How to Install a Coleman RV Rooftop Air Conditioner
An Overview of the Coleman Rooftop AC
Coleman RV air conditioning units are perhaps the most well known, efficient, and reliable air conditioner brands for RVs, whether they be motor homes, camper travel trailers, or pop-up campers.
Installing or replacing a new AC unit is something even the most hands-off type of person can accomplish with a little study and work. This article is intended to walk you through the steps of installing a new Coleman AC in a camping unit, or replacing an old unit, no matter the make or model of the RV.
How to Determine the Correct Coleman AC unit
If you want to replace your AC, it will be necessary to determine which replacement model to use in your travel trailer or motorhome.
Coleman rooftop AC’s are available in two models, 13,500 and 15,000 BTU (British Thermal Units).
The 13,500-BTU model is often used in applications where two units are used to cool a large motorhome or camper trailer. Working independently from each other, these 13,500-BTU units can be used singly or together for efficient cooling, depending on how hot the weather is.
For middle-sized camper trailers or motorhomes, there is the Coleman Mach 15 air conditioner. This fine unit fits the niche perfectly with enough cooling power to keep you cool on the hottest summer days. Installing one of the Mach 15 AC units is no more difficult than the 13,500 BTU model.
Check your old rooftop unit to determine the correct size if you have any doubts as to which Coleman unit to purchase.
If ordered from this page, for example, the AC unit you chose should arrive at your location in just a few days. In the meantime you can remove the old RV AC unit and prepare for the new one.
Coleman Rooftop RV Air Conditioners
The RV AC used in this article. Everything needed is included in the price.
If you want more power you can order this 15,000 BTU model.
Starting the Replacement Process
The first step in removing the old unit is to detach the ceiling assembly from the unit by removing the screws holding it to the ceiling. There are normally only four screws which need to be removed, but some older AC units may have more or less. Hold the AC ceiling assembly up with one hand while removing the screws to prevent the assembly from falling abruptly.
It may be necessary to unplug the wires leading from the AC ceiling assembly to the rooftop unit before it is completely free. It is helpful to have someone assist you in this step for ease of removal, but the assembly can be allowed to hang from the wiring while they are disconnected. Remove the cover from the electrical junction box and disconnect the electrical line wires. (For more help with your RV's electrical system, see my other article.)
Note the wire colors and the ground connection in the old junction box, because the new Coleman RV AC will use the same configuration when it is time to reconnect the electrical line to the new unit.
After detaching the wires, remove the long bolts from the ceiling bracket. These bolts go up through the roof and into the rooftop AC unit itself.
Detach the vent which connects the ceiling assembly to the rooftop unit. Some vents are made of thin aluminum and some use a flexible vinyl tube to make the connection. Both use screws to hold them in place. At this point you will need to gain access to the roof of the motorhome or camper trailer.
Removing the Old Rooftop Air Conditioner
Care should be taken when removing the old rooftop AC unit to prevent any damage to the motorhome or camper trailer roof.
For installation of the new Coleman AC unit into the Airstream travel trailer, we used thick padding to protect the surface where the ladder was used and on the roof itself.
Motorhome roofs are normally rubberized, and harder to damage than metal roofs. With the electrical wiring, the retaining bolts, and the ducting unfastened, the old unit is ready to remove.
It may be necessary to carefully slide a thin putty knife between the bottom of the old AC unit and the roof surface as any previously applied roof sealants will have caused the old AC unit to stick to the roof.
When the old AC unit is removed, carefully lower it to the ground. Clean the area around the vent hole carefully being sure no rough spots or adhesives remain to interfere with the new seal.
Installing the New Coleman Rooftop Air Conditioner
Remove the shroud from the new Coleman AC before transporting it to the roof of your camper. Check for any shipping blocks or other objects which may interfere with the moving parts of your new AC.
Finishing the AC Installation
Once you have centered the new unit over the duct hole, you may attach the retaining bolts and bracket. Tighten the bolts gradually moving from one to the others until the seal is uniformly tight against the roof.
Do not over-tighten these bolts. They just need to be snug enough to keep water from seeping beneath the gasket. You can always tighten them further later to stop any leaks if needed.
Replace the shroud using the retaining nuts, being sure the shroud is securely fastened to the unit. You are finished with the rooftop part of installing the new AC unit.
Follow the instructions provided with the new Coleman unit to attach the flexible duct in place.
If you purchased the optional heating element now is the time to attach it to the ceiling assembly. Reattach the electrical line wiring to the wiring in the unit junction box.
Using the provided screws, attach the ceiling assembly in place and re-connect the power source to the motorhome or camper trailer.
Test run the new AC unit to check for any malfunctioning parts or a lack of cooling or heating if the heating option comes into play.
Your new Coleman rooftop RV air conditioner will give you many years of trouble-free service if maintained properly; see my detailed advice on maintenance.
When Is it Better to Buy a New RV AC Than Repair Your Old One?
The old Coleman Mach, on the 1986 Airstream Sovereign Travel Trailer in the photos used to illustrate this article, had given many years of dependable service. But it had seen its better days. It still cooled fine, but the fan motor sleeves had worn to the point of the fan needing a nudge to get it going.
Since this AC fan motor had sleeves instead of standard bearings, the shaft itself was worn, making a rebuild prohibitively expensive. Instead of having only the bearings replaced, it would have necessary to replace the shaft along with the winding mounted on the shaft. It would probably have been cheaper to install a new motor than rebuild the old one.
But besides the fan motor problem, the RV AC shroud had begun to develop cracks at the stress points around the four retaining bolts and in some of the air vent louvers. Replacing the old shroud isn’t cheap either.
So, all things considered, purchasing a new Coleman 13,500 BTU air conditioner seemed to be the best option.
Now if the AC compressor in the old Coleman AC had gone on the blink, which often happens in old units, the owner would have definitely gotten a new Coleman unit. Buying and installing a new AC compressor would have more than paid for a new Coleman unit. The combined cost of the new AC fan motor, shroud, and compressor was just not acceptable when a new unit would solve the problem and perform more efficiently.
Can This Old Fan Motor Be Saved?
Covering your AC will make it last longer.