Water hammer in irrigation system

Discussion in 'Irrigation / Sprinkler Forum' started by JoeRI, Jun 19, 2020.

  1. JoeRI

    JoeRI New Member

    Joined:
    Feb 17, 2020
    Location:
    Rhode Island
    Hi all,

    Not sure if this should be posted here or in the pump forum.

    Anyway, I am trying to figure out a water hammer issue I am having with my irrigation system (this is the only water hammer issue I have in my house).

    I am on a well. The well pump is set to 40/60. Occasionally (not all the time) I get a water hammer during irrigation when the well pump kicks on (somewhere around 38) while a zone is running. It does not seem to coincide with any of my irrigation zone valves opening or closing. It happens while the zones are running and right around the time the well pump kicks on around 38.

    It does not happen all the time. Also, when it does happen, it ranges from very mild to sometimes pretty loud.

    I have no idea if this is a well pump issue or an irrigation issue (or both).

    thanks for any help.
     
  2. Reach4

    Reach4 Well-Known Member

    Joined:
    Sep 25, 2013
    Location:
    IL
    Check the air precharge. If it is above 38, drop it to 38. If it is already 38, try 37 psi. Air precharge is always checked and set when the water pressure is zero.
     
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  4. JoeRI

    JoeRI New Member

    Joined:
    Feb 17, 2020
    Location:
    Rhode Island
    thank you for the reply. To check the precharge, do you mean the little tire valve on the top of the well tank? If so, should I check it with a tire gauge? If I need to let air out do I do it like I would a tire? Also, do I need to drain all the water from the tank to check this?

    thanks again
     
  5. Reach4

    Reach4 Well-Known Member

    Joined:
    Sep 25, 2013
    Location:
    IL
    1. yes
    2. yes. To compare calibration on your water pressure gauge and the air pressure gauge, not those should nearly match when the water pressure is above 45. That is a good thing to check.
    3. yes. Put the cap back on when done.
    4. If the tank is working, all water will have been drained out for the water pressure to drop to zero. There is normally a spigot at the base of your tank. That not only drains pressure, but any sediment. If you see sediment, you might want to cycle a few times.
    It's not sure that air precharge is causing your symptoms. It is easy to check, and should be done periodically anyway. When people cite a recommended interval, they usually say to check annually. I don't check that often.
     
  6. JoeRI

    JoeRI New Member

    Joined:
    Feb 17, 2020
    Location:
    Rhode Island
    Ok wil
     
  7. WorthFlorida

    WorthFlorida The wife is still training me.

    Joined:
    Oct 28, 2009
    Occupation:
    Retired
    Location:
    Orlando, Florida
    JoeRI, did your resolved this issue over the weekend? Off the cuff it could be a bad bladder that failed and its working like an old non bladder pressure tank?
     
  8. valveman

    valveman Cary Austin Staff Member

    Joined:
    Mar 15, 2006
    Occupation:
    Pump Controls Technician
    Location:
    Lubbock, Texas
    Sounds like there is an above ground check valve? That valve should not be there as it will cause water hammer on pump start. However, if your pump is cycling on and off while the irrigation is running or even just between zones you need to solve that problem as well.
     
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