Plumbers - please decipher....

[JimK]

/My guess = Google pics "ball valve seat"

Jim K /q

Forgot to mention, there are at least two interchangeable versions, low & high pressure versions......

Jim K

[polygonum]

Quite a lot of ball valves have an optional insert to be used on high pressure mains (or removed on low pressure). I suspect one of those.

Of course, pedants will point out that they do not reduce the pressure when the valve is closed and are simple flow limiting devices.

Not using when needed can make the valve operate harshly and sometimes makes the water spray out.

[Peter Parry]

The ball valve works by having a water inlet orifice the open end of which presses against a rubber insert as the water level rises and thus cuts off the flow of water. These days it is usual to replace the ball valve entirely when it starts to leak because most are generally Chinese junk and only last a couple of years.

Not that long ago the standard repair was simply to replace the rubber sealing pad which had either hardened or got hard water deposits on it stopping it from sealing and this would still be appropriate on a good quality ball valve.

It would appear that your plumber went to replace the seal and found instead that the water inlet orifice which seals against the rubber pad had cracked. He replaced this with a second hand spare he had available and made no charge for it - which was rather decent as you cannot see that bit without dismantling the ball valve so he could easily have got away with charging you for a replacement.

His actions appear to be perfectly appropriate.

[Chris Hogg]

I think the term ball valve may be misleading you. The term is also used to mean a ball c*ck or ball float valve often used in domestic cold water tanks, where the piston in the valve assembly, with the replaceable rubber washer in the cap at one end, presses up against an orifice to cut off the flow of water when the tank is full. Some modern valves have replaceable orifice inserts with a smaller aperture for use where the mains water pressure is high. Such an orifice doesn't actually reduce the pressure, but the smaller area does require less force to close it off.

There's a diagram of older style valves without a replaceable orifice, here

and scroll down to Image 2, but you can imagine a similar arrangement with a replaceable orifice rather than the permanent one shown.

[Brian Gaff]

Well, I know the size of the hole in the valve can be different for different pressures of water, but I've only seen this mentioned on Toilet Cisterns, where they could be gravity fed or mains fed.

My experience of loft tanks apart from getting filthy dirty and trying to no go through a ceiling is that its lime scale built up that knackers them and if one cleaned them up they work again, but its often so bloomin hard the new one is often the best option! I cannot do this any more so I too have to get a man, or increasingly these days lady in to do it. Brian

[harryagain]

The above is probably correct. Orifice. Or float valve jet, availble in various sizes depending on waterpressure.

However the excess water in the tank should have run out of the overflow to the tank and discharged harmlessly outside. Could have frozen up too if bad designed/layout. Needs looking at anyway.

I think more insulation is needed to pipework and tank. NO insulation under tank. Leaves a small amount of heat from the building to warm the tank. (A bit)

[Brian Gaff]

I thought I'd had it sorted by a valve downstairs, but I wanted to stop it the other day, and I could not shift the newish tap. I guess its that bloody hard water again. If the valve breaks I may sue Thames water for crap water! Brian

[harryagain]

Probably both float valve and overflow outlet are too close to the top of the tank. Good to have separate valve to throttle water coming in so it can't exceed potantial overflow

[Andrew Gabriel]

There's pretty much no in-line valve that is guaranteed to work if not operated for years. It's important to operate them periodically to keep them working.

[JimK]

/Of course, pedants will point out that they do not reduce the pressure when the valve is closed and are simple flow limiting devices. /q

Correctly informed pedants will point out that the two variants are designed for different static pressure heads....

Jim K

[Tim Lamb]

In message , Andrew Gabriel writes

Somebody once told me to *back off a quarter turn* from fully open.

Local Affinity Water gives Thames hard water something to follow!

Happy and prosperous new year.

>

[Tim Watts]

Gate and regular valves - yes, it's a good idea or they can seize open.

Not applicable to ball valves.

[Tim+]

He's an obfuscating wanker who's playing with words to boost his bill and appearance of competence?

Tim

[Gazz]

well, in Taiwan they can remove your existing pipes and ballcock and replace it with an orofice, but it costs a bit more than this plumber charges :)

Well, that's the rest of my day sorted, i love reading the way we used to do things and the items in common use in the 50's and 60's.

[Dave Plowman (News)]

Quite. Really can't understand why so many don't fit an adequate watertight overflow. By that I mean a pipe which only outputs water at its end. Have seen cheap push together types which leaked so badly they did just about as much damage as non at all.

[Dave Plowman (News)]

He means a washer. Or if a more modern design, valve.

[Dave Liquorice]

I guess you mean "push together" solvent weld without the solvent...

As for the OPs plumber. If he's a competent and skilled plumber why is he signed up with a call out agency? A good plumber ought to make enough money on the M-F 9-5...

[Johny B Good]

Yes, the point being that this doubles your chances of successfully getting the tap to unstick.

[Bill Wright]

The overflow can get blocked.

Bill

[harryagain]

These quarter turn isolation valve are mostly total shit. Made out of metal alloy guaranteed to corrode.

They are a complete waste of money. You need a proper gate/globe valve made out of bronze/SS for use in mains water.