Deepening well to install geothermal system

Discussion in 'Solar and Geothermal Water Heating Forum' started by Twotone, Sep 7, 2018.

  1. Reach4

    Reach4 Well-Known Member

    Joined:
    Sep 25, 2013
    Location:
    IL
  2. Twotone

    Twotone New Member

    Joined:
    Sep 6, 2018
    Location:
    East Central Ohio
    Thanks for the education. I had planned to limit the flow through the heat pump to 6-8 gpm with a Dole valve. Minimum flow through the heat pump is 1.5 gpm/ton. A 4 ton unit would require a minimum of 6 gpm. Recommended range is 6 to 8 gpm. Depending on what the deepened well tests out at, should I limit the flow to the minimum to save pump energy?

    The driller is telling me he is required to case the deepened well top to bottom. I am assuming this means (need to find out) the 110' in the old casing would be blocked. The water quality at 110' is 18 grains hardness. 2.5 Iron. Not the best for geothermal equipment. Water quality at 460' near me is 3-4 grains and 0.5 to 1.0 iron. Thanks again for the education.
     
  3. Twotone

    Twotone New Member

    Joined:
    Sep 6, 2018
    Location:
    East Central Ohio
    Valveman,
    How would I determine the minimum pressure required or recommended for a geothermal heat pump.
    The online installation manuals do not cover this.
    They do cover the pressure drop. Ground water temperature is ~55F.
    upload_2018-12-1_0-12-12.png
    I'm asking in reference to sizing the sub pump. Would I size it for 20 psi or would 15 psi work for this model?
    Is there a pump model that would produce 15 psi set at 470 ft?
     
  4. valveman

    valveman Cary Austin Staff Member

    Joined:
    Mar 15, 2006
    Occupation:
    Pump Controls Technician
    Location:
    Lubbock, Texas
    Sorry I missed this. I normally use 20 PSI to make up for any losses in the heat pump. And yes you can size a pump to fit.
     
  5. Twotone

    Twotone New Member

    Joined:
    Sep 6, 2018
    Location:
    East Central Ohio
    Thanks, I put the project on hold over the winter. I'm on old Coal reclaim land and the drilling rig would rut and sink in the yard during the wet months in Ohio. The bottom of my hill side is still oozing/flowing water. The plan is to start the well deepening in late April. I did upsize the wiring over the winter from the breaker box to the local disconnect in the garage. I installed the cycle sensor. I just hand dug up around the well along the buried 12/2 with ground. It was buried shallow at first and then deep. Part of the shallow was in left over 1" black water hose. Eventually it got deep enough to be alongside the 1' black water hose supplying the water from the pitless adapter to the hold tank in garage. About 15 foot from the well head both went into a 4" heavy wall white pvc pipe. After digging out the wet clay around the end of the pipe and chipping out 6" inches of hydraulic cement, removing a wad of crumpled visqueen and a water bottle, rocks and other debis I was able to get a fish tape through from the basement garage wall to the end of the pipe. I put 1" grey pvc conduit from the 4" pvc to the well head. I need to reseal (old seal was starting to seep into the basement during heavy rains) where the 1" water hose pipe and the 1" conduit go into the 4" pipe.

    My thoughts are to clean the conduit and hose pipe and end of the 4" with pvc cleaner and seal with good stuff spray foam. Then put a 40# bag of sodium bentonite clay (kitty litter) around the end of the 4" pipe then cover.
     
  6. Twotone

    Twotone New Member

    Joined:
    Sep 6, 2018
    Location:
    East Central Ohio
    Cleaned the conduit, hose pipe and end of the 4" with PVC cleaner and sealed with spray foam. Added a 40# bag of sodium bentonite clay around the end of the 4" pipe and covered. No leaks into the basement after 2 rains. I'll monitor after heavy spring rains.
     
    valveman likes this.
  7. Twotone

    Twotone New Member

    Joined:
    Sep 6, 2018
    Location:
    East Central Ohio
    Driller came out for site survey and go over estimate yesterday. Estimate included a Goulds 7G10422 pump. Pump will be pumping 6 GPM through a Dole valve through the heat pump into hold tank or to tile field. Otherwise it will be off. Is there a more efficient pump brand at this flow?
     
  8. Reach4

    Reach4 Well-Known Member

    Joined:
    Sep 25, 2013
    Location:
    IL
    If you think the pump may sometimes draw down to near 470 ft, that seems like a good choice.

    If your geothermal system puts the used water back into the well, the pump would not draw down much, and you could reconsider different pump.
     
  9. Twotone

    Twotone New Member

    Joined:
    Sep 6, 2018
    Location:
    East Central Ohio
    Thanks for the input. Ohio does not allow you to put used water back into the well.
     
Similar Threads: Deepening install
Forum Title Date
Solar and Geothermal Water Heating Forum Any one installing these? Feb 17, 2012
Solar and Geothermal Water Heating Forum Is a heat pump neccessary for closed loop geothermal installation? Oct 23, 2011

Share This Page