Posting a message to the forum will remove the above advertisement
  1. This site uses cookies. By continuing to use this site, you are agreeing to our use of cookies. Learn More.
  2. Checkout our Plumbers Insurance area - heavily discounted Public Liability Insurance and Van Insurance specifically designed for plumbers.

Discuss Combi losing pressure in the Central Heating Forum area at UKPlumbersForums.co.uk.

  1. Simon Hill

    Simon Hill New Member

    Hi
    I have a Combi boiler that keeps losing pressure. I top up, up to 1.5, but this drops within 6 hours and the system switches off.
    We have looked everywhere and cannot see a leak. I have used the Fernox F4 leak sealer, but this hasn't helped.
    Any ideas?
    (Yes I have had a Gas Safe Engineer out before you post that)
     
  2. Harvest Fields

    Harvest Fields Trusted Plumber GSR Top Contributor!!

    Then I would get him back out. As it is clearly not fixed and you have looked at the external parts of the system. It maybe within the boiler? Is the copper pipe outside dripping?
     
  3. Simon Hill

    Simon Hill New Member

    No, no problems with the pressure release
    He suggested the leak seal, so I've tried that. Was just looking for advise before getting him back out.
     
  4. scott_d

    scott_d Plumber GSR

    What boiler?
    Top up the pressure
    Turn off the power to the boiler
    Shut the flow and return valves
    If the boiler looses pressure it's the boiler
    If the system looses pressure it's the system.
     
    • Agree Agree x 2
  5. Simon Hill

    Simon Hill New Member

    Perfect, thank you. I'll give that a go
     
  6. neil grimes

    neil grimes New Member

    Hi,
    please can you offer me some advice. I have a greenstar 37CDi boiler losing pressure. I charged to 1.5 barg and closed flow and return 90 degree boiler valves to shut position. Overnight the pressure had dropped to zero by the morning. I have already fitted a new expansion vessel and checked bladder pressure is still OK with no water on bladder side. I have left a container under the pressure relief valve and observed no water over 24 hrs leaking from it. Any other ideas for me to check?
     
  7. Harvest Fields

    Harvest Fields Trusted Plumber GSR Top Contributor!!

    Are you Gas Safe Registered mate?
     
  8. neil grimes

    neil grimes New Member

    Hi,
    im not gas registered, this id my own boiler. I thought i had a leaking pipes but not sure now after checking the boiler last night.
     
  9. Harvest Fields

    Harvest Fields Trusted Plumber GSR Top Contributor!!

    I would get a Gas Safe in mate. You shouldn’t be taking the case off your boiler.
     
  10. daWilko

    daWilko Member

    Yes - no playing with the boiler or its controls please. I had a couple of slow leaks that were in the CH plastic distribution pipes to ground floor rads at home. The rising connection to the rad was copper but there was a transition to plastic (90 deg elbow) in the concrete. Weep weep, ho hum. My first step was to put in valves to isolate the rads one at a time and locate the leak.
     
  11. neil grimes

    neil grimes New Member

    hi,
    Greenstar 37CDi boiler.
    Pressure relief valve is dry but i have noticed a constant steam of water from the condensate pipe. Any ideas what has failed in the boiler?
     
  12. ShaunCorbs

    ShaunCorbs S. Mod Trusted Plumber GSR Top Contributor!!

    Even when the boilers off ?
     
  13. Harvest Fields

    Harvest Fields Trusted Plumber GSR Top Contributor!!

    Gas safe? Condense? Just saying.
     
  14. neil grimes

    neil grimes New Member

    Hi Shaun,
    Yes even with CH not running. If I top up pressure to 1 bar then water starts to flow out of condensate pipe.
     
  15. neil grimes

    neil grimes New Member

    Hi
    I hope to have a GSE coming after bank holiday but i would really like to know any thoughts what the fault could be.
     
Loading...
Similar Threads - Combi losing pressure Forum Date
best combi boiler to replace aging worcester 35cdi without losing flow rates Plumbing Forum Nov 14, 2018
Boiler Heating too quickly (MAIN combi 30 eco) Central Heating Forum Yesterday at 4:03 PM