Thermostat Auto Fan Doesn T Work

Even if the current temperature is below the desired temperature the fan will not start if it is in cool mode.

Thermostat auto fan doesn t work.

Fan switch set to. At the end of a heating cycle when the thermostat is satisfied the fan will automatically turn off. Because the fan only runs when your home is in a heating or cooling cycle there are times when the fan is completely off and doesn t consume any energy. Likewise the fan will not start even if it is too hot if the thermostat is in heat mode.

Auto run let the fan be turned on or off automatically under control of the heater or air conditioner itself when the thermostat asks for heat and the furnace warms up the fan will turn on. If everything works switch the thermostat back to auto. Replace the screws and tighten them clockwise. Turn the breaker on and test the thermostat.

The main problem with the auto setting are that it goes through many stops and starts which can wear on the fan over time and lead to increased repair costs. With the thermostat calling for cooling check to see if the y terminal at the furnace is hot. Replace the cover on the thermostat. If the fan powers up then the board is good and you need to find where the thermostat wire is damaged or replace it entirely.

If the fan doesn t power up with the r and g terminals connected directly then there is a problem with the control board itself which most likely means replacing the board unless you can diagnose and solve it yourself. When you turn the thermostat to heat you are closing the switch to tell the unit to operate in heat mode again controls inside the furnace tell burners inducer motor blower etc when to come on through the control board and relays when you turn the thermostat to fan on you are closing another completely different switch which directly tells the blower to come on and run continuously regardless of whether heat cool off is selected on thermostat. Your fan will turn off automatically after the time you ve selected but you can turn the fan off early by selecting stop from the fan menu. Press system and select heat or cool mode as needed.

Digital or programmable thermostats may need the blue wire connected to them.