Thermostat Question

[509Airborne]

One year ago replaced both of my Dometic Penguin AC units as well as the 5 button thermostat. System has performed well during 14,000 miles of RVing during 2020, but yesterday I experienced a problem. That's right, on Christmas Eve. No one is answering any phones today!


Problem is this: I had zone 1 HP going as I was in and out of the coach (2003 Holiday Rambler Endeavor) and I noticed the furnace was running instead of the heat pump. The thermostat still said HP, but then it would toggle to Furnace, than back to HP. The actual heat pump isn't coming on in zone 1 or 2 now, but the furnace comes on if I attempt to set the thermostat on heat pump. I noticed the AC isn't operating either, when I tried it.


Does this sound like a thermostat reset issue (no idea how to do that) or more of a control board in the thermostat issue?


Thank you for any help, and have a Merry Christmas!

[Mr_D]

Furnace will come on if there is more than 5° difference in actual temp and the setting to assist the heat pump in bringing the temp up.

[YC1]

Sounds like it just too cold for the heat pumps to work properly and it is shifting. What is your OAT? Around 40 or perhaps a bit lower with the Penguins for the heat pump to work.

[Tugboat]

I know that a home heat pump will not work if the outside temperature gets below 26 after that the emergency (electric coils) heat comes on. In a RV unit that might be the furnace.

[momdoc]

I know our heat pumps will not work if temp outside is below 40 or so.

[509Airborne]

Thank you for your responses! You may have all nailed the problem. The outside temp yesterday was around 20 degrees when I noticed this. It's even colder today. It's supposed to be 37 tomorrow and 48 on Sunday. Do I dare expect things to return to normal?
Thanks again, and Merry Christmas!!!