How to Replace or Install an RV or Travel Trailer Rooftop Air Conditioner
Why Install A New RV AC
If you own a motorhome or camper trailer for any length of time, there will eventually come a day when the rooftop AC will need to be replaced. More than likely you have already spent a few bucks having minor repairs made over the years.
But now, there are a few problems which will entail spending quite a bit of cash in order to get a few more camping season out of the old AC unit. An old shroud needs replacing before it finally breaks away from the unit and ends up beside the road. Or even worse, in front of an oncoming vehicle.
Or perhaps the fan motor is making a noise and the old girl doesn’t cool like she used to. Just to replace these items will cost half as much as a new rooftop RV AC unit. And who’s to say the compressor won’t suddenly go kaput and cost another three or four hundred dollars. The best thing to do is just bite the bullet and install a new rooftop unit.
Can You Install The New Rooftop AC Yourself?
If you are a hands-on type of person with basic tool skills, there is no reason you cannot replace your old cooling unit with a new, more efficient rooftop AC unit. The whole replacement procedure doesn’t take very long to do, especially if you have a willing friend to help. The hardest part of the procedure is getting the old AC down and the new unit back up on the roof.
There are no special tools required for this job. Ordinary hand tools are all that is needed to quickly replace the old AC, with a new and more efficient unit. A basic knowledge of household electric wiring is required but there are only 3 wires to be connected in the entire process. So, if are you up for it, read on.
Beginning the RV AC Replacement
Removing the Old Air Conditioner
It is recommended that you protect the roof around the installation area with thick drop cloths or old blankets to protect the roof material against damage. This is especially important if the RV is an Airstream or other smooth metal roofed camper trailer which could be easily scratched or dented.
These cooling units are not especially heavy but they can cause damage if bumped or dropped on the camper roof.Also, be sure the roof will support your weight before clambering around on top of it. If you are not sure, it is best to use planks or plywood to distribute your weigh evenly on the rooftop.
Begin by removing the old AC shroud from the unit. Normally, there are 4 screw or bolts securing it to the old unit.The shroud is removed to make it easier to move the old unit.
Remove any old flashing or adhesives from around the base of the old air conditioner. Often there is quite a bit of this residue because of repeated coatings of the roof over the years to prevent leaks. A putty knife will come in handy on this job.
Unbolting and Removing the Old Unit
In most cases, four long bolts are all that holds the unit to the camper's rooftop. These bolts go up through a square bracket and thread into the rooftop unit itself. A thick rubber seal is compressed between the rooftop unit and the roof of the trailer or motorhome when the bolts are tightened. This seal ensures a watertight barrier against rainfall and humidity.
Remove the bolts with a wrench or socket and the ceiling flange should drop free. Depending on what kind of duct is used to connect the rooftop unit to the ceiling flange, unscrew or pull loose the ducting. The A/C unit is ready to be removed. After going back up onto the roof, it may be necessary to use a putty knife to loosen the rooftop unit from the roof surface.
Once it is loose, lift the old air conditioner out of the hole and remove it from the roof. Clean the surface of the roof well where the new seal will rest. A clean surface is imperative to prevent leaks. Old putty and adhesives may cause a leak in the new seal.
Correctly Placing the New Air Conditioner
With the shroud removed, transport the new air conditioning unit atop the camper and center it over the duct hole. It helps to have someone inside of the RV to help you get the unit centered correctly.
The rubber gasket on the bottom of the A/C should align with the 14”X 14” square ceiling hole almost perfectly. Check the installation instructions to be sure the ceiling assembly flange is turned the right way before threading the new bolts up into the unit.
Follow the instructions for your particular rooftop unit while tightening the retaining bolts. Some AC units, such as the Coleman unit illustrated here, have small tabs which contact the roof when the flange bolts are tightened properly.
This Coleman unit uses a flexible duct which attaches to the AC ceiling assembly by a small strip of adhesive. Remove the protective plastic from the adhesive strip and attach the flexible duct firmly into place. Cut off the excess flexible ducting before attaching the air filter cover.
Finishing the new Coleman RV AC installation
AC Electrical Connections and Finishing Up
Attach the line to the new wires inside the junction box of the ceiling assembly. The wires are color coded to match the electrical wiring. Using the wire nuts provided with the new RV AC unit, connect back to black, white to white, with the green ground wire being connected to the bare line ground.
Make sure the wire nuts are secure with no exposed wire on the back or white wires. A small strip of electrical tape wrapped around the connections will do no harm. If you are not confident in connecting these wires, ask someone with more experience to help you.
Plug the control wire harness from the rooftop A/C into the ceiling control assembly. If you are using the optional heat strip, now is the time to attach it to the mounting bracket inside of the ceiling assembly and plug the heating element connecting wires into the control cover.
The control cover on this Coleman RV AC unit uses four spring assisted screws which attach it to the flange. Attach the filter cover and the job is almost done.Carefully slide the new shroud over the unit and secure it with the retaining screws. Be sure they are snug. Reconnect the power and the job is complete.
Test the unit for correct operation and run it for a while to verify it’s correct operation. Now you can rest easy and enjoy a cool nights sleep in the hottest weather. You saved a few bucks and learned a few things in the process. Good for you and good luck with your new air conditioner!