"Water Hammer" When Turning Faucet ON ?

Discussion in 'Plumbing Forum, Professional & DIY Advice' started by Robert11, Sep 16, 2009.

  1. Robert11

    Robert11 New Member

    Nov 9, 2008

    Have the typical Delta single-handle faucet for the kitchen sink.
    At least 10 yrs old.

    Has the single good size ball type of valve inside the handle.

    Whenever we turn it ON, the hot or cold, there is a big "bang" in the pipes.
    Noise seems to truly originate in the faucet, but not 100% sure of this.

    Am tempted to call it a water-hammer, but I always thought water hammer, in the true sense of the word, was only when one closed a valve, and the
    ensuing pressure wave due to the running water being shut, suddenly, caused the hammer. Is this true ?

    We have no problem when shutting; only when turning it On.

    Anyway, I replaced the small hot and cold top-hat rubber seals and their
    springs. Also replaced the faucet's main ball-valve/handle, and the small Diverter valve that controls flow to the hose-sprayer.

    No change. Still happens.

    So, in effect, I guess, it can be considered a pretty much new valve.
    Nothing more to replace anymore; I think everything replaceable I
    have done ?

    I can buy a new valve of course, but hard to see the difference in a new one compared to the one I have now, now that it's been "updated" with the new components.

    This is really driving me crazy, and more important the wife.

    Any thoughts on this would be most appreciated.

  2. hj

    hj Moderator & Master Plumber Staff Member

    Aug 31, 2004
    Cave Creek, Arizona

    Now that you have done all that, replace the thing that is causing the noise. Put a new head on the sprayer.
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  4. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Sep 2, 2004
    Retired Systems engineer for defense industry.
    New England
    The divertor is slamming shut.
  5. Robert11

    Robert11 New Member

    Nov 9, 2008
    To hj, et al: From OP On My "Water Hammer" Post


    Thanks for help; really appreciate it.

    Your suggestion to replace the sprayer head is very intereting.

    I have just turned it on and off using its "trigger" on the handle, and yes I can hear the Diverter valve opening and closing. This could very well be the initiator of, or the actual source of, the noise I have been hearing.

    We never use the sprayer.

    There seems to be no leakage from the sprayer end (other than where the water is actually supposed to come out of), either when just sitting there unused, or when actually being used.

    Could you perhaps elaborate a bit more on what you feel might actually be wrong with the spray head, and what is happening there to cause the problem ? e.g., air leakage, or...?

    I'm a retired engineer, and I guess these kinda things always interest me.

    Regards, and thanks again,
  6. johnjh2o1

    johnjh2o1 Plumbing Contractor for 49 years

    Aug 9, 2009
    You need to replace the divertor. Replacing the spray head will not solve your problem.

  7. Robert11

    Robert11 New Member

    Nov 9, 2008
    From OP Re Water Hammer On Kitchen Faucet

    Hi all,

    Thanks everyone for help and suggetions.

    I did put in a new Diverter valve.
    No real improvement; perhaps a bit better, and less frequent, but still happens.
    Old Diverter valve was really banged up.

    So, problem still exists.

    That's why the suggestion of a new sprayer head seemed so interesting.

    But, I cannot truthfully understand why this would help ?
    There appears to be no leakage from it when off.
    When on, water just from where it should come out.

    Might have an air leak, of course, though ?
    Would this do it ? (see original Post)

    Any further thoughts ?

    Regards and thanks,
  8. Ian Gills

    Ian Gills Senior Robin Hood Guy

    Jul 24, 2007
    Robber, with some DIY on the side.
    I seem to get funny turn-on noises whenever I fit large runs of flexible stainless steel supply lines.

    Are your supply lines flexible and how long are they?
  9. hj

    hj Moderator & Master Plumber Staff Member

    Aug 31, 2004
    Cave Creek, Arizona

    Normally the spray hose is full of water so when you turn the faucet on the diverter is not fooled into thinking you have pushed the spray button. Your sprayer may not be "leaking" but it is probably allowing some water to drain out of the hose. When you turn the faucet on, the diverter senses a lack of water in the hose, assumes you have depressed the button, so it tries to send water to the hose. It only needs a smidgeon of water to refill the hose and the sudden flow against a closed spray head causes a water hammer, which along with the sudden reversion of the diverter back to faucet use, creates your sound. This is the classical cause of your noise, and is indicated by the fact that it usually occurs after the faucet has not been used for a while which gives the water time to drain out. If it does not cure the problem, then you have some other problem which we could only diagnose by being there and operating the faucet ourselves.
  10. Cass

    Cass Plumber

    Nov 12, 2005
    Have you checked your water pressure....
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