Why Is My Furnace Making a Loud Banging Sound?

October 19, 2022
HVAC repair in Dexter, MO

You expect to hear a little noise when you turn on your furnace. However, if you hear a loud banging noise, that’s not normal. There are several reasons why this might be happening.

The Fan Is on its Last Legs

Your furnace has a powerful blower fan capable of transporting hot air throughout the home. If something gets caught in the fan, the fan blade might still spin, but it could knock whatever is caught on the blade around inside the furnace. The technicians at Carlos Warren & Son can fix this as we have seen things ranging from tinfoil to child’s toys to small animals in fan blades. Sometimes, professional cleaning is all that’s needed. Other times, the fan blade may need to be replaced.

A Dirty Blower Wheel

An unbalanced blower wheel may cause the loud banging you hear. Blower wheels become unbalanced when there is a lack of maintenance, including a failure to change the furnace filter. As dirt, pet hair and crud build up on the blower wheel, they put it out of balance, leading to the frustrating banging noise and the eventual breakdown of the wheel.

Delayed Gas Ignition

If you hear the banging noise at the heater, a delayed gas ignition is likely the problem. This happens when gas builds up in the furnace instead of igniting immediately. When the gas does ignite, it creates a mini explosion. This could harm your furnace.

A delayed gas ignition could be caused by a poor air-gas mixture, restricted or weak pilot lights, or misaligned and dirty burners. You will need the assistance of professional HVAC technicians, like those we have at Carlos Warren & Son, to help you solve these types of problems.

Expanding and Contracting Air Ducts

If the banging noise is several feet away from the furnace, it could be that the ductwork is expanding and contracting as the unit starts and stops. This could be caused by undersized or dirty air filters.

Trusted HVAC Services in Dexter, MO

At Carlos Warren & Son, our trained technicians stand ready to take care of your HVAC system. We have more than four decades of professional experience providing thorough workmanship.

Our services include HVAC repair, installation and maintenance. We offer heat pump installation, maintenance plans and indoor quality services. Contact Carlos Warren & Son today to see what differentiates us from the rest.

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