Why Does My Furnace Fan Keep Running?

Feb 12, 2022

Hvac tech and breaker

Listen closely. Do you hear something? That might be the sound of your furnace fan. 

It’s normal for your furnace fan to run for part of the day. But if you hear it constantly, that indicates your furnace has an issue. It’s wasting energy without much benefit. Oftentimes, a fan that won’t quit is a sign of a larger issue. 

There could be a very easy fix for this complication (which we’ll explain in a moment). But, if that doesn’t work, you might need to call a professional to solve your problem.

What Does Your Furnace Fan Do?

To understand this issue, it helps to know what your furnace fan is used for. Its main purpose is to distribute warm air to various areas of your home. The fan ensures that temperatures are consistent throughout your house. 

Now, on to troubleshooting:

First, Check the Fan Settings

Sometimes, the most effective solution is also the simplest. On your thermostat, you’ll find the fan settings; this switch (as you might expect) turns the fan on and off. 

Start by locating your thermostat. Then, find the “Fan” switch. Is it set to “On” or “Auto”? With the former, the fan will always blow, regardless of your home’s temperature. This tends to waste electricity and makes your furnace work harder than it needs to. 

Try setting it to “Auto” instead. This ensures that your fan only runs when it needs to move heat around.

Next, we’re going to troubleshoot to see if that solved it. Go to your thermostat, and set it to a cooler temperature; this prevents your furnace from producing more heat. A few degrees lower should do the trick. 

Wait a few minutes for the change to kick in. But if you do this step and your fan is still running, it’s a sign that something else is causing the problem.

Other Causes

The issue may have something to do with the fan limit switch inside your furnace panel. This device also controls the fan, but it acts as more of a safety measure. If the temperature of the burner ever gets too high, the fan limit switch can automatically override other settings to shut it off.

Find the fan limit switch under the furnace hood. On most units, it’s a white button or switch. There are two settings: if the button is pressed, it is set to “Manual Override”; this causes your fan to run constantly. But if the button is not pressed, it is set to “Auto”. Set the fan limit switch to “Auto”.

Again, wait a few minutes for the change to take effect. Did that solve your problem? If you still hear the fan blowing, the issue might run even deeper.

At this point, the most likely cause is that a piece of equipment is faulty. It could be one of the switches you were using, a wire, or the thermostat itself. 

A faulty furnace is concerning in any home, but especially in Winnipeg. If your furnace breaks down, temperatures can plummet in no time. For your health and safety, you need to find another solution for your furnace problem. 

What To Do Now?

You’ve tried everything, but still, nothing solves it. No matter what you do, your furnace fan won’t stop running. What can you do?

At this point, it’s best to call a professional in for help. Our experts at https://www.provincialheating.ca/ will keep your furnace in good condition. To schedule your furnace repair, contact us today!


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