Motorized Valves are made up of Actuator and Valve Body.The Valve is closed,configurations of valve body are closed off;the thermostat  transfers a signal to actuator that will connect to power,and then open valve,input hot water or freezed water to fan coil unit;if the room temperature reaches to set-point,thermostat transfers a signal to actuator to cut off the power,and spring switch returns,valve is closed,and the hot or freezed water is block to fan coil unit.Therefore,the room temperature could be controlled in the
set-point through valve opened or closed.