Low pressure/low flow deep-well jet pump

Discussion in 'Pumps and Tanks Well Forum & Blog' started by Bill Webb, Jun 1, 2013.

  1. Bill Webb

    Bill Webb New Member

    Jun 1, 2013
    I am having trouble diagnosing a water well problem and would appreciate any help.

    This well originally supplied water to the house, but I now use it only for drip irrigation. The pump is a deep well jet pump (1/2 horsepower), and the well is a packer well (2 inch casing with a 1 inch central pipe), probably between 40 and 80 feet deep in sand, installed in the 1970's. A local well service company told me that it probably has a casing screen and a Bremer check valve at the bottom of the casing, and that the screen is probably clogged. This company can't get their well service truck to the well head, so they can't help me. They did not have the information of this post when they gave their advise.

    I inspected the pump impeller (the pump was new 5 years ago) - the impeller is plastic but looks OK. I pulled the 1 inch pipe up about 8 feet - the Baker pitless adapter looks OK, and there is standing water in both the 1 inch central pipe and the casing, so the check valves or leathers seem to be sealing. There is iron in the water and a lot of rust deposits on the central pipe and adapter.

    The well produced 4 gpm last year, and the pump cycled normally between 20 and 40 psi. This year, with no changes to the pump or the well or the pressure tank, the pump only will generate 15 psi at any output flow rate between 0 and about 1/2 gpm. Since the well is able to produce 1/2 gpm for hours without ever exceeding 15 psi, it seems to me that the low pressure, even at 0 flow, means that there is a problem with the pump or the ejector (venturi). The pump is primed, and it is turning normally. I have adjusted the flow-diverter valve over its full range of adjustment, but the pressure is always about 15 psi, as long as the flow is no more than 1/2 gpm. At higher flow rates, the pressure falls to 0 after the pressure tank empties.

    I'm thinking that the problem might be either a partially clogged ejector at the bottom of the 1 inch central pipe or a pump that does not supply enough water pressure and flow to raise water at better than 1/2 gpm or pressure better than 15 psi. Any suggestions as to what problems could cause these symptoms and what to check first will be appreciated. Thanks for any help.

    Bill Webb
  2. valveman

    valveman Moderator Staff Member

    Mar 15, 2006
    Pump Controls Technician
    Lubbock, Texas
    15 PSI on start up probalby means the jet nozzle is clogged.
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  4. Bill Webb

    Bill Webb New Member

    Jun 1, 2013
    Thanks, Valveman. I plan on pulling the well pipe, cleaning the jet nozzle, and replacing at least the leathers.
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