Furnace Question

[Jbh06751]

I'm a newbie to RV's. We have a 2013 Sunset Trail ST30RK with an Atwood furnace and Dometic Thermostat that controls Fan, AC and Furnace functions. It's getting chilly here in CT and we have guests coming to stay in the trailer so thought I'd try out the furnace. I set the thermostat to Furnace, set a temperature quite a bit higher than what it was (trailer was 60, I set temp to 76) and it came on just as it should. In a minute or two it was blowing warm air from the floor registers. Strangely though the AC fan came on at the same time. Is that normal? There was air coming out of the ceiling AC vents, not cold air, just seemed to be room temperature air. Is something wrong? Do I need to have someone look at it or is this how it's supposed to work? The AC is a Furrion if that is any clue. It was originally a Dometic AC but the former owner replaced with a Furrion.

 

[TJ&LadyDi]

Do you have a "fan" setting on your AC? It is relatively common to use the fan portion of the AC to circulate air in an RV. It sounds like that's what's happening in your case.

As long as there's no cold air coming from the AC vents, I don't think you have a problem. Obviously, you don't want the AC and furnace fighting one another, but using just the fan section to circulate room air might actually make it more comfortable inside.

If you do have a "fan" setting and don't want it to run, try turning it off and see if the furnace still produces warn air via the floor registers.

TJ

 

[LSG]

Put the thermostat on heat mode then find the selection for auto ( it might be a combination of two buttons at once? ) it’s most likely on a setting like low or high setting it to auto should fix it

 

[Jbh06751]

Our thermostat is pretty basic. There is no 'auto' selection. On the left there are three choices that you get to by pushing a button at the bottom. Fan, cool and furnace. On the right there are + and - buttons to set the temperature. When I select the furnace the ac fan comes on at the same time. When I turn off the fan goes out immediately but the heat keeps going for about 30 seconds to a minute then stops which is probably normal. The trailer heats up well but the blowing air out of the ceiling AC vents is a bit disconcerting. I suspect that when the AC was replaced the thermostat was somehow mis-wired or perhaps intentionally wired that way to circulate warm air better. As I said in the original post the Dometic AC was replaced with a Furrion but the thermostat wasn't changed. It's still a Dometic. Wondering if we should get someone in to take a look at it or if some systems just work that way.

 

[LSG]

Yes this is most likely the exact thermostat I’m talking about select heat

it should show one of three things? Low high or auto if it’s not on auto and on high the screen fan is turned on in heat mode you have to select auto which possibly was a combination of two switches at once but it’s been a while so I’m just not sure of exactly how you select auto I just tinker with it until it show auto but make sure your on heat. This should fix it no need to call for repairs yet

 

[Gronk]

Go to the FAN setting and set it to AUTO. That will let the fan on the A/C run only when needed.

 

[Jbh06751]

Thanks everyone!
I was able to find AU by scrolling the speeds on the fan setting. Once set on auto the AC fan didn’t come on when mode was set on furnace.
it’s nice to know there is an extra circulation option though.