If your fan limit switch is set to AUTO but the fan continues to run without ever stopping, you’ll need to call a professional. Two problems that could cause your fan to run without stopping include: A bad fan limit switch that needs to be replaced. Bad thermostat wiring.

Why is my furnace fan running but no heat?

Dirty filters are the most common cause of furnace problems. Dust and dirt restrict airflow—and if the filter gets too clogged, the heat exchanger will overheat and shut off too quickly, and your house won’t warm up. If the blower is running but no heat is coming out, replace the filter.

Why does my blower fan keep running?





Faulty Thermostat: If both the fan and either the cooling or heating system are running unexpectedly, you may have a faulty thermostat. Broken Relay Switch or Short Circuit: If only the fan is running, there may be a broken relay switch preventing the settings you enter on the thermostat from being sent to the fan.

Why does the fan on my heat pump keep running?

A common reason a blower fan keeps running is it’s simply set to the wrong mode. There is a setting or toggle on your thermostat that controls how the fan operates – the AUTO setting allows the fan to only run when your heat pump cycles, while the ON setting keeps the fan in operation all the time.

Why is my heat running non stop?

If your thermostat’s fan setting is set to “On,” the fan will run all the time, even if the heating equipment isn’t warming your home. Other fan setting that may cause the device to constantly run include “Manual,” “Low,” “Medium,” and “High.” The solution is to simply switch the fan setting to “Auto.”

Why wont my furnace fan shut off?

On your thermostat, look for the fan settings. There should be two, “ON” and “AUTO.” If it seems like your furnace won’t turn off, the thermostat may be set to “ON” for the blower. Toggle the switch to “AUTO” so your furnace’s blower fan only runs during a heat cycle.

Why is my fan running when my thermostat is off?





If the fan is the only thing running when the AC unit isn’t, there may be a faulty relay switch prohibiting the settings on the thermostat from being communicated to the fan. Another cause could be a wiring issue or a short circuit preventing the system from recognizing the on and off signals.

Should the fan on my furnace be running constantly?

Better Indoor Air Quality
Whenever the fan is on, air is going through the furnace filter. Leave it on continuously and you’re likely to see less dust around. It’s also important to have a good filter. The many types of HVAC filters can help reduce allergies, VOCs, as well as bacteria and viruses.