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GoodbyeCalif · 02-23-2015, 01:45 PM

Fortunately right now we are in AZ (Nice and warm with a little chill in the AM). Our thermostat has a 5 way control (Fan, Cool, Furnace, Heat Pump and Off. When we set it to "Furnace" only the Heat Pump and Furnace come on. In just a few days we are heading to Salt Lake and expect to hit VERY cold weather. This is not good as the Heat Pump will be blowing cold air. I unplugged our rig from power and the furnace runs as normal on 12v/24v. Does anyone have any ideas? My own suspicion is the thermostat control is bad. :-o

dennis45 · 02-23-2015, 02:08 PM

Quote:

Originally Posted by GoodbyeCalif

Fortunately right now we are in AZ (Nice and warm with a little chill in the AM). Our thermostat has a 5 way control (Fan, Cool, Furnace, Heat Pump and Off. When we set it to "Furnace" only the Heat Pump and Furnace come on. In just a few days we are heading to Salt Lake and expect to hit VERY cold weather. This is not good as the Heat Pump will be blowing cold air. I unplugged our rig from power and the furnace runs as normal on 12v/24v. Does anyone have any ideas? My own suspicion is the thermostat control is bad. :-o

Do you have zone 1 and zone 2?
The furnace and front AC/heat pump is zone 1 (on mine anyway) and the bedroom is zone 2 for heat pump/AC.
Check using the mode if zone 2 is off and not sitting on heat pump.
Other than that, I can't think of any reason other than a bum thermostat.

P/S, mine defaults to furnace around 35 Deg even if the stat is set to heat pump on zone 1.

GoodbyeCalif · 02-23-2015, 02:10 PM

The back unit is A/C only on a separate thermostat.

dennis45 · 02-23-2015, 02:14 PM

Quote:

Originally Posted by GoodbyeCalif

The back unit is A/C only on a separate thermostat.

Sorry, I should have looked at your signature. My system is not the same.

kimbo · 02-23-2015, 03:17 PM

if its more than 2 deg. below set temp, both systems may come on! what I mean is if its 65deg. inside and you set it at 70 both systems may come on,

GoodbyeCalif · 02-23-2015, 04:43 PM

Quote:

Originally Posted by kimbo

if its more than 2 deg. below set temp, both systems may come on! what I mean is if its 65deg. inside and you set it at 70 both systems may come on,

In the past if we set the thermostat to "furnace" only the LP furnace would come on. It seems we can't get away from the Heat Pump coming on no matter how we set things.

D Lindy · 02-23-2015, 04:49 PM

Try disconnecting the power from the "T" Stat for about 1 min. then repower it, sometimes a simple reset is all it'll need.

doublechevy · 02-23-2015, 05:10 PM

If the heat pump comes on no matter what the setting look for a stuck relay on the control board. as the thermostat is low voltage and needs to activate a relay to control the 120V for the heat pump. although it is possible that resetting the thermostat might work as these electronic thermostats can do strange things ( that is if it is an electronic stat )

doublechevy · 02-23-2015, 05:17 PM

Added comment you could also shut the circuit breaker for the A/C Heat pump to prevent it from coming on. Make sure you still have power to the thermostat. if you shut off the breaker you may lose power to the control board??? Then nothing would work if you needed heat.

palehorse89 · 02-23-2015, 05:17 PM

Maybe try a reset:
SYSTEM RESET
a. Turn the ON/OFF switch to .OFF. position.
b. Simultaneously depress and hold the MODE and ZONE
push-buttons while turning the ON/OFF switch to .ON..
FF should appear in the LCD display until the MODE
and ZONE push-buttons are released.
This is from the manual.

shiggs68 · 02-23-2015, 06:42 PM

If your fan mode is set to on, the overhead fan will run anytime the thermostat calls for heat from the furnace. This appears like the heat pump is on but actually only the fan. Set the fan mode to Auto.

GoodbyeCalif · 02-24-2015, 02:58 AM

After changing the fan from "Auto" to "High" and waiting at least two hours the system finally reset and started working correctly. Someone else posted that there is no ability to reset a Dometic Heat Pump (ie turn power off, etc). You have to wait those two hours regardless; turns out to be true. Thanks everyone for your input.

Lord help me as I head to SLC for two weeks then to Boise. Final destination Portland. We are in Lake Havasu City and the weather has been astounding for the last 3 months, usually in the 80's. SLC has highs of 44 and lows of 22. YUCK, I hate cold weather. Fortunately my rig should be just fine.