RV Air Conditioner Tips

A wonderful thing about RVs is their climate control appliances, such as the furnace and air conditioner (AC), to keep the temperature in your camper pleasant.  Each one is not like their counterpart in your house, and RVers do better when understanding how to use and maintain their RV versions properly.

Here are some use and maintenance tips about RV Air Conditioners:

1. They have a filter.  While inside your RV, if you look up at the air conditioner return air section, you will see a screen or foam-type filter.  These should be removed, cleaned with mild dish soap and water, shaken, and replaced when dry. Most have tabs or quarter-turn screws to remove them, so take a look and give it a try. If not cleaned, the AC unit won’t produce enough air to keep your RV cool.
   TIP: While you’ve cleaned your filter(s) and are drying, shine a flashlight up inside your AC unit if you can, and look for loose wires or dirty condenser coils. Make sure the “freeze sensor,” which is a white wire with a metal end, is wedged in the coils about ¼ the way up. Many AC units also have a divider between the return air and the cool air; ensure it is present and sealed. If necessary, please contact me or a reputable Mobile RV Technician to address any findings.
   
2. They aren’t as efficient as your home AC. But, they do a good job for what they are…light, affordable, and replaceable. They are designed to change the temperature between the input return air and the output cool air by 20 degrees Fahrenheit. Some do more, but 20 degrees is what they are designed to do, and is why it takes longer to cool your RV. 
   Also, they actually have very little coolant in their lines, and concentrate more on moving warm air out of your RV than blowing cold air in. That’s difficult to explain, but it may help to understand why cooling is slower than your house AC, and why you should use the fan on High speed.
   TIP: If possible, try not to let your RV get so hot that it’s hard for the AC to catch up and cool down to your desired temperature. Start it earlier than you would in a house.
   
3. Set the thermostat to the temperature you want.  Don’t set the thermostat any cooler than you want because that does not make it work faster or cool better…in fact, the opposite!  The AC unit needs to reach a temperature where the compressor (that’s what pumps the coolant through the lines up there) can shut down for a bit, melting any ice buildup.  If your AC was working fine earlier in the day, but later does not blow as much air or as cool as it recently did, you probably have ice built up, preventing it from working efficiently.
   TIP: Set your temperature at, say, 76 degrees, and leave it there. Set your fan speed on High to help melt any ice buildup quicker.
   
4. Water draining is good. While your RV AC unit(s) are running, there should be some water dripping from the roof, hopefully from the corner rain gutter spouts. This means your compressor is turning on and off, and the fan is melting any ice build-up.  If water is coming into your RV while the AC is running, something is not sealed correctly, or the drain holes are plugged, you should probably call me or a reputable Mobile RV Technician to diagnose and remedy the situation.
   TIP: During your routine roof maintenance, ensure the rain gutters and corner spouts are clean of any debris.
   
5. Close your dump valves.  If your AC system has round or rectangular duct vents in the ceiling, it may also have one or two dump slider vents right at the AC unit near the return air filters. (Refer to the photo below) Those dump sliders are designed to be opened when you first turn on the AC (and let cool air blow down the back of your neck), but close them during regular operation (or just leave them closed).  This forces the air through the roof ductwork (sometimes called “racetrack ducting”) to the duct vents, which should be open and pointed toward the outside walls of the RV. That brings the warm air risen near the ceiling to the return air where the filters are. This is the best way to maintain the same temperature in all areas of the RV, and is most efficient.
   
   If your RV doesn’t have duct vents, use the AC vents to point the cool air away from the return air filter.
   TIP: Point the ceiling vents toward the exterior walls of the RV to do the best job of evenly cooling the RV. Most can open and even rotate, directing the cool air where it should go.
   BONUS TIP: If your RV has more than one AC unit, like our 5^th wheel, we don’t use the unit right above our bed while sleeping due to the noise, but leave on another AC unit which puts cool air into the “racetrack ducting”, which we can feel in our bedroom, and we sometimes close the furthest away ceiling ducts.
   

6. Perform annual AC maintenance. The exterior portion of your AC unit on the roof of your RV (or storage area in some motor homes) should have the cover removed, inspected for damage or bug nests, and have the coils and drain holes cleaned. This should be done annually. Many evaporator or condenser coils get gunked up with bugs or tree pollen or tree cotton or dust, which needs to be cleaned out so air flows as designed.
   Inside the RV, remove the filter(s) and inspect up inside the return air side for dangling wires that may have come off, look at the fins for cleanliness up there, look for any loose aluminum tape or roofing material hampering airflow, and ensure the baffle is in place with no gaps around any part of it. This baffle sits vertically on most units and blocks the incoming return air from the outgoing cold air. If there are gaps, the cool air will just go back up the return air and not into your RV. Seal this with aluminum duct tape, or contact an RV technician.
   TIP: Most Mobile RV Technicians have been trained to perform this annual cleaning and maintenance safely and check the baffle is sealed correctly. They have the proper tools and cleaning solutions, and are worth every penny. They can also remove the interior cover and filters to inspect and correct any ducting problems (and many RVs have ducting problems from the factory, or occur while bouncing down the road) if you like.
   
7. RV AC units are replaceable. In the past 20 years or more, RV AC units have been manufactured as sealed so the coolant cannot be recharged.  Occasionally, you may find someone who can tap into the piping and charge the system with new coolant, but I have never seen that last very long. And it’s expensive.  They probably tend to leak due to the vibrations an RV goes through while traveling down the road.
   
   However, most RV AC units do have capacitors that can fail, so if your RV AC unit is not functioning as it should, contact me or a reputable Mobile RV Technician to diagnose, and hopefully, it just needs a new capacitor.
   TIP: If your AC unit has been diagnosed as having lost its coolant, it is best to replace the whole unit; they are easy to do, and most replacement units are “plug-and-play,” making the process affordable.
   
8. Exercise your AC. Air Conditioners need to be exercised to keep the compressor properly lubricated and reduce the chance of failure or seizing up.
   TIP: While plugged into shore power, run each AC for about 15 minutes once per month to exercise the AC unit, making sure the compressor turns on and cool air blows out.

Following these tips may help your AC run better, more efficiently, and keep your RVing experience “Fun, not frustrating!”

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