Your HVAC blower fan pulls uncomfortable air from your house and sends it to your furnace or air conditioner. It then sends the heated or cooled air into your home. The blower should run when the rest of your HVAC system is running. However, it may fail to turn off for several reasons. Depending on the cause, there are several steps you can take to solve the problem.
When you set your thermostat to “AUTO,” your blower fan will run only during heating and cooling cycles. It will turn off at the same time as your other HVAC components or after a few minutes, once your preferred temperature is achieved. On the contrary, your blower will run 24/7 when the thermostat is set to “ON.”
Ensure the thermostat setting is on “AUTO.” If you change the setting from “ON” to “AUTO” and the HVAC blower doesn’t turn off after three to four minutes, the problem is likely a result of something else.
Wrong Fan Limit Switch Mode
The fan limit switch in your furnace controls when your blower fan turns on and off. When it’s set incorrectly to manual override, the fan will run continuously. You’ll need to locate the switch to determine whether it’s been set correctly. You’ll see a white button or knob right below your furnace hood. That’s the fan limit switch.
If the button is pushed in, the limit switch is set to manual override. Pull the button out to set it to “AUTO” mode and enable proper blower-fan operation.
Faulty HVAC Equipment
If your HVAC blower fan is constantly running even though the thermostat and fan limit switch are set on AUTO, you could have bad thermostat wiring or a faulty limit switch that needs to be replaced. You’ll need to contact an HVAC professional.
An early HVAC repair is usually cheaper and simpler than a delayed one. If you’re having problems with your HVAC blower in the Dayton area, don’t hesitate to contact us at Detmer and Sons. We’ve served all the HVAC needs of our satisfied clients since 1978.