Combi not working after moving some pipe work.

Discussion in 'Plumbers' Talk' started by StevenThomson, Sep 12, 2019.

  1. StevenThomson

    StevenThomson New Member

    Hi Guys,

    First post, here we go,

    Just re routed some pipe work because it was all surface and looked shocking, so re piped it all above the ceiling. Everything fine plenty of flow and pressure, but the combi which is a Logic 30 will only get the call for hot water if the taps are on full chat!

    Now it’s a mixture of old and new pipework, 22mm and 15mm. Have I done something wrong or has something got caught in the boiler flow device.

    Like I say loads of flow and pressure but only kicking in when it’s absolutely flying out??

    Any ideas will be greatly appreciated.

    Thanks in advance
  2. KIAB

    KIAB Super Member

    Combi hot/cold water only needs 15mm pipe work, not 22mm,no benefits using it, as it will have twice as much cold water to push out before the hot gets there.
  3. StevenThomson

    StevenThomson New Member

    Cheers for the reply, the 22mm was existing, and all worked fine before.
    It’s not waiting for the hot to come through there’s no call on the boiler till the tap is on full, like it’s not seeing the flow.
  4. Mike83

    Mike83 Screwfix Select

    If you’ve altered the water main into the boiler then there’s a chance something has got into the pipe.
    This debris may well have found its way to the water turbine.
  5. StevenThomson

    StevenThomson New Member

    That’s what I’m thinking all worked fine before, surely If there flow then it should fire and begin heating.
  6. terrymac

    terrymac Screwfix Select

    Can't see how you have caused this if all you have done is re routed some pipe work ,after the boiler

    I assume boiler fires perfectly well when central heating is called for ?
    You will need an engineer visit.
  7. StevenThomson

    StevenThomson New Member

    Yeah CH is fine, no fault codes on the boiler. Strange one.
  8. Mike83

    Mike83 Screwfix Select

    I think the m
    i think the main has been rerouted going into the boiler.

    I think debris has got to the turbine.
    Maybe removing the turbine and checking the filter/restrictor will show something up.
  9. StevenThomson

    StevenThomson New Member

    Yes I agree, I’m just a sparky have no idea about boilers.

    I’ll strip it out tomorrow.
  10. terrymac

    terrymac Screwfix Select

    When the OP made reference to moving pipes above the ceiling ,I had assumed the boiler was below ,but of course that may not be after the boiler. If the mains cold before the boiler has been worked on ,its a distinct possibility as you said Mike.
  11. StevenThomson

    StevenThomson New Member

    Yes the mains has been altered.
    Damaged impeller maybe? There was a lot of “bodging” to tie in to existing.
  12. nigel willson

    nigel willson Screwfix Select

    The fact of I’ve no idea, and I’ll strip it out tomorrow, fill me with dread
  13. StevenThomson

    StevenThomson New Member

    Not for you to worry chap, it’s not your boiler and I’m not touching any gas related parts.

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