New 900ft low GPM well

Discussion in 'Pumps and Tanks Well Forum & Blog. Water is life.' started by tzclark, Apr 4, 2020.

  1. tzclark

    tzclark New Member

    Joined:
    Apr 4, 2020
    Location:
    British Columbia
    Looking for pump selection help, we recently drilled a 900ft well that is only producing roughly 1 GPM. I plan on installing the pump at 860 and pumping it into a cistern before treating. The well statics to 200 within 24hrs. We are a family of 5 and estimate 600 gallons of usage per day.

    What pump would you recommend and what drop piping would you suggest? Galvanized? Stainless?

    Thanks
     
    Last edited: Apr 4, 2020
  2. VAWellDriller

    VAWellDriller Active Member

    Joined:
    Sep 8, 2012
    Occupation:
    Mud rotary well driller, pump installer
    Location:
    Richmond, VA
    Might be a lot of different opinions here. 600/day is a high estimate for domestic use; unless you are doing a little irrigating. I do a lot of public water work and avg is more like 250-300/day/connection around here. Since its really not necessary, I would not set a pump at the bottom like you suggested. I would put a 1.5Hp, 5gpm pump around 600' and hang it on SCH 120 PVC, and have a 86 gallon tank to handle the occasional peak demand spike. I would install this without the cistern in the beginning; try it for a month or so and have the option of installing the cistern if you don't like the pressure/flow. Any time you can keep something simple you should try to do so. You could probably install a 1HP 5gpm around 400 and be just fine. Nobody wants to run out, but most folks tend to overestimate their water needs. As a matter of experimenting, I use a 1/2Hp 5gpm well pump that serves my house.....it never pumps more than 7 gpm and we never have any complaints of pressure/flow.
     
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  4. tzclark

    tzclark New Member

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    Apr 4, 2020
    Location:
    British Columbia
    Thanks for your reply, my estimate is likely high. It is based off three daughters and a wife that like standing in the shower.
     
  5. VAWellDriller

    VAWellDriller Active Member

    Joined:
    Sep 8, 2012
    Occupation:
    Mud rotary well driller, pump installer
    Location:
    Richmond, VA
    My 1st scenario would give you the 600 you think you need in reserve not counting any production from the well.
    Figure 2.2 gpm/shower
    1.6 gallon/toilet flush
    1.0 gpm hand and dishwashing
    20-30 gallons for HE clothes washer
    15 gallons dishwasher

    You'll be hard pressed to get that over 400 or 500 gallons/ day even with 4 women.
     
  6. fitter30

    fitter30 Active Member

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    Occupation:
    Retired service tech
    Location:
    Peace valley missouri
    At 860' that is going to be a special pump just a quick look at grunfos it's only rated to 780'@ 1.3 gpm and #8 wire
    860' is 372 feet of head 3/4" pipe weighs 1120 lbs 1" 1 420 lbs galvanized pipe. 860' = 41 lenghts of pipe
    Need to find someone in your area that knows exactly what it's going to take
    Grundfos 15SQE10-220 - 15 GPM 1 HP SQE-Series Deep Well Submersible Pump
    https://www.waterpumpsdirect.com/manuals/grundfos-pumps-edae0d5f14436392402aec9c491b171a.pdf
     
  7. valveman

    valveman Cary Austin Staff Member

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    Occupation:
    Pump Controls Technician
    Location:
    Lubbock, Texas
    Like VA says you have about 1.5 gallons stored in the well for each foot of standing water. Set at 600' is the same as having a 600 gallon cistern. The 1.5HP, 5 GPM pump would give you water and pressure from 600'. The 80 gallon tank won't hurt anything but doesn't really help with peak demands unless you use a low air charge. With a 40/60 switch and 38 PSI air charge the tank is empty at 38 PSI and not helping with peak demand. Reducing the air charge to 25 PSI would give a few gallons during peak demand, but the pressure would be really low. A 5 GPM pump can put out 7-8 GPM, so I don't think you need anything more for peak anyway.

    The 15SQ10 won't work any deeper than 400'. The SQ pumps are good but the SQE has the electronic variable speed thing that is not dependable.
     
  8. fitter30

    fitter30 Active Member

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    There are some unknowns how far well head from the house, with wanting pump at 860' and what piping and pump weigh would a bronze or brass pitless connector hold that much weight. Download that grundfos link and it has the pump curves even 5 sq pump is only good for 780'. That why i recommended a local well company.
     
  9. craigpump

    craigpump In the Trades

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    Connecticut
    A Martinson pitless will handle the weight of 1" galvanized with no problem. Given the reliability issues that Grundfos has, it would not be my first choice.
     
  10. VAWellDriller

    VAWellDriller Active Member

    Joined:
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    Mud rotary well driller, pump installer
    Location:
    Richmond, VA
    You had a lot of trouble?
     
  11. valveman

    valveman Cary Austin Staff Member

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    I heard there was some trouble with the 2 wire Grundfos motors. But that is all I have heard of.
     
  12. HardDrinkin'Lincoln

    HardDrinkin'Lincoln New Member

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    Location:
    Central Wahington
    If it were me, I'd leave the pump at 860' and go with a Goulds 5GS15. Looking at the pump curve it will deliver water from 200' to 800' with the volume dropping of as the level approaches 800' to around 1 gal. per minute. If your estimate of well capacity is close then the level and pump volume should reach equilibrium around 800' and the well shouldn't run dry.
    upload_2020-6-21_16-46-0.png
     
  13. craigpump

    craigpump In the Trades

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    Garbage. I've seen too many Grundfos fractional hp 2 wire motors pulling 40 amps on start. Most of the time they came back out and were returned and replaced with something else. You'd think Grundfos would notice the drop off in 2 wire motor sales, but I guess they're busy doing something else.
     
  14. valveman

    valveman Cary Austin Staff Member

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    Pump Controls Technician
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    Are they having any problems with the three wire motors? And what motor are you using for two wire?
     
  15. craigpump

    craigpump In the Trades

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    Self employed water system tech
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    Pentair with no issues so far.
     
  16. ballvalve

    ballvalve General Engineering Contractor

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    "retired" and still building and troubleshooting
    Location:
    northfork, california
    I have 2 rentals on a 1/2 hp pump in a deep well - 9 humans using it and a 60 gallon diaphragm tank, never lost water or pressure. Amazes me too.
     
  17. ballvalve

    ballvalve General Engineering Contractor

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    "retired" and still building and troubleshooting
    Location:
    northfork, california
    Here is a all stainless Myers good to 860' at 1.5 hphttps://www.pumpproducts.com/myers-...est-efficiency-flow-stainless-steel-body.html
     
  18. valveman

    valveman Cary Austin Staff Member

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    Pump Controls Technician
    Location:
    Lubbock, Texas
    I know Pentair was having problems with the capacitors in the 2 wire motors. They tried to blame the problem on Cycle Stop Valves until they figured out their capacitors where not meant for continuous duty. Debra Getz from Pentair was very rude to me and never offered an apology after they figured out they had bad capacitors. Thank goodness the customer had this house and 2 other houses using Cycle Stop Valves for more than 10 years, so he knew the CSV wasn't the problem. All 3 of his houses had heat pumps and he knew the CSV had made all the well pumps last many times longer than they had in the past. I guess they finally got the right capacitors because I haven't heard from him now in over a year.

    Another installer told me he is having problems with the top bearings going out in the Goulds Centripro motors. Didn't seem to matter if it was 2 or 3 wire. Since Pentair and Goulds are made at the same factory, I assumed Pentair was also having this problem.

    I also hear the 2 wire Grundfos motors are failing. But everyone seems to be having good luck with the 3 wire version.
     
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Pumps and Tanks Well Forum & Blog. Water is life. Adding 900ft Supply Line to House.... Jan 30, 2014

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