What are the main component of the zone control valves?

gate valve , flow switch , non return valve , test and drain valve

1-OS&Y Gate Valve.

2-Flow Switch.

3-Pressure Gauge.

4-Test and Drain Valve.

Zone control valves usually have Double Check Valve assemblies for prevention of backward flow into the mains, Gate Valves for isolation, Flow switches for the flow detection and Test and Drain valves for testing and maintenance purposes.