Furnaces are noisy systems, but there’s a difference between the standard noises that a furnace makes and the more unusual noises that could indicate a problem. If your furnace is making strange noises, it might mean that the system is in trouble. If you even suspect that your furnace needs repair, it’s best to call for professional help as soon as possible. In the meantime, let’s take a look at some of the unusual noises your furnace can make and what they mean.
Your furnace air handler is responsible for circulating warm air throughout the house. This puts it under a lot of stress, especially the motor. To help compensate for this, the motor is equipped with a number of lubricated bearings that reduce stress. The bearings do not last forever, however. As the bearings wear down, the friction on the motor increases. That’s the grinding sound you hear when your furnace starts up. You should call for repairs as soon as you hear this noise. Otherwise, the friction on the motor will increase until it burns itself out. Replacing the bearings on your motor is a lot cheaper than replacing the motor itself.
Though a deep booming sound coming from your furnace can sound pretty alarming, it’s actually not inherently dangerous. This is caused by a buildup of carbon particles on the burner assembly, which can cause one or more jets on the burner assembly to fire later than they should. When those jets finally do fire, they burn through the excess gas all at once, creating that booming sound. If you get your burner assembly cleaned, the problem should be taken care of.