Solar Piston Pump unable to start

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Comments

  • BB.BB. Super Moderators Posts: 26,768 admin
    Jonr's suggestion could be a "big help" here.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • AguarancherAguarancher Solar Expert Posts: 263 ✭✭✭
    BB. said:
    Jonr's suggestion could be a "big help" here.


    I agree, anything to get the voltage up at the pump. The 50m run from the panels to the pump is the killer..imo  Moving the panels closer to the pump would also help.

    The part I don't understand is that according to the OP, on the initial filling of the storage tank everything was fine. All I can figure is that the system was running on the edge initially and that the water in the discharge line provided enough head that the pump failed to start under load.
  • EstragonEstragon Registered Users Posts: 1,429 ✭✭✭✭
    > @Aguarancher said:
    > BB. said:
    >
    >
    > Jonr's suggestion could be a "big help" here.
    >
    >
    >
    >
    >
    >
    >
    > The part I don't understand is that according to the OP, on the initial filling of the storage tank everything was fine. All I can figure is that the system was running on the edge initially and that the water in the discharge line provided enough head that the pump failed to start under load.

    The problem could be compounded by changes from initial conditions. The pump may have been damaged to some degree by the big suction head OP mentioned, for example.
    Off-grid.  
    Main daytime system ~4kw panels into 2xMNClassic150 370ah 48v bank 2xOutback 3548 inverter 120v + 240v autotransformer
    Night system ~1kw panels into 1xMNClassic150 700ah 12v bank morningstar 300w inverter
  • BB.BB. Super Moderators Posts: 26,768 admin
    The surge tank with zero or 100 psi pressure could also cause singe issues (bigh back pressure pulses?).

    Or, first run, started against zero back pressure (empty pipe).

    Next day, starting against full back pressure?

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • mcgivormcgivor Registered Users Posts: 1,206 ✭✭✭✭
    If as the OP stated, the pump initially worked, now it won't, may indicate a problem with the motor, I would be inclined to remove the belt and verify it runs without load, a carbon fouled commutator may well be the source of the low torque no run situation.
      1500W, 6× Schutten 250W Poly panels , Schneider 150 60 CC, Schneider SW 2524 inverter, 8×T105 GC 24V nominal 

  • jonrjonr Solar Expert Posts: 845 ✭✭✭✭
    Conceivably the surge tank has a leak in the bladder that developed after the initial success.
  • atilevatilev Registered Users Posts: 11 ✭✭
    Hi Guys,
    Thanks for all the posts and help. To clarify
    - Batteries are for testing
    - 16mm^2 should endure the voltage drop on line is minimum on 50m from panels
    - the pump can only achieve 50psi
    - there is no pressure tank. Pressure tank cutoff was there by coincidence
    - The first run was with no pressure in the surge tank.

    Things to try:
    - move LCB closer to tank
    - open up Piston area to see if anything is causing extra friction

    I've yet to hear any comment back from Dankoff. unfortunatly their customer support seems pretty lousy.
    Thanks for all the ideas. Though, I think the LCB is the last thing to try here.  
  • BB.BB. Super Moderators Posts: 26,768 admin
    I just want to be clear... Move the LCB to be close to the pump. Near tank/surge tank does not matter (surge tank is near pump, water storage tank is relatively far away).

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • atilevatilev Registered Users Posts: 11 ✭✭
    @BB. Yes I meant closer to pump. (pre-coffee typing)

    After the test I noticed pump was still not running. I played with the brushes and the pump is running at full speed now. Looks like this was a problem. Will be doing another test this week.

    Thanks!
  • mcgivormcgivor Registered Users Posts: 1,206 ✭✭✭✭
    Good to hear you are making some progress, keep the brushes and commutator clean, with brake clean spray, if you can obtain it, washes away the carbon residue, alchol can be used as a substitute, use fine grit sandpaper to dress the commutator once in a while is also a good practice. Good luck.
      1500W, 6× Schutten 250W Poly panels , Schneider 150 60 CC, Schneider SW 2524 inverter, 8×T105 GC 24V nominal 

  • softdownsoftdown Solar Expert Posts: 1,498 ✭✭✭✭
    1) I did not read all the posts because a rattlesnake bit my dog yesterday and I lost my keys....so distracted.

    2) I have worked with water pumps for decades. Even the biggest do not push pockets of air. You must replace all of the air in the lines with water. Have saved many situations including my father almost going from 800' to 1200' and replacing his well pump....due to air in the line. The experienced well pump guys had no idea. They were ready to go deeper and replace the pump.

    This is likely a problem that costs various people hundreds of billions every year. Then again....I did not read all the posts. 
    First Bank:16 180 watt Grape Solar with  FM80 controller and 3648 Inverter....Fullriver 8D AGM solar batteries. Second Bank/MacGyver Special: 10 150 watt BP Solar with Renogy MPPT 40A controller/ and Xantrex C-35 PWM controller/ and Morningstar PWM controller...Cotek 24V PSW inverter....forklift and diesel locomotive batteries
  • atilevatilev Registered Users Posts: 11 ✭✭
    Hi Guys,
    It looks like the brushes were the problem, the pump can reach over 75 PSI now. 

    One other problem I'm having is that the foot-valve on the intake is loosing water over night when the pump isn't running. Which results in the pump needing to be primed every morning. Any idea's on how to solve this? Smaller intake hose?

    Thanks,
    Alp
  • AguarancherAguarancher Solar Expert Posts: 263 ✭✭✭
    edited September 14 #44
    Glad you got it running. Seems a bit strange the brushes wore out so quickly. Keep the foot valve at least 1/3 meter off the bottom and install a new quality (brass) foot valve for a start. Some people come up with all types of screens to protect the intake for gathering garbage.
    Another way would be to put in a check valve or a ball valve at the pump intake which should work, but then someone has to open the ball valve each time the pump is turned on. Either way you need to keep the intake up off the bottom of your water source.
  • jonrjonr Solar Expert Posts: 845 ✭✭✭✭
    I'd clean and test or replace the leaking foot valve.  
  • mcgivormcgivor Registered Users Posts: 1,206 ✭✭✭✭
    A secondary check value close to the intake would act as double insurance, however there is no guarantee that leak back would not occur, even the smallest piece of debris could result in loss of head, or air ingestion, a strainer made from mosquito net at the foot valve would prevent larger particles form being ingested, which may help. Just some thoughts 
      1500W, 6× Schutten 250W Poly panels , Schneider 150 60 CC, Schneider SW 2524 inverter, 8×T105 GC 24V nominal 

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