Banging, Grinding, Whining: 3 Furnace Noises You Shouldn’t Ignore

Old furnaces can make all sorts of noises.

While many aren’t any cause for concern for Framingham-area homeowners, there are 3 furnace noises you should never ignore:

  • Banging
  • Grinding
  • Whining

We’ll explore what’s causing these noises and what should be done to stop them.

Banging Noise When the Furnace Kicks On

Common causes of banging noises include:

Dirty furnace burners: Does it take several several seconds to a minute before the furnace comes on after you call for heat? This is a delayed ignition caused by dirty furnace burners. The dirt keeps the burners from igniting the gas, so the gas builds up. Once the gas ignites it makes the loud banging noise. Basically, it’s a mini-explosion in the furnace. Don’t ignore this noise. These small explosions can crack the heat exchanger, which is expensive to repair.

Expanding air ducts: If you hear this noise several feet from the furnace, then it’s probably the ducts expanding as the furnace blower turns on. This excessive expanding can be due to:

  • Undersized ducts (talk to a contractor to see if this is the case)
  • Closed vents (open more of your vents)
  • Flimsy ducts (brace the ducts)
  • A dirty air filter (change their air filter if it’s dirty)

Loud Grinding (metal rubbing metal) Noise

The cause of this noise is usually a problem with the furnace’s squirrel cage blower wheel. If you hear this noise, turn off your furnace immediately to prevent any further damage to the furnace and call a professional for furnace repair.

A few blower wheel problems include:

  • Blower wheel is loose from the motor wheel. Get a professional to tighten the wheel.
  • The blower wheel is broken and needs replacing.
  • The motor mount broke, causing the whole blower assembly to drop and hit the housing.

Whining Noise

This annoying noise isn’t as serious as the other two, but it needs addressing all the same. This noise is usually caused by:

  • A loose, slipping, or fraying blower belt. This should be adjusted by a technician or replaced if it’s fraying.
  • Shaft bearings that need oil. Add lightweight oil to the lubrication port at each end of the shaft.
  • A malfunctioning blower motor. This needs to be fixed or replaced by a professional.

Framingham Furnace Experts

The expert heating contractors at Nicholson Plumbing, Heating & Air Conditioning have experience with all furnace make and models. If your furnace is making any of the noises outlined above, contact us for help today!

Our level of commitment to our customer and superior service is the reason you can find comfort in choosing Nicholson Plumbing, Heating & Air Conditioning.

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