What shuts off the thermostat at a desired temperature?

Answer by  fancbiz (952)

Its the expansion of the contact plate due to heat which makes it bend and make the contacts for electricity contacts separate and thus switch off the power supply to the system.

Answer by  rathalosslayer (221)

There is a bimetal device in the thermostat that senses the temperature and switches it off when it reaches the proper temperature.

Answer by  Sherry65 (81)

Once a thermostat has been set to the desired temperature, the unit will run until that temperature has been reached. The thermostat has an internal thermometer to let it know when the temperature has been reached.