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These Sounds Mean Your Furnace Probably Needs Repair


It would be so lovely if your furnace could say to you, “I’m not feeling well. Could you please schedule a repair for me?” Unfortunately, your furnace can’t talk. However, it does have some ways of expressing itself. One of the clearest indicators that it’s time to schedule furnace repair is when your furnace makes unusual sounds. While they’re not words, they can tell you a lot about what’s going on. Here are some of the noises you should listen for and what they might hint at in terms of what’s going wrong with your furnace.


This one definitely sounds like a complaint. If your furnace starts to groan, it may be a sign that the motor bearings are wearing down. These are replaceable, so although it may sound like a dying groan from your furnace, it can easily carry on after a repair. However, if you don’t have the bearings replaced, it can damage the motor, so address it promptly.


Older furnaces have a belt connecting the motor to the blower fan. If it is slipping off its moorings, or starting to tear, it can make a screeching noise. Again, while a prompt repair means adjusting or replacing one part, a delayed repair can mean bigger problems. If that belt comes completely loose, it can do a lot of damage.


This could have a few causes. It may be that some part of the air handler has come loose, or the blower fan is wobbling off-kilter. It’s also possible that somewhere in your ductwork there is a problem, or a loose screw is allowing the duct to clatter against part of your house. A technician in furnace repair in Delaware County, PA will be able to pinpoint the issue and fix it for you.


You’ll hear this sound at the beginning of your furnace’s heating cycle. When the furnace turns on, there’s a delay, and then a sudden boom. This is the sound of a lot of fuel igniting at once. The probable cause is a dirty or corroded burner allowing too much fuel to build up in the combustion chamber before igniting. While it’s an alarming noise, it simply means a technician needs to disassemble and clean the burner. 


If you have a boiler, it keeps water at a high temperature to be circulated through radiators, registers, or a radiant floor heating system. Although that water does need to be hot, there’s a limit to how hot it should get. An overheating boiler can make a sound like an enormous kettle boiling furiously on the stove, and that means it’s time for repairs.


If you have an electronic ignition system, it can cause clicks at the start of the cycle if it is failing. Clicks can also be caused by something as minor as a loose screw allowing a furnace panel to move slightly. But clicking at the end of the heating cycle, when your furnace begins to cool down, can mean that the heat exchanger is cracked. Since this is the component that keeps combustion gasses separate from the air you breathe, a cracked heat exchanger is a major carbon monoxide hazard. If you hear this sound, get repairs immediately.

The next time you hear a sound you didn’t expect from your furnace, don’t ignore it. Be thankful your furnace has some way of letting you know there’s a problem, and get repairs before the issue gets any worse.

Reach out to Murphy’s Plumbing, Heating & Air Conditioning today to schedule an appointment with our professionals. It’s always “Integrity Before Profit.”

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