Service valves that don't service ...

[GRC]

Has anyone else found installations where the service valves don't actually shut off the taps etc that they're meant to service?

One 9-year-old installation (my house), another older, but not ancient (circa 1970s) house; tried to shut off the gravity feed with the standard red-top gate valves; and they don't shut off, unless aided by a 9 inch adjustable wrench. The older one still didn't shut off altogether

Am I the only one?

Regards, Graham

 

[Bas]

its not unusual for a gate valve to fail to completely shut off. It will probably need replacing I'm afraid. Use a reputable make for the new one.

 

[Johndug]

I agree, red top gate valves don't seem to work for long. Just as drain cocks seem to be useless after a few years.

 

[wilhelm]

twas ever thus

ahhh just spotted this beauty....

 

[GRC]

Add to this thread; red top valves that don't close completely by hand, and, when given just a LITTLE help with a wrench, not a lot, go completely loose and now won't open again.

The red top spins, the nut holding the red top, when turned by spanner, just spins the red top as well.

Have I goosed the valve altogether, necessitating total replacement, or is there anything that can be done with it in situ?

Regards, Graham

 

[Spindle]

I think the valve thread inside may have corroded and sheared as did a couple of mine. Unfortunately they will no longer move position and will require replacement. Not expensive but draining the system is a pain in the a***

 

[GRC]

The one that's in place has 3/4" stamped on the side; both B&Q and the local plumbing merchant, when asked for a 3/4" gate valve, sold me one stamped 22mm; the B&Q plumber advising me to "change the olives for 3/4" and you'll be fine"

Any thoughts?

Regards, Graham

 

[Bahco]

Good advice from B&Q but then I'm biased

 

[kevplumb]

why change the olives on a 3/4 valve
undo the nuts change valve tad of jointing compound biz

 

[GRC]

I've got 2 x 22mm gate valves, each from different retailers, one with a BS mark on the side (I hope that means British Standards....), and a brace of 22mm and 3/4 inch olives - all to replace one gate valve marked 3/4inch.

There can't be any other combination of stuff that I need, surely?

Oh, and to add to the fun, the valve to be replaced is about 9 inches vertically below the cistern that serves it; meaning I'll probably have to be extra careful not to twist the tank fitting when tightening the valve up...........

Regards, Graham

 

[Bahco]

You may find you need a slip coupler if valves are a different size.
Always expect to modify some pipework when you change something
Refer to my signature

 

[kevplumb]

why change the olives on a 3/4 valve
undo the nuts change valve tad of jointing compound biz

 

[ChrisR]

I think this is one of those oddities -a 3/4" valve can have 3/4" screwed connections - or 22mm compression ones! And a 15mm drain cock often has 1/2" on the side.

I don't use gate valves much, Full Flow Quarter Turn Ball Valves shut completely and don't rattle.

Of course if you come across a gate valve fitted in the 30's, it'll work fine. You need a spanner to crush the scale which might stop it closing, but everything's twice the strength the new ones are.

 

[shaggy]

Chris, any comment to make on Pegler gate valves at over 3 times price of cheapo one. Are they less likely to seize and shear the spindle or are you paying for an old respected name?

 

[GRC]

Add to this thread; red top valves that don't close completely by hand, and, when given just a LITTLE help with a wrench, not a lot, go completely loose and now won't open again.

The red top spins, the nut holding the red top, when turned by spanner, just spins the red top as well.

Have I goosed the valve altogether, necessitating total replacement, or is there anything that can be done with it in situ?

Regards, Graham

OK, so this was a week and a half ago. I got a local plumbing firm in to change the gate valve ( it was only 9 inches away from and underneath a 100-gallon cistern, so I'd rather someone else tightened up the fittings on that one without disturbing the cistern outlet, thanks very much....)

I watched the plumber at work - supplied him with the 22mm gate valve and 3/4" olives and watched as the nuts got tightened, and the framework supporting the cistern shook..... nervous? Me? Not a bit. He removed the old valve, and called for a junior hacksaw - the old olives proving a bit reluctant to let go...... put all back together, and ;

One week later, I need to shut the water off, and up into the attic I go, only to find a steady drip from our 'new' gate valve, and a wet bit o' wood below.

Call the plumber back, and a more senior partner from the firm arrives this time. Tighten the nuts first; no, still leaking. Take it apart, put PTFE over the olive, and tighten again. No, still leaking. Eventually, disappear back to home base for another 22mm gate valve, fresh 3/4" olives, a 22mm coupler, and cut about 3 inches out each side, and replace with a combination of new pipe, coupler and new valve.

On inspection of the discarded valve, I/we determine that the cause of the leak is "that scrape on the pipe letting water behind the olive"

Can anyone guess what caused the scrape on the pipe.....?

Regards, Graham