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Weathermatic Valve Stuck Open

Discussion in 'Irrigation' started by MEXANDME, Jul 4, 2011.


    MEXANDME LawnSite Senior Member
    Posts: 396

    If the homeowner closes the valve using the flow-control; the water turns off.

    Could this simply be one of those old bad square WM solenoids? I know a bad solenoid can cause a valve to not open. Can it also cause a valve to not close?

    (I have not been to the site yet.)


  2. bcg

    bcg LawnSite Bronze Member
    from Tx
    Posts: 1,835

    Probably a diaphragm. Stuck open is usually diaphragm.
  3. My experience with WM valves sticking on is the holes in the diaphragm swell shut or something of that nature. Not sure what WM valve you have though.

    MEXANDME LawnSite Senior Member
    Posts: 396


    ....it is the N100SF 1"


  5. I'm embarrassed or maybe should be proud to tell you I'm clueless as to which WM valve that is. Too lazy to look up either.
  6. DanaMac

    DanaMac LawnSite Fanatic
    Posts: 13,156

    Agreed. Most likely the diaphragm.
  7. Sprinkus

    Sprinkus LawnSite Silver Member
    Posts: 2,108

    That's the Nitro valve.
    I'd take an extra one with you.
    Could be diaphragm, solenoid sticking/debris in solenoid chamber or port, rock/debris in valve, valve bonnet might be loose, controller may be outputting a constant 24v to valve, etc.
  8. Wet_Boots

    Wet_Boots LawnSite Fanatic
    Posts: 47,677

    I've seen stuck solenoid plungers in the old W*M square solenoids - no debris seen, just stuck. Easily freed, but do you really want to put it back in service?

    MEXANDME LawnSite Senior Member
    Posts: 396

    At a minimum, I will replace the solenoid. Probably everything but the body.

    I was just curious if a bad solenoid alone could cause the valve to stick open.

    Thank again,

  10. mitchgo

    mitchgo LawnSite Silver Member
    Posts: 2,780

    in my experience .. It's best to not gut swap from those old wm valves .

    The brass threads that are placed inside the body just spin around because of the plastic and you can't fully tighten the top down to the body

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