Are rotors ok at 30 psi?

Discussion in 'Irrigation' started by soafone, Aug 10, 2012.

  1. Wet_Boots

    Wet_Boots LawnSite Fanatic
    Messages: 50,757

    How many acres are you watering?
  2. soafone

    soafone LawnSite Member
    Messages: 29

    I think it is an acre and a half.
  3. Wet_Boots

    Wet_Boots LawnSite Fanatic
    Messages: 50,757

    Simply put, if you want maximum coverage from a low pressure water supply, you will use heads with the most ability to function effectively at low pressure. Until further advancements, those heads are Maxipaw impact heads.

    However, if you do have a 40 gpm well, you should consider a new pump to replace what you have now. Something that will give you 20 gpm at 70 psi would be about right for wide-open spaces where you'd like long throws.
  4. Mike Leary

    Mike Leary LawnSite Fanatic
    Messages: 23,171

    Depending on the pump-down test/recharge rate, that sounds like a well to kill for. With the right pump, you could chuck some serious water. Re-charge is the name of the game.
  5. jvanvliet

    jvanvliet LawnSite Gold Member
    Messages: 3,944

    Use a centrifugal pump to make sure you get enough flow to feed your rotors; It's way cheaper than a submersible and produces loads more water than the much touted jet pumps.
  6. Wet_Boots

    Wet_Boots LawnSite Fanatic
    Messages: 50,757

    dude's in Canada, man
  7. soafone

    soafone LawnSite Member
    Messages: 29

    I still would like to know if anyone can answer the million dollar question. "Do rotors work well enough at 30 psi?" My distributor tells me they do, but I am reluctant to believe him. I suppose I could ask the home owner to change the pump in the well, but I am sure he won't be anxious to do it, since he just took possession of the brand new home. So, I have three options...

    1) run the rotors at 30 psi less the friction loss (end up with approx 25 psi at the rotors)
    2) use a booster pump to add psi, yet the flow will remain at 12 gpm
    3) ask the home owner to replace the pump.

    I think option three is the clear winner. Fortunately for me, my estimate read that it was based on the home owner providing a 1" water supply capable of 12 gpm's @ min 50 psi.
  8. Wet_Boots

    Wet_Boots LawnSite Fanatic
    Messages: 50,757

    No professional worthy of the name installs gear-drive rotors running at 30 psi.

    Is that clear enough for you?
  9. Waterlogged

    Waterlogged LawnSite Senior Member
    from Texas
    Messages: 587

    I would think you would loose more then just 5 psi, no backflow ? How long is the line from the pump ? how long is the main ? what valve ? I'm thinking you will have less then 25 at the head and no it will not work.
  10. soafone

    soafone LawnSite Member
    Messages: 29

    Short of replacing the pump, I think I have come up with a solution! Can I not just change out the pressure switch? When I did a gpm test, the pressure was at 30 psi, which leads me to believe the pressure switch is 30/50. I could swap it out with one that is 40/60 or even a higher one line 50/70 if available. Does this make sense? Would I still have 12 gpm's of flow, of would that decrease if the pressure is increased by the new pressure switch?

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