AC fan blowing while running furnace (Aircel thermostat)

[gengiant]

Went out on a 3-nighter last weekend to the coast. Had full hookups, so ran the electric furnace most of the time. It would cycle on and off to keep the rig at the set temperature. The last night there we had the furnace set to 60 degrees. The first half of the night it would occasionally cycle on. Then, the second half of the night, in addition to the furnace kicking on, the AC fan would start as well. I was not able to solve this issue the next morning until I turned off the breaker to the AC. Clearly, this is a band-aid solution only. I read that for Dometic thermostats, one has to have the fan set to "auto" for it not to kick on while running the furnace. That does not appear to be an option with the Aircel furnace I have (OEM). To get to the heat setting, one basically has to keep pressing the button on the thermostat to get to "heat, electric", bypassing the AC and fan settings. Any idea what might be the problem? A replacement Aircel thermostat is on $40, so I'm thinking I may simply try that route. But if I don't have to spend the money - especially not knowing if that will solve the problem...

Thanks!

 

[traveldawg]

Went out on a 3-nighter last weekend to the coast. Had full hookups, so ran the electric furnace most of the time. It would cycle on and off to keep the rig at the set temperature. The last night there we had the furnace set to 60 degrees. The first half of the night it would occasionally cycle on. Then, the second half of the night, in addition to the furnace kicking on, the AC fan would start as well. I was not able to solve this issue the next morning until I turned off the breaker to the AC. Clearly, this is a band-aid solution only. I read that for Dometic thermostats, one has to have the fan set to "auto" for it not to kick on while running the furnace. That does not appear to be an option with the Aircel furnace I have (OEM). To get to the heat setting, one basically has to keep pressing the button on the thermostat to get to "heat, electric", bypassing the AC and fan settings. Any idea what might be the problem? A replacement Aircel thermostat is on $40, so I'm thinking I may simply try that route. But if I don't have to spend the money - especially not knowing if that will solve the problem...

Thanks!

Not sure, but wouldn't you want to select "heat - gas" or "heat - furnace"? On mine selecting "Heat - Electric" means the AC's heat pump will run, not the furnace.

Also, I'm pretty sure that the furnace will come on if "heat - elect" is selected but the temp you select is over 2 or 3 degrees higher than what the temp actually is.

So - maybe when you went to bed the furnace ran because you selected a temp demand 3 degrees lower than the temp was in the rig. Then, half way through the nite, the rig heated up and the next demand for heat was probably just one degree above the temp in the rig so the heat pump (AC) kicked on.

 

[Bungy]

Went out on a 3-nighter last weekend to the coast. Had full hookups, so ran the electric furnace most of the time.

The furnace runs on propane not electricity, the roof ac has a heat pump built in. To select the furnace select ‘ heat gas’, to use the heat pump select’ heat electric’.

 

[gengiant]

Ok - learned something new. Thanks! But that does bring up another question. On "heat - electric", hot air is blowing out of the ducts just above the floor, but not the AC ducts. How does that work if the heat pump is built into the AC unit?

 

[gengiant]

Maybe Larry (traveldawg) is correct in that the furnace will kick on if the temperature difference between exist vs desired is greater than a few degrees. I was not aware of that. Can anyone else confirm this?
Thanks!

 

[Bungy]

Ok - learned something new. Thanks! But that does bring up another question. On "heat - electric", hot air is blowing out of the ducts just above the floor, but not the AC ducts. How does that work if the heat pump is built into the AC unit?

My 2018 blows out the roof vents only. Maybe the newer trailers are different (as per traveldog)?

 

[LanerC]

As well as the 3 degree temperature difference that will incorporate the electric ceiling heat pump as well as the gas furnace, in some models, the gas furnace will kick on to help the electric heat pump if the heat pump runs for more than 15 minutes without satisfying the thermostat,if set to electric heat. On mine at least the electric heat pump only blows out the ceiling vents where as the gas furnace only blows out the floor vents. When the heat pump is running at outside temps nearing 30 degrees the air from the ceiling vents wont feel very warm. The heat pump will likely not come on if the outside temps are below 30 degrees. Most will automatically lock out below 30 degrees because they just cant produce heat at that temp, then the gas furnace would automatically come on to meet the above conditions. Happy camping!

 

[wvyankee2]

Fan switch has 4 settings. High, Low, Auto, and Off. Make sure the Fan switch is in the Off ( O ) position when running furnace.