Troubleshooting Tips for a Rattling Furnace

As with any appliance within your home, your home furnace can encounter various problems over the years. While some of the ailments can be easily fixed, others require professional repair. One of the most common problems within home furnaces is a "rattling" sound. If your furnace is making this sound, you may pinpoint the exact cause by performing several troubleshooting steps.

Preparing the Furnace:

Like any other appliance, you must ensure its power source is turned off before taking its protective covering off. To do this, navigate to your circuit breaker and locate the breaker assigned to the furnace. Turn the breaker to the "off" position.

Once power has been disconnected, return to the furnace and take the front panel off. The steps necessary to perform this action will vary according to the manufacturer and model of your furnace; however, more-than-likely you will remove the panel by removing screws on the sides of the panel with a Phillips head screwdriver.

What to Look For:

After you have removed the front panel from the furnace, you will need to find the blower fan belt. The blower fan belt is attached to the furnace blower and appears to be a circular belt - much like one you would find on your car.

Once you have found the blower fan belt, inspect the belt for glazing, cracking or fraying. If you notice any damage to the belt, replace it. If the belt appears to be in good working condition, make sure the belt is not too loose.

Push the center of the belt down, and if it moves more than ¾ of an inch you need to tighten the belt. Do so by finding the attachment bracket, which is also typically found near the blower box, and loosen the bracket.

Move the motor gears by hand until the blower fan belt only moves ½-inch. Make sure you do not overly tighten the belt as this can severely damage the motor bearings and fan.

Although a loose or damaged fan belt is the common cause for the "rattling" sound, another typical cause are dirty burners. This is especially true for gas furnaces located in a dusty basement.

To check for dirty burners, disconnect the electricity to the furnace and turn off gas flow. Make sure the gas is completely shut off before proceeding.

Remove the front panel of your furnace in the same manner as above. Once the panel is removed, find the burners. Furnace burners are typically found in a horizontal line near the blower box.

Using a damp cloth, wipe down the burners and clean off any rust flakes and dust. Clean each individual burner by unscrewing the burner from its housing and cleaning the interior of the burner with a clean wire brush. Make sure to pay special attention to the burner openings as this is a common spot for dust and rust accumulation.

Finally, clean the inside of the burners with a can of compressed air. Return the burners back into their placement, replace the front panel and return gas and power to the furnace.

If neither of these troubleshooting tips remedies the "rattling" sound, contact a local furnace repairman as the rattling may be caused by a more serious problem.