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Serving the greater Cherry Hill, NJ area


Weird Furnace Noises: What They Could Mean

service-technician-furnaceSome day in the future, all furnaces will come equipped with precision self-diagnosing computer systems that will immediately diagnose operational issues and alert their owners to the exact problem and then send a request to a professional to service it. We’re not quite there yet—but your furnace does have ways to inform you when something isn’t right, such as higher heating bills, poorer comfort, or strange sounds.

We’re going to talk about the last one in today’s post, because it’s often the first warning sign a homeowner receives about a furnace issue. In most cases, these sounds indicate its time to call for an HVAC repair professional who knows furnaces in Cherry Hill, NJ to do the diagnosis and find out what service is necessary.

Below is a list of the more common warning noises your furnace might make:


There are a few possible sources for this sound. A simple one is that the door of the furnace cabinet is loose. That’s easy to check on and correct. Another possibility is loose mechanical parts in the furnace, likely inside the blower. It could even be trouble in the vents, rather than the furnace since the vents expand with the heat—if they’re damaged, this will result in rattling.


A high-pitched mechanical shrieking sound is certain to catch your attention. This noise comes from the bearings of one of the motors wearing down. If the bearings continue to wear down, it will result in serious damage to the motor. If you have a repair technician on the job soon enough, the technician can replace the bearings and save you the trouble of needing to have the whole motor replaced later on.


General mechanical grinding noises are signaling that a motor is wearing down or burning out. If the problem has already gone far enough, the motor will need to be replaced.


There are a few different reasons you might hear this sound. If you hear it when the furnace is starting up, it likely points toward trouble with the ignition system. You may notice a delay in the burners lighting. A technician can replace the electronic ignition system to repair this. A more serious situation is when you hear the clicking after the blower motor shuts off. This often warns of a crack in the heat exchanger, and this is a potentially dangerous situation, as it can lead to toxic gas escaping. Shut off the gas to the furnace and call for repairs.


When you hear a sudden, surprising “boom” from the furnace when it comes on, it’s probably a result of delayed lighting of the burners. Unburned combustion gas builds up inside the combustion chamber, so when the igniter finally comes on, a large amount of the gas combusts at one—with a boom! Although this may sound scary, you only have to call a repair expert to have it remedied.

Please, do not attempt to investigate these sounds on your own or try to fix them yourself! This is potentially hazardous! Only trust to a licensed heating contractor for this service.

Reach out to Gibson Heating & Cooling for your furnace needs in the Cherry Hill, NJ area. We’re family-owned and operated, and earn trust by treating families right.

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