Pump education

Discussion in 'Irrigation' started by FIMCO-MEISTER, Jun 11, 2007.

  1. The weakest part of my irrigation resume is pumps. Don't run into them that often so I refer them tho a bud who deals with a lot. Anyway I've decided to learn something. These are the pics. The pump works now but is really noisy. The customer said they have had 5 in the last seven years. Apparently the creek gets really high and floods in the pump area. The inlet pipes are in water 3-4 feet deep. Take a look and advise, educate puhleeeze.





  2. More pics.


  3. looks like a slow night. I guess I'll crash and see what the morning brings.
  4. drmiller100

    drmiller100 LawnSite Senior Member
    Posts: 562

    5 HORSEPOWER?????????

    GOOD GRIEF!!!!!!!!! so what are you irrigating, 20 acres??????

    how much pressure are you seeing???
  5. This was an existing system so I can't give any history. Just started working on it yesterday. They have 2 acres spread among 20 zones of spray and rotors.(Not mixed) Plenty of pressure.The rotors do not have overpowering pressure. Appear to be 5-6 pgps per zone with no9 nozzles. Now comes dumb question time. Is there a pump that can be installed where this one is and handle occasional flooding? I have another customer with a submersible pump. I'm wondering if there are above ground pumps that can handle being submerged. If not we will be moving and I think replacing this one because it is so noisy they can only run it in the daytime to avoid waking neighbors. Once again this is the fifth pump in 7 years according to the lady so who knows the history of the pump sizes.
  6. drmiller100

    drmiller100 LawnSite Senior Member
    Posts: 562

    someone check my math please.
    a 5 horsepower pump, assume you have 20 feet of lift, and produce 50 psi. I get something like 130 feet of total head.

    according to http://www.ajdesigner.com/phppump/pump_equations_discharge.php

    that should produce 150 gallons per minute.

    Now we take a pgp with 9.5 nozzles. 5 of them at 10 gpm is 50 gallons per minute.
    so, in other words, the pump is sitting there cavitating its entire life. Which destroys them pretty quickly.

    Figure out each zone, adn how much water each zone takes. for grins, try turning on 3 or 5 zones manually so they all come on at one time, then run the pump.
    My bet is the zones are waaaaaaaay undersized for the size of your pump.
  7. Thanks I will have more questions after I review the tutorial and understand cavitating. What about an above ground submersible? Such a thing?
  8. Also the zones are running closer to 20 to 25 gpm. pgps no 9 nozzle isn't 9gpm which means the situation is even worse as far as cavitation goes I'm guessing.
  9. drmiller100

    drmiller100 LawnSite Senior Member
    Posts: 562

  10. drmiller100

    drmiller100 LawnSite Senior Member
    Posts: 562

    above ground submersible is a sump pump. not what you are after.

    why not just move the pump further up the hill???? if you do, upsize the suction line, and don't make it more then about 20 feet of vertical from the creek to the pump.

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