GE Thermostats

The temperature of the air inside the drum is regulated using thermostats. Thermostats open and close an internal switch with respect to the temperature of their environment.

There are two different thermostats in your dryer: the operating thermostat(s) and the limit thermostat. The only difference in these thermostats is their opening and closing temperatures.

Operating Thermostats

Operating thermostats control the temperature of the air inside the drum. The operating thermostat is mounted just behind the lint filter and down under the door. The operating thermostat is in series with the heater element. The operating thermostat normally opens from 120 to 170 degrees and is always closed at room temperature.

Limit Thermostats

The limit thermostat is located on top of the heater shroud.

As its name implies, this thermostat shuts off the heater element if a dangerously high temperature is reached. This can happen if the dryer vent is blocked and the dryer can't get rid of the hot moist air from the drum. The limit thermostat opens at its rated temperature but does not close again when the temperature goes down and therefore must be replaced. This is done to encourage you to fix the problem.

Procedures for Checking Thermostats

UNPLUG THE DRYER
The operating thermostat is down under the lint filter in the front panel. Open the door and remove the 2 screws on the backside of the thermostat housing. Sometimes the screws are #15 Torx.
Remove the thermostat.
Visually inspect the operating thermostat. Does the paper label look charred? If it does, replace it. Set your ohmmeter at its lowest scale and confirm that it is closed by measuring less than 1 ohm. If a thermostat is not charred and it is closed it is usually OK. However, a thermostat's contacts can weld together and pass this test. They will usually get very hot before they weld and char the paper label. Replace a charred thermostat if the ohmmeter shows an open circuit at room temperature. The thermostat's operating temperature (temp that it will open) is stamped on its base. An L155 thermostat will open at 155 degrees. If you want your dryer to operate at a higher temperature, replace its operating thermostat with one bearing a higher L number.
You need to raise the top of the dryer to access the high limit thermostat. Remove the 4 screws securing the cabinet top in the front. Sometimes these are #15 Torx. Lift the top up and look for the limit thermostat on the top of the heater element shroud in the back behind the drum.
Test a high limit thermostat with an ohmmeter. If it shows 0 ohms at room temperature, it's OK but if you see an open circuit (infinite impedance), replace it.
Take all suspect thermostats to your nearest appliance store and purchase new ones. If the paper labels are charred and illegible, remember whether they were operating thermostats or the limit thermostat. The new limit thermostats have a plastic base to make them react slower to rapid changes in temperature. Buy only new GE replacement parts for the limit thermostats.Another approach for operating thermostats is to use generic Gemline thermostats and purchase them by their operating temperatures. Use an L155 for cottons and a L135 for permanent press.
Replace the thermostats (you can reverse the wires on a two-terminal thermostat with no ill effects).

All of the information in these Appliance Clinicprocedures is provided FREE OF CHARGE. No liability is assumed by theauthor for the accuracy of the contents or damages caused by the use ofthese procedures. By Oron Schmidt.