C/Water ballvalves failing ?

[Heating one2one LIVE]

I've got a customer who has had over 4 ball valves fitted in just over 3 years on the c/water storage tank.
Any ideas what might be causing the problem.Mains pressure is less than a bar and a half and the water line is clean.I suspect maybe surging pressure?Any ideas very welcome,thanks.

 

[Nige F]

not so much surging as rising overnight , maybe Dunno much about London or it`s water - Agile lives there somewhere and may have encountered it I`m out in the sticks.

 

[Heating one2one LIVE]

When you say rising is it the pressure your talking about?

 

[Agile]

I cannot come to any conclusion or make any suggestions unless you tell me why these ball valves have been changed!

Unfortunately there are many cowboys who will change perfectly good parts because they are short of work and know the customer, usually an old lady, will not question their judgement.

It would surprise me if there was any failure at all. I would expect that is is a faulty installation rather than the valve.

Tony

 

[Heating one2one LIVE]

I got a call about it only today.As far as I know the problem was that all the valve's wouldn't shut off (water coming from overflow).
The valve that's now in is very slightly letting by.
I'm going to change it but not sure what's causing them to break?

 

[Agile]

I would expect that the holes in the tank have not been drilled in the proper position.

That can be overcome by bending the valve arm so the full level is say 150 mm below the overflow.

If a plastic tank the wall may be deforming because no load spreading plate has been fitted and altering the full level as the tank fills.

But this is not my preferred speciality which is gas boilers and not plumbing

Tony

 

[spareshunter]

Keep old ball valve for analysis. Are you sure the ball valve is letting by?

If it is, fit new float at same time try a 6 inch if you have room.

Check old valve for grit on washer if it is fit in line filter to main feeding cistern. Old iron mains and grit cause havoc to any plumbing fittings.

Check seating for score marks, usually associated with brass type on equilibrium valves but check anyway. Always fit brass part 2 ball valves in water storage cisterns especially heating header tanks.

There are other reasons for a cold water cistern to overflow not just ball valves but these can be a little more problematic to solve.

PS> stand corrected its not a ball valve but a float valve before someone else does.

Yes, I do wear a suit to work (blue) and I did have a bad day at the orifice dear!

 

[spareshunter]

Oops forgot. Surging pressure? fit equilibrium valve or 3/4 in with longer arm and 6inch float. Tool station 22523 £ 9.77 inc, City tried to charge me £ 28.00 + vat once, plonkers.

 

[Agile]

Braders, can you comment on the positioning of the valve and the shut off level compared with the overflow?

If its correct then what is the cause of the valve leaking?

As suggested if there is dirt in the supply then that may be the cause.

Now the clever bit!

Remove the float valve "works" inside the tank and allow about 20 litres to run at full flow into the tank but THROUGH a piece of cloth!

The idea is to act as a filter and trap a piece of offending dirt that has been lurking in the pipe and not flushed out when previous valves have been changed!

Tony