Leak in hot water cylinder (ballcock related?)

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Good afternoon. I hope you are well. I have a problem and it looks like this:

BACKGROUND
==========
* I have a hot water cylinder
* It is a Gledhill 1050x450 flexiseven combi tank made in 2009 with two immersion heaters
* The inflow of water is controlled by a ballcock in the tank.
* Unfortunately, the ballcock does not completely cut off the flow of water: instead, there is still a trickle coming out of inlet "D" (see diagram)
* Over several hours, the trickle fills the tank and leaks develop at leak "A" (see diagram) or, more rarely, at leak "B"
* This leak does (if not caught) cause damage (sodden, dripping carpets and mould).
* A friend of mine does DIY and has attempted to cure the problem by (I think) adjusting rotator cap "E" (see diagram) but this has not cured the problem: the trickle still flows (drips at approx 1 per second for hours) and the leak still develops.
* I want to cure the problem by adjusting screw "C" (see diagram) and moving the ballcock downwards, this forcing an earlier, more forceful cutoff. But there is limited workspace (access via tank cap "F") and this is difficult.
* I have searched the DIYNot wiki and FAQ for a solution but to no avail

MY QUESTIONS TO YOU ARE
=======================
1) What solutions would you recommend for this problem?
2) Could that solution be carried out by me (office worker, better with spreadsheet than tools, but - hey! - got a screwdriver for Xmas), my friend (semiprofessional DIY person) or by a plumber?

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• 14 Oct 2011
• 1

 

[HERTS P&D]

Fit a new part 2 float valve.

http://www.screwfix.com/p/pegler-prestex-float-valve-part-2/27627
(Or just replace the washer)

Remove and refit overflow pipe using LSX

http://www.screwfix.com/p/fernox-ls-x-leak-sealer/23614

Andy

PS There should be an isolation valve/stopcock on the supply pipe work leading to the float valve which will enable you to turn the water off.

 

[ChrisOxford]

In other words, the float valve ("ballcock") in the top tank is allowing the water level to rise above where it should be. Adjusting it would only be a temporary bodge, replacing it is the way to go, as Andy has said.

Your DIY friend should be able to do it, I would guess, though the fact you've had to ask for advice here does make me wonder I would imagine a professional plumber would take about 30 mins max. to do the job, though that's pure speculation.

You also have a leak where the overflow exits the tank. If the water level's too high, water should drip out of the open end of the overflow, somewhere outside, NOT from the side of the tank. This should be sorted at the same time. Andy's advice about using Fernox LS-X silicone sealant is spot-on IMHO.

 

[viewcode]

Thank you for the above: your responses are sensible. Regarding the Fernox LS-X, my local B&Q doesn't seem to carry it. Is there another B&Q product that would do the trick?

 

[Terry7556]

no, but pop to screwfix item number 23614 £4.99 in the catalogue i have

 

[Charnwood]

It would be wise to replace the ballcock/ballvalve/float valve, but ensure that it is a part 2 and has a brass seat.

For cheapness, most 'combi' manufacturers (Rolyat, Elson, Gledhill etc) fit their tanks with float valves with plastic seats. I've known a few develop problems where the plastic seat has 'crazed' and disintegrated, which I've assumed was caused by the heat from the hot water compartment.

 

[viewcode]

Thank you for the above. I showed your posts and the situation to my DIY friend, who promptly kicked it upstairs and recommended a professional plumber. I phoned up the plumber, emailed him the link to this post, he read it, agreed with your diagnosis, and somebody's coming round Monday morning to get it fixed. So major result from my POV, thank you.

I'll ensure he's aware of the need for a part 2 with a brass seat.

Once again, thank you very much: I appreciate your help