Awkward Heat - A/C issue

[esfd243]

So we live in NY and are headed to FW in 12 days so of course we need to get the RV open. I checked everything and all is well except for the A/C.

We use a digital Dometic 3 step thermostat. "Fan" runs air just through the A/C. "Cool" runs the A/C. But when I turn on "Heat", the furnace and the A/C come on now. This has never happened before and we used the furnace several times last fall.

Any ideas? I dont know where to start. Maybe replace the thermostat?

[dougrainer]

If he does a RESET, he will still have the same problem. As other posters have told him, PUT the Fan in AUTO. That is what is in the owners manual for this tstat model. Doug

[time2roll]

esfd243 wrote:
We use a digital Dometic 3 step thermostat.

Is that the square single zone thermostat?

Reset:

A system initialization will need to be performed by the installer
after the system is installed.
• Make sure the Single Zone LCD thermostat is in the Off condition.
• Press the “+” button and, while holding it, also press and hold
the On/Off Mode button for three seconds. LCD will show - - . Press the On/Off Mode button again to turn system off.
This completes the initialization.


Dometic themostat manual

[wnjj]

2oldman wrote:
Where is FW?

Or Florida if it's Fort Wilderness.

[TakingThe5th]

2oldman wrote:
Where is FW?

Texas if it's Fort Worth.

[2oldman]

Where is FW?

[MFL]

Set the fan to auto, then set to heat.

Jerry

[LadyRVer]

Try setting fan to automatic.