HELP! Banging Radiator

Discussion in 'Plumbers' Talk' started by Kelly O'Flaherty, Jan 11, 2018.

  1. Kelly O'Flaherty

    Kelly O'Flaherty New Member

    Hi all!
    First time posting - really hoping someone can help me.

    When we turn on our central heating there is an loud banging noise from near the radiator in the main bedroom. It's not just when the heating is turned on or off/cooling down, it's ongoing.
    It's driving me mental!
    I've tried everything - we have an old boiler and initially looked at that as the issue, had someone come and service it and despite it's age/being a tad loud it's fine and not the cause of the noise. It's been given the all clear.
    It's not trapped air as when I bleed the radiator very little comes out before the water starts to flow out.
    The other radiators in the house are dead silent... it's just the one in the bedroom, but you can even hear the banging noise if you're in the room under the bedroom!
    I then thought it was loose pipes knocking against the joints as they expand/contract - so plagued my OH to pull up the carpet, move the furnishings and lag/wrap the pipes where they meet the joints to tighten it all up.
    He's just done that with his Dad...and low and behold....the banging continues!

    It's the only loud one in the house, it's an old radiator, quite old. It was in the house when we bought it - will replacing it make any difference? Will that solve the problem?
    The only other thing I can think of is power flushing the central heating system...but I'd rather try everything else before having to resort to that.

    ANY HELP is much appreciated. Please save my sanity before this knocking drives me over the edge!

  2. kiaora

    kiaora Active Member

    When you bleed the radiator, you may not be getting the air out!

    You will have a flow and return pipe, with two valves each side of radiator.

    Often what can happen is to get air in one of the pipes, and when you open the vent, the water flows from the pipe with no air, and leave the other with still air in it.

    To deal with this, turn off both valves, open vent and hold bowl to air vent, ( a little help needed here)

    Open one valve, and draw the water up one pipe, then repeat, closing the first valve and opening the other valve.

    Hope this helps
  3. Tricky Dicky

    Tricky Dicky Active Member

    Turn off this rad using the handwheel, also the lockshield (count the number of turns to lock it down).
    Does the banging cease ?
    If so we can move onto stage 2.
    kiaora likes this.
  4. kiaora

    kiaora Active Member

    Good advice !
  5. Kelly O'Flaherty

    Kelly O'Flaherty New Member

    Thank you both!
    I’ll have my OH & his Dad try both of the above.

    I’ve tried turning it off to see if it stops banging...alas it’s so old the handwheel doesn’t seem to do anything/ever stop turning.
    Hence why I’m wondering if a new one would help the problem.
    I’ll see if they can turn it off in a more crude/manual way by lifting off the handwheel and turning it off with a spanner.

    Any other advice/suggestions also welcome! Happy to plague OH to try everything to stop the noise!

  6. chippie244

    chippie244 Well-Known Member

    Drum and bass init :p:p
  7. Sheelin

    Sheelin New Member

    Do you have a TRV on the rad? These can sometimes cause the symptoms you describe.

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