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Thread: Valve leakage @ Low Pressure

  1. #1

    Default Valve leakage @ Low Pressure

    My dad has a sprinkler system that has five zones. The water source is a water well. When removing and testing each valve it was determined that four of the five leak initially when pressuring up but as soon as the pressure is high enough they quickly seal off fine. These same four also show condensation after the valve when the system is turned off indicating flow (due to loss of pressure in the line before the valve). The flow is just enough to create puddles around the sprinkler heads but not enough to spray. The valves are clean yet the pressuring up response is repeatable.

    Do valves require a certain amount of pressure before they will seat or are these valves faulty? Also I was wondering if high pressure should be against these valves all the time? If so, this shouldn't be an issue if I'm not loosing pressure in the line, but I don't know if that is possible if the water well is not supplying constant pressure!? I do have a check valve in the main line before the valve. Any comments would be greatly appreciated. If you could, please provide a response ASAP as I am helping my 81 year old dad and I am only in town until July 5th. Thanks so much!

  2. #2
    Sprinkler Guy Wet_Boots's Avatar
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    Mar 2007
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    Metro NYC
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    798

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    You need to describe the setup more fully, and give your location. Photos can help. Sprinkler zone valves seal on upstream pressure, and if you don't have enough, they may not close properly. The best thing you can do for a sprinkler system on well water is to use zone valves with flow controls, and throttle them down, which improves their reliability.

  3. #3
    Computer Programmer Bill Arden's Avatar
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    Sep 2006
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    MN, USA
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    Some valves use a pilot valve to run the main diaphragm.

    These kind of valves will leak unless they get a few PSI on the input.

    These type of valves also have problems if they are feed from a small long pipe since the pressure will drop while they are on.

    Either way the flow should stop completely once the input pressure rises.
    Important note Ė I donít know man made laws, just laws of physics
    Disclaimer: I'm a big fan of Darwin awards.

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