Dump Well Not Accepting Water

Discussion in 'Maintenance and Troubleshooting' started by bdfmddmd, Sep 3, 2014.

  1. bdfmddmd

    bdfmddmd New Member

    I have recently had about 1/3rd of my geothermal open loop system installed(we have two units, only one of which, a two ton unit, has been installed) and the dump well sprays water out of the well head whenever the unit is turned on. I have spoken with the well driller and he has seen issues with this rarely in his past experience. I am concerned because if the dump well can't handle the return flow from the 2 ton unit, it will never work to hook up the remaining 5 ton unit as well.
    I am open to suggestions as to how to overcome this problem.
    It seems to me that it is a pressure issue with putting water back in to the aquifer.
    Currently, the water is put back into the well at the top of the well(3 - 4 feet underground).
    I am wondering if it would solve the problem to introduce the water into the well at a much lower point, even all the way at the bottom of the well if necessary. I am thinking that this would possibly introduce concerns with back pressure, but it seems that it would overcome the issue of water spraying from the well head.
    It seems that others must have had a similar issue and I would like to know how they solved the problem.
     
  2. urthbuoy

    urthbuoy Well-Known Member Industry Professional Forum Leader

    This is hard to fix after the fact.

    Injection wells, by their design, typically have twice or more the screen than supply wells.

    But yes, you would want to inject below the water table to limit fouling. Your injection well may also need to be developed if silt or such has filled in the porosity of the materials.

    It does sound like the installation was a bit of guesswork or trying to make use of existing resources.
     
  3. waterpirate

    waterpirate Well-Known Member Industry Professional Forum Leader

    Lithology of the aquifer and experiance of your well driller are key here. Technique varies wildly based on location. If your driller is attentive to your needs and willing to back his work. His solution may be the most direct and useable.
    Eric
     
  4. Calladrilling

    Calladrilling Member Industry Professional Forum Leader

    I agree with both above responses.
    Generally we install double screen on our return wells we install.
    Not knowing anymore info is hard to suggest a repair though.
    Is this a cased well?
    Does it even have a screen?
    How deep is the well?
    What's the static water level?
    How many GPM is it required to handle? ETC....
     
  5. bdfmddmd

    bdfmddmd New Member

    Thanks for the input.
    The well driller has offered this as a solution.
    He wants to cement a cap to the top of the well head stating that this will stop the leaking(agreed). My response to him was, what happens to the system from the pressure that will obviously now be in the system instead of leaking from the cap on my injection well. He said that it may "trip" the system and then it simply would not work.
    He has also mentioned the possibility of a second injection well, but seems reluctant to put this in.
    I don't understand the reluctance. I have invested about $20,000 for this system and to put in a second injection well for about $2,000 seems like a reasonable plan to me...

    Both wells are just over 110 feet deep.
    It is a cased well, I think.
    Not sure of static water level, but I live about 1 mile from the ocean and have an abundance of wetlands within 1/4 mile of my home. So, I'm guessing static water level is pretty high. I think elevation of my home is about 14 feet above sea level, but we do have a basement that has never gotten water in it.

    Currently putting about 4 gal per minute through system. It will have to handle about 14 gal per minute.

    Thanks for the input, looking forward to additional info.
     
  6. geoxne

    geoxne Active Member Forum Leader

    Pressure building in discharge well will stop HP flow dead in the worst case. Best case may work if supply pressure is turned up high enough to overcome but at great running cost and subject to fluctuations due to changing water table. Do not cap. You will be trying to lift the whole water table around you with your supply pump (a waste of time and money). If your local authority allows it, a vented over flow pipe would be a better solution if you can figure a way to keep it from freezing in the winter and clogging at outfall.

    The discharge well should always be the better well as far as capacity. Discharge well should have twice the screen as supply well. Consider installing sediment filter on supply to make sure you are not clogging your discharge well screen.

    My experience has shown that discharge issues like this generally get worse over time. If your well driller can't get better performance with existing well easily, bite the bullet and put in the 2nd discharge well with lots of screen and develop the hell out of it. You may have to nix the second HP based on results or change over to closed loop vertical bores..

    Make sure you are not overflowing supply to heat pump(s). This will help take any unnecessary load off the discharge well. If your EWT is 50f or greater 1.5 gpm per ton is adequate in heating. You can choke down even more in cooling with 50f ground water. Consider installing flow controls (Hays) that supply only what the HP needs based on running mode and stage. Make sure valves are wired to run with compressor run circuit. If they are wired to thermostat calls water will flow forever during HP lockout.

    A geo guy doing open loop work should know all this. I rely on my well driller to let me know what the wells can do before I install equipment. His local experience is the key factor to success.
     
  7. waterpirate

    waterpirate Well-Known Member Industry Professional Forum Leader

    You could not buy better advice than has been offered here.
    Eric
     
  8. geoxne

    geoxne Active Member Forum Leader

    Why I know this - btdt.

    A 13 ton open loop installation in a locale with high water table, 4ft to grade. GC required discharge well head capped below grade because HO didn't want to see sticking out of lawn. I allowed only after GC accepted responsibility with my strong objections. System ran perfect for 9 months until a wet Spring turned the discharge well artesian with static 2ft above grade (confirmed by digging up and adding standpipe to well head). With well head capped (not vented) water flow was zero with pump pressure @ 30 psi (initial optimum setting). We had to bump pressure up to 70 psi just to get one unit flowing enough to over come. System ran fine at normal pressure with extended well standpipe 4ft above grade, vented to atmosphere.

    HO hates the "lawn ornament" we have constructed, but geo runs fine. Maybe this is a viable solution for you if your well has the capacity and the real issue is rising water table.
     
    Last edited: Sep 13, 2014
  9. bdfmddmd

    bdfmddmd New Member

    Thank you for all the info.
    Over the past few days the system has not leaked from the cap, the demand for system use has been very low as the temperature has moderated.

    My preference is to add the second injection well and not have the current well capped.
    I don't think the well driller will be happy with my choice…

    So next set of questions.
    Do I continue to deposit into existing well with "overflow" being directed into new injection well?
    I am thinking of a "T" in the line that runs into the well before it actually goes into the well and then run a second line to the new injection well.
    Thinking that the water will then just flow into whichever well has least resistance. I hate to give up the 2 or 3 or occasionally 4 gpm that the current well is accepting.
    Do I scrap this well all together and just try to put everything in to new injection well?
    Or finally, do I put everything into new injection well first and then send any "overflow" into existing injection well?

    When putting in new second injection well, should it be larger diameter(6 inch instead of 4 inch)?
    I am not sure what a "screen" is?
    Is there any advantage to making the new injection well deeper or a shallower than the 110 foot wells I have now?
    Anything else that I should know about adding this well?

    Should I tell my well driller about this forum, or will it tick him off…?
     
  10. geoxne

    geoxne Active Member Forum Leader

    Please reread my last 2 posts. You or your well guy have to determine whether overflow is a capacity or rising water table issue before you devise a solution.

    A pump down test can determine capacity. Adding a standpipe and observing static and dynamic water levels over time will determine raised water table induced hydraulic pressure issues.
     
    waterpirate likes this.
  11. waterpirate

    waterpirate Well-Known Member Industry Professional Forum Leader

    Prognosis without diagnosis = malpractice

    Any contrived solution that is not founded in diagnosis is a recipe for ongoing issues. Contrary to popular belief, injection wells are NOT " just an additional well ". While geoxne is trying to steer you in the right direction, you are not hearing us.

    Before starting any resolution proccess, you must determine the exact cause why the well you have now is not working. A simple pump test, and or doing a " specific capacity test " on the well is the only good start to diagnosis.

    We frequently return water in the coastal plain where the static water table is at ground level or even artesian in nature with great success. All of this is very location and driller specific. No generalities can or should be applied to your solution.
    Eric
     
  12. geoxne

    geoxne Active Member Forum Leader

    Or, to put it more bluntly-
    OP is headed down the road of turning a $20,000 system that doesn't work into a $24,000 system that doesn't work.
     
    engineer likes this.
  13. engineer

    engineer Well-Known Member Industry Professional Forum Leader

    I will cheerfully defer to the drillers here, but my $0.02 is to take a stab at redeveloping the existing injection well if not already done. Techniques vary wildly, but a quick and dirty shot at it could be to pump heck out of it using a borrowed or rented gas powered pump. With enough flow and light enough fines / silt blocking pores they might be pulled to the surface and pumped clear.

    FWIW - Injection well back pressure rose on one of my projects, and the driller came out and resolved the problem in one quick trip. I tried to meet them onsite, but they ducked me and I was unable to learn what they did...this particular driller isn't real big on returning calls. Bystander descriptions of what occurred are consistent with overpumping the injection well. In fairness, the work was done without additional charge and the system has been fine ever since.

    Static pressure shouldn't matter - delta-P attained by the pump should overcome whatever static exists if the wells are properly developed. if returning to source aquifer static pressures should cancel each other out. Most of our projects involve true artesian wells; the one the failed is in an aquifer normally artesian at the site's elevation save for two nearby paper mills yanking millions of GPD out of the aquifer, depressing water table locally.
     
    Last edited: Sep 14, 2014
  14. bdfmddmd

    bdfmddmd New Member

    I do hear what you are all saying.
    Admittedly, I don't understand it all.
    I'm not an engineer or well driller or hvac installer, just a homeowner with a problem.
    I do GREATLY appreciate all of the information and I will share it with the well driller and even have him read the posts on this site related to this discussion.
    As a layperson, I was just looking at this from a very simple perspective(sometimes simple works). Thanks to everyone here, I do understand the issues a little better and admit that the solutions are beyond my scope of knowledge. I hope that the well driller has a better perspective on all the issues raised here and can come up with a solution.
    I will continue to check the site and any additional information is greatly appreciated.

    I will also continue to post progress.
     
  15. geoxne

    geoxne Active Member Forum Leader

    You shouldn't have to understand it all. A lot of well drillers and geo installers don't understand it all and that brings us to your situation. Where is your geo installer in all this? He should be going to bat for you with the well driller or at least translate the alternatives. Or he shouldn't be doing open loop.
     
  16. bdfmddmd

    bdfmddmd New Member

    So, I called the well driller today and spoke to his office and am awaiting a return call from the well driller himself.
    I expressed that I do not want the well capped as per the discussion above and suggested that they look at the posts on this site and the proposed solutions.
    I think that I am likely looking at a new injection well for two main reasons.
    First, the current well is in the front yard and even though I may not mind if the well head is raised 4,6,8 feet and sticking out of the ground, I think that the homeowners association and neighbors would have an issue. So, the new well could and would go in the back yard where it is seen by no one.
    Second, the current injection well was an old well used strictly for lawn irrigation and I think that the well properties(except depth) were and still are a bit of an unknown. Although, we do know it does not handle 14 gpm of flow into it. So, if I tried to redevelop this well and then still ended up having to raise the well head, I would still have a problem.

    My understanding from everyone is that the best chance for this to work is a new well with a raised well head. It seems that this has been the working solution to similar problems elsewhere. I realize that some diagnostics from the well driller may be able to tell if this will work before the expense of yet another well.
    Or, if the well driller has some reason why a new well with a raised well head won't work, then I will assume that it will never work and am not going to complete the installation of this system, unless I get other ideas from the forum.

    After I speak with the well driller I will post that discussion.
     
  17. geoxne

    geoxne Active Member Forum Leader

    Suggested course for your discussions with well driller, keeping in mind that your high water table leaves you little margin for error.

    1) Well head should be vented to atmosphere. DO NOT CAP. Just like your finger over the end of a straw, a cap will hold a column of water in your well, preventing discharge.

    2) Existing well should be tested for capacity, static and dynamic water levels. Overflowing well head is not always a direct indicator of lack of capacity.

    3) If capacity is the issue, well should be developed to improve and retested to determine new capacity to flow.

    4) If overflow is caused by elevated water table either natural or discharge induced, a temporary stand pipe at well head can determine what levels to design remedy. If a stand pipe is a solution, it does not have to be at the well head. It only has to be piped to the well head. It can even be in your house vented out the roof (like a plumbing waste stack).

    5) A new discharge well could be considered based on results above, If it will allow increased total capacity to cover calculated geo system requirement. It is possible the new well will not perform any better than the existing well. Testing will determine any limitations.

    I wish you good luck, and thanks for keeping us posted.
     
  18. waterpirate

    waterpirate Well-Known Member Industry Professional Forum Leader

    Re using an existing well to be a integral part of a new geo system is a risky way to save money. Also be aware that well solutions and construction varies wildly from location to location. If someone applied the advice above in my local, it would fail. Listen to your local talent. Keep us posted
    Eric
     
  19. Calladrilling

    Calladrilling Member Industry Professional Forum Leader

    Raising a well head in my area would not either.
    Go how did the conversation with your driller go?
     
  20. geoxne

    geoxne Active Member Forum Leader

    I agree you should listen to your local talent over internet advise, If they can offer you a solution better than using more pressure to force the water in the discharge well.

    No one has offered how or why. Until then I stand by my statement. I am always willing to learn and improve.
     

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