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Thread: Shallow well pump lift ability?

  1. #1

    Default Shallow well pump lift ability?

    I have a shallow well pump, located in the house, which is built on slab. I understand that the lifting ability of the average pump is 25 to 29 feet. Am considering laying a new supply line from the well to the house, but to avoid cutting concrete, want to enter the front of the house, go up 8 feet, across a room, and back down again to the pump.

    Will the temporary lift of 8 feet affect the pump's operation, or will the subsequent down section of the pipe offset that initial 8 foot lift, so the pump will operate as if the vertical sections were not there?

    Thanks to anyone who can help.

  2. #2
    Moderator valveman's Avatar
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    The problem is air. Air will accumulate in the high spot and it will be impossible to keep prime. Pipe needs a gradual increase in height up to the pump, which should be at the high point of the suction line.

  3. #3

    Default Shallow well lift - air

    Valveman,

    Thanks for your quick reply. Your answer seems to imply it's not possible to keep all air out of the line, even if all connections are tight. Is that a good interpretation?

    Your explanation of a gradual incline might explain why my existing line starts at the well 3 feet down. That's well below the freeze depth here. I imagine by the time it reaches the house, it's about 2 feet deep.

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    Moderator valveman's Avatar
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    Even without a leak, air will separate from the water and accumulate in the high spots. When there is enough air in the high spot, it will gulp through, and cause your pump to loose prime.

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    I'm not sure I agree with that. Air takes a long time to come out of suspension under pressure and probably takes a long time under vacuum as well. Either way, once primed, it should stay primed even with the vertical loop. What I'm not sure of is if it would act the same way as water does going up to my solar panels. You have to push it up to get it there, but then when it comes back down; does the fall offset the up completely? I think because of friction etc, it's not totally going to offset the push up.

    Either way, it's a great question and I would like to know the scientific answer.

    bob...

  6. #6
    That's all folks! Gary Slusser's Avatar
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    I have always read that a jet pump can't suck from more than 25' at sea level, and you should always want to err on the conservative side bcause the static water level can vary.

    This might work IF you primed both ways at the high spot above the ceiling but, I don't think you'll like the results of working a jet pump at its maximum.

    You don't say what diameter well but if possible, I'd put a 1/2 hp 10-13 gpm submersible in the well.
    Gary Slusser Retired (= out of business)
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    Quote Originally Posted by donmcc View Post
    I have a shallow well pump, located in the house, which is built on slab. I understand that the lifting ability of the average pump is 25 to 29 feet. Am considering laying a new supply line from the well to the house, but to avoid cutting concrete, want to enter the front of the house, go up 8 feet, across a room, and back down again to the pump.

    Will the temporary lift of 8 feet affect the pump's operation, or will the subsequent down section of the pipe offset that initial 8 foot lift, so the pump will operate as if the vertical sections were not there?

    Thanks to anyone who can help.
    No it won't work unless this is a two pipe jet pump since 29 + 8 = 37 feet (25 is the recommended cutoff but it cannot exceed 32).

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    That's all folks! Gary Slusser's Avatar
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    But he hasn't said he has 29', he only mentioned 8' and 3' under ground at the well and 2' at the house. So far that's only 13' of elevation and we don't know what static water level he has.
    Gary Slusser Retired (= out of business)
    Click Here to learn how to correctly size or program a water softener.
    CAUTION, as of Nov 12 2013 all YouTube videos showing how to rebuild a Clack valve have an error in them that can cause damage.

  9. #9
    Moderator & Master Plumber hj's Avatar
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    Default lift

    AIr pressure, which makes a shallow well pump work, can only lift the water about 27' as a practical limit, and that is to the point where would have to go horizontal or drop down again. The closer you get to the 27' point the less water it will deliver. As I told a contractor one time who wanted to suck a liquid to the floors of a high rise as the building progressed, "You can pump it to the moon, but you can only suck it 27 feet".

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