How To Fix A Dryer That's Too Hot

The cycling thermostat in your dryer monitors the temperature in the blower housing and cycles the heating element or gas burner on and off as required to maintain the proper temperature. If the thermostat becomes defective or cannot accurately sense the airflow temperature, the heater or gas burner may stay on too long and create an unsafe temperature in the drum. The cycling thermostat has normally closed contacts that open on temperature rise and therefore testing for continuity will not easily determine if the thermostat is defective. You should first inspect the exhaust vent, blower wheel, drum seals and drive motor to verify that you have proper airflow before replacing the cycling thermostat. Remove power from the appliance before attempting this repair. Take note that a buildup of lint or other foreign material on the back of the thermostat will insulate it and prevent it from sensing the proper temperature.

The high limit or safety thermostat is used to protect the appliance from overheating due to a restricted airflow condition. This thermostat is normally located above the heat source and is designed to activate only when the air flow is reduced enough to allow the heat to rise and trip the thermostat, removing power to the element or gas burner. The thermostat is not designed to trip repeatedly and when this condition happens, the contacts inside may fuse together and no longer provide safety protection. This can allow the burner or element to stay on too long and the temperature may rise to an unsafe level. The high limit thermostat has normally closed contacts that open on temperature rise and therefore testing for continuity will not easily determine if the thermostat is defective. Verify that the exhaust vent is clear and not restricted and that the blower wheel and motor are operating properly before replacing the high limit thermostat. Remove power from the appliance before attempting this repair.

Some newer models of electronic control dryers may use a thermistor in place of a cycling thermostat, to regulate the temperature in the dryer drum. The thermistor is normally located on the blower housing and senses the airflow temperature as it exits the drum. The thermistor is a solid state device and will vary in resistance according to the temperature. This resistance is monitored by the electronic control board which operates a relay controlling the heater or burner. If the thermistor becomes insulated with lint or foreign matter or is damaged or otherwise defective, it will not register the proper resistance and the control board may not turn the heater or burner off at the proper temperature. Some models may display a fault code when this happens. If your dryer is displaying a fault code, you can refer to our list of common appliance fault codes to determine the source. You can test the thermistor with a multi-meter if you know what the resistance should be at room temperature. This information may be located on the schematic diagram for the dryer. Remove power from the appliance before attempting this repair.

If your clothes dryer appears to be too hot on top of the cabinet, the problem may be with the exhaust vent. If the vent becomes restricted, air flow will be reduced and the temperature inside may rise causing the cabinet top to be hotter than normal. This normally results in the high limit safety thermostat tripping and the clothes will take longer to dry. This is a safety concern and the exhaust vent should be checked regularly and cleaned when required.