Electrothermal actuator is constituted of heat tablet, paraffin wax propeller and other mechanical configuration.

When the heat tablet of actuator power on and heated, the paraffin wax expanded and drive the corresponding valve plug up going, For this valve with valve flap up going open, At the time, the valve is on.

When the heat tablet of actuator power off and cool down, the paraffin wax reduced and the main spring will be down going and push the corresponding valve plug down going. For this valve with valve flap up going open, at the time, the valve is off.

Observe the thermal actuator open status directly.