Solved! Why Does My Furnace Fan Keep Running?

Are you wondering why your furnace fan won't shut off? There are a couple of reasons why it might do that. Here's what you need to know.

It’s 3 in the morning, and you just can’t sleep. Instead, you toss and turn as the furnace fan continues to hum its annoying tune in your bedroom. Finally, you get up and check on it, but there doesn’t seem to be anything out of order with your furnace.

Frustrated, you head back to bed only to spend the rest of the night feeling too hot or too cold.

And that is the last thing anybody wants when it comes to their home, especially in the dead of winter. To prevent any additional comfort issues doing its job, learn what might be causing this problem. Read on!


Fan Furnace Limit Is Set to Manual

If your furnace fan limit is set to manual, this means that the fan will run continuously until it is turned off manually. This is typically done for energy-saving purposes, as the fan uses a lot of energy to keep running. However, if your furnace fan keeps running after the furnace is turned off, this indicates a problem with the furnace itself. 

There Is Blockage in the Vent System

This can be caused by various things, such as leaves and debris buildup, animals nesting in the vents, or a faulty vent damper. If the vents are blocked, the furnace will not be able to circulate air properly, which can cause the fan to keep running.

If you suspect that there is a blockage, the first thing you should do is check your vents to see if anything is blocking them. If you find a jam, you can try to remove it yourself or call a professional to help you.

Dirty Furnace Filter

The most likely reason your furnace fan keeps running is that the filter is dirty. A dirty filter will restrict airflow, causing your furnace to work harder to circulate air. Sometimes, a dirty filter can cause your furnace to overheat and shut down. To avoid this, check your filter monthly and clean or replace it as needed.

Fan Limit Switch Is Set Too Low

The fan limit switch is a safety device that turns the fan off when the furnace reaches a specific temperature. If the switch is set too low, the fan will turn off before the furnace reaches its maximum temperature, causing the furnace to cycle on and off. To fix this, you will need to adjust the setting of the fan limit switch.

Thermostat Needs Adjustment

If your furnace fan is constantly running, it could be due to your thermostat being incorrectly set. Your furnace fan should only be running when your furnace is actively heating your home.

Check your thermostat to see if it needs to be adjusted. If it does, follow your thermostat settings manual instructions on how to adjust it properly. Once your thermostat is set correctly, your furnace fan should only be running when your furnace is actively heating your home. It should turn off once your home has reached the desired temperature.

There Is a Problem With the Thermostat Wiring

If the furnace fan keeps running, it could be due to a problem with the thermostat wiring. The thermostat may be faulty, or the wiring may be loose. To fix this problem, check the thermostat and the wiring. If the thermostat is defective, replace it. If the wiring is loose, tighten it.

Thermostat Is Incompatible With the Furnace

It may be because your thermostat is incompatible with the furnace. There are a few things you can do to solve this problem. First, try replacing the batteries in your thermostat. If that doesn’t work, you may need to purchase a new type of thermostat. Be sure to read the reviews and choose one that is compatible with your furnace.

Furnace Fan Is Too Big

If your furnace fan is too big, it could be causing your furnace to work harder than it needs to. This could be the reason why your furnace keeps running. To fix this problem, you can try to adjust the size of your furnace fan. If you have a furnace that is too big for your home, you may want to consider replacing it with a smaller one.

Blower Relay Is Defective

A blower relay is a device that controls the operation of a furnace’s blower motor. The relay is designed to operate the blower motor for a specific period of time after the furnace has reached its preset temperature.

If the blower motor keeps running after the furnace has reached its preset temperature, it is likely because the blower relay is defective. Replacing the blower relay should solve the problem. But if you’re unsure of how to do it, you are better off contacting this parker furnace repair service so you will not do anymore damage.

Extreme Temperatures

When extreme temperatures hit, your furnace has to work harder to maintain a comfortable temperature in your home. As a result, the furnace fan may run continuously in an effort to keep up.

If your furnace fan keeps running after the temperature has been turned down or off, it may be working overtime to prevent your furnace from overheating. By checking the furnace and making sure it’s clean and unobstructed, you can help it run more efficiently and potentially prevent the fan from running continuously.

Solve Your Furnace Problems by Knowing Its Causes

If your furnace fan is running continuously, there are a few possible causes. First, check to see if your furnace filter is dirty. A dirty filter can cause your furnace to overheat, causing the fan to run continuously. If the filter is clean, then the problem may be with the furnace itself.

To make sure that you are maintaining your furnace fan to the its best condition, you have to be aware of these problems. This will not only help you sleep better at night but also have a more comfortable all throughout the day, all year in any season.

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