Mystery compressor start-up

[Brian Buchanan]

This morning while we were having breakfast the compressor on the front air conditioner started while the thermostat switch was in the off position, the unit is a Dometic and has worked fine all summer. The fan did not start when the compressor started, and moving switches on the thermostat did not stop the compressor, I ended up unplugging the the controller on air conditioner unit to get it to stop.

I suspect that it is a thermostat failure issue because if the temperature was changed the fan would run and quit as it was moved, the compressor ran in the heat position as well as the off position.

The second part of my question is has anyone replaced the old "Dou-Therm" with a smart thermostat? And if so any recommendations?

[Fred Brooks]

  Brian,
 The main piece of information that you must have is the following: 1- the model number of each air conditioner, 2- the model of the existing thermostat, If all are Dometic, they can advise you of your next action. If you have a 4 button or 5 button comfort control t-stat, they are obsolete. If you have the older "ribbon connector" T-stat Dometic makes an adapter cable from RG-9 to ribbon so you don't have to run new wiring. If you replace your t-stat with the newer 10 button comfort control, you will have to replace the air conditioner PC boards in each air conditioner. If you have the original air conditioners keep in mind they are now 24 years old. (life expectancy is 10-12 years). Dometic 800-216-5115
  Hope this helps, Fred Brooks