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9 Haunting Noises your Heating System Makes

It’s the season for ghosts, goblins, witches, and things that go “bump in the night”. Unusual sounds filtering up from your basement may make you think your home is haunted. But these noises are actually your heating system’s way of telling you something isn’t working right. In this month’s blog, the pros at Main Stream Mechanical identify the sounds you might be hearing from your furnace or boiler.

What’s that sound?

Any odd noise coming from a furnace or boiler could mean something in the system has malfunctioned and is in need of repair. It can be frighteningly unsettling – especially as you’re counting on your heat to keep you comfortable throughout another cold New England winter. If you’ve heard any one of these unusual sounds from your heating unit, contact a home comfort specialist to inspect and investigate the source of the problem:

1. Scraping

Scraping noises from your furnace sounds like metal rubbing against metal. This is likely the blower wheel. If left untreated, it will likely produce metal shavings or filings which will fall onto, and into other parts, reducing effectiveness and eventually causing failure. Turn off your furnace immediately and wait until a professional HVAC technician has had a chance to inspect your system.

2. Squealing

A high-pitched squeal coming from your furnace is usually the result of an issue with the blower motor. The blower in your furnace is powered by a motor, which has bearings that can wear out because of age or overheating.

3. Banging and Popping

If you hear banging or popping sounds when your furnace or boiler starts, it’s likely due to a dirty igniter or burner. Dirty burners can delay the ignition, which causes gas to build up. An excess amount of gas will make a “pop”, or if large enough a “bang”, as the larger mass of gas ignites and the ignition finally comes on. If not addressed, this problem could crack your heat exchanger.

4. Rumbling

A rumble sound is an indicator that your furnace hasn’t been maintained in a while. This usually means dirty gas burners or a pilot light that needs to be adjusted. If your furnace flame is any other color than blue, contact our home comfort specialists immediately. A lot of red, yellow, orange, purple, or green indicates inefficient and potentially hazardous conditions.

5. Clicking

Repeated clicking during your heating cycle means there is an issue with your furnace’s ignition system. If the furnace can’t ignite, then you may hear a clicking noise as the igniter struggles. Besides ignition issues, compressor problems or a broken fan motor can also cause a clicking noise.

6. Rattling

The rattling noise sounds like there is something stuck in your boiler, and it is being tossed around. It is quite loud, and it tends to be very inconsistent. Loose screws and components that shake and “rattle” when the unit is in use or excess air in the system are two main causes.

7. Loud Humming

If your boiler is making a high humming noise, it could be the water pressure. If it’s too high, it would cause a loud hum. A persistent hum can also be caused by the fan inside your boiler or the bearings in the fan. Bits of sediment heating up and expanding is a common source of humming in a boiler.

8. Vibrating

A vibrating or humming sound could suggest that the pump is malfunctioning and moving around too much inside its casing. Vibration is also caused by the pump running too fast, moving the heated water around the system too quickly. Additionally, if the pressure in your boiler is too high, the valves inside your home can hum. Finally, vibrating could be caused by a blockage of leaves or other debris in the air intake or flue.

9. Kettling

A boiler that’s whistling may be a sign of a limescale/rust buildup. If the boiler’s heat exchanger contains buildup, it can overheat and generate steam, a process called kettling because it makes a whistling noise.

HVAC Installation, Service, Maintenance and Repair

Understanding the sounds you’re hearing and addressing your concerns with a home comfort specialist can help avoid the need for an expensive repair and keep your system running smoothly throughout the season. Whether it’s a banging noise, rattling, whistling, or another concern, Main Stream Mechanical’s home comfort specialists are ready to care for and maintain your heating system. Contact us today.

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