Grind, Buzz, Click: Which Furnace Noises Should Make You Worry?

All furnaces make some noises, but learning the language of your furnace is important for detecting potentially dangerous problems. Rattling, humming or squealing noises from your furnace may be simply the result of loose screws. Other sounds, such as grinding or whining, could be expensive to fix but are probably not extremely dangerous. Some sounds in particular, however, can signal a dangerous situation.

If your furnace starts with a loud “Whomp!” and then sputters with a putt-putting sound, get the furnace checked out immediately by a professional. These noises often correspond with a poor air-to-fuel mixture and a delayed ignition—an extremely unsafe combination.

A loud, house-shaking rumble sound emitting from your FUEL OIL furnace subsequent to shutting down after a heating cycle should also be inspected by a professional as quickly as possible. The culprit of this sound is often unburnt oil in the combustion chamber that continues to burn after the burner shuts down. It is possible that this unburnt oil could be emitting the deadly carbon monoxide gas.

Another possible source of carbon monoxide is characterized by a loud rattle noise from your furnace before the furnace kicks on. This noise could also be a loud “bang.” In either case, a faulty heat exchanger is most likely the cause of the problem. The problem turns serious when the heat exchanger is faulty because of a crack in the exchanger; cracks can allow carbon monoxide to seep into your home.

If your furnace evokes a roaring sound, as if a blowtorch is being lit, call your P.K. Wadsworth furnace pro as soon as you can. The burner is not lighting properly. And when it does light, a large flame erupts in a potentially dangerous, unequal mixture of gas and air.

If you are worried about a particular sound, check with your local furnace professionals, who will be able to decode the message of your furnace. They know furnace basics.  It is always a good idea to have CO detectors in your home–especially if the furnace is older–just to be sure you and your family remain safe.