The draft inducer doesn't often take center stage. In fact, many homeowners may not even realize their furnace contains this critical component. Draft inducers are relatively small blower motors that pull combustion air through the exhaust flue, helping combustion gases escape your home. The draft inducer is essential for furnace efficiency and safety.

In most cases, problems with your draft inducer will stop your furnace from turning on. However, what happens when the opposite is true, and your draft inducer refuses to turn off? Keep reading to learn how to recognize this unusual condition, why it happens, and what you can do to resolve it. 

Recognizing the Symptoms of a Stuck Draft Inducer

Your draft inducer usually remains out of sight and out of mind. You shouldn't be able to hear this blower running throughout your home, but you might be able to hear it if you stand next to your furnace. Since the inducer is one of the first parts of your furnace to fire up, you'll usually hear it engage before the burners turn on.

When your inducer is stuck on, the most obvious symptom will be the droning of the blower near your furnace at all times. An easy way to check is to wait for your furnace to turn off. If you aren't feeling any air through your vents but can still hear a fan running in your furnace, there's a good chance your inducer motor isn't turning off.

Understanding Why Your Draft Inducer Won't Turn Off

Only a handful of issues can cause your draft inducer to run continuously. Modern furnaces use an electronic control board to control the draft inducer. The inducer itself is a straightforward blower, and these components typically turn on when they receive power and then shut off when the control board cuts power. If the fan won't stop running, it means the control board is still sending power.

This problem often points to an issue with the furnace control board. The control board will have a relay that switches power to the draft inducer; this relay can physically stick and continue sending voltage to the inducer without a control signal. If the relay isn't to blame, a faulty control board is the most likely culprit.

Repairing a Stuck Draft Inducer

The good news is that a stuck draft inducer doesn't usually point to a problem with the draft inducer motor. The bad news is that draft inducer manufacturers don't design these parts for a 24-hour duty cycle. Running your draft inducer non-stop will quickly wear out the motor, forcing you to replace the draft inducer and repair the original problem.

If you notice your draft inducer sticking, consider yourself lucky and cut power to your furnace until you can have an HVAC technician investigate the problem. Stopping your furnace from running will protect your draft inducer, saving you from unnecessarily replacing this fairly expensive part.

Contact a local heating service to learn more.