Snowbirding is all fun and games down in the nice, warm south—until the A/C goes out. But knowing how to maintain your RV’s air conditioner will keep your coach cool and comfortable so you can retreat from the heat when needed.
Whether you’re learning about seasonal AC maintenance or you need to replace AC accessories, or explore other air conditioner options, this guide has you covered. The video above goes over the three likely causes for A/C malfunction, how to remedy them, and includes a few best practices to make sure you’re not overworking the unit.
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Types of RV Air Conditioners
There are several different types of air conditioning units you might find in an RV. Roof-mounted AC units are by far the most common. But you may also find window-mounted units, basement units, and portable units that can be moved to provide cool air in different rooms of your coach.
For the purposes of this guide, maintaining and troubleshooting roof-mounted AC units will be our focus. But if you have one of the other types, be sure to check your owner’s manual for model-specific maintenance and troubleshooting tips.
Understanding RV Air Conditioner Components
Several different components make up an RV’s AC system. Being aware of these components and understanding how they work together will prepare you to maintain your RV’s air conditioner better.
Shroud
Starting from the top and working our way down, air conditioner shrouds protect your actual AC unit from the elements. If you go up onto your RV’s roof safely, you’ll see the shroud surrounding the exterior of the AC unit.
While AC shrouds are durable, they will last longer if you maintain them correctly. When storing your RV for long periods of time, it’s best to use an air conditioner cover to protect the shroud from moisture and UV exposure.
The AC Unit
Sitting underneath the shroud is the actual cooling unit of your RV’s air conditioner. This unit pulls air from inside your RV and passes it through a chilled coil. Heat is removed, and the air is then returned to your RV’s interior. The removed heat is then sent to the outside air via the unit’s outside coil.
Air Distribution Assembly
The air distribution assembly is responsible for circulating air throughout your camper. Most roof-mounted units have an air distribution box underneath them and inside your RV. This is what often contains the control dials or switches you’ll use to operate the unit.
Smaller campers tend to contain all the air distribution within this single box, which often has vents to circulate air 360 degrees throughout your coach. Larger RVs tend to contain internal ducting that provides more even air distribution over the rig’s larger area.
Air Filter
Your AC unit’s air filter is responsible for removing things like pollen, dander, dust, and other allergens from the inside air before it is recirculated inside your RV. This filter is usually contained within the air distribution assembly.
Thermostat
Many newer RVs feature AC systems with a wall-mounted thermostat that allows you to set the ideal internal temperature for your RV. Some units simply have a dial on the air distribution assembly that controls the unit’s internal thermostat.
How To Maintain Your RV’s Air Conditioner
Now that you have a better understanding of the various components of roof-mounted AC units, it’s time to focus on what you should be doing to keep your air conditioner running efficiently.
Inspect and Clean The Air Filter
This is the most important step for AC maintenance, and, fortunately, it’s also the easiest. You should find your air filter under a removable panel on your AC’s air distribution box. Consult your owner’s manual if you’re having trouble locating your filter.
Set a reminder to remove, inspect, and clean your AC’s air filter at least once a month if you’re a full-time RVer. If you’re a weekend warrior or you simply don’t use your AC unit all that often, you may reduce the regularity with which you perform this AC maintenance task. Taking care of your filter quarterly (every 3-4 months) should suffice.
When cleaning, you can simply use warm water to rinse the dust and other contaminants from your filter. Vigorous scrubbing shouldn’t be required, but you may gently use a sponge and mild detergent to remove any pesky residue. The most important thing is that you allow your filter to dry completely before putting it back into the distribution box.
When inspecting, you’re mainly looking for large tears in the filter. Really, any holes or tears that would compromise the filter’s ability to catch contaminants should signal that it’s time to replace your RV’s air filter.
Only the manufacturer’s intended filter should be used. Aftermarket or residential filters may cause the unit to malfunction.
Inspect The Shroud
As part of your RV’s annual maintenance routine, you should safely ascend your RV ladder onto your roof to check the shroud covering your unit. Look for large cracks or missing chunks of the shroud that would allow moisture and debris into the more sensitive components of your cooling system.
Using a cover for your air conditioner when it’s not in use is the best way to protect your AC’s shroud. But if it has been compromised, replace your shroud promptly to avoid more expensive repairs to the rest of your unit down the line.
Check The Seal On The Unit’s Exterior
While you’re already safely up on the roof to inspect the shroud, use a flashlight to inspect the seal between your AC unit and your RV’s roof. You are looking for the gasket to be 50% compressed, and you should also check that the unit is still securely mounted to your RV’s roof.
How To Troubleshoot an RV Air Conditioner
Let’s discuss the three main causes of AC malfunction and provide some tips to help you diagnose what’s going on with your unit.
Lack of Power Supply
AC units require ample power supply to operate effectively. If your RV requires 30-amp service, you won’t be able to run your AC unit with anything less than that. Many 50-amp RVs have dual AC units, and you won’t be able to run both units if plugged into anything less than 50-amp service.
At this stage, you can also check that the AC voltage is correct. You can accomplish this using a voltmeter that shows the safe range of 108 to 132 AC volts.
If you’re plugged into the proper 30-amp or 50-amp service for your RV, and your AC still isn’t working, here are a few things to check:
- Make sure the breaker on the electrical stand you’re plugged into is turned on.
- Check your RV’s circuit breaker panel to make sure the main or AC breakers haven’t been tripped.
- Check connections at both ends of your RV power cord to make sure nothing is loose.
- Check the fuse box to make sure no fuses are blown.
- Check the 12-volt DC power supply that runs your RV’s thermostat.
If none of these issues are presenting and your AC unit still isn’t working, your issue is likely with the thermostat itself. If you suspect thermostat issues, we recommend contacting your local Camping World Service Center.
Lack of Air Flow
If you’ve determined that the power supply isn’t an issue, your next troubleshooting step is to check your AC unit’s airflow. This is where regularly inspecting and cleaning your air filter will help to guarantee proper AC airflow.
So if you haven’t done that recently, start there. While the filter is removed, this is a great time to inspect the inside coil fins above the filter. Remove any buildups of dust, hair, fur, or dander and clean as needed.
Once your air filter is clean and you’ve inspected the inside coil fins, you may need to remove the shroud covering your AC unit and check for air blockages. Things like nesting materials from curious birds and damaged fins can restrict airflow and compromise your air conditioner’s efficiency.
While the shroud is removed, make sure the plenum separation is still in place. This separates return air from the discharge air and prevents the coil from icing up, which will cause the freeze sensor to shut down your air conditioner until it de-ices.
Blocked vents in your air distribution assembly or a terribly dirty air filter can also cause condensation inside your unit or assembly. If this condensation freezes, it will restrict airflow and can result in other damage as well. So you may need to check vents if you’re still experiencing an airflow issue.
Improper Usage
Because ACs draw a lot of power, limit the usage of other large RV appliances while your AC is running. That means being mindful about microwaving foods Because AC units draw a lot of power, you may need to limit the usage of other large RV appliances while your AC is running. That means being mindful about microwaving foods or plugging in blenders while using your RV’s air conditioner.
Overdrawing will usually trip a breaker that causes your AC to shut down before any major damage is done. If this doesn’t happen, however, it can result in damage to your AC unit and your RV’s electrical system. So just be cautious about running too many appliances concurrently.
Additionally, parking your RV in shaded areas will help your air conditioner run more smoothly without being overstressed. Keeping window shades closed and limiting the amount of time doors or windows are left open will also increase your AC’s effectiveness.
Finally, limiting the number of people in the unit, the length and temperature of showers, and the cooking of items that produce a lot of steam will reduce the humidity inside the RV. As much as 40% of the energy used by the AC system can go to dehumidification rather than actually cooling the air.
If problems persist, contact a Camping World Service Center to schedule a complete inspection of your RV’s air conditioner and cooling system. We’ll help you resolve any issues so you can get back to recreating with the peace of mind that you’ll come home to a nice, cool RV!
What problems have you run into with your RV’s air conditioner, and how have you solved them in the past? Let us know in the comments below!
If you’re still learning the ins and outs of RV maintenance, check out our downloadable RV ownership and maintenance booklet!
I have a dometic Mach 15 air conditioner that’s ducted in my 2018 avenger by primetime. The coils tend to ice up lately and I’m not sure what it is. Any help would be great?
Hi Venida!
These will ice up for several reasons. They require a minimum number of vents for airflow, and if any are blocked it will ice up. The return air filter must only be the Dometic filter and it must be kept clean or icing will occur. If equipped with the quick cool vent, this should only be used for initial cooling of the coach.
If left open more that 20 minutes or so, the inside coil will drop below 32 degF and ice up. The space above the return air filter is called the plenum. There is a divider between the return air and the freshly cooled air that must be tightly sealed with foam or foil tape, otherwise the cold air will enter the return side and ice the coil.
Running the fan on low speed will cause icing due to the reduced airflow across the coil. On manually controlled models, going to bed with the thermostat setting too low can cause icing at night especially at higher altitudes. Most models have a thermistor, or freeze probe, placed in the fins on the lower right quarter of the inside coil. If the coil gets too cold, it will shut off the compressor for a little while to prevent icing up. If this probe has failed or failed out of it’s location, there is no way to prevent the coil from getting too cold.
Hope this helps, but let us know if you have any follow up questions!
my dometic roof air kicks in and then kicks back off, do you think it’s the starter coil need replacing? The thermostat seem to be working okey.
Are you speaking of the unit “cycling” while in operation? Mine does the same thing if this is what you are speaking of. My unit is Dometic also. I have had a dozen rigs in my time and this is the 1st time this has occurred for me. I live in Florida nowadays, so I thought maybe the “humidity” may play a role in the “cycling”. By cycling I am describing the unit in cooling mode and both compressor and fan are operating then the unit will “cycle” and either go back into same mode or slow or speed up the fan speed. It’s been doing this since purchasing the rig just over 2 years ago. P.S. I am a maintenance/PMS junkie.
Hi Floyd!
Can you further explain the symptoms you’re encountering?
When you say kicks in, is the fan running continuously or is the fan turning on and off?
What signs and symptoms lead you to believe the thermostat is functioning properly?
It can sometimes be tough to troubleshoot from afar, and while there’s a lot you can DIY at home, there’s no substitute for having a certified technician inspect the unit!
We just replaced our first hail totaled travel trailer with a unit we feel suits us presently. Having two sets of grandchildren who love to camp with us it was imperative to have a bunks and a u-shaped kitchen. All of this leads to more length, however, what I found with the 2019 Forest River Grey Wolf was what we ended up with. Having experienced some wonderful camping trips helped us in our decision making. One thing I might add is beware of the designation i.e. 29TE in our case can be misleading. The camper is actually nearer 33′ plus hitch. The location of the tandem axels seems to make this a nicer towing vehicle than our previous unit and also has 15″ wheels vs 14″ And there is a difference where the rubber meets the road.