Symptom
Furnace making abnormal noise
Furnace noises are diagnostic: rumbling or popping at start-up suggests delayed ignition, squealing points at bearings or airflow, rattling can be loose panels or ductwork, and a roar can be normal combustion or a blocked vent. Each sound family points to a different check.
Short answer
Note when the noise happens (start-up, mid-cycle, shut-down), where it comes from, and what the furnace is doing at that moment. Popping or rumbling at light-off can be delayed ignition, which is a burner problem to fix promptly; squealing usually points at a motor bearing or a blower issue. If the furnace ever roars, backfires or smells of gas, leave and call FortisBC at 1-800-663-9911 or 911.
Have a code on the display?
Noises at start-up
A soft whoosh as the burner lights is normal. A hard pop, rumble or boom at light-off is delayed ignition: gas accumulates for a moment before igniting, which is hard on the heat exchanger and a sign the burner, gas pressure or ignition timing needs attention.
A metallic bang or tick early in the cycle is often duct or heat-exchanger metal expanding as it warms, and is usually harmless, but it should be distinguished from ignition noise by when it happens.
Running noises
Squealing or screeching from the blower area points at a motor bearing, a rubbing wheel, or a belt where the equipment has one. Grinding from the inducer at start-up or shut-down points at its bearings or a wheel touching the housing.
Humming can be a motor working hard, a transformer, or something vibrating against the cabinet. Rattles are often loose panels, screws or objects against the ductwork, and are found by listening while pressing panels.
When noise is an emergency
A furnace that roars, backfires, pops loudly and repeatedly, or produces any gas smell is not a service-call noise; it is a leave-the-house condition. Call FortisBC at 1-800-663-9911 or 911 before calling anyone else.
Related
- ServiceGas Furnace RepairFurnace repair in Greater Vancouver, diagnosed before parts are replaced
- ServiceFurnace DiagnosticsFind the actual fault before replacing parts: diagnosis by testing, not guessing
- ServiceFurnace MaintenanceAnnual furnace maintenance that checks what actually fails
- SymptomFurnace not heating
- ComponentInducer motor
Questions people ask
Is a furnace supposed to make some noise?
Yes: the inducer, burner and blower all make air noise, and condensing furnaces make gurgling as condensate drains. The question is whether the noise matches the equipment's normal character and when it happens.
My furnace pops when it starts. Is that dangerous?
Delayed-ignition popping is not a gas leak, but it is abnormal combustion and should be fixed; over time it stresses the heat exchanger. A technician checks the burner, gas pressure and ignition timing.
Can I fix a rattling furnace myself?
Tightening an obviously loose access panel is reasonable. Anything inside the burner or blower compartments is a technician's job on a gas appliance.
Still no heat?
Call BC Wide with the brand, model number and anything on the display. Or
Request service online with this page attached.