Well gaining pressure?

Discussion in 'Irrigation' started by j_nolesfan, Mar 5, 2008.

  1. j_nolesfan

    j_nolesfan LawnSite Member
    Posts: 81

    I fired my well up this year after having it off for probably 3 months. It feeds my sprinkler system that I have yet to install a control box for. Anyway, it's a 1/2 horse submerged pump that's 170' deep and I have a 50 gallon bladder tank as a buffer. Normally, I was running a two different zones out of four (separately, not together) at about 60 PSI and the pump stayed running. I haven't made any adjustments. When I fired it up the other day, my pressure guage was pegging past 100, probably in the neighborhood of 110 since the measure stops at 100 and the pump was cycling on and off about every two or three minutes. At first, I thought something was up with the pressure switch but I checked it and it doesn't look dirty. I checked the air pressure in the bladder tank and it was within tolerance. I can't remember the exact number but I can get it if it's crucial. I could understand if one of the two zones ran a high pressure and was caused by some blockage somewhere but it's obvious at the heads that the pressure is up because of the force that the water is coming out and it's that way on both zones. The only way I can keep the pump from cycling is to run both zones together and that causes the pressure to drop below a sufficient level.

    This brings me to my question, can a well that's 18 months old pick up say 55% in pressure/flow? If this is truly the case, I can probably put some larger nozzles on the heads and deal with it but I want to make sure that there's not something else going on that can cause permanent damage to part of the system.

    Below is a copy of my flow rate stats from March of 07 when I last measured it. I'll try to take new measurements today if possible:
    =====================
    First, let me say that my pump cycles off when the pressure reaches about 85 PSI. I can maintain several pressures up to a little over 70 PSI without the pump seeming to catch up and shut down (for at least five minutes at each level suggesting that it's not going to catch up or the pressure would have increased, right?). My 5 gal bucket is just a little over 5 gals, more like 5.2 gals.

    At 72 PSI, I fill the bucket in 16 seconds. According to my scale, that's about 18.75 GPM (19 GPM is safe considering the fact that it's over 5 gals).

    At 50 PSI, it takes 13 seconds, 23+ GPM

    At 30 PSI, it takes just over 10 seconds, about 30 GPM considering

    It seems I can maintain any of these flows at their respective PSI levels without cycling the pump. If I get close to 75+ PSI, the pump seems to catch up and shut down quickly.

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    Thanks in advance,
    Jeff
     
  2. Wet_Boots

    Wet_Boots LawnSite Fanatic
    Posts: 47,992

    Got a filter in the supply? It is possible for the water table to rise, and that increases well performance.
     
  3. j_nolesfan

    j_nolesfan LawnSite Member
    Posts: 81

    No filter beyond anything that might be before the pump. Wonder how I could measure the water table or if the local city wells might have this data available?

    Jeff
     
  4. Wet_Boots

    Wet_Boots LawnSite Fanatic
    Posts: 47,992

    You can purchase a Cycle Stop Valve, and cut that into the line before the pressure tank. That leaves you with 60 psi at the tank. The CSV is like a pressure regulator with a built-in bypass, so the pressure switch can control things as usual.
     
  5. Mike Leary

    Mike Leary LawnSite Fanatic
    Posts: 22,062

    Up in WA State, the well drillers are required to keep logs of a well's
    performance. I agree with Boots about a cycle stop or Cla-valve; your
    zones can be all over the place as far as gpm goes & you can still
    maintain even pressure.
     
  6. j_nolesfan

    j_nolesfan LawnSite Member
    Posts: 81

    Thanks WB,
    Would that valve put more strain on my pump? Maybe I don't understand? You're saying I can run that kind of pressure as long as I bypass my tank?
    Jeff
     
  7. j_nolesfan

    j_nolesfan LawnSite Member
    Posts: 81

    Ok, I did a little research of my own, as I probably should have before asking what a cycle stop valve is. To my understanding, it's a control that makes the single speed pump operate at variable speeds in order to match supply and demand. Is that correct?
    Thanks,
    Jeff
     
  8. Wet_Boots

    Wet_Boots LawnSite Fanatic
    Posts: 47,992

    The CSV will choke down the flow in order to maintain the 60 psi output, and that will increase the upstream pressure. If you do have a wide variation in the water table, something like this may save you from having to change nozzles every year.
     
  9. j_nolesfan

    j_nolesfan LawnSite Member
    Posts: 81

    And it looks to be something as simple as a gate valve upstream of the tank?
     
  10. Wet_Boots

    Wet_Boots LawnSite Fanatic
    Posts: 47,992

    I already described it.
     

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