Furnace, heatpump, thermostat problem

[Pixel_Princess]

Hello all,
So I have a 2024 3915tb and I started having some issues recently with the heating. I usually run the propane furnace since it's been so cold but recently tried the heatpump and it seems to have some issues. I set the thermostat to about 72 on "Elec Heat" mode and I can hear it kick on, the floor vents also blow a little cool air at this time. It'll run for a few minutes and then shut off. The thermostat actually seems to just switch to "OFF". So I went back to "gas heat" and it worked great for a couple days. But today I turned it to 72 "gas heat" when I got home after work and it ran and pushed out hot air for a couple minutes and went to "off" mode. There's still power to everything, but the thermostat seems to be switching to "OFF". I went out and checked the "sail switch", it seems to make contact the whole time it runs. I can't figure out what's wrong and this is my live-in unit, now with no heat in Washington.
For info: I have a Coleman-Mach 9420-381 thermostat, AirXcel Suburban vertical gas furnace, and a Coleman-Mach 48000 heat pump.
Thank you any help.

 

[LeftOverParts]

Here’s a link where there is a troubleshooting diagram in post 7.

https://www.montanaowners.com/forums/showthread.php?t=92084

We had a similar problem where the furnace would run for 30-60 sec and then shut off. It ended up being a semi-kinked hose on the propane tank (gas pressure on the TS diagram). I didn’t clock the tank just right when I reinstalled the after a refill. You might check that you have propane, the hoses, and your switch valve between the two tanks.

There is also a LED light on the furnace circuit board that will blink error codes. The board is in the same general area where you checked the sail switch. Picture of our unit shows the LED code sticker - it’s the middle one on the right. Circuit board is near the lower left of the motor. (Sorry, picture is rotated).

If your 2024 unit has In-Command and if you don’t get a temp reading on the thermostat, the system might need a reset. You have to turn the In-Command off, disconnect from shore power, and turn the battery switch off. Then restart. If that doesn’t work, there is also a reset button in the In-Command panel that’s in the storage area.

Always helpful if you find out what it was and tell us. Good luck!

 

[rell668488]

I have a 24 389BH. I had the same problem. Replaced the thermostat and it worked fine, Although the first new thermostat did the same thing so I tried another. I was told there have been issues with this model of thermostat.