Blower Won't Shut Off On Comfortmaker RPJ

Unregistered

My AC is working fine - turns on/off with thermostat as it should, but the blower keeps running. I can't get it to turn off without shutting off the breaker switch. Is this more likely to be a problem with a signal to the blower from the thermostat or with the reception of the signal on the blower? What is the best way to find out. Thanks for any help you can offer.

HVAC Doc

You can try taking the wire of the G terminal on your thermostat (usually a Green wire) and then turn the power back on. If the blower doesn't run, then a good chance it is the thermostat. To verify this, turn the power back off and remove the R terminal wire (normally red). Turn your power back on and touch the two together. Blower should come on. When you quit touching them, the blower should go off. Now if you remove the G wire and the blower still stays on, you could have a fan/limit switch (old bi-metal dial type) hanging up. They get old and dirty and will fail to reach the last contact and turn it off. If it is new enough, it could be a circuit board or blower control board.

Unregistered

if it has one the new smart gas valves try unplugging all wires from the valve and see if fan shuts off if so gas valve is bad i have alot of trouble with them being bad

Unregistered

better call a pro before you fry a transformer. assuming that you are a homeowner you need to be carefull there will be low voltage at the t-stat if you do not turn off the breaker. If you were to remove the low voltage wires from the t-stat and cross the wrong wires there is a chance you will fry a transformer and probably get a little tingle if your body is in contact. There are a few thigs that your problem could be and you might be getting over your head in this one.Be safe and call a contractor.