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

New Combi Boiler Pressure loss

Discussion in 'Plumbing and Central Heating' started by Paul JS, 29 Dec 2018.

  1. Paul JS

    Paul JS

    Joined:
    29 Dec 2018
    Messages:
    5
    Thanks Received:
    0
    Country:
    United Kingdom
    Hi there,


    Had a new WB 25i combi installed in Sept 2018 to replace an old WB combi (exactly same setup). Had all lockshields and Valves replaced at the same time.


    A month later I noticed the pressure had slightly dropped from the original 1.5 and noticed a very slight leak on the connector to the condensate.


    WB came out and replaced the part and another inlet as slight whistle when using hot water.


    Solved I thought however a month later I noticed the pressure had dropped approx to 1.1 so I topped up however reported to the installers as shouldn't be topping up so frequently. They checked all the lockshields and valves, no obvious leaks or damp patches anywhere (the pipes are vertical in the walls downstairs).


    Did the balloon check over the PRV exit outside over a few days to be sure - with no water at all.


    WB came out to check the boiler again and couldn't find anything obvious however replaced the heat exchanger just in case.


    I am now monitoring the pressure, however next step will be to isolate the boiler for a few days to see if it is the boiler or the system.


    Any other ideas or how to find any potential leaks?


    Thanks
     
  2. Sponsored Links
  3. MeldrewsMate

    MeldrewsMate

    Joined:
    27 Jan 2010
    Messages:
    1,021
    Thanks Received:
    245
    Location:
    Buckinghamshire, Darn Sarf
    Country:
    United Kingdom
    I think you have it covered with your last statement about isolating the boiler over a few days.
    Did your old boiler suffer the same pressure losses?

    I have had one occasion where a pinhole leak in the middle of a radiator caused the pressure to drop during the heating season, the water jet escaping was so fine it evapourated, but not when rads were cold. This was found after isolating the boiler and pumping up the rads to 10 bar hydraulically (after the previous fitter had changed the boiler!). Perhaps the powerflush could have opened-up a pinhole?

    MM
     
  4. shambolic

    shambolic

    Joined:
    25 Aug 2008
    Messages:
    5,754
    Thanks Received:
    2,853
    Country:
    United Kingdom
    If hex has been changed and nothing out prv then 100% not the boiler leaking
     
  5. Paul JS

    Paul JS

    Joined:
    29 Dec 2018
    Messages:
    5
    Thanks Received:
    0
    Country:
    United Kingdom
    Thanks for the replies, no previous pressure loss on the old boiler only had to top up very rarely.
    The new system wasn't power flushed it was treated with cleaner then inhibitor with a magnafilter fitted. I'll isolate tomorrow as I also suspect something in the pipes or radiators has been disturbed.
     
  6. mcmoby69

    mcmoby69

    Joined:
    19 Jun 2011
    Messages:
    6,574
    Thanks Received:
    2,220
    Location:
    Lancashire
    Country:
    United Kingdom
    Repressurise, shut boiler off of flow & return, leave for 24 hrs and re open, pressure drop?
    Leak on system . Pressure up? Boiler.......
     
  7. Sponsored Links
  8. kev25v6

    kev25v6

    Joined:
    17 Jan 2006
    Messages:
    213
    Thanks Received:
    3
    Location:
    Derbyshire
    Country:
    United Kingdom
    Air in the system releasing out the automatic air vent causing the pressure to drop?
     
  9. Paul JS

    Paul JS

    Joined:
    29 Dec 2018
    Messages:
    5
    Thanks Received:
    0
    Country:
    United Kingdom
    Could be, what's the easiest way to test, as WB engineer said it wasn't leaking water but obviously could be leaking air intermittently?
     
  10. dilalio

    dilalio

    Joined:
    20 Mar 2009
    Messages:
    7,774
    Thanks Received:
    1,249
    Location:
    Potters Bar
    Country:
    United Kingdom
    Any new flooring put down in recent weeks/months?
     
  11. Paul JS

    Paul JS

    Joined:
    29 Dec 2018
    Messages:
    5
    Thanks Received:
    0
    Country:
    United Kingdom
    no changes at all, I will check where the condensate was routed though as a hatch was cut in the floor to access outside - upstairs. thanks for all the replies
     
  12. Paul JS

    Paul JS

    Joined:
    29 Dec 2018
    Messages:
    5
    Thanks Received:
    0
    Country:
    United Kingdom
    Update, turned off the flow and return for 48 hours, no movement in the pressure in the period then when reconnected no movement.
    Very odd and implies something is leaking when perhaps under sustained use? Other strange thing was had a shower afterwards and the pressure increased slightly 0.1bar when the plumbing company said shouldn't increase after using the shower.

    I have used the heating for a few hours last night and pressure is very slightly higher only marginal i.e. 0.05bar if anything, with a system temp on 21c vs when I reconnected.

    Got another engineer coming tomorrow to check again.

    Any other things it could be? next steps as apparently to check under floor will be chargeable and will involve cutting the floors/walls i'm left with no choice but to continue monitoring after tomorrows visit and pay for a track and trace (not covered under insurance).
     
  13. 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