Originally Posted by c21bill
Greetings, I am on an extended trip and didn't want to take time to research my issue but perhaps one of you could help me out. I have a 14 AI with the Dometic thermostat. This morning I cycled thru the modes on my thermostat to turn the furnace on which worked fine but the AC also came on. When I cycled the thermo to off, both turned off but each time I cycled thru to the furnace the AC would also come on. (the AC comes up in the cycle before the furnace does). Any ideas?
Thanks in advance.
The issue is with your fan setting. It's been several months since I have done any A/C work, but using the proper fan setting resolves the situation. Try setting the fan to 'HI' rather than 'AUTO' and that might do the trick. If not, do it the other way around. One will work for sure and will initiate the furnace only.
BTW, your A/C compressor is not on when both unite are on, just the blower. Dometic did this (this is from their tech support group) to help distribute the warm air from the furnace thru-out the trailer and keep the hot rising air at lower levels.