Water Hammer Arrestors - Good Pratice to incorporate

Discussion in 'Plumbing Forum, Professional & DIY Advice, Tips & ' started by chefwong, Nov 7, 2013.

  1. chefwong

    chefwong New Member

    Messages:
    710
    Location:
    District of Columbia
    Is Plumbing in Water Hammer arrestors good practice ? -- aka, preventative mitigation of WH.

    About to remodel a bathroom, thinking about putting a Hydra Arrestor right before the toilet valve.

    I've never needed to use a WH arrestor except for when I put a ~tapmaster~ under the kitchen sink.
    That cause all sorta hammers....and in went a set of Hammer Arrestors to deal with it.
  2. Terry

    Terry Administrator Staff Member

    Messages:
    14,783
    Location:
    Bothell, Washington
    A toilet isn't considered a quick closing valve.

    So, we never install water hammer arrestors for them, though it never hurts to have them either.
  3. chefwong

    chefwong New Member

    Messages:
    710
    Location:
    District of Columbia
    Aside from DW, Laundry - I thought toilets were on the hit list of common issues where you may get hammering (not that I've ever had this issue).

    However, after installing the one under the sink, I tend to be proactive about mitigating these things, if I could from the get go --- INSIDE the walls..Cheap Insurance I suppose
  4. hj

    hj Moderator & Master Plumber Staff Member

    Messages:
    26,270
    Location:
    Cave Creek, Arizona
    I have NOT installed any "air chambers" or hammer arrestors in residences for the past 43 years and have never had anyone complain about water hammer in their systems, but that may be because I install the proper sized piping so the velocities, which cause the hammer, are kept low.
  5. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

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    Location:
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    It's not uncommon to see your WM hoses jump, sometimes violently, when the thing turns off, so that's a visible indication of the kinetic energy available...an arrestor may not be needed to stop noises, but it certainly helps to limit the stresses on the system on a fast closing valve.
  6. DonL

    DonL Jack of all trades

    Messages:
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    Location:
    Houston, TX
    I am not a expert.

    But one thing that you can do is install a California Water Restriction Washer on the machine hoses. It will take longer to fill, but will keep from banging the valve as hard.

    That is better than having more things that may leak.


    Good Luck.
  7. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Messages:
    21,817
    Location:
    New England
    Slowing the water flow decreases the kinetic energy available, so yes, it will work, as will putting in a PRV and lowering the pressure. Any quality hammer arrestor will allow full flow while helping relieve the shock, and while yes, they will fail eventually, there generally is no more risk of a leak, and it's certainly more reliable than a WM hose!
  8. Terry

    Terry Administrator Staff Member

    Messages:
    14,783
    Location:
    Bothell, Washington
    It didn't used to be an issue where I plumbed either.
    But then they started replaceing water meters in neigborhoods and the problems started. It was after the water meters where changed out that we needed expansion tanks too.
    If you have the old style water meter without a check in it, you're fine. But if the meter is a new style with a check valve, you may have pressure and hammer issues.
    I had a friend that was woken up several times a night when his ice maker refilled the ice trays. Everytime they filled and then shut off it was banging pipes.
    He installled a mini-rester inline and that solved it. He could have moved to Arizona too, and I guess that would have fixed it too. Too bad for him, that he lives in Snohomish County.
    But I'm pretty sure that if he did live in Arizona, that he at least would not hear banging pipes in Washington State.
  9. hj

    hj Moderator & Master Plumber Staff Member

    Messages:
    26,270
    Location:
    Cave Creek, Arizona
    Nor would he have to worry about needing an umbrella.
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