Rth6300b

[novice123]

On Page 19 of the install manual, it says to program "O" if I have a gas furnace (system controls fan operation)....or program "1" if I have an electronic heating system (thermostat controls fan operation).

My confusion is that I have a fan "on/off" switch on my current thermostat, and their instructions seem to contradict as I can currently control the fan operation from the thermostat unit. Any idea which program button is correct?

[jadnashua]

If you don't manually override the furnace with the fan switch to turn it on (i.e., if that switch is off), does the furnace turn the fan on when firing? Nearly all do. What you don't want is for the furnace to be on and not have the fan turn on.

[leejosepho]

... their instructions seem to contradict as I can currently control the fan operation from the thermostat unit. Any idea which program button is correct?

No, but I suspect that manual on/off fan switch on your present thermostat does not affect the answer to your question. My guess is that you have a typical gas furnace with a thermostat that does *not* control the fan if you have something like this in the system circuit inside your furnace controlling your fan: