Drive point well question

Discussion in 'Pumps and Tanks Well Forum & Blog' started by sucker dave, Nov 27, 2006.

  1. sucker dave

    sucker dave New Member

    Messages:
    35
    I’m having a problem with my deep well jet pump on a driven 2†well.
    My setup.
    Well depth 31’
    Driven point gauze size 80
    Pump: Goulds j+7. ¾ hp deep well jet with 2†packer.
    20 gallon holding tank

    Here’s my problem. When I first installed the pump on my system, I had great water pressure. After a couple of weeks I noticed that while pumping, the water would start and stop flowing. Almost as if I was running out of water. I have a second driven well close by allowing me to check the water level. The level appears ok. Is it possible that I’m over driving my drive point? Pumping water faster that It’s returning to the stand pipe?

    Thanks!
  2. speedbump

    speedbump Previous member

    Messages:
    4,540
    Location:
    Riverview, Fl.
    You can't pull the water from the well any faster than the screen will let it in. It's all under a vacuum. So if it's surging like that, I would guess the well is barely making water at all.

    You could have driven the screen too far. How do you test for water as you are driving the well? You should be checking it every 5 feet with a pitcher pump if the water level is less than 25 feet which I would think it is with a 31' deep well.

    What made you go with a deep well jet pump and ejector anyway?

    bob...
  3. sucker dave

    sucker dave New Member

    Messages:
    35
    Yea, I did check it as I drove it down. ( however It was my first time doing it)

    The reason I went with a deep well pump is, I have a 1.5 dia well about 3 feet away that with a 1/2 hp pump only produces around 2-3 gallons/min. ( although I never ran short of water or had any surging problems). In researching wells, I found that 25' is the max recommended depth for a shallow well pump. Anything deeper requires a packer and a jet pump to get any amount of gpm.

    Is there a better way for me to go?

    Can you relate the Gauze size to GPM for me? I thought I read somewhere that an 80 gauze equated to around 15 GPM. In which case my ¾ hp pump would be pretty much maxing out the screen.

    Because of my other pump not having any surging issues, do you think a smaller pump would work better? Something pulling around 9-10 gpm?

    Sorry for all the questions, I really do appreciate any help I can get!
  4. speedbump

    speedbump Previous member

    Messages:
    4,540
    Location:
    Riverview, Fl.
    Replies are in Red!

    Yea, I did check it as I drove it down. ( however It was my first time doing it) Ok, if you checked it, you must have used a Pitcher Pump. If so, the water level had to be less than 25 feet. A shallow well jet pump would have worked much better than a packer jet.

    The reason I went with a deep well pump is, I have a 1.5 dia well about 3 feet away that with a 1/2 hp pump only produces around 2-3 gallons/min. ( although I never ran short of water or had any surging problems). In researching wells, I found that 25' is the max recommended depth for a shallow well pump. Anything deeper requires a packer and a jet pump to get any amount of gpm. The 25 feet is the depth to water. The depth of the well has nothing whatsoever to do with deep or shallow well pumps.

    Is there a better way for me to go? Yes, put a shallow well ejector on that pump and see what it will do. If you have another well close by, the water level in it will be the same as the other well.

    Can you relate the Gauze size to GPM for me? I thought I read somewhere that an 80 gauze equated to around 15 GPM. In which case my ¾ hp pump would be pretty much maxing out the screen. An 80 gauze screen is a very fine mesh. It is used to stop sand a little larger in size than powder. The flow through it and the surrounding sand is quiet slow. I would be surprised if you were to get 5 gpm through it. Since you drove this well, you will never be able to see what the water bearing formation is like or it's size. The screen could be in Pea Gravel which could use a 25 slot screen which would yield a lot of water compared to the 80 gauze in fine sand.

    Because of my other pump not having any surging issues, do you think a smaller pump would work better? Something pulling around 9-10 gpm? The pump size has nothing to do with the flow. A 1/2hp pump can produce aroung 10 gpm. So your reduced flow is on account of the well and screen not the pump.

    Sorry for all the questions, I really do appreciate any help I can get!
    I'm sorry for the bad news, but I think you need to go back to the drawing board. The way to drill a two inch well; is to first knock the casing in the ground (no screen) then drill it out using a 1" pipe with a chisel shaped bit that water can be forced through with a good sized centrifugal pump. Once you go out the end of the pipe, you will get samples of the formation flowing up the 2" pipe. When you get into clean sand/gravel, that is where the water will come from. Not clay, or dirt. The well will also start drinking the circulated water you are drilling with, this is a good indication the formation will make water. Once you get there, you can drive an 1-1/4" screen through the end of the pipe that is consistant with the formations size, with a K-Packer on the end or with the use of a Bremer Check and the well is done.

    bob...
  5. Rancher

    Rancher Guest

    Bob, do you need lessons on how to quote also? I do like your color change.:)
  6. speedbump

    speedbump Previous member

    Messages:
    4,540
    Location:
    Riverview, Fl.
    I have to do that Rancher so I won't forget the questions. With my old brain failing like it is, I have to take every advantage.

    bob...
  7. sucker dave

    sucker dave New Member

    Messages:
    35
    If I switch to a shallow jet pump, do I need to run a 1.25 dia pipe with a foot valve down my 2" well so I don't have to draw the water all the way up each time?

    Outstanding information. thanks!!!
  8. speedbump

    speedbump Previous member

    Messages:
    4,540
    Location:
    Riverview, Fl.
    It makes for a much better installation. No loss of prime and you don't have to worry about air leaks in the casing.
  9. sucker dave

    sucker dave New Member

    Messages:
    35
    would you go with PVC or steel?
  10. speedbump

    speedbump Previous member

    Messages:
    4,540
    Location:
    Riverview, Fl.
    If it were a submersible I might be leaning toward the galvanized. It all dependant on the water quality.

    In a shallow well install, with you only needing 30 feet and a footvalve, go with the PVC. In fact we use 160 psi. PVC all the time for that and have 0 problems.

    A lot of people recommend SCH 40 PVC. We don't use it at all. Just the thinwall. It bends instead of breaking, has a larger inside diameter to carry more water (less friction loss) and can be bent into a U and inserted into the bed of a pickup. Don't try that with SCH 40.

    bob...
  11. sucker dave

    sucker dave New Member

    Messages:
    35
    thanks!!! I appreciate the help. I'm going to try the shallow well jet. I'll let you know what happens.
  12. sucker dave

    sucker dave New Member

    Messages:
    35
    I've now installed the shallow well jet pump.

    Because of the low level of water in the well, I hammerd down another 5' section of pipe. I'm now down 33' to the well point and have 5' of standing water in the bottom of my well. I wasn't able to use a picture pump to pump out the dirty water so I dropped a hose down to the bottom of the well and flushed out the silty water.

    I have 32' of 1 1/4" galvanized pipe with a foot valve at the end.
    With a 3/4 hp convertable jet pump, I'm only getting 2 gallons a min with no pressure out of the well now.Far from what I'd like have.

    Am I just too deep for the pump?

    Any suggestions???

    Thanks and Merry christmas!
  13. Rancher

    Rancher Guest

    I you're trying to suck water out of a well where the water level is 28" below the pump, yes you're too deep for a shallow well jet pump.

    Rancher
  14. sammyhydro11

    sammyhydro11 Previous member

    Messages:
    709
    Location:
    Massachusetts
    Dave,
    what happened with that other well? How deep is it in relation to your newly driven 2" well and what is the static water level in it? How long is your well screen and at what depth did you install that jet assembly? You have to keep that jet assembly out of the screen or the packers wont seal.

    Whenever someone drives a screen into unknown material,its a safe bet to go with a 10 slot(10 thousands of an inch) screen and try to get a good 5 to 10' past the water table. sometimes these wells need to be developed depnding on the size material you drove the screen into. I advise you to use sch40 pvc w/thin wall steel or brass couplings on your dop pipe. this will make it much easier to remove the jet assembly and will keep corrosion down.

    i would get some more info on that other well. if at one point it was producing a good amount of water,try to duplicate it the best you can.

    OR GET AN AUGER RIG IN THERE, HAVE SOMEONE PUT IN A 4" WELL,AND FORGET ABOUT It.

    SAM
  15. sammyhydro11

    sammyhydro11 Previous member

    Messages:
    709
    Location:
    Massachusetts
    Dave,
    a little typo on my part. Make suer you have a minumum of 5' of water above that screen.

    SAM
  16. sucker dave

    sucker dave New Member

    Messages:
    35
    Sam,
    I'm using a gause 80 well point which is 3' long. my static water level is 5' .My packer was at down 29' with a 3' drop. I have 6 sections of 5' pipe plus the well screen for a total depth of 33 feet.

    My earlier setup was down 25' + the well point. my packer was down 25 feet with a 2' stand pipe. I was using thin walled couplings. My water volume started falling off.We had a dry summmer and fall and I feared my water table had dropped so I went down another 5'.

    In this setup I was able to get a actual measurement to the last caseing union of 25' 4". My packer assembly is around 8" long. I thought I had the packer in the well screeen, however I always had a good seal. Probably because i was above the screen and the smooth stainless steel vs the rough galvanized pipe.

    I may try dropping my packer now to 30' to duplicate my previous setup.

    Can you tell me more on "developing the well"?

    And yes I'm about ready to have a well drilled for me. I guess you could say I'm stubborn.

    Dave
  17. sammyhydro11

    sammyhydro11 Previous member

    Messages:
    709
    Location:
    Massachusetts
    Dave,
    you should have stopped at 25' and pumped that well. Like speedbump said you could have driven that screen too far and into some impermeable material
    If your static water level is at 5' and you have to use a jet assembly to get that water out of the ground,you have to be getting alot of drawdown. That would tell me that either you are in a poor water bearing zone or your mesh size or gauze size is too fine. I would either bump that well back to 25' or try to develop what you have. There are two ways that you can develop that well without the use of a drill rig.
    1) get a handpump,install pvc pipe open end w/no foot valve.tighten up the well head to the casing. Plug the holes in your well head and install the hand pump so its sitting on top verticaly inline with the drop pipe. Start pumping that well. At first you should be getting some pretty dirty water,hopefuly w/alot of fines. Once the water clears up remove one of the plugs on the well head to drop the prime. By dropping the prime that whole colum of water will drop down the well and send water in the reverse direction of the well screen. That action will break up any bridging that you created and will allow more fines back through the screen. W/ the foot valve in place you will not be able to do that. So repeat the process and if all goes well you should be able to make a well. This is the cheapest route.

    2) go to your local rental spot and rent a mud sucker. get some fittings to hook it up and let it go. These pumps are awesome at developing wells. It will consistantly surge the well screen,breaking up the bridging around the screen.

    Remember: "THE HIGHER THE POROSITY THE HIGHER THE VELOCITY" the more fines you pull out of that zone, and the faster the water comes through,the more water it will produce

    There are alot of other ways to develop wells but these are the 2 that i advise for your application and limitations.

    SAM
  18. sucker dave

    sucker dave New Member

    Messages:
    35
    SAM,
    Thanks! I'll try the mud sucker route. will i need a drop pipe, or do I connect it right to the well casing?
  19. sammyhydro11

    sammyhydro11 Previous member

    Messages:
    709
    Location:
    Massachusetts
    Dave,
    go without the tube so you hit that screen hard. I just hope you don't have any vacume leaks in those couplings. You can try spinning that casing with a pipe wrench too. But i warn you,go easy when doing this,you could break a coupling at the same time. If you start spinning the casing and you feel it tighten up,snug it up a tad and stop. Next time you drive a well point you should tighten up that casing every 10 feet. The couplings do loosen up as you drive the well.

    Good Luck!!

    SAM
  20. sucker dave

    sucker dave New Member

    Messages:
    35
    The casing should be tight. I checked it quite often.

    Could I use compressed air to blow out the fines? I mean hook up a compressor fitting and pump in air?
    Last edited: Dec 26, 2006
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