Anyone who owns a home window air conditioning unit knows that the filters, as well as the condenser and evaporator coils need regular cleaning to remove built-up debris. This includes dust, leaves, insects, etc. An AC unit mounted to a recreational vehicle’s roof is no different. Simply cleaning the filter is not enough to ensure that the unit will work efficiently and “blow cold” when you need it on a warm summer’s day. A thorough cleaning of the condenser and evaporator coils should be performed at least every other season and will go a long way to ensuring your RV AC unit lasts a long time. The good news is anyone can perform this basic maintenance with simple household tools.
The first (and most important step from a safety point of view) is to make sure the AC unit is unplugged from the power source before attempting to clean it. Either turn the breaker off or unplug your RV from the shore connection.
If the roof of your RV is not designed to be walked on, use plywood to support and evenly distribute your weight upon the roof. Once you have access, remove the nuts/bolts holding the AC shroud in place. Place the loose fasteners in a plastic bag or aluminum can to ensure they don’t roll off the roof or into the workings of the AC unit.
Cover the electrical connections with plastic bags to reduce exposure to moisture. Most household kitchen/bathroom spray cleaners will do the trick, but there are commercial AC coil cleaning solutions available that will expedite the process. Whichever cleaner you choose, spray it on the coils and let the product soak for 15-20 minutes. Then use a garden hose (set to a gentle spray) to flush out loose debris. Depending on how dirty the coils are, you may need to repeat this step a few times, until the unit is reasonably clear of dust and debris.
A wet/dry shop vacuum is an effective way to remove excess moisture from the coils, but a household fan will speed up the drying process as well. Either way, make sure the AC unit has a few hours to dry completely, before reinstalling the shroud cover and reconnecting the power source. Your rooftop RV AC should be good to go!