Thor Forums

[TurnerFam]

sounds like you need to set your Thermostat 'FAN' setting to AUTO... when turning the Thermostat to HEAT...

The FAN setting is probably to most confusing of any AC and HEAT related issues with all coaches, since most all of these thermostats are the typical Dometic or similar type, and all work basically the same. The FANS are only to work the roof AC fans, not the HEATER/Furnace fan, which is a totally different fan unit for the Furnace.
The heater/Furnace's own fan will cycle on and off automatically, as needed, when you have the HEAT turned on.

If you have FANS coming on from your roof AC units, then you have the unit's thermostat FAN setting turned to either LOW or HIGH, but it should be on AUTO, unless, of course, you actually WANT your roof fans to operate : )