Dear Gurus,
I am a new house owner & not used to thermostats. We have Honeywell 8112D thermostat. We recently turned ON our Fan switch (in the thermostat). Now the fan is not turning off. It is continuously running even when the system is in OFF & Fan is in AUTO mode. We tried reducing the temperature but still the fan is turned on. Can any one help me out on how to turn off the fan? (There is no Fan Off switch there is only FAN Auto & FAN ON switches).
Any help will be greatly appreciated.
Thanks & best regards in advance.
Kannappan.S
[email protected]
716-697-3122.

Sounds like the fan relay must have stuck closed, could be a fan relay or a PC board that controls the fan.

Some of the newer furnaces keep the fan running when the transformer in the printed circuit board blows or the transformer goes bad, check for this fuse if it is blown then you may have another problem such as shorted thermostat wiring or shorted controls. Mike