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

Combi Hot water trigger

Discussion in 'Plumbing and Central Heating' started by Alan51, 3 Feb 2021.

  1. Alan51

    Alan51

    Joined:
    13 Oct 2020
    Messages:
    30
    Thanks Received:
    1
    Country:
    United Kingdom
    First time living in a house with a combi. When I run the cold tap it triggers the combi hot water setting, I've checked the pipes and they are all connected correctly. The combi is just over a metre from the cold tap, is this just the slight pressure drop triggering as the boiler is so close to the tap. It's a Main boiler.
     
  2. Sponsored Links
  3. fixitflav

    fixitflav

    Joined:
    20 Mar 2018
    Messages:
    1,163
    Thanks Received:
    134
    Location:
    Stoke-on-Trent
    Country:
    United Kingdom
    Does the water get hot?
     
  4. muggles

    muggles

    Joined:
    28 Oct 2005
    Messages:
    13,216
    Thanks Received:
    3,022
    Location:
    Daventry
    Country:
    United Kingdom
    Yes. A single check valve fitted to the cold inlet to the boiler will cure it
     
    • Thanks Thanks x 1
    • Like Like x 1
  5. Alan51

    Alan51

    Joined:
    13 Oct 2020
    Messages:
    30
    Thanks Received:
    1
    Country:
    United Kingdom
    Yes nice and hot.
     
  6. ianmcd

    ianmcd

    Joined:
    15 Aug 2010
    Messages:
    22,693
    Thanks Received:
    9,112
    Location:
    Lanarkshire
    Country:
    United Kingdom
    Not what he meant , he meant does the cold water get hot when the boiler false fires,Do as @muggles suggests fit a single check valve on the cold water inlet below the boiler
     
    • Thanks Thanks x 1
  7. fixitflav

    fixitflav

    Joined:
    20 Mar 2018
    Messages:
    1,163
    Thanks Received:
    134
    Location:
    Stoke-on-Trent
    Country:
    United Kingdom
    That's right :)
    So is firing for hot water triggered by a fall in pressure? Seems odd as the mains could be at a range of pressure. Unless the pressure switch setting is adjusted on commissioning. I always assumed there is a hot water flow switch.
     
  8. Alan51

    Alan51

    Joined:
    13 Oct 2020
    Messages:
    30
    Thanks Received:
    1
    Country:
    United Kingdom
    I've just checked and it fires only after the cold tap is turned off, I'll fit the single check valve, to be honest nothing surprises me with this house, it was a rental for decades and I don't think the landlord spent one penny more than he had to. It must have broke his heart when the boiler was replaced in 2016.
     
  9. 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

     
  10. Sponsored Links
Loading...

Share This Page