Plumbing - Leaking isolation valve?

Question

I want to isolate a hot tap fed from tank. when I turn isolation valve s***w away from 'on' I get water leaking from the valve. Is there a fault? Is the resure too high?

Any ideas?

Answer 1

IF YOU CAN'T FIX IT WITH A HAMMER, YOU'VE GOT AN ELECTRICAL PROBLEM.

Answer 2

I think you are talking about the straight valve where you put screwdriver in and quarter turn it off.  These often leak.  I suggest you put water catcher underneath with tin foil to guide drips, turn it off, have suitable fitting ready to put on disconnected end.  Fit it, turn it back on and it will probably not leak.  This will suffice till you at some time have to drain down.

Answer 3

If you have a gate valve, which is the type you turn a wheel to turn the water off, the leak is coming from the end of the valve spindle. Try tightening the nut at the end of the spindle to see if the leak stops, but not too tight that you can't turn the wheel. If that doesn't stop it, undo the nut and pull it back then wrap some PTFE tape around it and replace ( two turns of tape should be enough. If you have the type of valve that you turn off with a scredriver, then these can't be repaired, only replaced.

Answer 4

If your valve is leaking around the stem of the handle it may just be the packing gland of the stem, Tighten the hex gland on the stem.

If your valve is continuing to leak through the isolation seat in the valve, it may not be seating due to build up on the seat. Sometimes you can close and open several times and clear the seat, then snug it down tight to try again.

Answer 5

Many isolation valves with a 90 deg s***w turn are usually 'cheap and cheerful' quality. They only work a couple of times before they leak. If you can find one of decent quality, go ahead and replace the one you've got. You won't find one in a DIY store though - go to a plumbers merchant and even then be choosy! You're going to need to turn off all your hot water to do the job!