Furnaces make all sorts of noise during operation, and if you’ve had your furnace for longer than a few days, you are probably familiar with all of the usual sounds that the system makes. Some sounds, however, are not typical to furnace operation. It is these sounds that you need to listen for, as they indicate various problems with your system. The sooner you can identify a strange sound as an indication of a problem, the sooner you can get your system repaired and the more damage that you can prevent. Let’s take a look at a couple of the more common problem sounds that a furnace might make.
Gas furnaces use burner assemblies to produce heat. The burner assembly is comprised of a number of jets, which combust natural gas to generate the heat. One of the combustion byproducts of natural gas is carbon particles, which build up on the burner assembly over time. Eventually, the carbon buildup can become so bad that one or more jets in the burner assembly fire later than they should. When the delayed jets finally do fire, they burn through all the excess gas at once and create that booming sound. Getting the assembly cleaned off should get rid of this problem.
The air handler is the part of the furnace responsible for circulating air throughout the house during operation. In order to cope with the resulting intense friction, the air handler motor is equipped with lubricated bearings which help keep it from burning out. These bearings don’t last forever, though. Eventually, they start to wear down, which causes a loud grinding noise while the furnace is running. If the bearings aren’t replaced, the motor will eventually overheat and burn out.