Advice on Old Well

Discussion in 'Pumps and Tanks Well Forum & Blog' started by jfrank11, Jul 10, 2011.

  1. jfrank11

    jfrank11 New Member

    Messages:
    3
    Location:
    Decatur, AL
    I am constructing a new home on an 11 acre remote county site and my intent is to try to utilize an existing well for a geothermal Heating/Cooling system. The well used to service two or three house trailers that were on the site, but the pump/tank was removed and the pump house is in disrepair. It hasn't been used in about 10 years. My wife had a pro come look at it, but he did not want to mess with it, because it was not capped. Said there would be debris in it that would tear up his pump. It is a 6" PVC casing and is 55' deep with 18' of water (37' down to water). Should I purchase a pump and see how much it will pump? I would need about 4.5 to 6 GPM for the A/C system, while running. If so, what style, jet or submersible? I do not intend to use the well for potable water, as we now have a public water line close by. Is there any chance of this well producing enough water?

    Thanks.
  2. LLigetfa

    LLigetfa DIYer, not in the trades

    Messages:
    4,003
    Location:
    NW Ontario, Canada
    Drill a new well for a two well system and use the old well for the return.
  3. jfrank11

    jfrank11 New Member

    Messages:
    3
    Location:
    Decatur, AL
    I have pond nearby I was going to put the water to. Are you saying this one won't do it?
  4. LLigetfa

    LLigetfa DIYer, not in the trades

    Messages:
    4,003
    Location:
    NW Ontario, Canada
    If you have a pond nearby, why not use it exclusively as your heat source and put a closed loop in the pond? Closed loop systems don't need to be cleaned like open systems.

    A two well open system works better than a single well open system when water is returned to the same aquifer. Removing large quantities of water from one aquiifer and not returning it could draw down the supply and affect other users of that aquifer. When I put in my well and pumped it constantly for a week to develop the well, my neighbor complained that I affected his well. Since then neighbors on both sides had new deeper wells drilled.
  5. LLigetfa

    LLigetfa DIYer, not in the trades

    Messages:
    4,003
    Location:
    NW Ontario, Canada
  6. jfrank11

    jfrank11 New Member

    Messages:
    3
    Location:
    Decatur, AL
    I have not done detailed heat gain calcs, but rules of thumb would require about 1.5 gpm per ton of a/c. I am most probably talking 3 1/2 tons or about 5.25 gpm. If the unit runs a maximum of 15 minutes per hour it would use 1890 gpd. The pond is unreliable and is presently overgrown with brush. We have long term plans to rejuvenate it, however, I am less than impressed with a ponds geothermal abilities. Well water is much better (colder). In Alabama our real challenge is A/c. My guess is there aren't many neighbors who are using wells, as there is a public water system available.
  7. LLigetfa

    LLigetfa DIYer, not in the trades

    Messages:
    4,003
    Location:
    NW Ontario, Canada
    You could try using a large compressor to flush out the old well, similar to what is done to develop a new well. That should remove any debris that may harm a pump.
    http://www.lifewater.ca/Section_10.htm
  8. Texas Wellman

    Texas Wellman In the Trades

    Messages:
    536
    Location:
    SE Texas-Coastal
    I highly suggest you DO NOT construct a return well. All the return wells for geo I have ever seen eventually were not able to take the water that was being put back in....major headache.

    Couple of things to consider (from someone who once had an open geo like you want): Check your well water to see what kind of hardness it has. Hard water is the arch enemy of a heat exchanger. If the water has tons of rust or other hardness you will have to acid wash/clean your exchanger at least once per year. Also check the pH. If the well has a low pH, I would not even consider using the well for geo.

    If you're really dead-set on going with geothermal I highly suggest you install a truly closed loop system. This way you can control the chemistry of the water, have zero effect on the amount of water in the aquifer, and be freeze protected. The open source will initially be cheaper and more efficient to operate but as the water scales up your lines over time you will lose that advantage.

    Good luck and post up what you find out.
  9. masterpumpman

    masterpumpman New Member

    Messages:
    729
    Location:
    Virginia Beach, VA
    I'd use an air compressor to clean out and test the well for quantity. It's like blowing on a straw in a glass of water, it blowes everything out of the well.
    Supply and return wells for geothermal is old technology. After a few years the return wells plug up. The new technology is closed loops. I suggest that you look it up on the internet. There's a lot of great information on the internet. http://www.gogreendrilling.com/aboutus.html for one.
  10. LLigetfa

    LLigetfa DIYer, not in the trades

    Messages:
    4,003
    Location:
    NW Ontario, Canada
    First off, around here, geo is used mainly to heat, not cool so I need to adjust my thinking. I agree about the closed loop being better but I doubt a 6" PVC cased well 55' deep would provide enough of a closed loop. As mentioned, water quality will be a factor in the maintenance and efficiency of the unit.
  11. valveman

    valveman Moderator Staff Member

    Messages:
    4,472
    Location:
    Lubbock, Texas
    I agree injection wells will plug up. But I know an open loop system works better than a closed loop if the water quality is fair. A standing column well, (injecting back into the same well) works fine because you have a bleed rate. Which means you are not forcing water back through the screen. And dumping water in a lake or elsewhere works good as long as it is not wasting good ground water. Running a little acid through the heat exchanger ever year or so, if needed is not that big a deal. If the water quality is fair and the old well will make 6 GPM, I would go for it.
  12. gritres

    gritres New Member

    Messages:
    56
    Location:
    nw florida
    not sure if anyone else answered, but with water 37 feet down you need a submersible pump. a jet pump will not be efficient at all and if you're going geo you care about efficiency.
    if you don't want to dig a return well then dig a hole, make your own lake and call it waterfront property :)
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