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Snowbirding is all fun and games down in the nice, warm south—until the A/C goes out. Knowing how to maintain your RV’s air conditioner will keep your coach cool so you can retreat from the heat when needed.
Whether you’re learning about seasonal RV AC maintenance, replacing AC accessories, or exploring other air conditioner options, we’ve got you covered. This guide will cover the three likely causes of A/C malfunction, how to remedy them, and best practices to avoid overworking the unit.
Types of RV Air Conditioners
There are several different types of air conditioning units you might find in an RV. Roof-mounted AC units like the Dometic Brisk II are by far the most common. You may also find window-mounted units, basement units, and portable units that can 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. Check your owner’s manual for maintenance and troubleshooting tips specific to your air conditioner if you have another type.
Understanding RV Air Conditioner Components
Several different components make up an RV’s AC system. Understanding how these components work together will prepare you to better maintain your RV’s air conditioner.
Shroud
Air conditioner shrouds surround and protect your AC unit from the elements. While AC shrouds are durable, they will last longer if you maintain them correctly. When storing your RV, it’s best to use an air conditioner cover to reduce 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 box, which often has vents to circulate air 360 degrees. Larger RVs tend to contain internal ducting, which provides more even air distribution over the larger rig.
Air Filter
Your air conditioner filter is responsible for removing pollen, dander, dust, and other allergens from the inside air before recirculating inside your RV. This filter is usually contained within the air distribution assembly.
Thermostat
Many newer RVs feature a wall-mounted thermostat that allows you to set the internal temperature of 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 understand the components of AC units, let’s discuss how to keep your air conditioner running efficiently.
Inspect and Clean The Air Filter
This is the most important step for RV air conditioner maintenance, and, fortunately, it’s also the easiest. You should find your AC 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 don’t use your AC unit that often, you may perform this AC maintenance task less frequently. Cleaning 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 need a 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. Any holes or tears that compromise the filter’s ability to catch contaminants signal that it’s time to replace your RV’s air conditioner 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 your unit’s shroud. Look for large cracks or missing chunks of the shroud that would allow moisture and debris inside your cooling system.
Using a cover for your air conditioner is best to protect the shroud when your AC isn’t in use. If your shroud is compromised, replace it promptly to avoid expensive repairs to the rest of your unit.
Check The Seal On The Unit’s Exterior
While you’re on the roof to inspect the shroud, use a flashlight to inspect the seal between your AC unit and your RV’s roof. The gasket should be 50% compressed to provide an adequate seal. 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 AC 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.
You can also check that the AC voltage is correct at this stage. You can accomplish this using a voltmeter that shows the safe range of 108 to 132 AC volts. If you’re plugged into 30 amps or 50 amps, and your AC still isn’t working, here are a few troubleshooting tips:
- 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 the power supply isn’t an issue, your next step is to check your 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 evaporator coil fins above the filter.
Remove any dust, hair, fur, or dander buildups and clean as needed. You may need a soft bristle brush but use it gently to avoid damaging the coil fins. AC coil cleaners are also a great solution for servicing older units.
Once your air filter is clean and you’ve inspected the inside coil fins, you may need to remove the shroud 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 the return air from the discharge air and prevents the evaporator and condenser coil from icing up. Frozen coils will cause the freeze sensor to shut down your air conditioner until it de-ices.
Blocked vents and dirty air filters can also cause condensation inside your unit or assembly. If this condensation freezes, it will restrict airflow and result in other damage. 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 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. However, if this doesn’t happen, 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.
Here are some basic tips to improve your AC’s cooling capacity:
- Park in shaded areas to limit AC stress.
- Keep window shades closed.
- Limit how long doors and windows are open.
- Install window treatments to improve RV insulation.
- Limit the number of people inside.
- Reduce the length and temperature of showers.
- Avoid cooking items that produce a lot of steam.
Up to 40% of your AC’s energy consumption can go to removing humidity rather than cooling the air. Cooking best practices might seem unrelated, but utilizing your outdoor kitchen can help keep your RV cooler inside.
Contact a Camping World Service Center if problems persist to schedule a complete AC inspection. We’ll help you resolve issues so you can get back to recreating and know 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.