Furnace Thermostat problem? Doesn't shut off..

[earlnash]

I have a 2003 Chinook Concourse with the 5 button Dometic thermostat. In cold weather, when I turn the furnace on, it runs fine, even cycles on and off for awhile.... and then the furnace stays on and never seems to go off, OR it stays off and never comes on again. Doesn't seem to matter where I set the thermostat. If I switch the thermostat off completely, then turn it on again.... the furnace starts up.

Any ideas??

Thanks

[Manitou]

welcome to the forum. My first guess is a sticky "sail switch". I think that's what they call it. It's difficult to get to, but not impossible. Sometimes it can be freed ny movingnit back amd forth with a screw driver a few times. If that doesnt work, I'm not sure how to rwplce it (screw driver trick worked for me and never had a problem again) .

[earlnash]

Thanks so much for the advice....What, or where is the " sail switch"?

[chin_k]

I don't know anything about furnace, but here is a video about the sail switch:

https://www.youtube.com/watch?v=-g3_Y7MqChE

Hope this is useful.