US Patent 8082888 Thermal switch for energy sustaining water heater

A water heater is provided that includes a tank for storing water and a combustion chamber in thermal communication with the tank for heating the water. The combustion chamber contains a pilot burner and at least one main burner. The water heater also includes a flue containing a flue damper to control the passage of exhaust gases from said combustion chamber. The water heater further includes an electrical control circuit connected to said flue damper. The electrical control circuit includes a thermal switch positioned proximal to the main burner The thermal switch is configured to prevent the flue damper from closing while the main burner is firing.