Zone valve for use in closed loop hydronic systems that do not contain dissolved oxygen in system water, such as fresh water from frequent source of makeup water. For cycling and not constantly powered on applications. 2-way on/off low voltage valve consistent of an actuator and valve assembly for controlling the flow of hot water. 24V 3/4 inch sweat connection low voltage motorized zone valve with 3.5 Cv capacity. Manual opener for valve operation on power failure, valve returns to automatic position when power is restored. Can be installed without disassembling the valve.