Ball Valves types

[welsford46]

I had a problem with the ball valve on the CW tank in the loft and although I sorted it thought I might have a look at a new one.

I see there's two types..hign and low pressure..type 1 or 2..could anyone explain the difference please?

Thanks

 

[wiggikins]

Larger inlet orifice in low pressure type valve.

 

[Gasguru]

I think you may be confusing the two common types of float valves.

Part 1....piston type

Part 2....diaphragm type

Use a Part 2 valve...it normally comes fitted with the high pressure valve seating.

There are also other types...the differences concern the discharge position of the water (and its compliance with water regulations) and the method it uses to shut off the water.

 

[cowley]

High pressure for mains, low pressure or tank fed appliances.
Part one does not comply with byelaws, part two does.

 

[stevehayes]

this i know for a fact!!!

part 1 is the portsmouth pattern type, piston and washer but not allowed to install now without a double check valvae as water outlet is lower and can cause backpressure.

part 2 is diaphragm, brass bodied

part 3 is diaphragm, plastic bodied

part 4 - torbeck, equilibrium type

you can usually buy in the b & q / wickes plumbing section part 2/3 with either high or low pressure valve seats.

high pressure is uitable for cold water tanks in the loft as they have a smaller orifice and low pressure types for Wc's fed froma storage tank as they have a larger orifice!

hope this also helps!

 

[Whitespirit66]

as water outlet is lower and can cause backpressure.

Its not because of back pressure, its because theoretically water can flow from your tank, up the submerged outlet of the part 1 valve, and contaminate the water supply.

 

[stevehayes]

sorry that';s what i meant, it can be sucked back into the supply pipes! the part 2 and 3 valves have a higher oultet and an air gap which prevent this!