Furnace Troubleshooting
Furnace Making Noise — What It Means
Furnaces make some noise during operation, but loud banging, squealing, rattling, or booming sounds are signs that something needs attention. RG Mechanical diagnoses unusual furnace noises throughout Central Maine and fixes them before they become costly failures.
What to Expect
Loud bang at startup: delayed ignition from gas/oil buildup — needs prompt service
Squealing: blower motor bearing failure or loose belt
Rattling: loose panels, ductwork, or debris in the blower
Rumbling at shutdown: oil residue in combustion chamber — needs cleaning
Banging ductwork: normal expansion/contraction OR undersized ducts
Grinding: blower wheel hitting its housing or bearing failure
Frequently Asked Questions
My furnace makes a loud boom when it starts. Is that dangerous?
Yes — a loud bang at startup usually indicates delayed ignition, where gas or oil accumulates before finally igniting. This creates a small explosion and can eventually crack the heat exchanger. Have it diagnosed and repaired promptly.
Why does my furnace squeal?
Squealing from a furnace usually indicates a worn blower motor bearing or, on older systems, a slipping belt drive. Both are repairable.
My ducts bang loudly when the heat comes on. Is that the furnace?
Banging ductwork is usually expansion and contraction of sheet metal — often exacerbated by undersized or dirty filters causing pressure buildup. We can assess and resolve duct noise issues.
What's a grinding noise in a furnace?
Grinding usually means the blower wheel is contacting the housing (from a broken mount or debris) or that the motor bearing is failing. Fix promptly to prevent the motor from seizing.
Ready to get started?
Call us or request a project estimate. Contact RG Mechanical to confirm service availability for your community.
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