Float Valve High Pressure Part1 1/2 inch to 2 inch

On older tanks and large commercial cisterns you still meet the classic piston valve, and the Float Valve High Pressure Part1 is that pattern. A brass piston slides in the body and seals against the seat when the float arm lifts it.

Float Valve High Pressure Part1 sizes and supply

The high pressure seat has a small opening for mains-fed tanks. If the supply comes from a header tank instead, a low pressure seat is the right choice, because the high pressure one will be very slow. On sizes, 1/2″ covers most domestic storage tanks. 3/4″ and 1″ fill bigger tanks faster, and 1.1/4″, 1.1/2″ and 2″ are for large commercial or break tanks.

Fit it through the tank wall with a washer either side and tighten the backnuts. Then fit the arm and float, and set the level an inch or so below the overflow. Service it by cleaning the piston and changing the washer when it starts to drip.

Floats and diaphragm valves are in Filling Valves.

Float valves at our Glasgow trade counter

Plumb Parts is at 555 South Street, Glasgow G14 0QX. Opening hours: Mon-Fri 8am-5pm and Sat-Sun 8am-1pm. Online ordering suits if you cannot call in.

Specification

• Connection: Threaded tail fixed through the tank wall with backnuts
• Sizes: 1/2″, 3/4″, 1″, 1.1/4″, 1.1/2″ and 2″
• Suitable for: High pressure (mains-fed) storage and break tanks

Common Questions

Is a Part1 valve the same as a Portsmouth valve?

Yes, Part 1 is the piston pattern that the trade calls a Portsmouth valve. The piston carries a washer that closes on the seat as the float lifts the arm.

What size do I need for my tank?

Match the valve to the tank connection and the fill rate you need. The 1/2″ covers most domestic storage tanks, while 1.1/4″ to 2″ suit large commercial or break tanks.

Why does the valve drip after a few years?

The washer on the piston wears and grit can score the seat. Shut off the supply, take the piston out, clean it and fit a new washer, and it usually shuts off cleanly again.