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system problem, Help

Discussion in 'Irrigation' started by Precision, Mar 24, 2007.

  1. Precision

    Precision LawnSite Silver Member
    Posts: 2,995

    I do irrigation maintenance on a commercial system. 12 zone with a Rainbird ESP-12 LX plus controller and an electrical pump relay. The pump (3 hp / 240 volt) runs. System is a remote selonoid valve system (not an index valve system).

    Primarily I adjust the timer for the seasons, fix broken or clogged heads, fix the spray pattern or whatever. But I also do first line of defense when something else goes wrong.

    I think I know what the problem is but I want to double check and make sure I didn't forget something simple.

    Problem:

    At first glance it appears that no water is exiting the heads on any zones. I checked the pump to make sure it worked. At first it didn't, but there is a switch between the relay and the pump and someone had switched that to off. I switched that to on and I fired the pump, I could hear and feel water in the pump but no visible water coming out from any sprinklers, regardless of which zone I tried.

    I tried multiple zones in case one had a sticking valve. I also went to a remote box and manually opened the valve. When I did this, I was right next to one of the head on that zone and noticed water flowing from the head, just enough to spray past the nozzle of the pop-up (1 inch max) then it surged up to (3 inch spread) then fell back down to 1 Inch.
    I checked for prime at the pump and re-primed it. No significant change.

    I went to each of the well heads (1 1/2 inch pvc 13 feet apart) and checked for flow vibration and didn't really feel or see any. So I shut down the pump then removed the "priming cap" and filled the furthest one from the pump with city water and capped it, then filled the nearer one with water and capped it shut.

    Still no significant flow at the heads, but now I can hear and feel water in the well pipes. then I reprimed at the pump. Still no volume increase.



    My thoughts:

    1. the impeller is broken and isn't pumping water properly
    2. the circuit lost a leg and my pump is only running on 120 and doesn't have enough power to push the water
    3. We have had almost no rain in the past 2 months and maybe the wells are fairly close to dry.

    I will be checking #1 and #2 tomorrow. I didn't have the correct tools to do that today. Usually it is just some genius turns off the controller box.

    Really hoping it isn't #3

    Anyone have any other ideas of what I can check or what it might be.

    Thanks in advance for any suggestions.

    And this is florida and it is most likely a shallow well system.
     
  2. Mike Leary

    Mike Leary LawnSite Fanatic
    Posts: 21,595

    Does the system have a master valve? Did the backflow boys leave the
    the ball valves closed after testing?
     
  3. Precision

    Precision LawnSite Silver Member
    Posts: 2,995

    In florida, we don't have to worry about freeze issues, so no blowing and shutting off the system. We run irrigation all year long.

    I can't think where a master valve would be. No ball valves at all (above ground) between the two wells and the pump. Each well has an in-line one way valve to stop back flow but that's it.

    This is an existing system and worked fine 3 weeks ago when I adjusted for spray pattern. Damn UPS and FED-EX trucks always running over a couple of sprinklers (on the other side of a 6 inch concrete curb).
     
  4. Wet_Boots

    Wet_Boots LawnSite Fanatic
    Posts: 46,423

    A vacuum gauge would come in handy here. See what's happening on the suction side of the pump.
     
  5. Precision

    Precision LawnSite Silver Member
    Posts: 2,995

    ok, how would I utilize that assuming I can get my hands on one?

    Do i need to break the pipe really close to the pump or anywhere between the well and the pump.

    I assume it is just like a pressure gauge but works in reverse.
     
  6. Mike Leary

    Mike Leary LawnSite Fanatic
    Posts: 21,595

    Have you checked to see if've you've got 24 volts @ the pump start/master
    valve output @ the clock? You're right about the vacuum gauge Boots.
     
  7. Mike Leary

    Mike Leary LawnSite Fanatic
    Posts: 21,595

    Sorry...did not read your thread enough, if you're firing from the clock,
    pump start is fine.
     
  8. Wet_Boots

    Wet_Boots LawnSite Fanatic
    Posts: 46,423

    Pumps have a small plug on the suction side. Connect the gauge there. (buy one at Grainger) ~ In feet of water, you won't likely read higher than 25, before cavitation begins. You are concerned with suction leaks here, for one thing. Low water table is something else entirely. Can you measure it in either point?
     
  9. Precision

    Precision LawnSite Silver Member
    Posts: 2,995


    Ok the plug is there. I saw that when I was looking for the priming plug (doesn't have one).

    Can I measure it in either point? Not sure what you mean.

    the plug is there. I can put the gauge on there, should be room in the pump house. Where would the other point be?

    Low water table is the issue I don't have any clue how to check for other than by eliminating everything else.

    I am still hoping it is running on 120 instead of 240. Easy fix.
     
  10. Wet_Boots

    Wet_Boots LawnSite Fanatic
    Posts: 46,423

    By 'point' I mean well point - do you know what your water table is? You may be near a depth beyond what your pump can work with.
     

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