Lowering 3/4 hp submersible pump down 100ft

Discussion in 'Pumps and Tanks Well Forum & Blog' started by nc73, Sep 22, 2013.

  1. nc73

    nc73 New Member

    Messages:
    12
    Location:
    Aylett, Va
    I have a 371ft deep well. Pump is at 187ft. I'd like to move it down 100ft more to 287ft. I have no idea what the specs is on the pump except that it's 230v and 3/4 hp. I'm getting 6.5 gpm measuring with a garden hose. If I move it down that far would I need to upgrade the pump to a 1hp? It's not VFD btw. 2 wire. I'm doing this in order to install a geothermal closed loop. I can't fit the pipe down as-is.
  2. craigpump

    craigpump Active Member

    Messages:
    1,034
    Location:
    ct
    You're planning to put the loop into the well along with the pump?
  3. LLigetfa

    LLigetfa DIYer, not in the trades

    Messages:
    4,141
    Location:
    NW Ontario, Canada
    The pump only sees the depth to the top of the water. It won't know it is set deeper unless you draw the well down further.
  4. nc73

    nc73 New Member

    Messages:
    12
    Location:
    Aylett, Va
    yes. It'll be a tight fit for sure.
  5. nc73

    nc73 New Member

    Messages:
    12
    Location:
    Aylett, Va
    If the pump is set deeper to make room for the geo loop, it will be further from the top of the water. Water is currently at 46ft.
  6. LLigetfa

    LLigetfa DIYer, not in the trades

    Messages:
    4,141
    Location:
    NW Ontario, Canada
    What's your point? It will still only lift 46 feet.
  7. nc73

    nc73 New Member

    Messages:
    12
    Location:
    Aylett, Va
    So you're saying even though the pump is deeper, the pumping energy required will still be the same therefore I don't have to upgrade the pump? I didn't know it only had to lift the water 46ft. i feel stupid.
  8. craigpump

    craigpump Active Member

    Messages:
    1,034
    Location:
    ct
    There was a guy here in Ct back in the 80's who tried to do geothermal the way your proposing to do yours, the results were less than satisfactory.

    1 there really isn't enough room in a six inch well for the loops, the drop pipe, pump and the 3 pitless adapters
    2 when the pump had to be serviced, the loops had to be pulled up out of the pitless to get the pump out, which meant the geo system had to be serviced to get the air out of the system
    3 closed loop geo systems lose their efficiency when they are not completely submerged in water or grouted in. In your case you have at least 46 of loop to air contact.

    I am NOT a geo expert by any means, just reporting what my personal experience is.
    Last edited: Sep 23, 2013
  9. nc73

    nc73 New Member

    Messages:
    12
    Location:
    Aylett, Va
    I agree with 1&2, even worse the well is 4.5". I'm not expecting it to handle 3 ton, the most will be 1 ton, the other two I will makeup with other methods. It'll save me time and money if I don't have to dig another well. It may end up being a hybrid, with horizontal and vertical loops.

  10. LLigetfa

    LLigetfa DIYer, not in the trades

    Messages:
    4,141
    Location:
    NW Ontario, Canada
    I'm not very well versed on geo, but what is your water quality like? Would an open loop, returning the water to the well be an option?
  11. valveman

    valveman Moderator Staff Member

    Messages:
    4,549
    Location:
    Lubbock, Texas
    You could use a heat exchanger at the bottom of the Geo loop. It would transfer heat much better than a plastic pipe loop. You could make one out of copper pipe easy enough. Either way, with the heat exchanger or an open loop setup, you will need to bleed enough water from the well to make it work. When you are using water from the well, it is bleeding plenty to transfer the heat/cool. When not using water you could hook up a bleed valve controlled by temperature coming from the loop pipe.
  12. DonL

    DonL Jack of all trades Master of one

    Messages:
    4,441
    Location:
    Houston, TX

    Do not feel bad, 1 atmosphere is on your side.
  13. VAWellDriller

    VAWellDriller Member

    Messages:
    171
    Location:
    Richmond, VA
    I'm local to you and know the area.....if your well driller did his job remotely right, there should be almost no draw down in your well when pumping, so if that's the case, most of the loop will be in a stagnant section of water and you'll have terrible heat transfer...not to mention the problems with the pitless adapter connection and pump in your 4.5" well. You should confirm that he did a good job and put in a larger pump and run an open loop system. Water quality is good and open loop is more efficient anyway.
  14. craigpump

    craigpump Active Member

    Messages:
    1,034
    Location:
    ct
    VAWelldriller

    Everyone I know up here installs a Porter Shroud when they do an open loop so that the water has time to exchange heat for cold and vise versa.

    How would you do that in a 4.5" well?

    I think the best option is to drill a well dedicated for geo.
  15. VAWellDriller

    VAWellDriller Member

    Messages:
    171
    Location:
    Richmond, VA
    I'm not familiar with a "Porter Shroud". but I get the idea....he's in an area with a screened mud rotary well, so screen is at bottom, and like I said earlier, if it's properly done, there will be probably less that a 1ft of drawdown per gpm pumped....(specific capacity of >1). That being said, any water above the pump, usually just sits there and never moves... It's not really an issue, since there just isn't room for any type of shroud or even the loop for that matter with his installed pump.

    Most geo around here is done with closed vertical loops....I'm a big fan of open loop, since we have good water and lots of it. If you don't want to waster the water, drill a return well...it will still pay in the long run. You save on the geo system without having the manifold work and circulator pump to buy, and it's more efficient.
  16. craigpump

    craigpump Active Member

    Messages:
    1,034
    Location:
    ct
    VA,

    Ok, I know that as a pump n dump system where you're not returning any water back to the source.
  17. LLigetfa

    LLigetfa DIYer, not in the trades

    Messages:
    4,141
    Location:
    NW Ontario, Canada
    A two well, open loop returns the water to the same aquifer from where it came.
  18. Texas Wellman

    Texas Wellman In the Trades

    Messages:
    550
    Location:
    SE Texas-Coastal
    FWIW the return wells always seem prone to plugging. The hardness in the water will drop out in low pressure situations (like after a CSV), eventually causing the return well to lose acceptance rates and generally making a mess in the yard.
  19. LLigetfa

    LLigetfa DIYer, not in the trades

    Messages:
    4,141
    Location:
    NW Ontario, Canada
    That was why I asked about water quality.
  20. nc73

    nc73 New Member

    Messages:
    12
    Location:
    Aylett, Va
    You know it was dug in 91, and there is no cap or pitless adapter, piping is from the top directly down, sealed with spray foam and some insulation! Oh man it looked like a diy affair but oh well it works. I do agree with open loop. What's the going rate to dig a reinjection to the same aquifier? If cost is up there I'd like to go with just a dry well enough to dump into if I'm going to do an open loop. I have another dug well but its only 40ft and not taking any water. All else fails I'd do a horizontal trench.
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