Dryer Overheating

If the vent is clogged or partially clogged, it will restrict the airflow through the dryer, substantially increasing the drying time. To ensure proper dryer performance, you should clean your dryer’s venting system at least once per year.

A dryer's drive motor will drive the drum belt to rotate the drum as well as spin a blower wheel to circulate the air through the drum during operation. If the dryer runs for a while and then stops, and won't start again until it cools down, it's likely the drive motor is malfunctioning and will need to be replaced.

A dryer thermistor monitors the dryer temperature and sends a resistance reading to the control board. If the thermistor is malfunctioning, it may fail to send the correct reading to the control board resulting in the dryer overheating. If you've determined there is good air flow coming out the home's outside vent hood and the dryer venting is free of obstructions, the thermistor is one of the components you can test for electrical continuity with a multimeter to see if it's functioning properly. While the thermistor should have continuity at room temperature, the ohm’s reading should go lower as the temperature on the sensor increases. If the thermistor has shorted or shows no continuity it should be replaced with a new one. Thermistors rarely get out of calibration.

A dryer's main control board controls the voltage being sent to all of the appliance's electrical components. If a relay on the board has shorted, it may sent continuous voltage to the heating circuit causing the dryer to overhead. To help determine this, you can inspect the board for signs of damage or a shorted component.

A clogged lint filter will cause a loss of air flow, which can cause the dryer to overheat and eventually trip the thermal fuse. For the best drying performance, clean the lint filter before starting the dryer. If you use dryer sheets, residue can build up on the lint filter. If you cannot blow air through the dryer lint filter it will need to be cleaned with a brush, soap, water. Confirm the lint filter housing and grille, if applicable, are free of lint build up as well.

The cycling thermostat cycles the heat on and off to maintain the proper air temperature. If the thermostat is defective, it may keep the heat on too long, causing the dryer to get too hot. However, this is rarely the case. Before replacing the cycling thermostat check all the more commonly defective parts. If you have determined that all of the other components are working properly, test the thermostat by using a multimeter to test it for continuity. If the thermostat does not have continuity, replace it.

Most dryers have a felt seal at the front and rear of the drum to prevent heat from escaping the drum. If the seal is worn out or missing, the heat will not be drawn through the drum properly, causing the dryer to get too hot. Check the drum seal to ensure that it is creating a reliable seal around the drum. However, this is rarely the case. Before replacing the felt seal check all the more commonly defective parts. If you have determined that all of the other components are working properly, replace the felt seal.

The high limit thermostat monitors the air temperature in the dryer's blower housing, heating element, or heat duct and is intended to shut off the voltage to the heating circuit if the air temperature gets too hot. If the thermostat is defective, it may allow the heat to stay on too long, causing the dryer to get overheated. However, this is rarely the case. Before replacing the high limit thermostat check all the more commonly defective parts. If you have determined that all of the other components are working properly, test the thermostat by using a multimeter to test it for electrical continuity. If the thermostat does not have continuity, replace it.

The blower wheel works with the drive motor to draw air into the dryer drum. Clumps of lint, socks, and small articles of clothing can escape the lint filter and get caught in the blower wheel. In addition, the blower wheel sleeve can wear out, allowing the blower wheel to wobble on the motor shaft. If the blower wheel is obstructed or defective, the dryer may get too hot. To determine if the blower wheel is working properly, remove the dryer vent and assess the strength of the air flow. If the air flow is weak, check the blower wheel for obstructions. If no obstructions are present, try rotating the blower wheel by hand. If the blower wheel wobbles as it turns, replace it.