he hot days of summer lure RVers to the road, visiting places where the weather makes it possible to enjoy the outdoors, including participating in water sports and other activities. Of course, it also raises the temperature inside the RV — which can quickly end all that outdoor joy when retreating to the inside. Fortunately, almost all RVs are equipped with air-conditioning to help moderate the inside temperature — but many owners don’t used their air-conditioner(s) during the other seasons and simply turn it on when temperatures rise and expect them to work.
And sometimes, they don’t.
I am also guilty of neglecting my air-conditioner — and I know better. However, I didn’t use my air-conditioner very often during the last three or four years, so there was a huge build-up of grime and dirt on everything from the evaporator to the condenser — leaves, dirt and cobwebs seemed to be everywhere. Very few RVs come with an adequate manual for the appliances (including the air- conditioner) describing in detail proper maintenance procedures. At the very best, the owner’s manual suggests that you take your RV to a certified dealership for service. Fortunately, servicing (think cleaning) your air-conditioner is accomplished easily without specialty tools except for maybe for the fin straightening tool.
Cleaning the evaporator is one of the most overlooked maintenance tasks. I’d venture to say most RVers have never even seen the evaporator, much less cleaned it. The evaporator is deep inside the return air cavity and is not easy to see or clean. While the return air-filter assembly is off, grab a bright flashlight and look up into the cavity and check for oil, dirt and debris on the evaporator fins. If the evaporator needs cleaning, you’ll find this cleaning task easier by removing the entire ceiling assembly. The aluminum fins are delicate, so be careful when cleaning. I found that a soft bristle dishwashing wand works very well for removing lint/dust.
For some reason the evaporator assembly itself always tends to get oily or greasy, which requires cleaning. You can use a mild cleaner and water in a spray bottle, but rinsing off the soapy water from the fins can make a big mess as the water splashes everywhere. I use an evaporator coil cleaner foam made by Nu-Calgon that comes in a spray can that sells for $22 on Amazon (Nu-Calgon 4171-75 Evap Foam No Rinse Evaporator Coil Cleaner, 18 oz.). This is a no-rinse formula that utilizes condensation to rinse the cleaner from the fins on the evaporator. If you live in a dry climate, however, condensation is going to be limited, which might make it necessary to rinse the foam off with water from a spray bottle. This can be done carefully by starting at the top and working your way to the bottom of the evaporator. Don’t overdo it, because the water will not run out through the condensation hole as quickly as you can spray it on. Be sure to wear eye protection and some type of a mask when using this cleaner and follow the directions printed on the spray can.
Using an air compressor — set no higher than 110 psi — blow out all the debris, dust and spider webs. If you do not have access to an air compressor, you could use a vacuum cleaner — but it won’t be quite as effective when cleaning the condenser. Blow the dust and dirt out of the condenser, being careful not to hold the air nozzle any closer than 8 or 10 inches to the condenser; the air pressure could damage the delicate aluminum fins. If you do have a large area of bent fins, now is the time to straighten them — using a specific fin straightening tool designed for this purpose. I recommend the Malco FST2 Fin Straightening Tool (available on Amazon for $15.86). You can also use a dull knife, but that could take hours. It is important to straighten the fins to restore cooling efficiency.
You can also use a soft-bristle toothbrush to clean some large pieces of debris that may be stuck in the fins on the condenser before blowing out the area with compressed air. Spray on the evaporator foam cleaner if some of the fins are oily or greasy, followed by a rinsing with very low-pressure water. Use a wet towel or a rag to wipe off dirt or oil from the compressor and fan housing, being careful not to damage any of the wiring. If water was used for cleaning, let the moisture dry before reinstalling the shroud. When replacing the shroud, make sure the front is hooked over the metal catch (if so equipped) to prevent lifting during travel — and, again, be careful not to bend any of the fins during reinstallation of the shroud.
Tools and supplies needed for this project are pretty straightforward and include the aforementioned evaporator cleaner, a soft-bristled brush, screwdriver or impact driver, fin straightening tool (or dull knife), flashlight, cleaner and rags, air compressor with nozzle or vacuum cleaner (if air is not available), water, hose and spray bottle.
Plan on spending a few hours completing this project — and be careful when working on the roof. Your hot body will thank you for restoring the cool air on hot days, especially when trying to sleep at night.
