Can't turn hot water stop tap!

[Snowman]

I need to turn off the hot water to fix a tap, but I just can't turn the stop tap. This is on a pipe behind the hot water cylinder running up to the loft and it's got a flat oval shaped piece to turn. I've found it tight in the past and have use mole grips, but this time I can't budge it.

Am I likely to damage anything if I really get brutal, or is there any way of freeing it up? Alternatively, I presume I can turn off the cold water feed to the house and drain the tanks. (In the long term, I think I'm going to have to replace this tap.)

Peter.

[Christian McArdle]

Yeah. Probably a gate valve. These are almost guaranteed to seize within a few years. I had to replace mine a few weeks back for the same reason. Don't get too brutal with a tank full of cold water to come out of the broken end. Drain the cold tank and replace the valve. I've started using lever ball valves instead of gate ones. From what I can tell, they are what is used in Europe.

Christian.

[Dave Baker]

There should be a nut behind the handle where the spindle goes into the body of the tap. If you loosen this first you stand a better chance of not breaking the spindle or the handle. It's probably jammed because you had it fully open. Better to leave stop taps half a turn back from fully out.

Dave Baker - Puma Race Engines

I'm not at all sure why women like men. We're argumentative, childish, unsociable and extremely unappealing naked. I'm quite grateful they do though.

[Snowman]

There's no nut. The tap is one where a quarter turn turns it off. ie when the oval bit you turn is in line with the pipe, it's open, if you turn it quarter of a turn so that it's crosses the pipe it's closed.

Peter.

[Nick Nelson]

It sounds suspiciously like a gas tap to me. Anyway, there may well be a nut on the back of the tap you could loosen (just a bit mind).

Nick

[Bob Mannix]

Sounds like a gas tap to me as well! Assuming you are certain that it's a water tap(!) you could try spraying every evening for a few days with WD40/PlusGas or whatever. It has (occasionally) worked for me in the past. Then get brutal, but if it turns a little turn it back and then forward again, then back etc., Make sure you can drain the system quickly.

[Snowman]

Yes it's definately water - at least it stopped the water last time I managed to turn it. I'll give WD40 a try - does that work best in the evening? :-)

Thanks, Peter.

[Bob Mannix]

Oh yes, it's a well known fact!

If I try and remember to do things in the morning I always forget and end up doing them in the evening anyway so that's why not cut out the middle man?

I fear that, if it's a gas tap that someone used for water, the water will make it prone to complete seizure. I have not seen a water tap like this, you might be advised to consider changing it. Mind you, the cheap gate valves always stick (as another poster said). The only real way round this is to shut and open them every 6 months, except you never remember :-(

[Tim Mitchell]

In article , Bob Mannix writes

This is a feature I like on the Keston boiler, if it's sitting there idle and hasn't used its valves and pumps for a while it wiggles them around just to make sure they don't stick. Now if only someone could invent a gate valve with similar features...

[Snowman]

Unless you do it in the evening !!

[PM]

Washing machine valve?

Pete

[Bob Mannix]

I know that was a little tongue in cheek, but a serious response is that the (only?) advantage of gate valves is that they are full (22mm) bore as they only deal with the hydrostatic head from the header tank. Washing machine valves, which may have to withstand mains pressure, are not full-bore (in terms of the 22mm pipes they would be isolating) and would severely restrict the flow.

[BillR]

I've got gate valves on my CH pump. They have been there 25 years and pump has been changed 3 times without a problem with the valves. Mind you I never leave any stopcock or valve so its hard open, just keep them a fraction of a turn from the fully open position.

[David W.E. Roberts]

I have just replaced my grotty 15mm isolation valves (screw to turn on/off and constriction in middle) with quarter turn valves from B&Q which have a long red handle and are full bore.

I did this for 2 reasons: (1) Full bore seemed better than constricted. (2) The isolation valves turned out to be harder to get to than I first expected, especially with a screwdriver, so long red handles made everything much easier.

Slightly concerned now after the comments about mains water pressure (valves are on cold mains to handbasin and cistern, hot tank to handbasin), but they will spend 99% of their time fully open.

So there are water isolation valves which are quarter turn, much like the isolation valve on my gas meter.

HTH Dave R

[Mike Tomlinson]

In article , Bob Mannix writes

Then they start leaking, so you have to change them anyway...

[John Stumbles]

Or plug the outlet from the cold tank to stop the flow. There are custom made plugs by Drayton (look like giants' earplugs and cost about 12 quid a pair) and compression plugs from BES (and real plumbers merchants) or you might get away with a wine bottle stopper (Vacu-vin) ... or use your ingenuity!

Agreed: full bore level valves (under £5 for 22mm from Screwfix) are the mutt's nuts

-- John Stumbles

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-+ Bob the builder / it'll cost yer Bob the builder / loadsa dosh

[Christian McArdle]

Very much like. In fact, they are likely to be the same part number. The one I bought had ticks against "Water", "Steam", "Gas" and "Heating Oil".

Christian.

[PM]

I replaced my cold water tank two years ago, within a year one of the gate valves wouldn't shut off :-(

[Bob Mannix]

I believe somewhere (in a mythical land) it is possible to buy "proper" gate valves (at greater cost of course). What we all buy, of course, are the two quid ones from the sheds, which seize.

This will probably seize at £1.39:

This *probably" won't at £3.58 plus fittings: