How to Tighten a Furnace Fan Belt

A furnace fan is bound to need some maintenance work done every few months to keep it running smoothly. One of the common issues with a furnace fan is the fan belt getting worn out and causing the fan to squeal or turn irregularly. If you have noticed this problem with your furnace fan, then it is time to tighten the fan belt. You do not need to call in a professional to do this job, with the right tools and this guide you will be able to do the job yourself. Here’s how you need to go about tightening the fan belt on your furnace fan.

Step 1 – Turn off the Power Supply

The first step in tightening your furnace fan belt is turning off the power supply. Do not try to work with the power supply on.

Step 2 – Remove the Screws

Use the screwdriver and unscrew the screws to remove the cover on the motor of your furnace fan.

Step 3 – Remove the Cover

Remove the fan motor cover and place it aside, keep the screws in a place where you will not lose them.

Step 4 – Locate the Motor

Find the motor mount on the furnace fan and look for the fan belt. Check and see how slack the fan is, this is normal for any fan belt with constant use.

Step 5 – The Adjusting Nut

Find the adjusting nut on the motor near the base or side of the motor. There will be two large nuts protruding from either the side or the base of the motor; these are the adjusting nuts which you will need to adjust to tighten the fan belt.

Step 6 – Adjusting the Nuts

Use the adjustable wrench to turn the nut counterclockwise, this will loosen the nut. Once you have loosened the nuts you will be able to move the motor back and forth.

Step 7 – Push the Motor Backward

Now that the motor is loose, push it backward into the mound. When you push the motor backward it increases the tension on the fan belt.

Step 8 – Tighten the Nut

With the motor pushed back, tighten the nut so that the motor does not move back and forth.

Step 9 – Check the Fan Belt

Use the ruler to check the tension or play of the fan belt. You should have a flex of ¾-inch on the fan belt.

Step 10 – Adjust the Nut

If you do not have the ¾ of an inch flex on the belt, loosen the nut and adjust the motor once again like you did in step 8 till you get the required flex on the belt.

Step 11 – Tighten the Nut

Once you have reached the required amount of flex on the belt, tighten the nut firmly.

Step 12 – Replace the Cover

Replace the cover on the motor and turn on the power supply. Now check your furnace fan. It should be working fine.