Shallow irrigation well - from great to nada.

Discussion in 'Pumps and Tanks Well Forum & Blog. Water is life.' started by GeneOtt, Jul 12, 2018.

  1. GeneOtt

    GeneOtt New Member

    Joined:
    Jul 12, 2018
    Location:
    South Carolina
    Hello all.
    I have a shallow-well yard irrigation system which has performed perfectly every Summer for years; common 1 and 1/4" driven PVC paired with a STA-Rite 3/4 hp pump. I've used it for 12 years, the well itself could date back to the 1960's. The well is 25ft deep with the static waterline at 13ft (checked that this morning.)

    View here::http://BrianMcCulloughShow.biz/WellHead&Pump.jpg (I'm anticipating putting in underground sprinklers soon, so, yes, that's all new PVC you see - new air tank, check valve, the pump was given new seals (everything else in it, impeller, injector, etc was OK. Tested in a barrel.) Put system back together, and all working fine for several weeks after the "refurb."

    Yeah, things were going too...well. At startup today my normal 9gpm flow is down to a surging dribble, and not enough oomph to trip the on-at-30/off-at-50 pressure switch.

    The pump holds its prime. The pressure switch works.
    I tested for leaks on all the joints - inlet & outlet side with soap.
    I don't think there could be a foot valve since I'm pretty sure it's just a pounded in wellpoint.
    We've had nowhere near our normal amount of rain this Spring in South Carolina, so I cut below the check valve and dropped a line in to make sure "hey, dummy, y'all ain't gettin' water 'cause there ain't none"...and water was there at 13ft.
    I ran a hose with city water all the way down the 1 & 1/4" casing to see what would flush out, got clean water back up with a very slight trace of sand. Let the garden hose (with approx 25# city water pressure) run into the well for 10 min, and it took it easily. Put everything back together, no improvement.

    The above pretty much exhausts my repertoire of well smarts. What's my next move?
    Thanks in advance for all who are kind enough to comment.
     
    Last edited: Jul 12, 2018
  2. Reach4

    Reach4 Well-Known Member

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    Sep 25, 2013
    Location:
    IL
    Last edited: Jul 12, 2018
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  4. valveman

    valveman Cary Austin Staff Member

    Joined:
    Mar 15, 2006
    Occupation:
    Pump Controls Technician
    Location:
    Lubbock, Texas
    I am guessing either the jet nozzle is clogged as Reach says, or you have a suction leak letting in air.
     
  5. GeneOtt

    GeneOtt New Member

    Joined:
    Jul 12, 2018
    Location:
    South Carolina
    Reach4, Valveman...Ran coat hanger through venturi nozzle, no blockage. Ran pump briefly with city-water input through one of the discharge hose bibs, and the venturi access plug out to wash out any crud just in case. (That did prove the pressure switch working.) Closed up, reprimed; same result - poor water discharge, lots of air.

    So, that leaves the only remaining reason a suction-side air leak?, and since I don't see anything above ground, it's got to be below? Am I correct in assuming there isn't any cure for that other than boring a nearby new hole?

    P.S. Pump & well have a cover, just is off for access & photo.
     
  6. valveman

    valveman Cary Austin Staff Member

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    Occupation:
    Pump Controls Technician
    Location:
    Lubbock, Texas
    Suction leak is usually right where the pipe screws to the pump.

    Could also pump out of a bucket or barrel to test the pump.
     
  7. GeneOtt

    GeneOtt New Member

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    Jul 12, 2018
    Location:
    South Carolina
    Pump ran fine with a fishpond water as alternate intake source instead of the well. Was also tested after being rebuilt.

    I did not find any above ground suction leaks with soap, so wound Saran wrap from wellhead to pump, didn't make a difference.
     
  8. valveman

    valveman Cary Austin Staff Member

    Joined:
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    Occupation:
    Pump Controls Technician
    Location:
    Lubbock, Texas
    Soap won't do any good, and you can't check for a suction leak unless the pump is running and drawing a vacuum. Foaming shaving cream will show a small hole where the air is going in.
     
  9. GeneOtt

    GeneOtt New Member

    Joined:
    Jul 12, 2018
    Location:
    South Carolina
    Pump was running w-vacuum with intake line wrapped in Saran, brings up some water, just not much. I thought perhaps if discharge increased when wrapped that would point to the air leak being along the inlet piping above ground. I'll unwrap and try again with shaving cream tomorrow, it's started to thunderstorm now.
     
    Last edited: Jul 14, 2018
  10. GeneOtt

    GeneOtt New Member

    Joined:
    Jul 12, 2018
    Location:
    South Carolina
    OK, fast forward one day. Checked venturi again, is clear. No airholes with the shaving cream, same behavior with running pump...holds prime overnight, with outlet bib closed builds pressure and shuts off >> open bib >> good water 'till pressure falls enough to have pump kick in, then flow slowly falls off to no better than a steady dribble.

    I'll dig up around wellhead tomorrow when it's cooler and see how far down I can get in search of a possible air-leaking joint near the top. Then, the only options left are pull the 25' of PVC and inspect?, or sink a new wellpoint & PVC next to the old?
     
  11. Reach4

    Reach4 Well-Known Member

    Joined:
    Sep 25, 2013
    Location:
    IL
    If you can put a vacuum gauge on the suction line without introducing a suction leak, you could get info.

    If vacuum is high, water is too far down after you pump a bit, or the inlet screen is plugged.

    If vacuum is low, pump is bad, or there is an air leak, or your well runs out of water.

    If your well runs out of water and admits air at the input screen, I would expect air in your water. You did not report air in your water.
     
  12. GeneOtt

    GeneOtt New Member

    Joined:
    Jul 12, 2018
    Location:
    South Carolina
    (Hello again Reach4)
    Re: air in water...only a bit/a few "coughs" when first starting, but not ongoing.
    I won't be able to get away to buy a vacuum gauge until late next week, could you comment on this small insight?...just for shiggles and gits I unscrewed the plug on the pump (above where the venturi is internally) and held my thumb over the hole. Felt the suction, but seemed pretty mild, I was expecting much more. Would you take this "analog organic vacuum test" as pointing towards air leak rather than clogged-up wellpoint intake? Water level @ 13ft a few days ago, so I know I'm not out.
     
  13. Reach4

    Reach4 Well-Known Member

    Joined:
    Sep 25, 2013
    Location:
    IL
    I don't have an expectation/guess of what the vacuum there should be.
     
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