A/C fan running with furnace?

[Mikendebbie]

We have been living full time in our new unit for 3 weeks. We have been using the furnace a lot and the past few days I have noticed the rear A/C runs constantly and (of course) blowing in cold air - I assume cold outside air. We like it cold so we set the thermostat between 55 and 60. The furnace will shut off but the a/c fan still runs. I hypothesized maybe the heat pump function was running and that was why the fan was running. I don’t know if the fan ran during week 1 or 2 - I can’t say that I noticed it. I just noticed this week. I shut the breaker off so the a/c is not running now.

Can anybody tell me if this is normal and proper (yes -the heat pump is trying to supplement the furnace) or maybe yes-the unit is designed to run with the furnace to take in hot air up at the ceiling and circulate it throughout the coach.

If this is not normal then I assume some control wires are crossed in the thermostat somewhere and this needs to be fixed. I appreciate your help and opinions.

[DQDick]

This will happen if the fan speed is set on anything but Auto when you use the furnace. Change the fan speed to Auto and it should function correctly.

[BuilderBob]

You need to set the thermostat to auto and the A\C won't run when the heat is on.

[Rvdan]

Sorry to sound dumb, but how do I set te fan to auto? I dont see anywhere that I can do that. Thanks, rvdn.

[jsb5717]

Originally Posted by Rvdan

Sorry to sound dumb, but how do I set te fan to auto? I dont see anywhere that I can do that. Thanks, rvdn.

Welcome aboard! We’re glad to help but need a little more info. What year and model of trailer do you have? Do you have a picture you can post of the thermostat?

[Pocketlake1]

Should be on the thermostat