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Discuss Banging Pipes After New Megaflo Cylinder Installed in the Plumbing Forum area at

  1. AOIS

    AOIS Member

    I recently had a new Megaflo unvented cylinder installed and have noticed that when the washing machine is running there is a significant banging noise coming from the pipework by the cylinder. This noise was not present before the new cylinder was installed.

    Could this be water hammer?

    Any help or advice appreciated.
  2. ShaunCorbs

    ShaunCorbs S. Mod Trusted Plumber GSR Top Contributor!!

    Yes water hammer are the pipes you can see clipped ?
  3. AOIS

    AOIS Member

    Yes they are clipped, although looking at them again one of the clips is broken off following the new cylinder being installed. The pipework has been moved as the side that was not painted silver is now visible.

    Is this easy to fix please?
  4. ShaunCorbs

    ShaunCorbs S. Mod Trusted Plumber GSR Top Contributor!!

    When holding this pipe does the water noise stop ?

    Might be hot so be careful
  5. AOIS

    AOIS Member

    Good idea, will check and update the thread. Thanks for your help and advice.
  6. townfanjon

    townfanjon Trusted Plumber GSR Top Contributor!!

    Was the original cylinder unvented?
  7. AOIS

    AOIS Member

    Yes it was.
  8. townfanjon

    townfanjon Trusted Plumber GSR Top Contributor!!

    Strange , can you post a pic of the pipework?
    • Like Like x 1
  9. AOIS

    AOIS Member


  10. YorkshireDave

    YorkshireDave Plumber

    Bit concerned that the never changed the control set, but aside from that I cannot see why it would knock so! Hmm.
  11. Chuck

    Chuck Well-Known Member

    By 'running' do you mean 'filling with water' or just washing/spinning? Does the banging start suddenly when the filling stops or or does it start happening while the filling is in progess.

    I'm wondering whether what you are hearing is stick-slip noise as a cold pipe, initially warm due to conduction from the the Megaflo tank inlet, is cooled rapidly when cold water is being drawn by the washing machine.

    The photos don't show quite enough to see whether this possibility is a plausible explanation in your case.
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