Thermostat: Testing and Inspection
INSPECTIONReplace the thermostat if the valve does not close completely at an ambient temperature or if the following test shows unsatisfactory results.
^ Inspection method
Immerse the thermostat and a thermometer in water. Raise water temperature gradually, and measure the temperature and valve lift when the valve begins to open and when the valve is fully opened. During the test, agitate the water for even temperature distribution. The measurement should be to the specification.
NOTE:
^ Leave the thermostat in a boiled water for more than five minutes before measuring the valve lift.
^ Hold the thermostat with a wire or the like to avoid contacting with the bottom of container.