Chimney making noise: five causes and what each one means

A chimney that has changed its sound is telling you something. The trick is knowing which sound means a two-minute fix and which means stop using it.

Rattle

Usually a filter not seated properly, or the oil collector loose. Switch off, push each filter until it clicks, check the cup. If the rattle is still there with the filters out, something inside the housing has come loose — that is a technician job.

Low hum, louder than before

Grease on the fan blades unbalances them and the motor works harder. This is the sound of a chimney that is overdue for service. Cleaning fixes it; ignoring it wears the motor.

Grinding or scraping

The fan is touching the housing, or a bearing is going. Stop using the chimney. A bearing that grinds today seizes in a few weeks, and a seized motor sometimes takes the control board with it.

High whine

Often the motor bearings drying out, sometimes a capacitor on its way. Both are repairable if caught early.

Clicking with the light or a speed

A relay or switch on the control panel. Annoying rather than dangerous, and a small part.

Any noise accompanied by a burning smell means switch off at the wall and do not turn it back on. That combination is a motor overheating.