Do these calculations seem right?

Discussion in 'Irrigation' started by ple_1969, Sep 21, 2011.

  1. ple_1969

    ple_1969 LawnSite Member
    Messages: 204

    OK, I've been going back and forth about what pump to by for an irrigation system where I'm pumping from a river. In a nutshell I'm looking to get about 35 - 40 PSI at the heads (I20 rotors). Here are some measurements:

    Pull to the pump from the river - 8'
    Elevation change from the pump to the highest point - 27'
    Looking for 20 GPM max
    Mainline will be 1 1/2" schedule 40
    Valve will be 1"
    Laterals will be 1 1/4" poly

    Currently have the following jet pumps in mind:

    F&W - CPJ15S
    Goulds - HSJ15N
    Goulds - J15S

    Since there is about a $400 difference between the single stage and multi stage pump I want to make sure I have all my numbers correct so I can make a proper decision. A lot of my indecision has to do with PSI I can get out of each type of pump - don't now if a single stage will be have enough. But if I can use a single that $$$ in my pocket.

    Below is what I'm figuring.... does this look correct?

    11.7 - elevation change (27’ x .433)
    3 - filter
    2.28 - Mainline (200’ Schd 40 1.5”)
    3 - valve
    7 - laterals (20% if of head pressure)
    35 - 40 - heads
    TOTAL PSI LOSS = 61.98 - 66.98

  2. Without A Drought

    Without A Drought LawnSite Bronze Member
    Messages: 1,088

    Check out watertronics.

    central has recommended them, specifically the waterpak 3. its a 30gpm pump with a VFD. it comes all in an enclosure and you just need to hook up suction, electric and output.

    i'm gonna use it on a similar project.

  3. ple_1969

    ple_1969 LawnSite Member
    Messages: 204

    Interesting... any idea how much these go for?
  4. Mike Leary

    Mike Leary LawnSite Fanatic
    Messages: 23,174

  5. Sprinkus

    Sprinkus LawnSite Silver Member
    Messages: 2,326


    SPEEDSKI LawnSite Member
    from TN
    Messages: 67

    What did the price end up for the Water Pak?

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