Shallow well - temporary loss of prime / pressure - no air in line

Discussion in 'Pumps and Tanks Well Forum & Blog' started by unique, Jul 2, 2011.

  1. unique

    unique New Member

    Messages:
    8
    I am hoping for a little direction from the forum. I have searched high and low while wracking my brain trying to figure out my problem.

    2" shallow well with Gould JS+ pump (http://www.goulds.com/pdf/7297.pdf) and check valve connected to pump just prior to 2" well pipe

    About 3 weeks ago our problem started. No change in plumbing within the house for several years. Problem mostly occurs after several hours of not using water.

    The water pressure functions properly - i.e. there is good pressure until the pump turns on... then the water stops... the pump runs for a few seconds (to as long as 45 seconds)... until you hear the pump "prime" and then water flows again appropriately (no air in line - water just stops and then starts again), the pressure tanks fills to capacity, the pump turns off appropriately... the water empties from the pressure tank, pump kicks on correctly, and fills again. If the water is used frequently during the day, there really isn't much of a problem until the next morning. The issue is most apparent after not using water for a long (several hours) of time.

    A few years ago we had a similar problem, but there was air in the line... I found the hole where the well pipe entered the check valve and fixed the problem.

    Is this a check valve problem, dirt in the pump, or is the pumps dying (i.e. propeller is worn and it takes a little while to create enough vacuum to open the check valve)?

    Any thoughts would be greatly appreciated!

    Carey
  2. LLigetfa

    LLigetfa DIYer, not in the trades

    Messages:
    3,991
    Location:
    NW Ontario, Canada
    If there is a foot valve at the bottom of the well, try taking out the checkvalve at the pump. You should not need two checkvalves. The one at the pump might be sticking shut.

    Also, check the precharge on the bladder tank. If cut too fine (too much air) or watterlogged and there is no reserve left at the kick-in pressure, the pressure will drop to zero when the pump comes on. A jet pump uses pressure to make more and relies on a bit of reserve from the tank.

    It could also be the pressure switch has crudded up under the diaphragm.
  3. unique

    unique New Member

    Messages:
    8
    I am assuming there is not a foot valve... however, one never knows!

    Just checked the pressures... the pump shuts off at 58 psi and kicks on at 32psi. The first time I tested (after not using the water for a while) caused the pump to kick on at 32 - at which point the pressure dropped to ~10. The pump ran for about 30 seconds until I could hear water flowing into the pump, then the pressure jumped to about 40 and subsequently filed the pressure tank until it cut off at 58psi. We then ran the water until the pump kicked on again at 32psi. This time the pressure did not fall less than 30 and the pressure tank filled and cut off again at 58psi.

    If you think it is a diaphragm issue, am I able to take the pump apart and clean it or does the diaphragm need to be replaced?

    Thanks for your thoughts.
  4. DonL

    DonL Jack of all trades Master of one

    Messages:
    4,167
    Location:
    Houston, TX
    I do believe the the diaphragm issue referred to the pressure switch not the pump itself.

    If it is not the pressure switch problem then, it sounds like you have a suction leak, or the check valve is not keeping the suction line full of water.

    The pressure switch difference should be 20PSI if it has not been readjusted. Check the line that connects it.


    Good Luck on your project.


    DonL
  5. masterpumpman

    masterpumpman New Member

    Messages:
    729
    Location:
    Virginia Beach, VA
    There's a suction leak somewhere! While the pump is at rest for long periods the air in the suction line settles to the highest point. In your case it's the pump. When the pump comes on after being off for some time, it immediately loses prime for a time. After a time it will usually reprime itself and work OK until it's off for extended periods again.
  6. unique

    unique New Member

    Messages:
    8
    Thanks for they replies! I'm out of my ball game here, so your help is appreciated. I'm hoping to figure this out on my own...

    If I have a suction leak somewhere, wouldn't this cause cavitation? I had this problem a few years ago and fixed it after finding the leak. However, this time, there is no air in the line... the water simply stops when the pump turns on and then starts again when I hear water "moving through" the pumping.

    Is it possible that the impeller is worn and the pump needs to run for a while to create enough vacuum to open the check valve? ... thus I'm not getting air in the line? Or... that the check valve is having issues where it is causing excessive vacuum to open the valve?


    Thanks again!
  7. DonL

    DonL Jack of all trades Master of one

    Messages:
    4,167
    Location:
    Houston, TX
    Chances of it being the impeller is slim.

    If you think that it is a pump problem then you might want to remove the Nozzle clean out plug and run a wire thru it to make sure the jet is clean.

    I would not think that it is the impeller.


    DonL


    P.S. A very small suction leak would not necessarily cause pump cavitation.
    Last edited: Jul 2, 2011
  8. unique

    unique New Member

    Messages:
    8
    Thanks to all who responded.

    Today I worked on my well pump and solved the problem. I replaced everything between the pump and the shallow well pipe. It appears to me that the check valve between the pump and well pipe was getting "stuck" - as in it would have taken "excessive" vacuum to open the valve.... seems as though the valve was "catching" on the sides of the check valve on the outflow side of the valve. The check valve I replaced it with did not have valve "guides"... so I'm hoping this will solve the problem!

    If there was a leak somewhere... I fixed that too! :)

    I cleaned the nozzle as Don suggested also.

    Thanks again for the help!

    Carey
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