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Discuss Pipe size and advice in the Central Heating Forum area at

  1. Brendon Bradshaw

    Brendon Bradshaw New Member

    I am moving a radiator 4m across a single story extension. I haven't got access to the roof and I have a concrete floor. I am happy to route the pipe around the wall which would mean a pipe run of 6m. Should I use 22mm pipe or 15 mm. If I went across the floor it would be 4m but ruin the floor covering. I have a combi boiler. I am thinking of using copper and solder ring fittings. Any advice appreciated
  2. CBW1982

    CBW1982 GSR Top Contributor!!

    What is it currently fed in? How many rads on existing system? What KW rating boiler do you have?
    • Funny Funny x 1
  3. Brendon Bradshaw

    Brendon Bradshaw New Member

    Thanks for your reply. It is currently fed in 15 mm, 8 radiators and it is an Ideal mini logic 30 (I think) Pardon me as I am on a bus to look at precise model. There are 22 mm pipes in the system but all radiators are fed in 15mm
    • Like Like x 1
  4. Craig Watson

    Craig Watson Plumber GSR Top Contributor!!

    If your just moving the current radiator then extending the existing 15mm pipes in 15mm will be fine.
    • Agree Agree x 2
  5. CBW1982

    CBW1982 GSR Top Contributor!!

    Hello Brendon, so moving that radiator using existing 15mm pipes and extending in 15mm shouldn’t give you any issues, providing the system is balanced correctly.


    Edit: Craig Beat me to it :p
    • Agree Agree x 1
  6. Brendon Bradshaw

    Brendon Bradshaw New Member

    Thank you
    • Like Like x 1
  7. Millsy 82

    Millsy 82 Plumber GSR Top Contributor!!

    Unless your radiator is huge then 15mm will be fine.
  8. Brendon Bradshaw

    Brendon Bradshaw New Member

  9. Brendon Bradshaw

    Brendon Bradshaw New Member

    The radiator is a type 22 2200mm x 400mm and the radiator has been hot at the top and cooler at the bottom in the past
  10. Ben-gee

    Ben-gee Plumber Top Contributor!!

    That will be fine on 15mm as I expect it is about 2kW; take this opportunity to flush the rad out with a hose pipe- might help it heat up evenly (do this outside!)
    • Agree Agree x 1
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