficiency of the AC suffers along with the airflow. Feel free to ask for more info if needed. Thanks for the question. :)

Randy


Doug 2 years ago

What would cause my a/c unit to kick on and off consistently after reaching the desired temperature and eventually causing it to trip the breaker?


Randy Godwin profile image

Randy Godwin 2 years ago from Southern Georgia Author

Might be a low freon charge, Doug. How old is the unit?


joy 2 years ago

My ac keeps bogging down every few mind and smells very hot like electrical hot. It is also not blowing very cold air like usual. I went on the roof fan spinning fine and it appears to be clean. Me and my babies are HOT any ideas could it be low on freon maybe. The fan mode works just fine also


Randy Godwin profile image

Randy Godwin 2 years ago from Southern Georgia Author

Hi Joy,

Your smelling the described aroma is indicative of either a bad capacitor or compressor. Even though the coil may appear clean from the outside it may be very dirty as the unseen side of the coils is where the dirt collects.

I hope it is either the start/run capacitor or dirty coils as a bad compressor usually requires a new AC. Feel free to ask for more info.

RG


joy 2 years ago

Thank u so much for answering my question:-) is the capacitor something we can locate and check ourselves or should I leave it to a proffesional?


Randy Godwin profile image

Randy Godwin 2 years ago from Southern Georgia Author

The capacitor(s)-- there may be one each for the fan motor and compressor-- simply plugs in and looks a little like a battery. This link will show you what they look like:

http://www.amazon.com/s/ref=sr_pg_2?rh=i%3Aaps%2Ck...


Doug 2 years ago

Thanks Randy for taking my question....I bought the camper used

it's a 2005 so I would say it's the same age.


Randy Godwin profile image

Randy Godwin 2 years ago from Southern Georgia Author

Several things cause this problem, Doug. I'd try cleaning the coils first as the compressor may be overheating if the airflow isn't sufficient through them. Clean coils help the AC cool better also.


Sharon 2 years ago

we have a Coleman roof AC on our Fleetwood. It just started leaking inside the RV, not from around the perimeter of the unit but from inside of it. We can't find trouble shooting info or schematics. Where are the weep holes ? We figured that would be the first place to start in the process of elimination. Thanks !


Randy Godwin profile image

Randy Godwin 2 years ago from Southern Georgia Author

Hello Sharon,

More than likely the coils are so dirty the fan can't disperse the excess moisture into the air causing the water leak down inside the RV. A good cleaning with coil cleaner will more than likely cure the problem.

The newer Rooftop AC's usually don't have any drain holes like the older models but it is possible they are clogged if your unit drained the excess moisture where you've noticed it before. This link may help:

http://www.amazon.com/s?ie=UTF8&field-keywords=ac%...


John c 2 years ago

I have a 1986 popup with Coleman roof ac with heat cool good but when compaser shout off it get warm inside before it comes on where it use to run all the time an when you turn control knob off fan still runs you have to unplug to turn completely off an as sone as you plug it in the fan runs.


Randy Godwin profile image

Randy Godwin 2 years ago from Southern Georgia Author

Hi John, it sounds as if you need a new thermostat in your AC unit. It could also be a control switch issue. Anything else you can tell me about the unit?

RG


Jim Shurtleff 2 years ago

John, In my Colman 733B887 ducted AC unit I replaced the existing electronic board with the new modification. I have 115v power to unit but can not find/get any low voltage to T-stat! where is it? i see no transformer nor can I pull up any DC Voltage. I was successful once only getting fan to run I think by using 12v power from heater stat wire. Help

jim


Randy Godwin profile image

Randy Godwin 2 years ago from Southern Georgia Author

I cannot advise you on this problem, Jim. I don't have a schematic to look at for your model AC. Sorry! :( Perhaps the company could help you?

Randy


Ken Murray 23 months ago

Randy, I have a duro therm a/c. Just bought the camper. I have read all of the post and you are a good person. Lots of help.

My problem is I know nothing about electricity nor camper a/c. A/c will not start. The fan runs when I turn it to fan. But a/c won't kick on. Like I said the fan runs when turned to fan but when turn to auto, nothing. When I move the temp setting up or down there is no clicking or noises. Where do I start?


Randy Godwin profile image

Randy Godwin 23 months ago from Southern Georgia Author

Hi Ken, is your AC controlled by a wall mounted thermostat? Or is it on the unit itself? If it is a wall mount, the thermostat could be malfunctioning. Not that a AC mount couldn't be bad, it's just a wall mount would be more susceptible to going bad. Either way, you should hear a click if the stat is working properly. The fan should probably run on auto anyway if the thermostat isn't at fault. Feel free to ask for more info if you need it. :)

Randy


Ken 23 months ago

Randy it is a wall mount. I have another camper that when I move the air setting up and down I hear a click. With this one nothing.


Ken 23 months ago

Can I get the thermostat checked or just go buy a new one.


Randy Godwin profile image

Randy Godwin 23 months ago from Southern Georgia Author

A new thermostat will usually cost less than having your old one repaired, Ken. They are easy to install if the color coded wires match up.


Guy Roberts 21 months ago

I have a 1991 Alumalite I purchased about 4 years ago & been living in year round here in Florida. The rooftop unit is a Duo-Therm BriskAir. Within the past 3 days I turned the A/C on due to higher temps. I had to turn the thermostat 1 notch from the lowest setting to hear the compressor come on, Last night around bedtime I noticed there was no air coming from the vent. I pulled the filter & saw the coils were frozen up. After reading the posts above, I see I can try to clean the coils. Should this be done front the bottom (or inside the camper as well as from the rooftop with the cover removed? Also, if there are connections for recharging, are the connections a different size indicating what type of refrigerant to use?

I might add I do not have a means of transporting this 5th wheel. When I purchased, I made arrangements to have delivered to my property where we are building a permanent residence


Randy Godwin profile image

Randy Godwin 21 months ago from Southern Georgia Author

Hey Guy,

The coils may be frozen due to a low freon charge or from dirty coils. I hope it is the latter in your case. When cleaning the coils on the Rooftop AC, you should be able to clean both condenser and evaporator coils from the top. Be sure and cover the hole where the filter goes to keep the dirt and debris from leaking down on the floor.

As for the AC recharging ports, I doubt seriously there are any unless the unit has been recharged since it was new. I'd try cleaning the coils before recharging the freon.

Randy


Pam 20 months ago

Randy ,

My A/C is a DUOTHERM DOMETIC , When it turns on it cool fine , after a few minutes , it seems like a short power surge , you can hear the difference , goes down, goes back full force! i went up top removed cover fan turns fine by hand, coills look pretty clean. Any ideas ?

Thanks , Pam


Randy Godwin profile image

Randy Godwin 20 months ago from Southern Georgia Author

Hi Pam, does the AC continue to surge as long as it is operating? And does it cool okay even though it's surging? If so, it may be a bad capacitor causing the surging. Let me know if I can be of more help. :)

Randy


Chuck 20 months ago

Hi, I have a dometic roof ac.

When ot reaches set

Temp the unit shuts off but then continues to come on and go off again. I was thinking thermostat but according to earlier post it could be low on freon?? How can i tell ??


Randy Godwin profile image

Randy Godwin 20 months ago from Southern Georgia Author

Hi Chuck, usually when a unit gets low on freon it gets really cold right before it runs completely out. Hopefully it is just the thermostat.

Randy


Chuck 20 months ago

Ok. Thanks a bunch !!


Mark 20 months ago

Randy, my thermostat does not work on my 2002 Holiday rambler Motorhome. I bought new one and it won't power up either. Checked the 3 amp fuse at the control box. Any thoughts?


Randy Godwin profile image

Randy Godwin 20 months ago from Southern Georgia Author

Hi Mark, what voltage are you getting at the thermostat? I assume you you have a wall mounted stat? Does it make a clicking sound when it is turned to a cooler temperature? A bit more info may help me assist you with the problem.

Randy


Joe 19 months ago

Hi randy I got a duo therm roof top ac unit. And I just recently took the motor apart and freed it up from being frozen. Now the fan and everything works good and when switch to ac the compressor I can hear kick on and blows really cold then come back little later and is just blowing about the temp of the fan air? Ideas?


Randy Godwin profile image

Randy Godwin 19 months ago from Southern Georgia Author

Hey Joe! This could be a capacitor problem as it's possible it may be getting hot after a bit of running and fails to start the compressor when it is suppose to give it that extra power jolt. I think I described how to test a capacitor in this article.

Do feel free to ask for more info if the cap is good, Thanks for the question and your time. :)

Randy


Jim 19 months ago

My wife has a trailer with a Coleman roof top AC. How do you get access to the blower wheel to see if the fins are clean? Does the motor and blower wheel get removed from the top outside of the unit as an assembly? I don't see how to access the fan otherwise. I am concerned the blades have built up with dust and debris and want to inspect or clean it, to make sure it is pushing the air properly.


Randy Godwin profile image

Randy Godwin 19 months ago from Southern Georgia Author

Hi Jim, and thanks for the question. To access the squirrel cage fan it is necessary to remove the covering from atop the unit above the fan itself. Depending on the age of the unit there are several ways of doing this.

Usually the covering is attached with 1/4 inch nut driver screws and are easily removed and replaced after the cleaning is done. However, the cover may be a combination of screws and insulation. I hope yours is the former.


Dave 19 months ago

Hi, Randy. Great site. We have a 2015 Jayfight 32BHDS that we got in December. It has two Coleman Mach rooftop units (15K BTU main ducted unit with wall-mount thermostat and a 13.5K BTU unit in front bedroom with controls in shroud at ceiling integrated with unit). We've camped several times using AC with no problems. Last weekend I was running only the main 15K unit and it ran most of the afternoon and night. The next morning no air was coming out of ducts. Upon inspection I found that my evaporator coil had iced up. We shut it down and just ran the 13.5K front unit Sat and Sunday. Both evap and condenser coils are pristine (as you would expect on new trailer). Could this just be normal reaction to user (me) error? We had thermostat set pretty low (65-70) and nighttime temps outaude got down into the 60s. Fan was on Auto and unit ran pretty much constantly. From all I've read online since we got back it sounds like I should have had thermostat set higher (ex. 78) and had fan set to "On" (instead of Auto) and "High". Appreciate any advice.


Randy Godwin profile image

Randy Godwin 19 months ago from Southern Georgia Author

Hello Dave, yes you probably had the thermostat set too low which caused the icing you've described. It's actually better--and perhaps easier on the two AC units--to always run both of them when you desire the temperature lower in the camper. Running only one of the units at a lower temp can cause problems. Thanks for the question and for reading my RV repair hubs. :)

Randy


Dave 19 months ago

Randy, I wanted to add that it appears my freeze control sensor had become disconnected from the evap coil. When I removed my filter cover and shroud from ceiling, a white wire was hanging down. Several veteran RVers on RV tech forums have said it is the sensor and they are notorious for coming loose. Wanted to pass that along in case it helps someone. Thanks again!


Randy Godwin profile image

Randy Godwin 19 months ago from Southern Georgia Author

Thanks for coming back and relating the fix, Dave.I 'll keep that in mind for future reference. :)

Randy


Glen 19 months ago

Hi Randy, I have a 2015 salem Hemisphere 300BH with a dometic thermostat that is showing the E1 error. The problem I have is that the A/C will not cut out. The only way to cut out the A/C is to turn off the breaker. Then I can not get the fan or furnace to come on.

Any idea's?


Randy Godwin profile image

Randy Godwin 19 months ago from Southern Georgia Author

May be either the thermostat or the control board, Glen. The warranty should still be in effect since it is a 2015 model. Anything you do may affect the warranty on the AC, so you'd best contact the dealer or maker of the camper before trying to repair it yourself. Thanks for the question. :)

Randy


Blue Seal profile image

Blue Seal 18 months ago

Hello,

I have a 2001 Prowler with 13.5 Coleman Mach.

Live in it Mon-Fri for work. Worked fine on Friday but when I got back on Monday... It worked fine for about 5 minutes then I could hear a change in tone(louder hum) for about 20seconds then would blow warm air. After about 15 minutes it will start blowing cold air(68degrees with laser temp) again for about 5 minutes then louder Hum again start blowing warm air. interior Controls on unit not ducted. Any thoughts?


Randy Godwin profile image

Randy Godwin 18 months ago from Southern Georgia Author

Hi Blue Seal, hopefully it's a troublesome capacitor causing this problem. I say that because replacing a capacitor would be an easy fix compared to a compressor starting to go bad. I think I went into how to test a capacitor in this article using a multimeter, but if you don't see it come back and I'll go through the process. I have several AC repair articles so I can't be sure. Have you cleaned the coils before? Sometimes clogged coils will cause the compressor to get hot and kick off until it cools down enough to reset.

__RG


Blue Seal profile image

Blue Seal 18 months ago

Update:

The Campground owners took a look at it. Coil that can be seen from inside RV was embarrassingly dirty(dog,smoke, cooking oil, clay like substance) and was causing the compressor to overheat and shut down on our first truly hot day yesterday. They cleaned it with a solution until it looked new and straightened out my fins. Works great now and seems to be much more efficient. It must have been working harder then it should have for awhile. Thanks


Randy Godwin profile image

Randy Godwin 18 months ago from Southern Georgia Author

Thanks Blue Seal, most people neglect the cleaning of the coils and they do cause a few problems when they get clogged. :)

Randy


Jason 18 months ago

I have a Sprinter camper with a roof top a/c. I used it a month ago with a 5000 watt generator and the a/c worked great. I put the camper up till now. Now I'm setting it up in my back yard, where I have a 30amp hook up and the a/ c want do anything. I have a wall mounted thermostats and nothing comes on. No fan, furnace or a/c. Not even a noise. This happened last year also and a RV shop couldn't find anything wrong. In fact it started right up for them. But not for me. Help!!!


Randy Godwin profile image

Randy Godwin 18 months ago from Southern Georgia Author

Hi Jason, this could be a bad capacitor or the thermostat, among other things. The capacitor is the easiest and most economical part to replace at this point. You can check it yourself with a digital multi meter set on ohms.

It should read a random number which decreases in valuer the longer you hold the probes to the two connecting poles.


Daron L 18 months ago

Hey Randy,

Came across your sight doing a search. We have a 1998 Thor Fifth Ave. First rig we have bought. Previous owner didn't use it much last year (only 4 times) and said the AC went out at the end of the year. The unit has a wall mounted thermostat and roof top AC. It runs the furnace fine and blows hot air. Also the fan works in that mode. Any clue on what I should be checking out this weekend for diagnosing? I was going to take the cover off and check it out. Im assuming its a bad compressor or low on Freon.


Randy Godwin profile image

Randy Godwin 18 months ago from Southern Georgia Author

Hello Daron, and thanks for the question and visiting one of my RV articles. I'll need to ask a few questions to narrow the problem down a bit.

When the thermostat is set on COOL/ AC, does the unit try to start up and does the fan run? If not, my first guess is that it may be a capacitor. You may have two capacitor, one to start the compressor and another to run it, or your unit may only require a single combination START/RUN capacitor. let me know if I'm understanding the problem correctly.

Also, if you want to know how to test a capacitor then see the post right above your question.

Randy


Daron L 18 months ago

Hey Randy,

When you turn on the AC on the thermostat, the fan starts up and you would think the cold air would start blowing out. Sort of sounds like its going to kick on. Im not on site yet but will be tomorrow. So not sure if there are 2 capacitors as you mentioned. With the fan starting up could it be a possible second capacitor (if there is one) or possibly freon low? Just debating if Im going to need to replace this whole unit or not.

Appreciate all your help!


Randy Godwin profile image

Randy Godwin 18 months ago from Southern Georgia Author

You'll know for sure if there's one or two caps when you remove the shroud from the AC, Daron. It may also be that the fan has its own separate capacitor to start and run it with the compressor utilizing a different one.

At any rate, replacing a capacitor could be the cheapest and easiest fix. Let me know when you start your examination of the unit if you need further advice. I'd also be interested in what you eventually find out so I may be able help others with a similar problem. :)

Randy


Alpinexplorer 18 months ago

Hi Randy,

I have a 2001 Monaco Dynasty with twin Duotherm Penguin A/C units. A few days ago we were running the units and noticed an unusual sound of flowing water coming from one of them that lasted a couple of seconds. A few hours later we noticed water starting to drip onto the floor from the return intake and one of the output vents. This had never happened before. I took the shroud off of the unit and the drain tray was empty. The tray drains to and outlet hose under the RV. I haven't been able to determine exactly what happened although I have suspicion the drain pan may have cracked. Do you have any insight what might have happened and how to determine if the pan is cracked? It doesn't appear to be very easy to access the pan.

Thank You, ... Christopher


Randy Godwin profile image

Randy Godwin 18 months ago from Southern Georgia Author

Hi Christopher, this sounds like a problem with dirty coils in the AC causing the excess water to exit through the return instead of through the drain. A good cleaning of both coils should allow the moisture to collect in the drain pan and exit through the drain as it should. I think I have some coil cleaner advertised on this page. As always,ask for more info if this isn't the problem. I've never encountered a cracked drain pan, but I cannot rule it out at this point.

Randy


Alpinexplorer 18 months ago

Hi Randy, thank you very much for your thoughts. I'll give a coil cleaning a try and let you know how it goes.

Christopher


Randy Godwin profile image

Randy Godwin 18 months ago from Southern Georgia Author

Hope the cleaning solves the problem, Christopher. If not, we'll go from there.

RG


Daniel 18 months ago

Hello, I have a 2012 forest river sunseeker with a dometec a/c . I am getting an E5 error code which is causing the a/c to turn on for a few seconds and then shut off. When I tried running the a/c with my generator the a/c functioned properly. Any suggestions?


Randy Godwin profile image

Randy Godwin 18 months ago from Southern Georgia Author

Hi Daniel, unless you have a problem with the shore power where you are, then I have no guess as to the problem. Do you have a switch which controls whether the shore power or generator is being utilized?


Jesse 18 months ago

I just bought a 94 30' kit camper with a ducted roof top ac, when I attempt to turn on the ac, I can hear the compressor start but no fan, when I turn it to fan instead of auto and flip it to high fan I hear a clicking noise coming from a relay or something up top in ac. What I've done so far: I've taken the shroud off spun the fan seems to spin free easily, had someone turn ac on and tried to spin fan to manually start it, no luck, replaced the larger capacitor that has the 3 different areas, only change was it tripped the power strip I had the camper plugged into, I put the original back on, now doing the same as origanly stated, I thought the smaller capacitor was for the compressor but not sure. Could it be the relay? The guy I bought it from said he was told it was the motor by a mobile mech and was quoted 400 to replace it, after the things I discovered I don't take his word for anything he's just not very bright when it comes to these things or plays like he's not, and I can get a new unit for 500 with shipping so I thought 400 was way steep for a fan motor. I have a feeling it's something simple possibly fan but it spins free so I'm hesitant to just start replacing it. Any help appreciated!


Randy Godwin profile image

Randy Godwin 18 months ago from Southern Georgia Author

Hi Jesse, usually if the fan is spun while the unit turned on and it starts working, the capacitor is at fault. Since yours didn't star using this method it may indeed be the motor.

However, the price quoted you seems to be extraordinarily high. Check out the fan motors sold on this page for a much better deal. :)

Randy


guru4u 18 months ago

I have a carrier Air V air conditioner in a 2007 travel trailer with a remote control. The unit will shut off when in air conditioner mode. The heater and fan will both work butt when switched to cool it will shut off.

Two weeks ago the compressor would at least run for about 20 seconds but now shuts off immediately. The emergency cool button won't do anything either.


Randy Godwin profile image

Randy Godwin 18 months ago from Southern Georgia Author

Hey guru, I suspect a bad control board in your A/C. Your problem sounds typical of those associated with the CB. You might try testing the compressor capacitor to see if it's okay, but I lean towards a bad CB. I assume you don't have a wall mounted thermostat that's bad?


robert 18 months ago

I got a 2001 terry camper. When i turn my ac on it blows cool air but its weak and also the fins are coming off the outside coil. What do you recommend


Randy Godwin profile image

Randy Godwin 18 months ago from Southern Georgia Author

A good coil cleaning would probably work wonders for your unit, Robert. Especially the inside coil which tends to clog much easier than the outside coil because the filter doesn't catch all of the dust and debris.

RG


captaindb00 18 months ago

Hi Randy, First of all, this site is AWESOME. I have a 1985 Chevy Shasta. 4,500 original miles on the replaced engine and 42K on the RV. I have a leak in the A/C unit. Water comes inside. I removed both covers above, completely cleaned EVERYTHING, oiled where needed, removed a terrible caulk job around the a/c basket it sits in and professionally reapplied sealant. Inside, I tightened the bolts that came through the inside control shroud and cleaned as well. Up above, I noticed inside the styrofoam cover, a "channel" if you will, with a little water stain. It looked like this is where the condensation water should be allowed to travel out of either end when needed. I blew both of these out as well. After doing all this, the air was definitely colder, but alas, I still have a leak. RV is parked level. PLEASE Randy, any advise. Thanks and God Bless, Dave


Randy Godwin profile image

Randy Godwin 18 months ago from Southern Georgia Author

Hello Captain, and thanks for the compliment about my hubs. :) Where does the water leak down from the AC? If it's through the vent--where the filter goes--the coils may still be dirty and prevent the fan from exhausting the excess moisture. If the leak is around the AC ceiling assembly itself, then a new gasket may be in order. It's not uncommon for the old gaskets to get hard over the years and lose their ability to maintain a tight enough seal, even when you tighten them up.

Feel free to ask for more info and I hope I'm understanding your problem correctly, Dave?.

Randy


Kelly 18 months ago

Hi Randy I have a 2000 Dolphin with dual ducted roof air. Changed settings and both units quit working. Check breakers reset them still nothing. Is there a fuse that .ay cause this?


Randy Godwin profile image

Randy Godwin 18 months ago from Southern Georgia Author

Hi Kelly, when you say you "changed settings" what settings did you change?

Randy


Kelly 18 months ago

Changed zone setting then turned stat off now air will not restart.


Randy Godwin profile image

Randy Godwin 18 months ago from Southern Georgia Author

I'm not familiar with the zone setting procedure, Kelly. Is it a separate setinng than the thermostat? Where is it located?


Kelly 18 months ago

It is a function of the thermostat. Zone 1 is front unit zone 2 is rear. Also realized that water was leaking on the rear furnace under the bathroom sink could this have anything to do with this issue. Thanks


Randy Godwin profile image

Randy Godwin 18 months ago from Southern Georgia Author

I t could possibly if the furnace utilizes the same thermostat as the A/C units, Kelly. The leak may have shorted out the thermostat, if so.


captaindb00 18 months ago

Hello Randy, captaindb00 again from 2 days ago. Still getting leaks inside as it's getting REALLY hotter here in NV! After doing hrs. of research, I found out there were possibly 1 of 3 a/c units used for my RV, but nobody can tell me what 1 of 3 they may be. I want to replace the gasket but don't know what to ask for. I am also going to raise the "basket" or "tray", (whatever it's called), that the unit sits on. The nearby RV dealer said there should be a 1/4" to no more than 3/8" gap between this tray and the metal on the roof allowing the water to travel away from the unit. I have NO gap at all, Thus the need to raise it, install a gasket and seal it. Two questions please. Any ideas on who to contact to see which gasket I could match up to in order to find one? Lastly, where does the water exit out of the unit and go onto the roof? I would like to see if this area could possibly be plugged. Thanks again Randy and God Bless.


Kelly 18 months ago

The furnace does share the same thermostat. So, if the water leak did short out the thermostat, wouldn't the lights on the thermostat be non-functional. Because the thermostat control still looks like it always did. Lights up when buttons depressed, etc.

If it is the thermostat shorted out, how would I fix that? What would need drying or replacing?

If the thermostat lighting up is an indication that it is not shorted, what else might cause both ac units to suddenly cease at the same time?


Randy Godwin profile image

Randy Godwin 18 months ago from Southern Georgia Author

Hey Cap, as all of the units are made for a 14x14 inch square hole in the roof you should be able to use a generic gasket to stop the leaks. Look for a universal gasket on Amazon--links are on this page--as I believe they carry them.

If the present gasket is bad, it will allow the water to seep into the area between the roof and ceiling.

RG


Randy Godwin profile image

Randy Godwin 18 months ago from Southern Georgia Author

Kelly, there are so many types of thermostats used in RVs, that I cannot offer you a certain answer as to how one would react when getting moisture into the mix. I can't imagine both units not operating unless there is some sort of thermostat malfunction or a power supply shortage. Have you tested the voltage at either of the units to make certain there is power available to them?

RG


Kelly 18 months ago

Haven't done so yet, but that is my plan for tonight. It is the 5 BUTTON 3109228.001 COMFORT CONTROL CENTER SYSTEM and the two roof ac units are the Duo-Therm by Dometic. My wife found an operation manual for the thermostat online, as well as a detailed trouble shooting guide. If I get this figured out, I'll let you know, and if you have any other ideas, please feel free to share. Your willingness and helpfulness are greatly appreciated.


Randy Godwin profile image

Randy Godwin 18 months ago from Southern Georgia Author

Kelly, glad to hear you've found the manual for the control center and the troubleshooting guide. It's more difficult with all of the new electronics systems these days to keep up to date with them all. I'd really appreciate finding out if the control center is indeed the problem so I may help others with similar situations.

Thanks for your question and your time participating on this article. Kelly. Will look forward to your return. :)

Randy


Brandon 17 months ago

I have a 1980s pull along camper I had out two weeks ago and the ac worked just fine. Now today I went to turn it on and there was nothing.. Checked breaker and it wasn't tripped. Do you know what the problem could be? Thanks Brandon


Randy Godwin profile image

Randy Godwin 17 months ago from Southern Georgia Author

Hi Brandon, I suspect a bad capacitor could be the problem. Have you checked the voltage where the unit is connected to the trailer wiring?

RG


Brandon 17 months ago

Got it working!! No voltage was going to the ac from the breaker..Got a new breaker


Randy Godwin profile image

Randy Godwin 17 months ago from Southern Georgia Author

Good news, Brandon! That's why I wanted you to check the voltage at the unit itself. It's not uncommon for a breaker to go bad. :)

Randy


Jesse 17 months ago

Hi randy,

I am in the process of replacing my fan motor on an older 1994 duo therm roof top ac, I have the old motor out, the motor cam with new squirl cage and fan blade however this duo therm isn't friendly when it comes to getting the old squirl cage out and new one in and I really prefer to replace it and not use the old one. What I've tried so far, I got the foam cover off with minimal damage.. Took a smal chunk out of the to think area but that's it... Any suggestions on a patch appreciated if you think it needed, behind that foam is a cover that has the mounting bolts on it first I thought it's peranatly attached then I noticed it appears like it may have been removed so I gently started to try and tap it off and one side started coming off ok but as I got to the top it wasn't wanting to go anymore and I wasn't going to force it so a taped it back in place, little nervous that I would screw it up and the motor won't mount straight but I will make sure it's back in place and metal tape it well around the seems. Next thing I did was remove 3 bolts inside the camper the mounting plate I couldn't get the fourth bolt out it's just spining hopfully it tightens back up. But I was able to see the opening isn't large em ought to get it out from inside. Now I assume I'm looking at loosening the coil that makes me nervous as I don't want to damage it or the lines. What is your suggestion or the proper procedure to remove this squir cage? Also a question on the bolts I remove inside I assume they are the mounting bolts and my plan is to re instal and tighten them down good before I go back up too and jar anything around as they were the last thing I did. My question is how tight should I thighen them and how do I go about tightening the 4th bolt that would come all the way out? I hope it tightens up fine won't know till tomorrow. By the way is the condensation suppose to drain out on the roof or is there supposed to be a drain line somewhere? When I had it working last week it was just draining on the roof.

Thanks in advance sorry for the long post.


Randy Godwin profile image

Randy Godwin 17 months ago from Southern Georgia Author

Hi Jesse, it seems you've figured out the removal of the fan and don't be too concerned about damaging the coil if you are careful with it. Some units have a drain which empty through a pipe while others simply use the fan to disperse the moisture into the air. I'd suggest cleaning the coils well before reassembling the unit completely and this should stop any excess water from causing any future problem. tighten the bolst back as much as you feel safe doings so and it should be fine.

Randy


Jamie 000001 profile image

Jamie 000001 17 months ago

I have a 2009 Zinger with Coleman Airconditioner. The fan blows properly at all settings however the air will not cool. I cannot hear the condenser even try to turn on. I have wall mounted thermostat. I am thinking capacitor?

Great site by the way :)

Jamie


Randy Godwin profile image

Randy Godwin 17 months ago from Southern Georgia Author

Hey Jamie, I assume you meant the compressor doesn't sound like it's trying to start. Yes, it may be a bad capacitor as it may not be providing enough power to enable the compressor to start up. A new capacitor is rather inexpensive and easy to install and worth a try unless you suspect a bad thermostat. Personally, I'd check the capacitor first with a multimeter set on ohms. You should get a random number which decreases in value the longer you hold the probes to the terminals if the capacitor is good.

Thanks for the question and the nice comments. :)

Randy


guru4u 17 months ago

original post two weeks ago. Thought I would let you and your readers know that the compressor is bad. No replacement parts available for the Carrier unit, replacing the entire unit. Did Carrier get out of the RV air conditioner business?


Randy Godwin profile image

Randy Godwin 17 months ago from Southern Georgia Author

Hey guru, and thanks for the update. Unfortunately, we now live in a disposable society for the most part. It's sad that replacing the entire unit is often less expensive than repairing it. Have a good camping season! :)


Jamie 17 months ago

Thanks Randy. I felt a lot more assured making a two hour drive with only one part with me. New capasitor worked and cold air blows again!


Randy Godwin profile image

Randy Godwin 17 months ago from Southern Georgia Author

That's good news, Jamie! I love it when a plan comes together. :) Enjoy your 4th of July celebration!


arwalker 17 months ago

Hi Randy. First, let me apologize ahead of time for my poor terminology and wording as I'm not experienced with this type of thing. We have a '93 terry pull camper. I'm not sure of the make of the AC but it's ducted and has a wall mount thermostat. The AC worked fine last summer with no problems but the first time we turned it on this summer it wouldn't blow cold. The fan came on and worked fine as it did blow air...just not cold. I didn't hear the noise I used to hear right before the cold air kicks in. (would that be the compressor kicking in?) A couple weeks later we tried to use it again and nothing happened at all, not even the fan. While trying to figure out what was wrong I realized the breaker where the camper is plugged in to electricity had tripped, so I flipped it back on and everything worked fine including the air being cold! So I was thinking everything was fixed...until the next time we went out and turned it on and just the fan would run again...no cold air. Any ideas as to what the problem may be? I can use a meter to detect the voltage of things if I have specific instructions as far as the settings, which wires to test, and what it should read. I also should mention that we have not done any cleaning of the AC accept the inside filter since we have owned it (11 years) because I wasn't aware that we needed to. That will be taken care of while trying to fix this problem. :o) Thanks for any help you can offer.


Randy Godwin profile image

Randy Godwin 17 months ago from Southern Georgia Author

Hey arwalker, I don't suspect the dirty coils--although you're smart to clean them in the meantime--I do suspect you have either a capacitor or thermostat problem. Since the A/C worked fine the previous time and then failed the next, I'd try replacing the compressor start/run capacitor first. If that doesn't solve the problem the thermostat may be at fault.

As always, feel free to ask for more info. :)

Randy


Ken Clemens profile image

Ken Clemens 17 months ago

Hi Randy, i have 2006 travel trailer. Recently my ac unit has developed a squealing noise when it kicks in. Fan is working fine, just when it kicks in and reaches temp and shuts off it has a squeling noise. Couple people said i need to oil the shaft??


Randy Godwin profile image

Randy Godwin 17 months ago from Southern Georgia Author

Hi Ken, you can indeed oil the shaft on both sides of the motor to see if that stops the squeaking. Depending what type of A/C you have, there may even be oil ports especially for this purpose. I seriously doubt it though because most of the newer RV A/C fan motors use sleeves instead of sealed bearings so they can't be repaired easily and cheaply and require an entire new fan motor. Yes, we do live in a throw away society unfortunately. Try a good spray lubricant, Ken. :)

Randy


arwalker 17 months ago

Thanks for your reply! You said in your article ...

"Check the required voltage and model numbers on the new AC capacito when ordering a new one. "

Will this information be on the old capacitor or is it in the AC manual somewhere? Also, does it have to be the exact model number that's in there now, is there a certain brand I should be looking for, and can I use the turbine oil my husband has to oil the motor? Just trying to make sure I understand everything before I drive to where the RV is and get started. :o) Thanks

Anissa


Randy Godwin profile image

Randy Godwin 17 months ago from Southern Georgia Author

Anissa, the new capacitor may be any model as long the specs match up and it fits the holder in the A/C. Any A/C parts repair store should be able to help you with this. Or electric motor repair shops, for that matter. There may be a capacitor ad on this page if you want to check it out.

And yes, the info will be on the capacitor when you remove it. Don't touch the terminals on the old capacitor as it may still hold a charge. The turbine oil should be fine, Anissa. I'll be looking out for you to tell me how your repairs came out or if you need some more help. :)

Randy


Bill 17 months ago

We have a 2008 Motorhome with a 2 ton Coleman A/C Model 6537-871 that is freezing up, checked the coils they look good, it has no piercing valves to add freon so what now?


Randy Godwin profile image

Randy Godwin 17 months ago from Southern Georgia Author

Hi Bill, check inside where the filter goes to be sure the wire(s) to the anti-icing sensor is located. If the Freon is low a self-piercing valve may be used to add more Freon if you have the know-how to do so. Otherwise you may have to get an A/C guy to do it for you.

Randy


Bryan 16 months ago

My problem is my A/C works fine until the outside temp gets over about 92 degrees. When it gets hot the compressor won't stay on and even kicks the breaker off sometimes. The compressor gets too hot to touch. Did not have this problem last year. What would cause the compressor to overheat?


Tim 16 months ago

Have a57915.622 brisk air in my sundowner horse trailer. Worked fine last season, this year the compressor wont kick in. The fan works fine. I changed out both the capacitor and hard start capacitor. Can you give me a clue as to what I need to look at next?


Randy Godwin profile image

Randy Godwin 16 months ago from Southern Georgia Author

Hello Bryan, have you cleaned the coils lately? When the coils get clogged they not only don't cool efficiently but also cause the compressor to overwork and therefore overheat and/or kick off because of the inhibited airflow over the surface of the compressor.

Randy


Randy Godwin profile image

Randy Godwin 16 months ago from Southern Georgia Author

Hey Tim, do you have a wall mounted thermostat or is it located on the unit itself? Does the thermostat click but the compressor won't start or make any noise at all? A bit more info may help me figure the problem out. :)

Randy


Ted Dickinson 16 months ago

Randy, my roof air is on a 2007 Damara we bought used with very low miles. The wall mount thermostat is not the original. The a/c seems to work ok on low speed, will work for awhile on high (no mid speed because its not the right thermostat) will eventually pop the breaker. As long as the tv, microwave and fridge are off, it will run on low but turn one on and the breaker pops. I ran it all ok, everything on, in my driveway on 20 amp...but every camp site, 30 or 20, the breakers pop. Any suggestions? Any idea of brand model thermostat I should have? (07 Safari Damara 293ts)


Randy Godwin profile image

Randy Godwin 16 months ago from Southern Georgia Author

Hi Ted, is the unit been cleaned before, especially the coils? And are the tv, microwave, and fridge on the same circuit as the A/C? I suspect not, and if I'm correct the compressor may be drawing too many amps and causing the main breaker to trip. This could be one reason running the unit on high also contributed to the breaker tripping. Feel free to chime in with more questions if you need too and I'll be happy to help you all I can.

Randy


Ted Dickinson 16 months ago

I don't know if it's been cleaned before, we bought it used a year ago and we haven't had it cleaned. Now even low speed pops the breaker and it will not start again. Do you have any idea what the original thermostat make and model should have been? We are currently on the road, so we'll probably have to fix this when we get home in a few days.


Randy Godwin profile image

Randy Godwin 16 months ago from Southern Georgia Author

Ted, I really have no clue about the model of the thermostat because there are so many different kinds used. I believe any thermostat with the same voltage and fan speeds will do for replacement. I still believe the compressor is either overheating due to clogged coils or is drawing too many amps causing the breaker to trip. I fear the compressor may be on its last legs but hope not for your sake. If you can get hold of an amp meter somewhere you can see if the compressor is pulling more amps than is normally required. You may find the amps normally required on the compressor itself.

Randy


Ted Dickinson 16 months ago

Thanks Randy. Heading home for a look see. The replacement thermostat has 8 wires, the motorhome has 7 so whomever installed it left off the mid speed wire so everything else would work.


Randy Godwin profile image

Randy Godwin 16 months ago from Southern Georgia Author

Let me know what you find, Ted. :)

Randy


steve 16 months ago

Randy... i have a 1983 prowler travel trailer with a coleman roof mount a/c. My question is how to find a replacement fan motor for it? I have searched the Model # however it says RMR is no longer in service and it doesnt give any replacement #'s.

Thanks


Randy Godwin profile image

Randy Godwin 16 months ago from Southern Georgia Author

Hey Steve, have you checked for a universal fan motor anywhere? I know there used to be some sold where one could cut the shaft off to the needed length and included a mounting bracket with it. Perhaps look at some electric motor dealers if you don't find one on the Amazon ads on this page. Good luck finding one that'll fit. :)

Randy


Ben 1981 16 months ago

Randy, I have a 1988 Coachman Classic motorhome. It has a Coleman tsr mach 3 roof unit on it. The fan motor will come on but cuts off after running for 3 to 5 minutes. If I turn it to cool before it cuts off the compressor comes on and cools fine. So the fan cuts off if I have it turned to fan or if I have it turned to cool. It's does not trip any breakers. After a period of time it will cut back on on its on and run for 3 to 5 minutes and cut off again and so on. I replaced the run capacitor and no change. Any suggestions as to what the problem may be?


Randy Godwin profile image

Randy Godwin 16 months ago from Southern Georgia Author

Hello Ben, have you checked the fan motor after it stops to see how hot it is getting? If this is the original fan motor in the rooftop AC the bearings--or sleeves in some cases--may be so worn they are causing the motor to overheat and kickoff until it cools enough for the motor to reset. Feel free to ask for more info if needed. :)

Randy


Ben 1981 16 months ago

Thank you for the quick response. I held my hand on the motor till it kicked off and waited for it to come back on. It did get pretty hot. It got got enough that I didn't want to leave my hand on it. It didn't get as hot as I would figure a bad motor would get. That still could be the problem though. How can I check the motor other than just by it getting hot? I hate to buy another motor and it not be the problem and not be able to return it.


Randy Godwin profile image

Randy Godwin 16 months ago from Southern Georgia Author

Ben, unless you have access to an amp meter, it's hard to detect a bad motor sometimes, especially if it turns freely when off. You could remove the motor and take it to a electric motor repair shop and they will test it for free in most cases. Removal is often a pain and especially just for testing. If you can test the voltage on the fan motor both while running and after it shuts off, this may indicate either a relay or thermostat problem. Obviously, if the voltage drops when the fan stops working, it isn't the fan motor. Hope this helps you out. :)


arwalker 16 months ago

Hi Randy! I think we've solved our problem! I got up there to get the capacitor out and realize there were 3 of them. I took out the one that I thought looked most like the ones I'd seen while researching this problem (the black one). While I was there, I noticed that a black wire that goes from the compressor to the square relay box (I think that's what it's called) had a broken disconnect....one crimped end was broken in half and so it was not making good contact. I went ahead and took the capacitor in to have it tested since I already had it out and the guy said it was the correct one and it tested good. We replaced the broken disconnect and the AC worked fine after that. We haven't been out to use it since then but I'm hoping that was the problem and it'll continue to work fine the rest of the summer. Thank you so much for all of your help! It's greatly appreciated!

Anissa


Randy Godwin profile image

Randy Godwin 16 months ago from Southern Georgia Author

Anissa, thanks for letting me know what the problem was. I'm so pleased you repaired the broken wire and didn't have to spend any money that could be better spent on camping. :) I appreciate your nice comments and please check out my many other RV repair hubs by going to my profile at the top of the page.

Randy


Tim 16 months ago

Hi Randy, I have a 2000 windsport rv, it has 2 air conditions, the rear works just fine, the front doesn't work at all, I hear a click noice when trying to turn it on but it won't start up at all, any suggestions would be appreciated thanks.


Randy Godwin profile image

Randy Godwin 16 months ago from Southern Georgia Author

Hello Tim, I assume you've checked the voltage to the A/C so I'll go from there. The clicking noise is either the switch itself or the thermostat. You may have an A/C unit which uses one capacitor to start and run both the compressor and fan. I'd check the capacitor first as it's an easy and inexpensive item to replace if bad.

Let me know if this helps or if it doesn't and we'll go from there. :)

Randy


Tim 16 months ago

Thanks for quick respond, how do I test capacitors, looks like this one has 3 of them, sorry I never done this before.


Randy Godwin profile image

Randy Godwin 16 months ago from Southern Georgia Author

Tim, with a digital multimeter set on ohms, touch the two probes on the multimeter to the two terminals on the capacitors being careful not to touch them with your bare fingers. If the capacitor is good, the mulitimeter will display a random number which decreases in value the longer you hold the probes to the capacitor terminals. If bad, the numbers--if there are any--will remain the same.

Randy


Craig 16 months ago

Helo Randy my ac made a loud pop sound the ac is on the top of rv it is a 2010 Jayco on the in side it smells like electric wire had burned.did not find any, found that the capacity had blow the top off. Is that all in need to do is replace it?


Randy Godwin profile image

Randy Godwin 16 months ago from Southern Georgia Author

Hi Craig, occasionally a capacitor will explode but it usually doesn't affect the AC itself. A new capacitor will hopefully get you fixed right up again.

Let me know if this is indeed the case or if you have any other questions. Thanks for your time and query. :)

Randy


wjell 16 months ago

Opinion please. I have an old (circa 1988) 6799-714 Coleman A/C that cools fine. Non-ducted and thermostat self contained.

It was dripping inside and the tech went up and cleaned some drain holes out a couple of weeks ago. No water. The sound of the unit changed and continued to change. Last night the motor slowed down and stopped.

Now the fan will not spin up any mode. When I turn the unit, on all it will do is hum (even in fan only mode). I can turn the blower wheel by hand, but it is not "free spinning" and when I turn the unit on it seems to "seize up" the wheel. Hasn't blown a circuit breaker. We are in TX so the unit has been on almost 24/7 for the last two months.

I'm physically not able to get on the roof myself, but knowledge is power. I'm leaning towards a bad blower motor?

???

Thanks,

Bill


Randy Godwin profile image

Randy Godwin 16 months ago from Southern Georgia Author

Hi Bill, this does indeed sound like a fan motor problem. I've ran into a similar problem before and it turned out to be the winding in the motor was causing it to work against itself when operating. I'd have the capacitors checked first before ordering a new fan motor though.

Your A/C being an older model, you may find it difficult to find a replacement motor for it. If so, check the ads on this page as they have some universal fan motors made especially for the older obsolete RV A/C units. As always, feel free to contact me again if you have any questions.

Randy


Craig 16 months ago

Helo Randy thanks for your help went and pick up a capacitor this morning. They told me that it was a run capacitor put new one on working grate.

Thanks

Craig


Randy Godwin profile image

Randy Godwin 16 months ago from Southern Georgia Author

Thanks for the update, Craig. I'm pleased I could assist you with your problem. :)

Randy


Troy 16 months ago

My unit is running backwards what I mean is the outside coil is cooling the inside is heating what to do


Randy Godwin profile image

Randy Godwin 16 months ago from Southern Georgia Author

Hi Troy, I've never encountered this problem before. Is the fan running in reverse, or is it operating normally?

Randy


Andrew58 16 months ago

Hi Randy

My Coleman RV air conditioner runs and cools great. My concern is when the compressor kicks on I hear a rather loud 'thunk' which has the habit of waking me up at night. I'm assuming the compressor is torquing in its mount at startup and making this thunk sound. It also thunks when it shuts off but not as bad. The fan motor runs quiet without any issue. This is strictly the compressor. Any idea? Thanks in advance.


Randy Godwin profile image

Randy Godwin 16 months ago from Southern Georgia Author

Hi Andrew, it sounds as if one or more of the rubber shock absorbers on the compressor mounting bracket has worn out. You may be able to find one at any AC repair business or even make one yourself. It shouldn't be very difficult to replace.

Randy


Andrew58 16 months ago

Thanks. I'll find new parts and let you know how it works out. Thanks for the quick reply.


Brent 16 months ago

I just bought a 1995 Gulf Stream conquest I turned the ac on and it ran fine for a few hours in auto mode and then it kicked out and you could hear it clicking at the thermostat but it would not come on and then after a few times it would kick the breaker out. Any suggestions.


Randy Godwin profile image

Randy Godwin 16 months ago from Southern Georgia Author

Hi Brent, this problem may be due to a bad capacitor. Hopefully this is the case as it will be a relatively easy and inexpensive fix. Remove the shroud on top to get access to the capacitor. If you don't know what a capacitor looks like I think there are some ads for them on this page. Be careful not to touch the terminals with your bare hands when disconnecting the wires.

Any A/C repair shop will more than likely test your old capacitor for you and furnish a replacement for your unit. If you're not in a rush you can save a few bucks ordering one online.

Hope this helps you solve the problem and if not, let me know and we'll go from there. Thanks for the question. :)

Randy


Topcop2 16 months ago

Helping a friend work on his motorhomes ac's. He has three, the front unit is working the two rear are not. He had an unknown surging problem with the motorhome not the campground. Units were working fine prior. He bypassed the surge protector which was not help. Since the surge happen several times with a few minutes in-between them and the units having time delays, could it be the capacitors? Thanks for any suggestions Kevin


Randy Godwin profile image

Randy Godwin 16 months ago from Southern Georgia Author

Hi Kevin, it is possible the capacitors could be at fault and it is easy enough to check them as a first fix. It could also be the control boards at fault but it's difficult to tell at this point. Have you checked the breakers or are all three of the units controlled by one breaker? A bit more info may assist me in helping you with the problem.

Randy


wabet 16 months ago

Hello , this thread is great, but I haven't seen my exact problem, can you give me some advice? On my 2002 R-vision (by trail lite) my rooftop A/C is a Duotherm and the 3 speed fan isn't functioning properly, the speeds all seem to slower than they use to and not pushing enough air volume. I'm guessing capacitor(s) and or motor (maybe dry bearings?) Any advice you can offer would be great


Randy Godwin profile image

Randy Godwin 16 months ago from Southern Georgia Author

Hi wabet, yes it could be the fan start/run capacitor causing the problem. I'd think dry bearings or sleeves in the fan motor would cause a breaker to trip but it is easy enough to oil them up and see if it makes a difference. :)

Randy


wabet 16 months ago

Hi Randy, thanks for the quick response! I'll look into it and let you know how it goes.


wabet 16 months ago

Hi again Randy, I oiled the one side of the motor, at the sleeve, I turned on the unit and it hummed, squirrel cage didn't spin, I manually started it spinning, it worked properly on L, M and H for a few seconds, then it slowed down and didn't move as much air. So firstly, I'll replace the start capacitor (when I took it out, it seemed to be covered in a clear, oily sticky substance). Since it ran for a bit but then slowed down do you think I should replace other capacitor as well? (is the other larger capacitor a run capacitor?) Thanks again


Randy Godwin profile image

Randy Godwin 16 months ago from Southern Georgia Author

That's up to you, wabet. Sometimes a capacitor will last for the life of the unit and sometimes they don't. The oil on the fan cap is a sure sign it is bad. I'm glad you didn't have to replace the motor as that would have required more work and expense.

The larger cap is a start/run for the compressor I'd think. Thanks for the question and feel free to ask more if needed. :)

Randy


buddy 15 months ago

I came here to figure out how to fix my compressor issue and all it says is it is usually better to replace it... I know it doesn't need to be refilled with refrigerant because if they leak at all they leak all the way to nothing.... kinda obvious. So someone here know anything about them because this forum didn't help me at all. My problem is that the compressor starts up, but draws a lot of power from other devices, possibly bad capacitor, but they are pretty new. After running properly for a while it starts to only run a few seconds at a time and then bogs down and shakes a bit and dies.

Old rooftop duo therm quick 12 a/c with a starting capacitor, run capacitor, and relay all hooked up to compressor. The capacitors have runners connecting them together and the other end of each goes to a different terminal on the the relay, while the thermostat wire and black power to compressor are on another terminal. The thermostat wire provides 120v as well as week as whatever the capacitors put out to run and start. Thx for any tips


Randy Godwin profile image

Randy Godwin 15 months ago from Southern Georgia Author

Hi Buddy, see if you can borrow or rent an amp meter from somewhere and you can check the compressor to see if it is pulling more amps that it's supposed to. The correct amps will be listed on the compressor or near it on a metal plate.

If the coils are very dirty the compressor will get too hot and quit operating until it cools down and resets itself. Replacing the compressor will usually cost so much it is often better to replace the A/C itself. Feel free to ask more questions if needed. :)

Randy


wabet 15 months ago

Hello again Randy, I'm just back to update you (and others) on my repair. Long storey short...both capacitors were bad, motor was fine. The smaller capacitor had leaked oil, the larger silver capacitor had blown out the back side. $50 in parts and back in business, thanks for your help!


Randy Godwin profile image

Randy Godwin 15 months ago from Southern Georgia Author

Hello again, wabet. Pleased as punch the capacitors did the trick for you. Thanks for returning and relating how the repairs went. I'm always glad to help a fellow RVer save a few bucks on repairs. More money to go camping with! :)

I have other RV repair articles when another problem pops up so don't be a stranger if you need any more advice. Happy camping! :)

Randy


Jamie Wall profile image

Jamie Wall 15 months ago

When i came home today my ac was only working half power what just happend??? It was working fine all week its way less noisey too... but still blows cold air... im clueless


Randy Godwin profile image

Randy Godwin 15 months ago from Southern Georgia Author

Hi Jamie, is everything else working properly? Or is it only the AC?

Randy


mike prather 14 months ago

I have a duo therm model 59516.531 can I wire the fan up directly to 110 or is it dc


Randy Godwin profile image

Randy Godwin 14 months ago from Southern Georgia Author

Hi Mike, it should be 110 volt ac but you still need to control the fan speed by some method or are you planning on routing it through the fan control?

Randy


cowboy1802 14 months ago

i have a new dometic 13,500 a/c unit . it will run for about 1 1/2 hrs the it will stop and the compressor will not start again. what going on with it


Randy Godwin profile image

Randy Godwin 14 months ago from Southern Georgia Author

Hi cowboy! If the unit is new you should contact the dealer because anything you do may tend to void the warranty.

Randy


cowboy1802 14 months ago

let ask you this i got 2 new 2000w yamaha gen tie toghter is this enought to run that a/c it 13,500 and pull 14.8 amps

i wont touch that a/c due to the warranty


Roy 13 months ago

How do I clean the drian hole on my roof top a/c? Do you have to take it up or can it be done from the inside?


Randy Godwin profile image

Randy Godwin 13 months ago from Southern Georgia Author

Roy, simply remove the AC shroud to get access to the drain hole and to clean the coils if needed.

Randy


Don Bobbitt profile image

Don Bobbitt 9 months ago from Ruskin Florida

Great Article. Clear and concise instruction that even I could follow! DON


Randy Godwin profile image

Randy Godwin 9 months ago from Southern Georgia Author

Thanks so much, Don. Coming from a fellow RV aficionado that means a lot to me. Thanks for your time. :)


JonHailey 6 months ago

Randy, this is a good no, nonsense article. Thanks for it.

I'm having some problems with my Carrier ducted unit. I have good flow out of the rear vents but the front vents aren't getting any pressure. When I feel up inside the intake I can feel cold air in that vent. It really seems like there is leaking between the blower vent/fan and the intake. I've sealed all of the possible seams in the lower unit. This feels like its above the lower unit. Is there a way to service this area of the unit? Looks like the whole thing is a big plastic cowl on the top portion held on by a few screws and clips, is this where I should look?

--Jonathan


Randy Godwin 6 months ago

Hi Jon, there may be some air leakage or perhaps the duct is collapsed or blocked in some manner. Often overhead ducts are very narrow in thickness and this allows a minor blockage to divert the airflow through the other vents. This seems to be a common problem in ducted systems. You may access the ducts through the vents or by removing the upper unit if you have to. Any way to check into the ductwork will do to check for obstructions.

Randy


Lyle 6 months ago

Hello Randy , I have a duo therm from 1995 , when it is first turned on it blows cold and semi swift but as time progresses it seems the wind speed slows way down to barley any air flow ..... I've read on other post about cleaning coils , have not attempted in shroud removal as of yet ....thanks for any suggestions , sincerely Lyle


Randy Godwin 6 months ago

Hi Lyle, This problem sounds more like a fan capacitor than dirty coils. The fan has a capacitor which starts it up and which keeps it running at normal speed. Or you may have one that runs both compressor and fan. These are relatively inexpensive and easy to replace. I'd recommend replacing the capacitors first but the coils still may need cleaning. Ask for more help if needed.

Randy


Ashley 6 months ago

We've had our fifth wheel for a few years and it would randomly squeak now and then. Well starting yesterday when it kicks on it squeaks but not a high pitched squeeking. Then it stops and runs completely normal. Its a 2005 keystone laredo. We took the plate out on the inside when we got it so the air blew directly into the living room. We decided to put it back in and see if it cooled better a few days ago now these noises are happening.


Randy Godwin 6 months ago

Hi Ashley, more than likely the fan motor bearings are getting worn. You may try lubricating them and this may help for awhile, but it may be only a matter of time before the fan motor needs replacing.

Randy


Daryl G 5 months ago

I have a 2013 Heritage Glen 5th wheel and my roof AC unit is blowing ambient air. I hear the compressor kick in, but the temperature doesn't change. It is a dometic 1500w AC unit. I have already changed out the thermostat, but no change. I have visually looked at the unit and it does not look dirty or clogged.


Randy Godwin 5 months ago

Hello DarylG--Are you sure the Freon in the unit is fully charged? If the compressor is working and the fan is blowing properly, the Freon may have leaked out. Anything else you can tell me about the unit?

Randy


Daryl G 5 months ago

Thanks for answering, I suspected as much. I don't know how to check if there is freon in the unit. I have been told this is a sealed unit and adding freon is impossible. Is that true? Does this mean the unit is trash?


Randy Godwin profile image

Randy Godwin 5 months ago from Southern Georgia Author

Daryl, as far as I know there is no AC unit which cannot be recharged. You can even do it yourself if you have the know-how. If you don't, you can probably find a local AC repairman to do it for you. Good luck with the repairs! :)

Randy


Ron 5 months ago

we have a 2013 voltage with 3 a/c 2 work but the 3 one trips a breaker can you help


Randy Godwin profile image

Randy Godwin 5 months ago from Southern Georgia Author

Ron, do I understand correctly that you have 3 AC units on board your RV? If so, you are pulling a lot of amps when all 3 are running anyway. The problematic unit may be pulling too many amps for the circuit to carry properly because of the compressor being older or either a bad fan motor bearing. Does the number 3 unit work well with the other two off?

Randy


Ashley 5 months ago

Well we didn't get it greased in time. Its started squeaking and making a thumping noise today. Then about 5 minutes ago it started making noise so I stood by it and it slowly slowed down until it completely stopped and blew no air or made any noise. When I switch it to on instead of auto it runs hot about a minute then slows down until it turns off again. Still think its the motor?


Randy Godwin profile image

Randy Godwin 5 months ago from Southern Georgia Author

Ashley, this sounds as if it's either the fan motor or a capacitor. With the squeaking I lean towards the fan motor as being the culprit. I think there's an ad for fan motors on this page which will lead to others you can choose from for your particular AC unit. Good luck and if you need more info please ask. :)

Randy


Mr. Thomas 5 months ago

Good evening. I have a 1998 Dutch Star with two ducted AC units. The one in the back is fine, the one in the front stopped blowing The compressor runs; I got on the roof and looked - the fan was not spinning. I gave is a "push start", and it started to run, but by the time I got down into the rig, it wasn't blowing. I'm thinking start capacitor first, then motor. Can you help? Thank you!


Randy Godwin profile image

Randy Godwin 5 months ago from Southern Georgia Author

Mr. Thomas, yes it does indeed sound like a bad start/run fan capacitor. This is relatively easy and inexpensive to replace. Let me know if this doesn't solve the problem and we'll go from there. :)

Randy


Leah 5 months ago

Hi Randy. I have a 1998 Road Ranger 5th wheel. We recently had a new converter installed. Now my air conditioner/furnace won't come on. I'm thinking it's the thermostat. The thermostat clicks but the air conditioner doesn't do anything-- no sound like it's trying to come on-- simply nothing. Am I right in my assessment and if so, do you know of any articles that could help my husband change it out and whatever circuit board the dealer said we'd have to change if we replace the thermostat. Thanks for your help.


Randy Godwin profile image

Randy Godwin 5 months ago from Southern Georgia Author

Hi Leah, and sorry to take so long to respond to your query. For some reason I'm notified of comments but can't see them for several--and in your case-up to 9 hours. I'm trying to get the tech people to fix this problem.

Did the AC work okay before you replaced the converter? If so, it may be a problem other than the thermostat. Another question is, why would the circuit board have to be replaced if you used the same model thermostat?

If you had the new converter installed by an RV repair service I'd ask them to check it out for you, that is, if the AC was working before the new installation. Looking forward to your answers. :)

Randy


Aaron 5 months ago

Hi Randy,

My Dometic Duo-Therm Brisk Air unit has stopped working, even blowing. I can hear a clicking sound when it should turn on, but nothing happens. Any thoughts on what I might test and/or try? Thanks.

Aaron


Randy Godwin profile image

Randy Godwin 5 months ago from Southern Georgia Author

Hey Aaron, if your AC suddenly doesn't start up it may be simply a bad start/run capacitor. If you know how use a multi-meter you can use the Ohm setting to see if it is good. You should get a reading of a random number which decreases in value if the capacitor is good.

Otherwise, you can take it to any electrical motor shop and they will test it for you. In some RV AC units the same capacitor is used to start and run both compressor and fan. Hopefully this is the problem. You can order a capacitor from any of the Amazon links on this page if needed.

Thanks for the question! :)

Randy


Bryan Fisher 5 months ago

I'm planning on replacing my old duo-therm 13.5k ducted that I'm starting to have a lot of problems with. Its about 15 years old

I was looking at replacing it with a new 15k unit. Do I just need a new upper unit. Descriptions don't say if they come with the control circuit board .


Randy Godwin profile image

Randy Godwin 5 months ago from Southern Georgia Author

Bryan--The new ducted AC will come with everything you need to replace the old unit. Good luck with the replacement. :)

Randy


Jimbo2 5 months ago

Hi Randy, Thanks for your help in advance.

I have a new rv with a Coleman Mach 8 9000 btu a/c rooftop model. Hooked up to 30amp service. I have run the unit a couple times in temps high 70s and low 80s. Fan starts and runs and compressor kicks in. But with the thermostat turned up completely the compressor runs abour 4 minutes and then shuts off for 5 to 6 minutes. This happen however warm is is inside. Is this a normal cycle for this kind of unit? I also put a wattmetter on a plug and see about 110volts with compressor on, 113 to 115 when its off. A laser temp guage shows temperature at output vents are 18 to 20 degree colder than what is going in. Seems like it should run longer to get inside temps lower in the initial startup. Unit is under warranty but I am in remote Alaska location for the summer with no access to dealer or service shop unit fall. My experience with older a/c units is they do not run compressor just 4 minutes regardless of conditions. Thanks. Jimbo


Randy Godwin profile image

Randy Godwin 4 months ago from Southern Georgia Author

Hey Jimbo, I apologize about the long delay in responding to you but the comment approval program is screwed up at the moment. I just had to approve a comment I made 38 hours ago, so bear with me.

This sounds like a thermostat problem, Jimbo. But unless you can bypass the thermostat in some manner to see if the unit runs longer then there's no way to know for sure. Have you checked to see if the compressor is hot when it cycles off? It should be very warm but not overly hot if it's operating correctly.

Randy


Jimbo2 4 months ago

Thanks Randy,

I will check the compressor temp and see if I can figure how to bypass the thermostat. Good ideas. Am I correct in thinking the 4 minutes on and 5 to 7 minures off is a little short when first starting it up?


Randy Godwin profile image

Randy Godwin 4 months ago from Southern Georgia Author

Yes Jimbo, that length of cycle is entirely too short to enable the AC to reach the proper temperature. Good luck with getting it straightened out. :)


Cason 4 months ago

Hey there...WONDERFUL thread here!

Just installed a Dometic Brisk Air 2 in my Skyline Weekender 247. Installed very easily, power, control plug, manual inner control unit, everything. Powered back up and turn the fan on, but the compressor won't kick on. The only variable I have is I didn't install the supply/return divider due to lack of tools.

Could this be causing the compressor NOT to come on, or do I have another issue?


Randy Godwin profile image

Randy Godwin 4 months ago from Southern Georgia Author

Hey Carson, there must be another issue if the compressor isn't coming on at all.

Randy


Roger Leroux 4 months ago

Hi Randy,

I have a different problem than most. I have a 2005 Bounder 37U with two AC units. The rear unit works fine. The front unit will blow cold air when needed, but will not produce heart when the controls are set to use the AC unit as a heat pump. We often camp in the spring and fall and up in northern NH & Maine the nights get cold so the AC units are typically used for heat if the outside air is over 45 - 50 degrees. This unit worked properly last season, but in the spring it will only blow cold air when we have set the thermostat and control panel to AC heat. Again, using the same settings on the rear unit works correctly. Any ides as to what to look for?


Randy Godwin profile image

Randy Godwin 4 months ago from Southern Georgia Author

Hi Roger, are you sure you don't have a bad heat element in the front unit? These need replacing on occasion. It's an easy task if this is indeed the case as they are normally a plug in attachment beneath the filter compartment.

Randy


kirk 4 months ago

I .ve been having a problem with my ac and furnace it seems like a relay or the wall mounted thermostat the air wont shut off when it gets to temp and sometimes the furnace blower will run and not shut off untill I kill the power ? then today my wife went to turn on ac and it would try to run then kick out then in then she smelled it getting hot and shut it off any thoughts ?


Jeremy 4 months ago

I have an older model Coleman mach and the fan blows just fine but when the compressor tries to kick on it boggs a little then clicks and the fan keeps running a couple days ago it was working just fine till the power cord came unplugged now that's all it will do what could be the problem


Kirk 4 months ago

Randy did I do something wrong that you haven't responded ?


Randy Godwin profile image

Randy Godwin 4 months ago from Southern Georgia Author

Jeremy, Your AC may have only one capacitor to start and run both the fan and compressor and it may be bad. If the capacitor won't hold a sufficient charge it cannot start both the fan and compressor at the same time. It's a relatively easy chore to replace the capacitor but be sure the power is off and be careful not to touch the terminals with your bare hands. Hope this info helps. :)

Randy


Randy Godwin profile image

Randy Godwin 4 months ago from Southern Georgia Author

Sorry Kirk, we've been having trouble with the comments not showing up until many hours after they've been posted. Hopefully they'll fix this problem soon. Your thermostat nay be at fault, Kirk. I had a similar problem reported to me just a day or so ago. That problem was caused by the thermostat trying run both the heat and AC at the same time. I'd start with the thermostat and go from there. Feel free to ask for more info.

Randy


Kirk L 4 months ago

Thanks Randy how hard is it to replace the thermostat its a duo-therm wall mount ? Kirk


Randy Godwin profile image

Randy Godwin 4 months ago from Southern Georgia Author

It's a fairly simple job if you get an identical thermostat, Kirk. The wires are color coded so there's no mistake in reconnecting them. Make sure the power is off to the AC before

removing and replacing the thermostat. Hope this solves your problem, Kirk.

Randy


Kirk L 4 months ago

Thanks Randy I will let you know how it turns out


Randy Godwin profile image

Randy Godwin 4 months ago from Southern Georgia Author

Thanks to you too, Kirk. I pass on the things I learn--and I'm constantly learning about weird stuff--to fellow campers to save them a few dollars, and more importantly, from pure frustration. LOL!

Randy


Bill 4 months ago

I sealed around base of my AC unit now when it rains water builds up and drips on the inside of trailer, should I remove the sealant. Does this prevent rain from draining?


Randy Godwin profile image

Randy Godwin 4 months ago from Southern Georgia Author

Hi Bill, sealing around the base of your AC shouldn't cause moisture to drip inside the trailer. More than likely the coils are dirty allowing the excess moisture from the rain to cause the leakage. Dirty coils prevents the moisture from being expelled into the air by the fan unless your AC has a drain which is stopped up. Hope this info helps. :)

Randy


Rusty 4 months ago

Randy,

Have a 2014 Coleman Mach 13.5 A/C only (no heat) unit as 2nd air in trailer. Probably have used this unit less than 15 times. Just discovered it is not blowing cold. Blowing hot air only.

Have tested both capacitors and they are strong and good. Verified thermostat is working fine. Inspected coils and evaporator, they are clean (look new).

When on top of trailer, it seems like the fan motor to the compressor is not working, but the compressor is warm to the touch.

Being such a "new" unit, would think the compressor would not be the issue.

Any input would be appreciated and thank you in advance for your response.


Randy Godwin profile image

Randy Godwin 4 months ago from Southern Georgia Author

Hello Rusty, does the compressor run when you operate the AC? You should be able to hear it cut on if it is working properly. Your unit may have a leak and may be low on Freon if the compressor is running. Anything else you can tell me?

Randy


Rusty 4 months ago

No, compressor is not running.

Is this a sealed unit? Can Freon be checked or added to??


Randy Godwin profile image

Randy Godwin 4 months ago from Southern Georgia Author

If the compressor is not running then adding Freon will not help. The only way to check the compressor is with an amp meter to see if it is pulling more amps than is required according to the stated amps the compressor requires. This value should be either on the compressor itself or on a plate nearby. And yes, some AC units can be recharged with Freon.

Randy


Randy 4 months ago

Thank you for the input and pointing me in a direction that hopefully is the right one!!


Randy Godwin profile image

Randy Godwin 4 months ago from Southern Georgia Author

Sorry I couldn't be more help, Randy. (great name by the way) Sometimes it's difficult to prescribe a fix without actually seeing the AC unit personally. Let me know if there's anything else I can possibly assist you with. :)

Randy


Randy 4 months ago

Just an update on the a/c... Had to have a tech come out to determine issue. Ended up being circuit board control box. $100 part & $200 service call. Guess still cheaper than a new unit, but you'd think as expensive as these things are they would last more than 2 years!

Not happy, but cooler now


John 4 months ago

Hello Randy, I have a 99 dometic dual ducted ac system. Rear unit works fine, front air runs up to 3 minutes then throws E5 code on thermostat. Compressor cycles then throws code again. Do you know what this means? Thank you.


Randy Godwin profile image

Randy Godwin 4 months ago from Southern Georgia Author

Hey John, I have no idea what the e5 code indicates. Have you ever cleaned the coils in the front unit? If the coils are dirty the compressor may be overheating for lack of air flow. Other than that the control board may be at fault. I've had several complaints of this being the problem lately. As always, feel free to ask more questions. :)

Randy


Jimmy Tenison 4 months ago

When I turn my Coleman Mach on fan it works great,but when I put it on cool the compressor hums but fan goes off


Randy Godwin profile image

Randy Godwin 4 months ago from Southern Georgia Author

Hi Jimmy, this sounds like a bad start/run capacitor. It's inexpensive and relatively easy to change out. Hope this helps you out with your problem. :)

Randy


John 4 months ago

Thanks Randy,

Although the coils in both units were surprisingly clean, prompting me to get up there and look did something right. The wiring was a jumbled mess in front. I rearranged everything, replaced the covers and its worked ever since. I did remove all mud dobber nests, blew out a few leaves. Thanks for the suggestion.


Roger Schindler 4 months ago

With the fan on manual it just hums and will not come on this is on a road trek van


Randy Godwin profile image

Randy Godwin 4 months ago from Southern Georgia Author

Ha John, sometimes it is better to be lucky than good as I know from experience. It never hurts to simply clean an AC as best you can before doing anything drastic. Mud daubers cause all sorts of problems ,especially if they are placed on one of the fans. They'll make the fan sound like an out-of-balance washer on spin cycle. Pleased you got things straightened out, John. :)

Randy


Randy Godwin profile image

Randy Godwin 4 months ago from Southern Georgia Author

Roger, sounds like a bad start/run capacitor which is easy and inexpensive to replace.

Randy


Dave 3 months ago

Hey Randy, My ac unit leaks water inside my rv when it shuts off. But not always. 2014 Hill Country,I just use the one roof top unit because it vents to the bedrm via ceiling ducts. Last summer was first use and almost immediately noticed a brownish small stain from corner of unit go down the side of rv. any thoughts? Thanks pal


Randy Godwin profile image

Randy Godwin 3 months ago from Southern Georgia Author

Hi Dave, the leakage is usually caused by the coils being clogged with dirt or debris. If the coils are clean the AC fan will expel the excess moisture into the air as it's being condensed. When the coils get dirty the moisture collects in the AC pan and leaks down inside the camper.

Use a good coil cleaner and this should fix the problem. I recommend cleaning the coils every couple of years, especially if the unit is used frequently.

Randy


Al 3 months ago

Hi Randy,

I have a 2003 Fleetwood Prowler with roof mounted ac. Couple of weeks ago the fan moter wouldn't start (it would hum and was hard to turn by hand) so I replaced it and the capacitor. Worked great for a few weeks but now nothing seems to work on either the ac or heater.

Can't get the fan to start and the compressor never kicks on. I have checked the breaker and it's good. Also checked the fuses and they are all good.

I checked the fuse on the thermostat and it was good. I had a newer thermostat I was going to install anyway so I replaced the thermostat, still didn't fix the problem.

Any ideas?


Randy Godwin profile image

Randy Godwin 3 months ago from Southern Georgia Author

Hey Al, this may be a control board issue since you've covered most everything else. Seems as if there's been a lot of control boards going bad lately. I don't know if there's a connection with the age of the AC units though. Feel free to add more input on your unit's problems.

Randy


Al 3 months ago

Thanks Randy. I found the manufacturers repair manual online and following their flowchart I tested the voltage between the red and Y, B, GH and GL at the thermostat and I only read 10.5 volts instead of 12.

Also, if I have any lights on, the readings at the thermostat drops down to less than 10v.

I also tested the 9 Pin connector in the ceiling that plugs into the control board and I should have 115v between Term 1 & 3, 5 &9, and 6 & 9. However I'm getting very low ac readings there - like 20v.

I tested a couple of outlets just to be safe and got 120 at the outlets.

Thanks again for the help so far.


Al 3 months ago

Thought I might add this just in case it matters. My Battery is not hooked up to the camper at moment. I'm just plugged into a 30amp connection. The battery hasn't been hooked up in years, but I've never had a problem.


Randy Godwin profile image

Randy Godwin 3 months ago from Southern Georgia Author

Al, this may be a power converter problem. Try turning off the breaker or fuse which controls the power converter and hook a good battery charger--not a trickle type--to the batteries and see if it makes a difference. If so, the converter is at fault. Hope this helps you find the culprit. Feel free to ask for more info if needed.

Randy


Jack 3 months ago

Hi Randy,

Have read all the threads and found one that sounded like our problem (Larry about 3 yrs ago and closer to the top) but he never wrote back to tell if he got a fix. Here is our problem: 1993 Fleetwood southwind, we are 2nd owners for last 18 years. Coleman duo top mount AC units. Never had a problem with either unit, mostly run only front unit. Arizona heat most of year. At Lake Powell in July, hooked up to park power, ran front unit all day as had to leave one older dog in RV while out on lake. Ran fine. 9pm AC quit. Checked back unit, it also would not come on. Checked every breaker. REset button on generator and tried to start each one with generator, had selector switch set on rear or front as we checked each unit. No wall thermostat, only on ceiling unit. Fans would not even come on. Then went back to campground power with same result. All other appliances and lights worked. Just took OHM meter out to check connections of circuit breaker and tested all outlets and gfis. It is like no power is getting to the units. Checked coils and inside shrouds for dirt, pest damage found none. Suggestions?


Randy Godwin profile image

Randy Godwin 3 months ago from Southern Georgia Author

Hello Jack, sorry to take so long to respond, but I'm on vacation so I try to check in every few hours to see if there's any new queries. Thanks for being patient with me.

The first thing I would do is remove the ceiling assembly of each unit and check the power at the junction boxes where the AC's power supply is wired. You didn't mention if there were two circuit breakers or not in the power panel or whether each AC was on a separate breaker.

It's possible the power supply goes from one unit to the other and is on a single breaker. I can't tell you which is first in the circuit but you may have some loose connections in the junction box of the first in line AC which are also affecting the second. Feel free to ask for more info if this doesn't work for you.

Randy


Camper Dave 3 months ago

Frequently when we start up our A/C or just the roof A/C fan alone a dry white powdery dust comes out initially. Any causes or fixes?


Randy 3 months ago

Hey, My Coleman ducted 15k unit started squeaking, then stopped running all together. I ordered a new motor and replaced it. The fan now runs, but NO COOLING. It was cooling fine before the motor gave out. Any ideas? Its an 06 Raptor with just one unit, wall thermostat.


Randy Godwin profile image

Randy Godwin 3 months ago from Southern Georgia Author

Have you checked the start/run capacitor, Randy? It could be the culprit.

Randy


Randy 3 months ago

I removed all three capacitors-one is for the fan,the other has what i guess is a hard start thing. i don't have a capacitance meter, but, when i attempted discharge, no sparks on any of the three. when i ran resistance check with a Greenlee DM-20 set at 2000k, it started out counting up then stopped at one on all three capacitors


Randy Godwin profile image

Randy Godwin 3 months ago from Southern Georgia Author

Randy, if the capacitors are good you should get a random number which slowly decreases in value the longer you keep the probes in place.

Randy


Sydney Skov 3 months ago

Hi Randy, I have a rooftop Dometic AC and the front AC clicks but wont turn on. Any suggestions for me?


Randy Godwin profile image

Randy Godwin 3 months ago from Southern Georgia Author

Sydney, this sounds like a bad start/run capacitor. Check it with an ohm meter or take it to a electric motor repair shop and they will check it for you.

Randy


Sue 3 months ago

Have a 2014 Winnebago Travato with Coleman AC w/Heatstrip. When I turn on AC runs/cools for few minutes then compressor shuts off. Then no cool air & compressor does not kick back on. In fact it almost feels like it is blowing hot air.


Randy Godwin profile image

Randy Godwin 3 months ago from Southern Georgia Author

Hey Sue, this could be several things. If you have a wall mounted thermostat it may be defective. This would be the most inexpensive fix so I'd check it first. Next would be the control board which tells the compressor when to turn on and off. Lastly--and most expensive to repair--would be a compressor going bad or overheating. If the coils are clean then overheating shouldn't be a problem.

The only way to see if the compressor is bad is to check it with an amp meter. An amp meter is something an amateur electrician usually doesn't have, but you may know someone who works on motors or AC compressors who does. Otherwise you may be able to rent one to check the amperage your compressor is drawing.

The normal amperage should be listed on the compressor itself or on a plate nearby. The compressor is bad if it's drawing more amperage than usual. If the compressor checks out then the control board may be the culprit.

Randy


J dogg 3 months ago

heater comes on when I turn on ac what causes this? turned it on to check it out and heard a click then ac came on and then heater came on also disconnected wires for heat at thermostat and it still ran


Randy Godwin profile image

Randy Godwin 3 months ago from Southern Georgia Author

J dogg--this problem may be due to a bad control board, especially if you've disconnected the thermostat wires.

Randy


Garrett 2 months ago

Hello I have a 2005 35 ft holiday rambler and yesterday I had the AC going and all a sudden lost all power. It turned out to be the breaker coming from the outside power source and reset it came inside and no AC. All I hear is a click. And also my gfi isn't resetting. Are both of those powered together cause they say they are on different breakers. Anybhelp would be awesome.


Randy Godwin profile image

Randy Godwin 2 months ago from Southern Georgia Author

Garrett, usually a GFI is on a circuit by itself and on the AC circuit. I've had to replace many GFI outlets as they are prone to be overly sensitive and will eventully not reset at all.

As for the AC, I'd check the capacitors first because they can go bad all of a sudden. This is especially true if your AC has only one capacitor to start/run both the compressor and fan motor. Let me know if this isn't the problem and we'll go to the next phase of the troubleshooting.

Randy


Garrett 2 months ago

Thanks randy, where can I find these parts locally??? Or is my best bet online? Thanks for the response sir.


Randy Godwin profile image

Randy Godwin 2 months ago from Southern Georgia Author

You may find these parts locally at any electric motor repair shop or either order them online, Garrett. Hope this solves the problem for you.

Randy


Bob waz 2 months ago

My penguin heat pump unit blower quits for 3 minutes then restarts. Sounds like the thermal limit in the blower motor is cutting power out. Compressor is unaffected. It still did this with all ducts open on top of the unit. I checked the dual run capacitor and it is at spec. The run cap field wiring shows resistance. What else can I check?


Randy Godwin profile image

Randy Godwin 2 months ago from Southern Georgia Author

Hey Bob, Do you have a wall mounted thermostat, and if so, have you checked it yet? If this checks out, you may be looking at a control board issue. Anything else you can tell me about the problem?

Randy


Bob waz 2 months ago

Randy, I tried the operation with the the thermostat in blower "auto" and manual low and high. It did not sound like there is a mid speed change when that is selected. The motor was spinning freely but it was running real hot. That is why I thought the problem would be the "run" capacitor. There is no issue with the compressor, I believe. The cap does have an internal cutoff of some sort. Not sure if that could be the problem. Not sure how to test that. I have a new blower motor and capacitor coming. I'll try the blower first since the cap is a week out.


Randy Godwin profile image

Randy Godwin 2 months ago from Southern Georgia Author

Okay Bob, I meant to ask if the fan motor was getting hotter than it should but forgot. Yes, a new motor should fix the problem but if not, feel free to check back with me. Thanks for the question.

Randy


Dan 2 months ago

Randy, sorry I'm not very technical so this could be a stupid question, the rooftop AC was working fine, then we drove for 2 days through an intense rain storm. A couple of days later I tried to turn on the AC and got nothing. Dead. I tested the fuses and they appear to be OK. The breakers are set to "ON". Could the rain have caused this?


Randy Godwin profile image

Randy Godwin 2 months ago from Southern Georgia Author

Hey Dan, yes the moisture may have affected either the start/run capacitor(s) or the control board. I'd check the capacitor(s) first. Let me know if you need assistance with the procedure.

Randy


Mike 8 weeks ago

Hello Randy,

Having a problem with my Duo Therm Brisk Air 57915.531 AC unit. (No heat and air ducts right from the unit) Turned the switch on and the compressor ran fine but no fan. Fan ran ok if given a nudge so replaced the start cap but still have no fan at initial start up; although the fan motor spins freely and will still run if given a nudge.

Also, this is a three speed motor and selector switch but it's only operating on low speed, no matter what position the switch is in so hardly any air movement in the TT.

Do you think this could be a fan motor or control board problem? (Air is plenty cold coming out of the ducts)

Thanks in advance...


Randy Godwin profile image

Randy Godwin 8 weeks ago from Southern Georgia Author

Hi Mike, with the motor only working on one speed it may be the motor itself. On the other hand, if the switch is located on the ceiling assembly I'd check that first. As for the heat, have you checked the heating element Yet?

Feel free to ask for more info if needed.

Randy


Mike 8 weeks ago

Hey Randy,

When I said "no heat" I meant that this unit does not have an element for the optional heat mode, and I have not upgraded it to do that. Sorry for the misleading statement!!

The AC / Fan switch is located on the ceiling assbly. That said, even in just fan mode, the speed does not change from low - med - high. My suspect is the fan motor - and now I noticed some vibration that I failed to mention. The motor shaft movement is fine for up and down, but does have some play when moving it in and out.

I have no real life experience at this stuff, but am thinking the motor may have had a winding go south and that's why the new start cap didn't help at all.

I'd appreciate your thoughts on this - I know without "being here" it's pretty much of a guesstimate, but you certainly have more experience at this than I do!! : )


Randy Godwin profile image

Randy Godwin 8 weeks ago from Southern Georgia Author

Mike, I too suspect the fan motor of being the problem, but I just wanted to suggest a few things before you went and purchased a new motor for your AC. If the unit has some age on it, this too is another indication a new motor may be needed. Let me know if a new motor solved the problem, Mike. Good luck!

Randy


Mike 8 weeks ago

Thanks Randy - appreciate all the help and advice and will let you know.

Mike


fsfirecook2 8 weeks ago

Hi Randy

I have a Damon UltraSport with a Carrier V ac unit. The problem I'm having is. The unit will run fine without no problems while still, on gen or plugged in. But when I try to run the unit while traveling the unit after about 10 to15 min. Trips the 20 amp breaker.

I have trying tighten all the wires,I also ran a seperate wire from the breaker to the unit with same out come. I also changed the breaker. I even changed the capitator. Do you have any other solutions. to this problem?


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Randy Godwin 8 weeks ago from Southern Georgia Author

fsfirecook2, what do you have powering the AC while you are traveling?

Randy


fsfirecook2 7 weeks ago

my onboard generator Genrac 7.5 Kw diesel.


Mike 7 weeks ago

Hello Randy,

Thought I'd post the results of my AC dilemma!!

I changed the hard start cap earlier, since oil was leaking out of the top. Of course that cap is for the compressor and has nothing to do with the original evaporator fan problem.

That said, I went ahead and changed the run cap and the fan motor would start, but would still only run on one speed - so new fan motor installed and I'm back in business.

Kinda strange to me that all three would have issues at the same time, but that seems to be the way it goes for me with about anything!!

Thanks for the suggestions - much appreciated!

Mike


Randy Godwin profile image

Randy Godwin 7 weeks ago from Southern Georgia Author

Thanks for the update, Mike! I'm pleased the new motor solved the problem. Yes, problems seem to come in bunches for me also. Feel free to contact me with any other RV problems you encounter or check out my other RV repair hubs.

Thanks again,

Randy


Paul 4 weeks ago

Hello Randy I have a 06 motorhome with 3 Duo Therm conditioners. Recently the front one will start blowing cold air for about 5 mins then start blowing warm air. Is this a sign of low freon or compressor going bad


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Randy Godwin 4 weeks ago from Southern Georgia Author

Hi Paul, this could be several things. When an AC gets low on Freon it typically blows really cold shortly before it stops cooling at all. This doesn't fit your AC's problem it seems. As for the compressor, can you tell if it is still running when the AC stops blowing cool air? If not, this could be a capacitor problem or perhaps a control board malfunction.

Feel free to ask for more info if needed.

Randy


Paul 4 weeks ago

It sounds like the compressor is still running but not positive. I have not taken cover on roof off yet. I have not left air on to see if it goes back to cooling or not, hate to put that much warm air in house. We are in south Texas and weather has been warm.


Chris Conway 7 days ago

Purchased Atwood Air Command Ducted 13,500 BTU A C Roof Air Unit for a Montana fifth wheel. The one we purchased is run by thermostat and the one that was damaged was run by remote. Is there any way to bypass the thermostat because we do not have a thermostat on this fifth wheel. Mexico, Mo


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Randy Godwin 7 days ago from Southern Georgia Author

Chris, I believe it would be easier to simply install a new thermostat rather than trying to manually operate the system. You can also buy a remotely operated thermostat if you wish. It should be a rather simple installation whatever you choose.

Randy

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