need help with add on system with flow

Discussion in 'Irrigation' started by tyjohnso, Feb 18, 2012.

  1. tyjohnso

    tyjohnso LawnSite Member
    from OK
    Messages: 10

    Hey guys... I am adding on to a system that was installed back in 1993.
    I have the blue prints of the system... Its on a well.

    Static Pressure is 55 PSI, Residual Pressure is 25 PSI, and Design Pressure is 50 PSI....

    whats the residual pressure deal? is that my Flow? Thanks
    I have looked online and stuff and cant figure it out...

    If it is not the flow.... how would i figure the flow on a well with it alread in the ground?

    Out of 15 Zones, the highest GPM is 24.6


    Messages: 18,668

    How did you determine that 24.6 gpm? Is the well on a meter?
  3. tyjohnso

    tyjohnso LawnSite Member
    from OK
    Messages: 10

    On my blue prints i have zone schedule.... how many heads, what type and GPM of each zone...
    The well has no meter....
  4. Wet_Boots

    Wet_Boots LawnSite Fanatic
    Messages: 50,758

    Wells are their own animal, and each one is different. If you don't have a performance log of a well install, you do best to make your own. It isn't very difficult to extend a zone and suddenly find you are running a well dry.
  5. Mike Leary

    Mike Leary LawnSite Fanatic
    Messages: 23,174

    Boots is correct, it's real possible to exceed the re-charge capability. I'd be doing a pump-down test, or hire a pump guy to chart it out. You're going to standing there with your zipper open if you don't. Click on "flow meter".
    Last edited: Feb 19, 2012
  6. 1idejim

    1idejim LawnSite Fanatic
    Messages: 11,358

    using MLs suggestion will allow you to accurately measure your supply. a bucket test will ballpark your supply.

    assuming that this is an average submersable pump on an average domestic well the maximum realistic supply will be between 18-22 gpm.

    if your blueprints are correct you may be overtaxing the supply which would explain lower operating pressure.

    this manual may be of some help.
  7. jvanvliet

    jvanvliet LawnSite Gold Member
    Messages: 3,944

  8. 1idejim

    1idejim LawnSite Fanatic
    Messages: 11,358

  9. txirrigation

    txirrigation LawnSite Senior Member
    from Texas
    Messages: 977

    I am guessing residual pressure means dynamic pressure? Just a thought.

    I would design around 15-16 gpm just to be safe, this will also increase your dynamic pressure because the water will move through the pipes slower.

    Boomer Sooner!

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