Answers to questions about RV Repair and Maintenance from RV expert Dave Solberg, author of the RV Handbook and the managing editor of the RV Repair Club. This column appears Monday through Saturday in the RV Travel and RV Daily Tips newsletters. (Sign up for an email reminder for each new issue if you do not already receive one.) Today Dave discusses a malfunctioning air conditioner.
We have a 2004 Jayco 5th wheel trailer with an air conditioner that cools and then waits a long time before it starts up again, leaving us cool then hot. We have asked our local RV dealer to help, but they say there is nothing they can do. Do you have any suggestions, or is this just the nature of the beast? —Gayle B.
To provide more specific troubleshooting information regarding your roof air conditioner, we need the make and model of your air conditioner. Since it’s a 2004 model, it should be either a Dometic or Coleman, and I’m assuming ducted since it’s a 5th wheel? The next thing is to record the temperature. Your roof air conditioner can only cool ambient inside temperatures down about 16 degrees, so any technician trying to help troubleshoot will need to know the temperature that is coming out of the vents and the temperature that is at either the thermostat or the temperature sensor called a thermistor. You can use an infrared thermometer.
How the thermostat works
The thermostat is powered by 12-volt house batteries and should call for the air conditioner to start within 4-5 degrees of what you are setting the thermostat at. If it gets warmer than that, I would suggest first testing the condition of your house batteries. Typically the house batteries will drain down to approximately 50 percent and the converter kicks on and charges them back up. If your batteries are sulfated, they will not hold a charge as intended and can drop rapidly. If your temperature rises to the point the air conditioner should turn on, but the batteries are weak, it will have to wait until the converter kicks on to charge them. You can verify this by plugging in an external battery charger and see if that helps.
The problem could be the thermostat
Another issue could be the thermostat itself, as these have been the frustration of many RV owners. We have a local campground in our area and have changed out about 10 of these just this summer! Make sure you get the correct model for your unit as some have zones and others do both the air conditioner and the furnace. If you have a zoned unit, such as the Dometic model, there will be a thermistor in the bedroom that senses the temperature. These are very inexpensive and easy to change.
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Dave Solberg worked at Winnebago for 15 years developing the dealer training program, as marketing manager, and conducting shows. As the owner of Passport Media Creations, Dave has developed several RV dealer training programs, the RV Safety Training program for The Recreation Vehicle Safety and Education Foundation, and the accredited RV Driving Safety program being conducted at rallies and shows around the country. Dave is a leading expert in the RV industry and author of the “RV Handbook” as well as the Managing Editor of the RV Repair Club, a one-stop go-to online resource for RV enthusiasts.