Pump not keeping up

Discussion in 'Pumps and Tanks Well Forum & Blog' started by willobegolfer, Aug 31, 2008.

  1. willobegolfer

    willobegolfer New Member

    Messages:
    4
    Hi. I'm new to the forum but I'm in need of some answers.

    My water is cutting off after about 15 mins of being on full force with only one spiget on. When I turn the water on, the pressure goes down to 40 psi and the pump comes on. It never increases pressure, instead it gradually goes from 40 to 27-30 psi (about 15 mins). When it gets down to this range, the pressure drops to zero in a matter of seconds. When it drops to zero, I close the valve and it takes about 5 mins for the well/tank to recover to 60 psi. If I turn the water back on right after it cuts off, it will drop back down to zero in a couple of seconds. I can let it sit for about 30 mins and it will run for about 15 more mins before cutting off again. It seems to me that the pump is struggling to keep up, over heats and eventually cuts off. Could it be a lack of water supplying the pump or more demand than the pump can handle?

    I checked my pressure switch and made adjustments to have it cut on and off at 40-60 psi. The switch is working correctly. I checked the pressure in my pressure tank. Made adjustments to set at 38 psi. It is working correctly.

    My well info is: 6" dia., casing is 154ft deep, well is 245ft deep. The static yield is 25 and the gpm is 7. Pump is 1/2 hp.

    Any help would be greatful.
    Shannon
  2. Bob NH

    Bob NH In the Trades

    Messages:
    3,317
    Location:
    New Hampshire
    The rapid cutoff at 27 to 30 psi suggests that that is the prechrage pressure of the tank.

    How high is the water in the well when not pumping?

    What kind of pump do you have? Submersible? Jet?

    What model is the pump?

    The comment about "static yield is 25" isn't a term that means anything to me. Does that mean that the water is at 25 ft from the top when not pumping?

    If it is a jet pump then you cold be running out of water.

    If you have a 1/2 HP 7 GPM submersible pump and the water is at 25 ft from the top you could be overloading the pump.
  3. Gary Slusser

    Gary Slusser That's all folks!

    I think you are pulling the water in the well down to the point where the pump can't deliver any more water.

    Due to the depth of water well, I assume a submersible pump, and it probably isn't very far down the well or the water level is much lower now than it had been. Are you in a drought condition?

    Shut off teh outside faucet some and see if the 15 minutes doesn't increase.
  4. willobegolfer

    willobegolfer New Member

    Messages:
    4
    Thanks for the reply.
    I went back out and read the tag on the casing. I miss read. It's not static yield but static water level which is 25. Could you please tell me what static water level is. Is it the water level from the top or bottom of the casing? The pump is a 2-wire Franklin Electric submersible, model number 2445059004, 1/2 Hp, 230V 3450 RPM.

    Thanks
    Shannon
  5. Bob NH

    Bob NH In the Trades

    Messages:
    3,317
    Location:
    New Hampshire
    The part number is for a 0.5 HP motor; not for the pump.

    The 25 ft static level is the distance of water below the surface.

    The pump will pump more than its rating when the pressure in the tank is at or below the START setting of the pressure switch. That could cause it to overload, but it might work OK.

    Do you have another controller on the pump, such as a Pumptec? That would cause the pump to shut off if the water level gets too low.

    If the pump is very low in the well and pumps down very low in the well it would not be able to build pressure.

    It could also be like Gary said; the pump runs out of water.
  6. nhmaster

    nhmaster Master Plumber

    Messages:
    3,189
    Location:
    S. Maine
    Is this a recent problem or on going?

    when you set the tank at 39 lbs. which is correct (2 lbs. less than cut in) was the pump off and the tank empty?

    Did you check to be sure the tank diaphragm is intact?

    Check the inlet to the pressure switch to make sure it is not plugged.

    Finally, put an amp meter on the pump and see how it reads throughout it's operation.
  7. willobegolfer

    willobegolfer New Member

    Messages:
    4
    Thanks for the input. I'll try all these suggestions tomorrow and give you an update. Till then...
  8. willobegolfer

    willobegolfer New Member

    Messages:
    4
    OK. I checked the amps. L1 is 6 amps and L2 is 6.7 amps. The label for the submersible illustrates a draw of 5 amps. I know that this is a little over but not enough to indicate that the windings are weak. There are no other pressure/ safety switches in plain site but I'm not for sure if the submersible has a fell safe intergrated into it if the water runs low. I did the calculations for volume. At 245 ft deep (submersible level unknown) with a static water level of 25 ft, I have 330 gallons available while the well is at rest. I'm not sure of the well recovery rate is though. At 7 gpm, shouldn't that be sufficient to keep the well recovery above the pump? With one spiget on, could I be using 300 gallons or so of water in 15 mins. and the recovery rate isn't enough to keep up with demand?

    The submersible is 7 yrs. old and sat idle for a yr 2 yrs ago while the house was vacant. I don't know how it was before I moved in but it has been an ongoing problem for the two yrs. I've been in the house.

    nhmaster, you asked "when you set the tank at 39 lbs. which is correct (2 lbs. less than cut in) was the pump off and the tank empty?"
    I emptied the tank and had the well off while I adjusted the tank pressure. I checked the tank today and it is still hold a 38 psi.

    Bob NH, You said "If you have a 1/2 HP 7 GPM submersible pump and the water is at 25 ft from the top you could be overloading the pump."
    What do you mean I could be overloading the pump? Should I get a bigger pump to keep up with demand?

    As far as the drought situation. We had a drought last yr but this yr, we've had good rain fall. A couple of tropical storm remnants also helped the situation. I'm in eastern NC.
  9. Bob NH

    Bob NH In the Trades

    Messages:
    3,317
    Location:
    New Hampshire

    OVERLOADING: YOU SAID: "My water is cutting off after about 15 mins of being on full force with only one spiget on. When I turn the water on, the pressure goes down to 40 psi and the pump comes on. It never increases pressure, instead it gradually goes from 40 to 27-30 psi (about 15 mins). When it gets down to this range, the pressure drops to zero in a matter of seconds. When it drops to zero, I close the valve and it takes about 5 mins for the well/tank to recover to 60 psi. If I turn the water back on right after it cuts off, it will drop back down to zero in a couple of seconds. I can let it sit for about 30 mins and it will run for about 15 more mins before cutting off again."

    When you run the water full force at a spigot the pressure drops to less than 30 PSI. That is 70 ft of head. Add 25 ft for static level and you have 95 ft of head. At 95 ft of head the flow will be 12 to 13 GPM which is much more than the 10 GPM limit for a 7GS05 pump.
    http://www.goulds.com/pdf/7310.pdf

    Check the amps when the pump is running with that spigot full open.
    http://www.franklin-electric.com/Manual/AIM_13.htm
    Full load amps is 5.0; Service Factor Amps 6.0 for 0.5 HP Franklin 2-wire motor. The 6.7 measurement is high.

    You could have a split in a pipe in the well which would overload the pump.

    The amps have nothing to do with "weak windings".
  10. speedbump

    speedbump Previous member

    Messages:
    4,540
    Location:
    Riverview, Fl.
    In my experience, you can run a 1/2hp pump out of a bucket wide open and never trip the overload. This is not true of a 2 thru 5 hp pump motors in some cases, but for the little motors, open discharge is rarely a problem.

    bob...
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