Most issues with a furnace tend to revolve around failure to turn on or produce hot air, but occasionally the opposite problem can happen and your furnace is overly active. There are several reasons why a furnace may fail to turn off properly. The following guide can help you track down the issue so you can get it fixed and keep your home at a comfortable temperature.
Check the Thermostat
Checking to make sure the thermostat is set properly is normal procedure. But, what you really need to check for here is thermostat issues. For example, a thermostat installed on a wall that's joined to the exterior of your home may stay cool longer than an interior wall between the living room and dining room. This can result in a false cool reading and a longer than necessary furnace cycle.
Another issue that can throw of a thermostat is if it isn't level – this can also give a false temperature reading. You can check it quickly with a level and straighten it as needed.
Wiring issues or a malfunction inside the actual unit can also cause the furnace to run non-stop. This will require a new thermostat installation to fix. However, if the furnace is still running, even though your home is warmer than it is set to, it may be time to call in an HVAC technician.
Look for Blower Motor Issues
The blower motor moves the heated air from your furnace through the vents, but it doesn't heat the air. If you can hear your furnace constantly running, but you aren't necessarily experiencing high heat, then the blower mower is a likely culprit. Place your hand in front of a vent to see if the air feels cool. If so, make sure your thermostat fan setting is on the "auto" setting, as opposed to the "on" setting. The "on" setting results in constant air circulation so the blower must stay operational, while the "auto" setting turns off the blower when the furnace isn't running. If the thermostat is set correctly, you likely have a blown relay switch or another more technical problem in the blower itself. This will require a call to an HVAC technician to fix or replace the blower motor.
Inspect Your Duct Work
Leaking ducts are the final thing that can lead to an overactive furnace. Since most of the warm air is leaking out into your home's walls, it takes longer to warm up your home's interior and the furnace runs longer. You can check your ducts for gaps at the joints if you have a basement with exposed ducts. If you find gaps, you can seal these with foil tape. For ductwork that is inside the walls, you will need a tech to perform an airflow test to see if there are leaks, and then allow them to seal what they find.
If you have an overactive furnace, consider contacting local HVAC specialists to discover more about the services they offer and discuss your furnace concerns.