Your RV air conditioner may not be like the one "back home"

With summer heat turned up, RV technicians are getting their usual (heat) rash of complaints about RV air conditioning. Sometimes the problems are appropriately directed to them -- air conditioners can break down. But in many instances, it's not so much an air conditioner fault, but an operator fault. RV air conditioners work on the same principles as those back home, but there are a few things that set them apart from "sticks and bricks" units, and knowing and working with these differences can make the difference between a comfortable trip or a miserable experience.

Some things to keep in mind:  Often depending on the size of your rig, you may find air conditioning controls fairly similar to those "back home." Larger RVs often have a thermostat on the wall where once set for "cooling" the system cares for itself. Smaller rigs, however, often have controls on the ceiling mounted grill unit. Regardless of the type of thermostat, there are a couple of problem areas common to all RV air conditioners:

Humidity problems: Nearly all a/c units allow a choice of fan speed. What to set it at? For the most part, it's largely a matter of choice, low or high. However, whenever you're in a humid area, it's best to keep the fan set on "high" as an air conditioner pulls moisture out of your RV and pushes it outside. A higher fan setting will help push that damp air through the a/c unit, making it less likely that it will hang up in the system.

Too, if you try and keep the "room air" too cool and don't allow the a/c compressors to cycle off and on (as noted by a deep rumble versus just a fan noise) you run the risk of turning your inside moisture into a block of ice inside the a/c unit. A block of ice will hamper or even stop your a/c unit's ability to cool you. If your unit has been running continuously for some time and you find it's not cooling like you think it should, turn it off for a few minutes. This allows an ice block to melt away and restore the unit's ability to cool.

Filters: Air conditioners pull air from inside your rig, treat it, and return it to the living area. Along the way filters remove dust and pollen. These are typically found in a ceiling mounted grill area. With the a/c unit off, open the grill and take out the filter medium. Most are washable--simply run tap water through them, dry them, and reinstall them. Particularly grimy filters can often be cleaned up with a little dish soap and a good rinse.

At the height of the cooling season it's a good idea to clean your filter at least once a month. A dirty filter makes your a/c unit work harder.

Thermostats: Here's where things can really differ from home. Smaller RVs often have air conditioning units with a thermostat mounted on the face of the ceiling mounted grill. Typically you'll find a switch that will turn on the fan (in two speeds) then advance to "low cool" or "high cool." These last two don't really change how cold the air comes out, it simply allows for cooled air at low or high speed. An adjustment knob allows you to set the "cool" level--the more clockwise you turn it, the cooler the room before the cooling compressor shuts off. With these units, the fan is on all the time, regardless of whether the a/c unit is actually producing cool air.

Larger rigs usually have wall mounted thermostats like back home. You'll have to choose "cool" as opposed to "heat." Again you'll have a selectable fan speed, but the thermostat itself will let you pick an actual temperature. Another switch allows you to run the fan all the time, or cycle it on when the compressor comes on. To cycle  or not is largely just a matter of your own taste.

Run it on the road? If you're a motorhome owner, you'll likely find that the "dash mounted" air conditioner driven by the engine isn't enough to really keep anything but the immediate area around the dash board cool. If you have an on-board generator, yes, you can often run your a/c by starting up your on-board generator and then firing the air.

AT ANY TIME that you use a generator to run any load, be sure to have all loads turned off when you start the generator. And when you're ready to shut the generator down, FIRST turn off all loads.

Two air conditioners? Some big RVs have two air conditioners--and your rig will wired for 50 amp service. If you stay at an RV park where you can't get a 50 amp hookup, you'll be using an adapter to plug in your rig. Don't try to run both your air condioners at once on this lashup--you'll only blow breakers and cause problems all around. An optional switching system you can have installed can overcome this problem--but it only serves to automatically swap between air conditioner units.

Apply a few simple tips and keep your cool!