Recovery time help

Discussion in 'Pumps and Tanks Well Forum & Blog' started by theplayer11, Sep 9, 2013.

  1. theplayer11

    theplayer11 New Member

    Messages:
    7
    Location:
    Rhode Island
    I'm trying to figure out what is going on with my well and what size pump to get..I've read about TDH, friction loss, ect, read the charts, graphs of different size pumps and my head is spinning. From my previous posts, I own greenhouses and water 5-6 hours straight during spring, summer.

    some facts:

    -well is 180', artesian dug in 1993
    -refrac in 2010(10GPM)
    - I believe pump is set about 20' off bottom
    - today I measured water level before I started irrigating - 25 feet down
    - I watered for about 2 hours and measured- water was now 50' down
    - current pump(which I believe is on the way out) is delivering 5GPM.(used to be more) This was measured from a 15 foot hose filling my 1500g storage tank right next to Amtrol tank and 10 feet from well.
    - lots of iron(rust)

    Ok..what is this telling me? Is down 25 feet in 2 hours when the pump is delivering 5 GPM mean my recovery rate is below 5GPM??..That would be troubling....but only 50 feet down after 2 hours when well is 180'...would be a positive?
    I water by using a booster pump(water gun) that is gravity fed from the 1500g storage tank. I get about 10GPM on the end of 200-250 hose this way.(pressure to water plants is right where I want to be)

    My goal is to have the well pump deliver the same or close(7-8 GPM min) to the storage tank so that tank never runs out during 6 hours of watering. I do remember that it used to keep up, but over the years it seems to be draining down faster. The well pump has been replaced a few times, and I'm guessing that maybe it has not been matched up properly. The last time was about 4 years ago and I believe a 1/2HP 7GPM pump was installed. This might have been a used pump even..a plumber friend had it laying around.

    From reading the pump charts, I believe I should try a Goulds 1/2HP 10GPM pump. If it is pumping too much, couldn't I just turn down the faucet(usually wide open) on the Amtrol tank to increase PSI?

    Any suggestion or input on my situation would be appreciated. I'm trying to learn what I can.
  2. valveman

    valveman Moderator Staff Member

    Messages:
    4,388
    Location:
    Lubbock, Texas
    From a pumping level of 50’ a 7 GPM, ½ HP should produce 7 GPM at 70 PSI. Even if the water level pulled down to 170’, that pump should still deliver 7 GPM at 17 PSI. Recovery rate doesn’t mean anything until the water level is pulled all the way down to 170’. If the water level doesn’t pull down more than 50’, the pump is the problem, not the well.

    A 10 GPM, ¾ HP pump will deliver 7 GPM from a water level of 170’ and still produce 40 PSI. If the well makes enough water to keep the storage tank full when sprinkling, then you just need a well pump that makes enough pressure for the gun, and the extra pump and storage tank would not be needed. If you let me know how much pressure the gun needs, I can tell you what size pump to put in the well so the storage tank and booster pump are no longer needed. No reason to pump the same water twice if it is not needed.
  3. theplayer11

    theplayer11 New Member

    Messages:
    7
    Location:
    Rhode Island
    not sure what the gun needs. It's a Stay-rite 3/4hp, website states 80 psi max inlet pressure. It's gravity fed now from my holding tank and I'm getting 10-12 GPM at the end of a 250' hose and plenty of pressure to water my plants. I went to a storage tank and booster pump because the pressure wasn't enough when original well pump and Amtrol tank were installed about 20 years ago.
    Right now with the booster pump I'm getting 10-12 GPM at the end of a 250' garden hose and the pressure is great.
  4. valveman

    valveman Moderator Staff Member

    Messages:
    4,388
    Location:
    Lubbock, Texas
    If the well will make 10-12 GPM, you don’t need the storage tank and booster pump. 80 PSI max inlet pressure doesn’t tell us anything. But a ¾ HP jet pump will deliver 12 GPM at about 50 PSI. You could just use a 1.5 HP pump in the well and it would give you the 12 GPM you need with the extra 50 PSI required for the gun.
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