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Understanding Unusual Furnace Noises: Signs, Causes, and Solutions

Unusual noises may be a warning sign that something’s amiss with your furnace. An experienced HVAC technician can diagnose your issue and perform any repairs that may need to be made.

Noises Associated With Blower Wheels

A noise that sounds like metal scraping on metal could signify that something’s up with your blower wheel, which is the piece of equipment that blows warm air out of the furnace and helps circulate it through the house. Blower wheels are sometimes called squirrel-cage fans.

When furnace air filters go unchanged for too long a period of time, dust can begin to accumulate on the blower wheel. This means your blower wheel has to work harder to do its job. As little as one-tenth of an inch of dust on your blower wheel can decrease the overall efficiency of your blower wheel by a whopping 20 percent.

When your blower wheel has to work extra hard to do its job, it has a much higher risk of breaking. A scraping sound could indicate a broken blower wheel motor mount or a loose or broken blower wheel. Whining noises often indicate problems with the blower wheel’s belt or motor.

Unusual Noises Associated With Furnace Startup

Many furnaces make soft sounds when they first ignite and are warming up.

If the ignition apparatus in your gas furnace is covered with dust or debris, your furnace flame will take a lot longer to ignite. During this time, gas will build up. When it finally ignites, you may hear a loud bang. That’s the sound of a small explosion that’s capable of damaging your heat exchanger or causing a carbon monoxide leak.

Loud bangs can also be associated with the contraction and expansion of metal air ducts and could be a sign of clogged vents or a dirty air filter. If your furnace makes a banging sound when it starts up, schedule a service call with an HVAC technician as soon as possible.

HVAC Technicians Serving Lincoln

At Wellmann Heating & Air, Inc in Lincoln, NE, we offer furnace repairs, maintenance, and replacements as well as equivalent services for your cooling equipment. Contact our office today to find out more about the ways we can assist you.