Float Valve High Pressure PART1 1/2 inch to 2 inch

A Float Valve High Pressure PART1 is the traditional brass pattern ball valve, with a piston inside the body that closes against a seat as the float rises. The high pressure version has a small seat, so it can shut off against mains pressure in a tank or cistern fed straight from the main.

Choosing a Float Valve High Pressure PART1

Match the thread size to the tank connection. 1/2″ is the usual size on a loft cold water tank or a large cistern. 3/4″ and 1″ suit bigger tanks and faster fills. The large sizes from 1.1/4″ to 2″ are for commercial storage and break tanks.

Backnuts and washers clamp the valve tail through the side of the tank. Fit the float and arm, then set the shut-off level a little under the overflow. If the tank is fed at low pressure, a high pressure seat will fill very slowly, so check the supply first.

Floats and other valves are in Filling Valves.

Buying float valves in Glasgow

Part 1 valves are available from Plumb Parts, 555 South Street, Glasgow G14 0QX, open Mon-Fri 8am-5pm and Sat-Sun 8am-1pm. Or order online.

Specification

• Connection: Threaded tail through the side of the tank, with backnuts
• Sizes: 1/2″, 3/4″, 1″, 1.1/4″, 1.1/2″ and 2″
• Suitable for: Tanks and cisterns fed at mains pressure (high pressure seat)

Common Questions

What does Part 1 mean on a float valve?

It refers to the valve pattern. BS 1212 numbers its float valve patterns, and Part 1 is the traditional piston type, often called a Portsmouth valve.

Why is my new valve filling the tank so slowly?

A high pressure valve has a small seat, which suits a mains feed. On a tank fed from a low pressure supply, that small seat lets water through very slowly, so a low pressure version is the right choice there.

Where should I set the water level?

Bend or adjust the arm so the valve shuts with the water a little below the overflow. That way a small leak past the valve shows at the warning pipe before the tank overfills.