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Threaded Rubber Expansion Joints

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Anyone ever install this kind of product (see URL above)?

After making subtle changes to rad and pipe pitch, I think I've gotten rid of the water hammer issue I posted about a few months ago.  But now noticeable is my single pipe steam system makes annoying banging noises just while the steam begins traveling down the pipes and gets to the rads after the air vents out. It's most annoying at the line going into my master bedroom and of course, me being a light sleeper, well...

But I came across this product and wonder if I install it (have it done by a pro) into the 10 foot run if it might not solve the problem.  The position of the end of the pipe rising to the radiator doesn't leave room to get a swing joint put in (I don't think..) so I'm curious if anyone has experience with this product and if it would solve my problem.

Thanks for any advice...

Bill in Elmwood Park


  • guinea pig?

    you will be the guinea pig with this product!

    what is your reasoning behind its use?

    i think those chambers will act as little water-hammer-chambers, so best to install it in a test location first.

    what is your pressure? do you have wet steam? are you over-vented on the radiator, while being under-vented on the mains?--nbc
  • bob_46
    bob_46 Member Posts: 813

    When your 10' pipe goes from 60º F to 212ºF it grows .127". I would look for where it touches the structure or a hanger and put a piece of plastic milk jug in between.
  • Rubber Joints

    I agree with NBC that the bellows pockets when filled with cold water will probably cause the steam to collapse resulting in water hammer.  You might want to try using a slower vent on the radiator as this would cut down on the amount of condensate initially produced when steam first enters the radiator and result in less noise.

    - Rod
  • pokerbb
    pokerbb Member Posts: 11
    Forgot to also mention...

    Thanks to you guys for the replies...

    I did remember after I posted that these occasional banging noises also come while there is no steam being circulated but shortly thereafter and also while my basement cools down.  So I'm convinced it's expansion/contraction of the pipes.

    NBC...I didn't think about the chamber filling with condensate and hammer then happening...maybe that's why no one used these in the past.  Well I'm trying to reduce noise, not get more, so I'll take Bob's advice and look for places along the path that have contact with the wood sub-floor and I did see some pipe hangers to fix per the milk container plastic fix.

    Rod..I don't think it's hammer anymore because, as I mentioned above, it does occur before the system calls for steam and at some times when the steam has long stopped.

    Maybe the only answer is swing joints then...I'll get a steam pro over here and let him have a look and listen.

    Thanks again for the suggestions...

    --Bill in E.P.
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