Thermostats & Thermal Fuses

Thermostats and thermal fuses are what electric dryers use to cut off voltage supply to the heating source if the temperatures get too high. Some are self-resetting, meaning they can open and then close. Others are one-time use. If they open, they will need to be replaced.

Heater Housing Fuses

Most heater assemblies will have 2 fuses on them. One is a resettable bi-metal, the other is not. If the temps get too hot, the resettable will open and allow the unit to cool back down. If the resettable happens to fail, then the secondary non-resettable one is there to save the day.

Failure of either of these two fuses will prevent the unit from heating. It will not affect the motor spinning.

If the thermal fuse fails open, then you will need to investigate why they failed open. Generally this is due to airflow.

Blower Housing Fuses

• Cycling Thermostat. The cycling thermostat is the 3rd thermal protection device in the heating circuit. This is what cycles on and off heat based on temperatures in the blower housing.
• Thermal Fuse. This fuse (the pill shaped one) is NOT in the heating circuit. It’s in the motor circuit. If the temperatures in the blower housing get hot enough to trip this fuse, the motor will stop.

Thermal Fuse

The thermal fuse is wired in series with the motor circuit. It is placed on the blower housing. If the thermal fuse trips, the motor will not run.

Testing