banging noise ( cold water supply on unvented system)

Discussion in 'Plumbing and Central Heating' started by RK_London, 24 Jan 2021.

  1. RK_London

    RK_London

    Joined:
    22 Dec 2020
    Messages:
    93
    Thanks Received:
    2
    Country:
    United Kingdom
    Can someone explain to me what a balanced cold water supply is.

    I've updated my system from vented to unvented after some extension work and am trying to understand the reasons why turning on cold water taps from the old part of the house cause a banging noise in a wall between the new extension and the old house.

    Any help appreciated. Thanks.
     
  2. Madrab

    Madrab

    Joined:
    4 Oct 2012
    Messages:
    8,560
    Thanks Received:
    2,481
    Location:
    East Renfrewshire
    Country:
    United Kingdom
    A balanced cold water supply is where the pressure/flow from an unvented hot water cylinder is balanced with the cold water supply at the outlet. This is done by taking a cold supply from the Pressure Reducing section of the combination valve that services the unvented cylinder. This to ensure that the pressure to mixer/monobloc mix in the body outlets are at the same pressure/flow.

    Wouldn't suggest that has anything to do with the banging you are getting from your pipes though. I would suggest that's more liable to be from loose pipework knocking against themselves/something when the water starts or stops running.
     
    • Thanks Thanks x 1
  3. Sponsored Links
  4. RK_London

    RK_London

    Joined:
    22 Dec 2020
    Messages:
    93
    Thanks Received:
    2
    Country:
    United Kingdom
    Thanks - what happens if the pressure to mixer in the body outlets are not at the same pressure?
     
  5. Madrab

    Madrab

    Joined:
    4 Oct 2012
    Messages:
    8,560
    Thanks Received:
    2,481
    Location:
    East Renfrewshire
    Country:
    United Kingdom
    You can either get backflow or resistance at the tap and the weaker flow can be reduced/stopped. Tends to me more where the difference in pressures are quite significant.
     
    • Thanks Thanks x 1
  6. Sponsored Links
  7. RK_London

    RK_London

    Joined:
    22 Dec 2020
    Messages:
    93
    Thanks Received:
    2
    Country:
    United Kingdom
    I do have a tap where the is a big difference between pressures - hot tap has very high pressure which I didn't understand because another hot tap two feet away was fine and they are both from the same pressurised cylinder
     
  8. 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

     
Loading...

Share This Page