This listing is for a Pack of 1 Fitted to the inlet and outlet these valves are used to isolate central heating circulating pumps When fully open, the gate retracts entirely out of the flow path. This creates zero obstruction inside the pipe, keeping friction losses and pressure drops virtually non-existent—making them ideal for low-pressure or gravity-fed systems. A gate valve is primarily used for full-system isolation—meaning it is designed to turn the flow of liquid or gas completely ON or completely OFF. Operated by a square drive key (not included), Manufacturer: Navigator