Isolation Valves Query

[BobbyJoe]

Hi what is the purpose of isolation valves on pipes? All of my tap pipes have isolation valves and should they be fully turned for the water pressure?

Thanks

 

[steadyon]

1. They make no difference to the pressure. They can make a difference to the flow.
2. They should normally be fully open.
3. Where taps have copper pipe into the body of the tap, full bore isolation valves will generally give better flow than the cheap, limited bore ones. However, if the taps are connected with flexible hoses, these are already of so narrow a bore that it makes little difference.
4. The are meant to be fitted close to each outlet, so that the outlet can be worked on independently without shutting off the water to other outlets.

 

[Chuck]

Hi what is the purpose of isolation valves on pipes? All of my tap pipes have isolation valves and should they be fully turned for the water pressure?

They are 'service valves', essentially for water conservation and convenience. The idea is that if the tap washer fails you can isolate it and then change the washer easily at your leisure. I think that they are nice to have as long as they are decent quality and haven't seized open when needed. There's plenty of plumbers who'd disagree with me and say that they're more trouble than they're worth in a domestic system.