Replacing the Belt On a Furnace Blower

A man works on a furnace.
  • 1 hours
  • Beginner
  • 100
What You'll Need
Phillips screwdriver
Adjustable wrench

Replacing the belt on a furnace blower is an easy and important step to keep your oil or gas heating system the best working order. Aside from the usual maintenance, it may also be necessary to replace the belt if your blower is not working properly or if it is making a lot of noise. Replacement belts can be purchased at a local or online retailer and this is a relatively quick and simple task that a homeowner can do on their own without the need to spend money hiring a professional.

Step 1 - Prepare the Furnace for Maintenance

Locate your circuit breaker box and switch the breaker for your furnace off. There may be a power switch on your furnace that can be switched off for extra safety as well. A good way to double-check is to make sure your furnace is off is by turning the thermostat all the way up and waiting a minute or two to ensure that it doesn’t start up. The motor has a lot of moving parts that could be dangerous when not handled properly. To do this job safely, this is the most important step.

Step 2 - Access the Blower Belt

Most furnace blowers have an access panel on the housing that can be removed. On some furnaces, the panel slides right off the top of the chassis of the blower and on others, the panel door may be attached to the blower with screws on the top or side of the machine. Use the Phillips head screwdriver to unscrew the fastener screws and gently slide the panel up and off of the unit.

Step 3 - Remove the Belt

To remove the belt. use your wrench to carefully loosen up the bolts. Make sure you don’t loosen the bolts all the way. They only need to be loose enough to move the motor slightly in one direction. Move the motor and the blower closer together so the belt will no longer be pulled tight and will be ready to be removed. Pull the belt off and around the wheel pulley and then the motor pulley. Inspect for any debris that could interfere with the belt or motor.

Step 4 - Replace the Belt

When your new belt is ready and the area is clean and clear, the new belt can now be placed on the pulleys, motor side first, then the wheel side. Pull the motor back and away from the blower again, just slightly. The belt should be tight, but should give about a 1/2 inch when pressure is applied. You can test this by using the screwdriver to press gently on the belt in the middle of the two pulleys. When you get the motor in the position you want, tighten the bolts back down. Attach the panel back to the furnace, turn the circuit breaker back on and set your thermostat back to normal settings. After powering the furnace back up, the motor should be running quietly and efficiently.