Low pressure problem

Discussion in 'Irrigation' started by dkeisala, May 6, 2006.

  1. dkeisala

    dkeisala LawnSite Senior Member
    Messages: 911

    I'm not an irrigation contractor. Besides minor/routine repair and maintenance, I refer out most irrigation installs and repair but I'm having a problem I thought I'd throw out here.

    Started a clients irrigation system yesterday. All zones are running but they've got very little pressure running through them. The main water valve is fully open and valves on the backflow device or fully open. There's no break in the main line because the water meter (irrigation system has it own meter) isn't running when the system is off. I did notice that one of the zone valves was making a pretty severe vibrating sound when in operation.

    Any ideas what could be causing the problem? Something I can fix or should I just call my irrigation guy?
  2. SprinklerGuy

    SprinklerGuy LawnSite Bronze Member
    Messages: 1,778

    Main water valve a gate valve or ball valve? PVB valves gates or balls? If gate valve it could be broken not allowing it to open all the way.

    Water meter valve on all the way?

    Have they had a plumber over the winter who installed a new pressure regulator and didn't turn it up past the factory setting?
  3. dkeisala

    dkeisala LawnSite Senior Member
    Messages: 911

    PVB ball valve going to irrigation meter and it's full open. Not sure about main water meter. Don't see why the water meter valve wouldn't be full open but suppose I should check (I turn my own down due to ultra high water pressure). Just sent him an email (commercial building) asking if anyone has required access to the water system.

    Thanks for your suggestions!
  4. kozmo

    kozmo LawnSite Member
    Messages: 70

    Although all your answers surely would cause the problem i will go with the jack-ass who installed system has his zones overloaded or a leak.The chip on my shoulder from service this past 2 weeks has been growing into a arm amputation.
  5. DanaMac

    DanaMac LawnSite Fanatic
    Messages: 13,226

    I agree with this one. Even if it may have worked last year, doesn't mean it will work the same this year.
  6. dkeisala

    dkeisala LawnSite Senior Member
    Messages: 911

    The system has operated just fine for the 7 years I've had the account. I have no idea who installed it but pressure was never an issue. Additionally, only a leak in the main line would cause pressure loss in all zones, right? As I said, the meter doesn't move when all zones are off. The main line from the irrigation meter to the valve box is about a 150 foot run.
  7. Wet_Boots

    Wet_Boots LawnSite Fanatic
    Messages: 50,751

    Make and model of backflow preventer?

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