Furnace Exhaust Fan Turning On And Off

Steps to turning off the air fan if there s no heat if your furnace air fan runs when there s no heat turn the electricity to it off and follow these steps to disable the running fan.

Furnace exhaust fan turning on and off. Your fan limit switch is located directly under your furnace hood and controls when your furnace blower turns on and off. First it means that hot newly combusted gasses are building up inside of your furnace hindering its performance and possibly introducing a dangerous situation. With any luck you ll never need to use this advice but if a fire advisory should come down on your community using your hvac unit effectively can filter out a large. Recently after the blower fan runs for a period of time the exhaust fan starts turning on off quickly without a definite cadence to it.

The fan limit switch is responsible for turning the blower on and off at the appropriate times. So when the switch is working correctly your furnace fan should turn on several minutes after thermostat calls for heat and turn off several minutes after the heat cycle ends. A flue limit switch is a switch that turns your furnace off if air is not properly ventilating out of the exhaust flue. Your blower should run constantly until the heating cycle ends.

When heat is called for the exhaust fan starts up this is followed by the gas lighting after a period and then the blower fan coming on. Second heat will continue to build up in the furnace tripping the high limit switch. Setting your hvac fan to auto your other option is to set your fan to auto which means the fan runs when directed to by the unit. In normal operation your furnace blower fan should come on 1 5 to 3 minutes after your thermostat calls for heat and should turn off several minutes after the heating cycle ends.

A probe inside the switch monitors the temperature of the burner assembly to turn the fan on once the burners are hot and turns the fan off once the burners cool down when the thermostat stops calling for heat. Keep bathroom fans and window units turned off. Locate your fan limit switch. Why would this be a problem.

When your furnace isn t actually heating though your furnace blower shouldn t be running at all. Use a screwdriver to remove the bottom metal panel from the furnace find the circuit board which will have a slew of electrical wires attached to it. When your system reaches the temperature you ve set for it the fan will shut off until the next cycle. Your fan limit switch is located inside the furnace panel cover usually near the upper right corner.

The result is better air quality since particles are constantly being removed from your air. Here are the pros and cons to this approach.