Heat & A/C on at the same time!

dougrainer wrote:

Mont G&J wrote:

dougrainer wrote:

Mont G&J wrote:
Perhaps it's like mine. My T-sat has a selection for 'Furnace' and in that case the furnace will come on and blow out of the lower furnace ducts. Also, I can select 'Auto' and in that case if the T-stat calls for heat the AC comes on and works as a heat pump blowing warm air out the upper AC ducts. If the trailer is warmer than the set temperature the AC blows cold air out of the same upper duct.

Sorry, not correct. AUTO does NOT turn on the Heat Pump function if you have a AC/HP upper unit. ALL AUTO does is allow the system to select the fan speeds and shut the fan OFF when temp is met. You still have to select HEAT PUMP on the wall tstat for the HP to function if you have one. If you do not have a HP display on your tstat, you do not have a HP. Doug

Doug, My AC does operate as a Heat Pump or Air Conditioner. In the 'Auto' Mode it will turn-on either function.
Below is copy and paste from owners manual.
G. “AUTO” - Auto Change Over Mode In the AUTO mode the system will automatically change the mode of operation from cool to heat or from heat to cool. In order for this mode to operate, the zone being programmed must contain either a heat pump, heat strip or furnace heating source. When in the AUTO mode, all pre-programmed operations for the heat pump, heat strip, and furnace will apply.

NOTICE it states the MODE MUST be programmed for that to happen. I will bet you have a CCC2 Dometic wall tstat. On your tstat, IF NO OPERATIONS PRE PROGRAMMED, then the system will NOT auto switch between AC and HP. So, if NO programmable Tstat(very RARE to have one), then the AC/HP will NOT switch between the 2. Doug