MHC heat pump is confused. So am I.

[Moondragon]

2020 MHC 331RL. When I bought it new last year, the heat pump only blew cold air. When I got it back to the dealer (in October), it turned out the factory swapped the units when they installed them (the one with the heat pump was installed in the bedroom), so of course it never worked. Now, with them in the correct position, I cycle the thermostat in the living room until it says Heat - Elec. The heat pump blower comes on for about 5 seconds, then the thermostat display changes to say Heat - Gas - Elec, and both the heat pump and gas furnace start blowing away. Of course, the only heat I'm getting is from the floor registers, which sort of defeats the purpose. Am I doing something wrong, or does this need to go back to the dealer again?

[Ram Montana High Country]

Is it a Coleman or Dometic? My Dometic screen on 373RL 2020 does not do that

[Moondragon]

Coleman Mach, with an AirXcel thermostat. Fortunately the "fireplace" is working again after they replaced it.
As delivered, the water heater also did not work on electric. Someone at the factory put a strip of silver foil tape over the on/off switch on the tank with it in the off position, so I never even saw it. That's why I'm wondering if I have something similar going on with the heat pump.
The AirXcel starts out saying Heat - Elec and cycles the unit on, but then quickly adds the Gas and starts that unit as well. There are settings for Heat - Elec and Heat - Gas, don't know why they would ever be trying to run both at the same time.

[PhilC]

I had that system in my last rig. It will run both gas and electric heat if the outside temperature is too cold for the heat pump to heat the coach. I know we are in spring time but Depending upon your location and outside temperature it will turn on both. If it’s only in the forties outside I would say there’s a problem with the control module.

[mhs4771]

With the Coleman setup, you can only raise the HP temp approx 3 to 5 degrees above the inside temp, more than that causes the furnace to also kick in.
Start with it only 3 degrees above the inside temp, once it's gone up several degrees, raise it again.
A bit of a PITA but it's how that system works.

[Moondragon]

Stat said it was 57 inside (amazingly, the same as outside! lol). Was trying to take it up to 63. Fireplace has it up to 67 now. I'll shut down the fireplace tonight and set the heat pump for 62, and see if it maintains it without firing up the gas unit.
Thanks for the suggestions.

[Ram Montana High Country]

It can be frustrating when manufacturers HAVE to add bells/whistles without offering a basic function also ... IMHO

Fancy is not what I always want , let me pic what I want.

[MAWilsonPE]

Hello Moondragon,

You should check which controller was installed on your heat pump. Keystone installed a "Cool Only" controller on my heat pump and that is why mine is doing the same thing.

Unfortunately the controller is hidden inside the inlet air plenum in the unit on the roof. You have to remove the cover, remove the duct tape and two screws and you can see the controller box inside the plenum. Check that P/N.

Good Luck, Mike

[Moondragon]

That's probably in mine as well. Turned off the fireplace and set the HP to 60, woke up to 58 and cold air. Considering how (in)securely the interior was assembled (pivot door, edge trims), I'm not suicidal enough to try climbing that chair hanger on the back. Dealer said they would warrant their work from last fall, so I'll let them deal with it.

[JamesD]

I have a Dometic heat pump, and the system is supposed to automatically switch to the propane heat if the temp is too low. If the temp sensor is messed up, or the logic board isn't configured right, it could switch over at higher temps.