Isolating valves

[David]

Hi there,

Stupid questions here.

What is the difference between a standard isolating valve and a full bore isolating valve?

What is the best type of isolating valve used to isolate a sink?

Thanks

[A.Lee]

Std have a flow restriction, typically around a 10mm diameter bore, full bore have 15mm bore - thus not restricting the flow at all. For a downstairs sink, I have found no problem with using std. iso valves. If you have a poor flow from your present taps, then full bore may be the better choice. If both hot and cold are at mains pressure, then std. will be fine.

I've been using the type with a handle recently, much quicker to turn off.

Alan.

[David]

Lol, check out the review.

Thanks for the prompt reply.

[The Medway Handyman]

I wonder if the reviewer fitted it the right way around?

I use the SF 79p cheapies, never had the sightest problem with them.

[TheScullster]

"A.Lee" wrote

The so called "service" valves with a screw slot shut off tend to have a smaller bore than 10mm in my experience. If you have the traditional gravity hot water, then I would always fit full bore valves on this to maintain flow. If you have mains pressure cold, then the reduced bore service valves will be fine. Only gripe I have with the service valves is that they seem inclined to develop a leak passed the valve stem IME

Phil

[David]

Cheers for the replies.

[<me9]

Which way is that? The last ones I bought were full bore pegler ones. I'd exect them to be marked if it mattered.

Which way round would one be fitted in the return from CH radiators?

[The Medway Handyman]

The ones I use have an arrow denoting the direction of flow, fitted the wrong wya around they don't shut off properly.

Which way round would one be fitted in the return from CH radiators? Why would you want one there?

[<me9]

I've had trouble with cheap ones leaking when the wrong way round. The ones I fitted recently weren't marked, so I've assumed (until I know better) that they can be fitted eithr way.

I have them fitted to isolate parts of the system so that it can be drained independantly (and the downstairs bog (on whenever anything else is) can be isolated in the summer). The one on the return is fitted in the direction of the flow, but then leaks when it is used for isolation (just like the gate valve it replaced!).

[John]

>> I've had trouble with cheap ones leaking when the wrong way round. The > ones I

Think about where the head of water is - irrespective of the flow direction.