When you can hear your furnace kicking on and off, but you're not getting any warm air throughout your house, you'll want to check the belt on the furnace. Chances are that the belt that runs from the motor to the blower has become worn and broken. You will need to replace the belt to get the warm air flowing throughout your home again. Here is how you can replace the blower belt.
Turn Off Power
Turn off the electricity to the furnace. The last thing you want to have happen when you are working on the moving parts in the furnace is to have the unit kick on and grab your clothing, fingers, or hands. Turning off the electricity prevents the furnace from cycling on and off and makes doing the job a lot safer.
Open Furnace Door
You need to take off the furnace door to reach the blower belt. Some doors simply hang from slots running along the top of the door, but others are screwed in. Check your owner's manual if you can't remove your furnace door easily to find out if there are any clips or screws that have to be removed.
Take Off Belt
If the belt is broken in half, you can just grab it; but if it's still wrapped around the pulley and motor, you'll need to adjust the motor pulley to lessen the tension on the belt. Once the tension is relieved, you should be able to just pull the belt out of the pulleys with any problem.
Get New Belt
The blower belt should have a model number stamped in white on the side. Make sure you purchase a new belt with the same number (unless the manufacturer suggests other belt numbers that can be used instead). Take the belt with you to the hardware store to make sure you are getting the right replacement part.
Install New Belt
Put the belt around the motor pulley first (this is the smaller pulley), and then stretch the belt over the top of the blower pulley. Hand crack the blower pulley until the belt slips all the way around the pulley. Press down on the middle of the belt to check for slackness. If the belt dips down more than an inch, you'll have to tighten the tension on it. This is done by adjusting the motor pulley until you get the right amount of tension in the belt.
Turn Furnace On
Replace the furnace door and turn the electricity back on. Wait for a few minutes until the furnace starts working. Check the furnace grates in your house to make sure warm air is blowing throughout your home.
A broken furnace blower belt can make for a cold winter's day. If you see your belt is broken, and you don't want to repair it yourself, call a professional furnace repair shop, one like A OK Appliance Service, to come in and do it for you.