A/C fan blows with furnace

[cyclepath]

I have a Dometic electronic thermostat. It has 3 settings, fan-cool-furnace.
When plugged into 110v, when I turn the heat (furnace setting) on there is heat from the floor vents but the roof vents (A/C vents) blow at the same time.

The trailer is less than a year old and we do all but 1 trip dry camping (not plugged in, just generator & 12volt) The problem doesn't happen on 12volts because the A/C system works on 110. But it is a problem still.

Anyone have any info on this problem?

Thanks.........

[Johnnyfry]

This is a "feature" actually, not a fault. The system is designed to run the AC fan if you set the fan to any other setting than "Auto".

Set the thermostat to "Fan" and cycle the + and - buttons. You will cycle through "Hi", "Lo" and "Auto". If you set to the "Auto" setting, the AC fan will not come on.

[Halibutman214]

Check out this previous post it has a little more info. http://www.keystonerv.org/forums/showthread.php?t=2195

[craigsmith]

We had the same issue with our 267BH. As others have mentioned, turn the fan on auto and you can also check and raise your A/C temp setting well above the heat temp setting. Between the two of these adjustments, your A/C fan should not come on with the furnace.