1. Visiting from the US? Why not try DIYnot.US instead? Click here to continue to DIYnot.US.
    Dismiss Notice

Combi boiler (LOGIC +) leaking isolator valve

Discussion in 'Plumbing and Central Heating' started by AP77, 7 Dec 2019.

  1. AP77

    AP77

    Joined:
    8 Aug 2017
    Messages:
    97
    Thanks Received:
    0
    Country:
    United Kingdom
    Hi, hope someone can help please.

    I needed to change a bathroom tap washer so I turned the screw on the isolating valve which feeds the mains water into the Combi boiler.

    I turned the screw 90 degrees but a fine spray of water came from the isolating screw (presumably as it couldn't cope with the man's pressure?).

    I quickly turned the screw back, but now I can't stop a slow weep from the screw (one drop every 10 secs) no matter how careful I am turning the screw back to the correct position.

    So I think my next option is to turn off the mains stop cock under the sink and replace the weeping valve/screw. Only trouble is I can't turn the stop cock as it seems to be seized.

    Not sure what best to do:

    1) Find a way to stop the weeping screw. It only seems to turn 90 degrees clockwise and 90 degrees anti clockwise.

    2) Find way to turn off the mains stop cock. Afraid to give this too much force. Could try WD40 on spindle or loosen the to tap nut a touch.

    Hoping to get some suggestions for things to try in the morning, hopefully there will not be too much water on the kitchen floor by then!!!

    Many thanks in advance.
     
  2. Sponsored Links
  3. muggles

    muggles

    Joined:
    28 Oct 2005
    Messages:
    11,506
    Thanks Received:
    2,363
    Location:
    Daventry
    Country:
    United Kingdom
    You won't stop the valve leaking, it needs replacing. You could find your outdoor stopcock and see if you can turn that off, then take the opportunity to replace your indoor one with one that actually works
     
    • Thanks Thanks x 1
    • Like Like x 1
  4. AP77

    AP77

    Joined:
    8 Aug 2017
    Messages:
    97
    Thanks Received:
    0
    Country:
    United Kingdom
    Thanks for the advice.

    I managed to turn off the mains stop cock under the sink and this has stopped cold water coming out of the kitchen tap.
    I have aso turned the boiler control to "off".

    However, the isolating valve from the mains that is just before entry to the boiler still seems to be under pressure. It is still weeping and is still under pressure if I try to turn the isolating screw (it squirts out water)

    I thought that once I had turned off the mains stop cock under the sink. No more water would be heading through the pipe wiith the isolating valve into the boiler....have I got that wrong?

    Also. I notice that the hot and cold taps in the bathroom still have water coming from the taps (when open). Is that because the bathroom taps are getting water from the boiler directly and the boiler needs to be drained ? I have left the running for 5 minutes but water is still coming out of the bathroom taps.

    I will probably have to call out a plumber tomorrow but would still like to understand how this all works.

    Thanks again for helping me.
     

    Attached Files:

  5. muggles

    muggles

    Joined:
    28 Oct 2005
    Messages:
    11,506
    Thanks Received:
    2,363
    Location:
    Daventry
    Country:
    United Kingdom
    Sounds like your stopcock isn't fully turned off, or you have more than one!
     
    • Thanks Thanks x 1
  6. AP77

    AP77

    Joined:
    8 Aug 2017
    Messages:
    97
    Thanks Received:
    0
    Country:
    United Kingdom
    Thank you.

    The mans stop cock under the sink is definitely fully turned off as the kitchen cold tap does not let out any water.

    The boiler is only a couple of feet from the stop cock so is it likely there could be another stop cock feeding the boiler? I certainly can't see one......only the leaking isolation valve as seen in my photo above.
     
  7. Sponsored Links
  8. terryplumb

    terryplumb

    Joined:
    8 May 2017
    Messages:
    3,893
    Thanks Received:
    783
    Country:
    United Kingdom
    Show a pic of stopcock / pipework under sink.
    If no cold water comes from kitchen tap when the isolator under sink is closed ,but cold water comes out of other taps ,in bathroom for instance , then you have not identified the mains stopcock ,it will be somewhere else.
    Where the underground pipe comes into the property ,above floor level ,is where the mains stopcock should be.
     
    • Thanks Thanks x 1
  9. AP77

    AP77

    Joined:
    8 Aug 2017
    Messages:
    97
    Thanks Received:
    0
    Country:
    United Kingdom
    Thanks terryplumb, really appreciate you taking the time to reply.

    Attached is a photo from under the sink. Two pipes are visible in the lower half of the picture:

    The one on the left I assume is the main stop cock (large tap handle in left side of upper half of picture)
    The one on the right goes to the isolating valve (just visible in right hand access hole in upper half of picture) for the cold kitchen sink tap.
    There is a further isolating valve higher up for the hot kitchen sink tap.

    Is it possible there is another stop cock? I can't seem to find one.
     

    Attached Files:

  10. terryplumb

    terryplumb

    Joined:
    8 May 2017
    Messages:
    3,893
    Thanks Received:
    783
    Country:
    United Kingdom
    Definitely a stopcock ,but can't be the main one if other outlets give water continually whilst it's closed.
    Do you have a water meter ? Or trace the external stopcock to isolate water from coming into the property ,to enable you to swap the leaking isolation valve.
     
    • Thanks Thanks x 1
  11. AP77

    AP77

    Joined:
    8 Aug 2017
    Messages:
    97
    Thanks Received:
    0
    Country:
    United Kingdom
    Thanks again for your advice.

    Seems strange to me that there could be another stop cock as it is only a one-bedroom ground floor flat (converted victorian house). But as you say, as closing this stop cock off doesn't shut off the water in the bathroom, there must be another source.
    I have seen the external stop cock out on the pavement but I think I will have to admit defeat and call in a plumber tomorrow.

    Yes, we do have a water meter, which I believe is also out in the pavement.

    Thank you for your help and suggestions.
     
  12. DIYnot Local

    DIYnot Local

    Joined:
    3 Sep 2019
    Country:
    United Kingdom

    If you need to find a tradesperson to get your job done, please try our local search below, or if you are doing it yourself you can find suppliers local to you.

    Select the supplier or trade you require, enter your location to begin your search.


    Are you a trade or supplier? You can create your listing free at DIYnot Local

     
Sponsored Links
Loading...

Share This Page