How to get a/c fan off on heat

**masterdrago** · 12-23-2022, 09:45 AM

I seem to be only able to have the A/C fan running on hi or lo when I set the heat to run. It's very uncomfortable having the ceiling vents blowing what seems like cold air when the heater is blowing hot air. Is there a way to prevent the A/C fan (aka ceiling) from blowing during heat cycle? Maybe just kill the A/C breaker?

**MoonShadow_1911** · 12-23-2022, 09:51 AM

Originally Posted by masterdrago

I seem to be only able to have the A/C fan running on hi or lo when I set the heat to run. It's very uncomfortable having the ceiling vents blowing what seems like cold air when the heater is blowing hot air. Is there a way to prevent the A/C fan (aka ceiling) from blowing during heat cycle? Maybe just kill the A/C breaker?

Do you have two A/C units?

**masterdrago** · 12-23-2022, 10:04 AM

My 2600RB has only the single A/C. I did turn off its breaker with no ill effects other than stopping the ceiling vents from blowing. Seems like a crude way to accomplish. I suspect that the "Grand Design" thinking is to circulate warm air produced by the furnace which seems clearly wise, as it should rise to the ceiling. At 13°F outside temp and a blowing wind, I don't want heat loss thru the roof and duct work. Nor do I want the rush of seemingly cool air from those vents hitting me in the face.

**JCR GD** · 12-23-2022, 10:10 AM

Put fan setting on "auto" then the fan will not run with furnace.

**xrated** · 12-23-2022, 10:11 AM

Originally Posted by masterdrago

My 2600RB has only the single A/C. I did turn off its breaker with no ill effects other than stopping the ceiling vents from blowing. Seems like a crude way to accomplish. I suspect that the "Grand Design" thinking is to circulate warm air produced by the furnace which seems clearly wise, as it should rise to the ceiling. At 13°F outside temp and a blowing wind, I don't want heat loss thru the roof and duct work. Nor do I want the rush of seemingly cool air from those vents hitting me in the face.

That fan in the A/C unit should only run when the A/C is on..... or you have selected the fan to run continuously. The other reason it would run is if the A/C unit is actually a heat pump unit....and not just an A/C unit. If yours is strictly an A/C unit, and you have the thermostat selected for heat (via the propane furnace), that fan should not be running. If it is, there is an issue and likely it's the thermostat.

**stroguy** · 12-23-2022, 10:25 AM

Originally Posted by JCR GD

Put fan setting on "auto" then the fan will not run with furnace.

This. Furnace has an internal fan I would believe, mine did. Thermostat fan to AUTO and select heat.

**masterdrago** · 12-23-2022, 12:45 PM

I've got only fan setting = Hi/Lo. If I set it on Lo, the A/C fan cycles with the furnace. If I select Hi, the A/C fan runs continuously if the thermostat has heat selected. So far, the only thing I have found to keep the A/C fan off during heat is to turn off the A/C breaker. It's a kluge, but it works. And yes, the independent fan in the furnace runs before, during and after the ignition of the burner. The furnace fan shuts off after the heat ex-changer is scavenged of remaining heat but the A/C fan remains running as long as the thermostat is set on heat and Hi fan. Again, some sort of "Grand Design" kluge. Our Montana 3791RD did something similar with a similar thermostat in the bedroom (2 stats). The living room stat was for the heat pump on it.

**Redapple63** · 12-23-2022, 01:10 PM

Originally Posted by masterdrago

I've got only fan setting = Hi/Lo. If I set it on Lo, the A/C fan cycles with the furnace. If I select Hi, the A/C fan runs continuously if the thermostat has heat selected. So far, the only thing I have found to keep the A/C fan off during heat is to turn off the A/C breaker. It's a kluge, but it works. And yes, the independent fan in the furnace runs before, during and after the ignition of the burner. The furnace fan shuts off after the heat ex-changer is scavenged of remaining heat but the A/C fan remains running as long as the thermostat is set on heat and Hi fan. Again, some sort of "Grand Design" kluge. Our Montana 3791RD did something similar with a similar thermostat in the bedroom (2 stats). The living room stat was for the heat pump on it.

I have the same settings on my Reflection 315( low, high, auto fan setting). Never really paid attention to which motor provides the fan, I do believe that would be coming from ac blower, high low auto setting for fan is not available on heat mode only ac.

Bill

**Petrovsky** · 12-26-2022, 08:19 PM

Originally Posted by masterdrago

I seem to be only able to have the A/C fan running on hi or lo when I set the heat to run. It's very uncomfortable having the ceiling vents blowing what seems like cold air when the heater is blowing hot air. Is there a way to prevent the A/C fan (aka ceiling) from blowing during heat cycle? Maybe just kill the A/C breaker?

Seems GD has switched to a new A/C and thermostat from the 2021 model. On my thermostat (not a real thermostat only controller) I can set the fan to off so just the heater works. The issue for 2021 owners is that the thermistor is in the A/C box. This really messes up heating and AC. Especially heating when dry camping as you can imagine. Luckily GD supplies an extension thermocouple that can be placed a chest level somewhere in the coach. Furrion design issue for dry camping.

**Riverbug** · 12-27-2022, 05:20 AM

Something isn't right here. Maybe pics? Or, check with your service department. The furnace and AC blowers should not be running at the same time. There is something wrong with the system or user error.