How to Troubleshoot a Duo Therm Air Conditioner

Dee Em

While Duo-Therm air conditioners are installed and serviced by qualified personnel there are some steps a motor-home owner can go through before calling the service center. Optimal climate conditions are achieved when the unit is running well and used properly.

Properly working climate control is key to a comfortable camping trip.

Troubleshooting your air conditioner gives you a chance to save money and perform some maintenance at the same time. Use care when you are investigating the problem with your air conditioner, if you suspect a coolant leak contact the service center immediately.

  1. Keep doors and windows shut to prevent moisture buildup when air conditioner is in use.

  2. Check the control knobs for the correct setting. Adjust them to the temperature and fan speed you require. Air conditioners set too low on cold days may cause frost to develop on cold surfaces.

  3. Examine the air filter for dust and debris. The filter needs to be installed properly so the evaporation coil does not get plugged and hinder the performance of the unit. A dirty filter may also cause frost to form on the evaporation coil.

  4. Look at the air housing and control panel for dust and debris.

  5. Check the motor generator. It needs to be running and supplying power to the air conditioner or the unit will not work.

  6. Investigate the power cords and power supply. The correct size line is needed to run the air conditioner. Power must be plugged in or the unit will not run.

  7. Inspect the fuse and circuit breaker.

  8. Call your local repair shop. The Duo Therm air conditioner must be serviced by qualified personnel. Have your serial number and model number handy when you make the call. Remove the air box at the bottom of the unit and look inside for the numbers you need.


Park in shade and cover windows to help keep the motorhome cool. Do not use heat producing appliances, such as the oven, on hot days. Start the air conditioner before the day gets too warm.


Do not disassemble the unit, only qualified personnel should do this.