What Would Cause a Heating Element to Keep Burning Out on a Furnace?

Electrical Problem

• If your heating element continually burns out, it is most likely due to an electrical problem. Heating elements work by resisting the flow of electricity to them. This resistance causes heat to build up on the element due to friction. If the element burns out, it will have "infinite resistance" but won't heat up.

Testing the Element

• To test whether an element has burned out, turn the power to the furnace off. Disconnect one of the wires from the element and attach it to a multimeter or continuity tester. If the machine doesn't beep or otherwise show increase of resistance once you do this, the heating element is broken. You need to replace the defective element if this is the case.

Double Duty

• Most furnaces have more than one heating element. However, if one element burns out or otherwise stops functioning, the other element takes on the work both elements were doing. This makes it more likely that the second element is going to burn out because it's doing too much work. If an element continually burns out, check the other element or elements to make sure they are all working correctly.

Other Problems

• If your thermostat doesn't work properly, it might interfere with the proper functioning of the element. If the thermostat allows too much heat to go to the heating elements, eventually the elements may burn out. In addition, your heating elements may cease functioning due to a loose wire in the furnace somewhere. This doesn't necessarily mean the element has burned out; you need to test it with a multimeter to determine whether this is the case.