Just like any other type of mechanical equipment, a gas furnace makes certain noises when it’s running. Some sounds are completely normal, but others can signal trouble. Here are some common furnace noises and what they could mean.

  • Popping in the ductwork – When the thermostat signals the furnace to start up, the blower fan responds and starts to pump warm air through the ductwork. The resulting increase in air pressure inside the ductwork can cause a popping or pinging sound. When ducts are new or recently cleaned, these sounds are more noticeable, but they’re not a cause for concern.
  • Clanging inside the blower compartment – When the blower motor fan belt is badly worn or has slipped out of place, it can make a clanging noise. If you’re not comfortable replacing a furnace fan belt, it’s best to call for professional help. Don’t wait until the belt breaks, as it can flap around and damage other furnace components inside the compartment.
  • Loud clicking noises – A loud clicking that originates from inside the furnace cabinet can be deadly serious. It can indicate a cracked heat exchanger that’s letting carbon monoxide (CO) escape. If you suspect this is the case, shut the gas valve, turn the furnace off at the thermostat and call your HVAC contractor.
  • Squealing or grinding sounds – Both of these noises can point to worn or dirty motor bearings inside the furnace. If the bearings aren’t replaced, the motor can overheat and burn out, so it’s best to have the problem taken care of before you face a costly component replacement.
  • Booming and rumbling in the burner compartment – If a furnace isn’t serviced and cleaned regularly, dirt and grime will build up on the gas burner and cause a booming or rumbling sound when it ignites. This dirt buildup can block the gas jets and prevent ignition, so have the burner cleaned and tested by an experienced pro to ensure its safe operation.

If you’re concerned about unusual furnace noises in your greater Cincinnati home and you need expert advice, contact us at Apollo Home Heating, Cooling and Plumbing today.

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