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Discuss Are isolating valves necessary on cw tank & HWC? in the Plumbing Forum area at

  1. fasltd

    fasltd New Member

    We recently had a bathroom renovation and although we are pleased with the result there were a few problems along the way and the job cost twice as much as estimated.

    Our installer insisted we needed isolating gate valves adding to our cold water tank in the loft and to the Hot Water cylinder. In fitting these he caused a leak in the loft as 'disturbed' the pipework and had to reseal with an underwater sealant which he said should be ok as am emergency fix.

    Whilst adding the valve to the HWC he 'disturbed' the shower pump which meant these caused a leak and had to be replaced at an extra cost to us.

    Are these valves really necessary? It's not a newbuild project- and he only managed to fit one on each item whereas I think there are 2no inlets which leads me to think they are pointless? Never had any problems before and now I feel like we are likely to need to make more repairs in the future.

    He assures me that they were necessary. Could anyone offer any advice.

    Many TIA
  2. Jim Goodenough

    Jim Goodenough Plumber

    It's standard practice to have either a stopcock or qtr turn lever valve on the mains supply to the CWS cistern (some people fit qtr turn isolating valves which personally I don't think good as the bore is very restrictive).
    Also it's standard practice to have gate valves on all connections from the CWSC, sometimes you only have one which is the cold feed to the HWC - this isolates the supply to the cylinder which is used to work on the DHWS without having to drain the CWSC; saving water and potentially hot water.
    It sounds like you've got a least another cold feed from the CWSC which feeds the shower pump (if it's a twin impeller type) again it's standard practice to install a gate valve on the supply to enable work to be carried out without draining the CWSC.
    Does this help?
    • Agree Agree x 1
  3. Best

    Best Trusted Plumber Top Contributor!!

    Your plumber was probably fed up with having no valves to isolate the hot and cold water supplies, so he made the correct decision to install them. (If you needed water stopped in an emergency, you wouldn't want the entire contents of your cold water tank to be uncontrollable, for example.)
    However, this should have cost little to do, particularly if straightforward.
    I would not have used gatevalves because they are highly likely to fail, perhaps first time you turn them. Full flow large lever valves for any of the cold feeds from the cold water tank and for hot and cold feeds to shower pumps are the best. Not much different in cost also. Brass stopcock, or good quality isolating valves for the mains feed to tanks.
    How much did this extra work cost you?
    • Like Like x 1
    Last edited: Feb 12, 2018
  4. mfgs

    mfgs Plumber GSR

    Its a good thing to have as it will make future maintenance work cheaper as no draining down required. However its very unlucky for the installation of two gate valves to cause leaks nearby.
  5. fasltd

    fasltd New Member

    Thanks for the replies - I see your point but he didn't actually use them as far as I know as all of the current sanitaryware had isolating valves and he changed the rad 'live' because he didn't want to drain the system. He said they would be useful if we had a leak somewhere.

    I think the idea was good but in practise but in hindsight probably not worth it. Its hard to say how much extra as there were a few extra things but the estimate was £2k and it ended up being £4k just for labour.

    Anyway good to know it is standard practise.
  6. Best

    Best Trusted Plumber Top Contributor!!

    Sounds like must have been major extras to warrant £4k labour!!
  7. fasltd

    fasltd New Member

    Well that's why I'm questioning his work!! We had the window replaced and that added a day or 2 as the wall needed some extra repair after that, then some extra boxing out and levelling the floor etc but nothing else major as far as we were told. He said the tiling took alot of work as we had metro tiles - but his workmanship wasn't perfect by any means.

    Really annoyed that we didn't get a fixed price as we trusted it couldn't possibly get that out of hand.

    You live and learn I guess!
  8. Jim Goodenough

    Jim Goodenough Plumber

    It's a shame - most decent tradesmen would have a good look at the job and sus out if they need to fit extra valves etc (obviously it's impossible to cover for everything e.g. checking CWSC's in lofts or removing pipe boxing's) when you're quoting for the job.

    As for creating leaks on existing pipework when fitting valves/connections this is something that a skilled person is very careful about - it's absolutely essential to hold existing pipework/fittings VERY rigidly while cutting/tightening etc otherwise you're just asking for trouble.
  9. Jim Goodenough

    Jim Goodenough Plumber

    I agree with you Best, except I only buy Pegler/Prestex gate valves now and they work great time after time, the cheap one's are useless and should be taken off the market in my opinion! o_O
    • Agree Agree x 2
    • Like Like x 1
  10. ShaunCorbs

    ShaunCorbs S. Mod Trusted Plumber GSR Top Contributor!!

    Just to give you an idea most people won't give fixed prices on bathrooms / large jobs are you don't know what your going to find under stuff etc
  11. jtsplumbing

    jtsplumbing Plumber GSR

    By your description this work was done by a builder who also tinkers with plumbing that's why all these isolating valves were not fitted to start with
    • Agree Agree x 2
  12. Best

    Best Trusted Plumber Top Contributor!!

    Yes the Pegler gate valves are lovely quality no doubt. But I still think lever valves are far better. Gate valves are always just a brass gate seal and will seize easily and worse in hard water areas. Plus a small bit of crud blocks bottom of gate.
    The cheap gate valves as you say, shouldn’t be used. Only thing they are fairly decent for is heating systems, to act as a balancing valve, or isolating valve.
    • Agree Agree x 1
  13. plumbandplumber

    plumbandplumber Member

    Sounds like there are more things to worry about on this job than some isolation nalves.
    • Like Like x 1
  14. SavageW

    SavageW Plumber GSR

    Sounds odd mate,puts islotation valves on CWSC an cylinder but changes a rad live? Cause he don’t want to drain the systemo_O
  15. fasltd

    fasltd New Member

    Should he have been able to shut off the water using these valves then? .. my concern is that they don't work!

    Also just to clarify it was lever valves that were fitted! Sorry I'm not up to speed on the terminology..
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