LG dryers feature several internal components designed to ensure that the appliance operates safely. The safety thermostat, or thermal fuse, serves as the dryer's last line of defense against fires caused by overheating. When the dryer heats beyond the factory-set high temperature limit, the safety thermostat activates and disrupts the electrical circuit to the heating element. Though replacing the safety thermostat restores the electrical circuit and allows the dryer to heat, the problem may reoccur if the reason for overheating is not found and corrected.
Poor Air Circulation
Operating the LG dryer in a small, enclosed laundry room without a source of fresh air can cause the appliance to overheat. Fortunately, this type of overheating problem is easily avoided. The more fresh air the dryer gets while it's in use, the better. Leave the door to the laundry room open whenever the dryer is running. If there's a window in the laundry room, crack it open.
Clogged Lint Filter
Cleaning the lint filter in your dryer is more than just a minor irritation: it's absolutely essential to keeping the dryer working properly. If you fail to clean the lint filter after drying each load, the lint can build up inside the filter and filter housing. As the lint collects, it blocks the flow of hot air and prevents it from escaping the machine, which can eventually result in the activation of the safety thermostat. Be diligent about cleaning the filter and periodically check the filter housing for trapped lint.
Restricted Exhaust Hose or Vent
A restricted exhaust hose or vent is one of the most common reasons that a dryer's safety thermostat activates, according to "Troubleshooting and Repairing Major Appliances" by Eric Kleinert. To prevent overheating, the hot exhaust produced by the dryer must pass through the exhaust hose and exit at the outdoor exhaust vent. Fix any kinks in the exhaust hose and periodically check the inside of the hose for trapped lint. Keep the outdoor exhaust vent clear of lint, leaves, birds nests or other obstructions.
Faulty High-Limit Switch
The purpose of the high-limit switch in an LG dryer is actually similar to the safety thermostat. The component is designed to disrupt the electrical circuit to the heating element when the temperature of the dryer reaches 257 degrees F. If there's a problem with the high-limit switch and the dryer continues to overheat, the safety thermostat activates at 266 degrees F. to prevent the machine from catching fire. The high-limit switch automatically resets when the dryer cools down. However, if the safety thermostat activates repeatedly, it may be an indication that the high-limit switch needs to be replaced.
- Troubleshooting and Repairing Major Appliances; Eric Kleinert