Dometic Furnace, Brisk Aire A/C running at the same time on heat

[Toy4Rick]

In our 2022 GD Image 2500RL, the last couple of trips we noticed the A/C fan coming on when turning on the heater. Never did that before and we have camped a lot with this RV since we bought it new in Mar 2022.

We always run the fan on Low b/c auto has huge temp swings on both A/C and Heat

The only way I could get the heater only was to flip the A/C breaker off

When the heater did start up, all was well until it reached temp then it shut off like being in Auto mode

Now I'm really confused

 

[lineman1234]

Things break. I have seen a couple thermostats helping people with high electric bills, go bad. It sucks when the central air kicks on when the gas heat kicks on in the winter. It gets to be a nasty electric bill, as well as gas bill.
Till its replaced, just remove the wire that controls the thing you dont want to turn on, like heat or AC.

 

[huntr70]

Leave the fan on "auto" for heat. If you have the fan set or high or low, it will activate the fan.

The furnace will shut off when it reached temp because it is thermostatically controlled, not because of a fan setting.

 

[Riverbug]

Leave the fan on "auto" for heat. If you have the fan set or high or low, it will activate the fan.

The furnace will shut off when it reached temp because it is thermostatically controlled, not because of a fan setting.

x2. Can't run ours on low/high or both run at the same time depending on temps. Needs to be in auto only.

 

[Toy4Rick]

Interesting b/c I don't believe my a/c fan ever ran before on low or high since we generally never use auto b/c of the huge temp swings which low/high help to even out. I'll have to play with it more