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Discuss Gas Supply and Gas Meter Issue When Running 2 Boilers in the Plumbing Forum area at

  1. Masterpop

    Masterpop New Member


    I wonder if someone can help answer some questions please.
    In our house we have two boilers : a 37kw and a 30kw.
    The max flow rate required for the two is 4.1 and 3.24 cu m/h (7.34 cu m/h)

    this exceeds the meters limit of 6 cu m/h.

    What options do I have resolve?

    I have been told that a U6 meter can go up to 64kw total. So one option is to downgrade the 30kw boiler to 25kw. However, if we do that, the flow requirement is still more than 6 cu m/h. So how does that work? (what is the relationship between kW and flowrate?)

    Is it possible to change to a different meter with a qmax of 10 cu m/h. (without going to a U16) :: Would that solve my issue?

    I am in the process of getting a GT1 test done to establish what the current pipes to the house are capable of supplying.

    Incidentally the 30kw should never have been installed but that is done and due to unforeseen circumstances, are now in a position where I have to deal with it.

    Any suggestions/explanations on how this all works would be greatly appreciated.

    The energy company is saying that I may need to upgrade to a U16 meter which may require new pipes from the streets. This seems overkill to me, so I am looking for a sensible solution..

    I have noticed meters being designed with a U6 or a G6, is there a difference? So a G6 diaphragm has a flow rate up to 10 cu m/h, which would meet one of the requirements, as well as work with existing standard connections...

    thank you kindly for your time
  2. ShaunCorbs

    ShaunCorbs S. Mod Trusted Plumber GSR Top Contributor!!

    Get a u16 fitted you will be fine then

    Any other appliances on gas ?
    • Agree Agree x 1
  3. Masterpop

    Masterpop New Member

    Hi Shaun,

    Thank you for your msg. There are no other gas appliances.

    It may be more cost effective to downgrade the boiler. The chap from SGN was just doing the GT1 test this afternoon. We'll see where we get to....

  4. ShaunCorbs

    ShaunCorbs S. Mod Trusted Plumber GSR Top Contributor!!

    Do you know what boilers they are ?
  5. Last Plumber

    Last Plumber Plumber GSR

    You need a U16 installing unless - as you say - you reduce the Boiler sizes.
    Why do you have Boilers that big?
    Are they Combination Boilers?
    How big is the house?
    • Agree Agree x 1
  6. king of pipes

    king of pipes Trusted Plumber GSR Top Contributor!!

    As others have said a U16 meter is needed some boilers can be down rated in the parameter settings what boilers are fitted ? Cheers kop
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