pressure switch problem

Discussion in 'Irrigation' started by IRS, Apr 16, 2007.

  1. IRS

    IRS LawnSite Member
    Posts: 40

    I have taken over maintenance on a system that has a 5 H.P cent pump pulling out of
    a lake, 2" discharge, 2" swing check valve, 60/40 pressure switch,galv pressure
    tank 240' away 20' up the hill. Problem is this; when pump reaches cut off point
    switch keeps going on & off like the tank is waterlogged or full of water but it's not, any ideas?
     
  2. Midlo Snow Maker

    Midlo Snow Maker LawnSite Member
    Posts: 183

    you have got to spread the 60/ 40 out to like 80/40 or even 90/40
     
  3. jerryrwm

    jerryrwm LawnSite Bronze Member
    Posts: 1,274

    You might be better off in raising the setting to 70/50 or up. If you don't know what you are doing by changing the differential setting you can really mess things up.
     
  4. bicmudpuppy

    bicmudpuppy LawnSite Silver Member
    Posts: 2,781

    if the switch is "bouncing", then it isn't set at 60/40, your just giving us the factory settings. If you don't know how to adjust it, I would take jerrys very good advice and leave it alone and call a pump guy.
     
  5. speedbump

    speedbump LawnSite Member
    Posts: 117

    The above would be a wise move.

    First of all centrifugals don't work well with pressure switches. The other thing is, the pressure switch needs to be with the tank not the pump. While it's doing this, it's doing real damage to the motor.

    bob...
     
  6. bicmudpuppy

    bicmudpuppy LawnSite Silver Member
    Posts: 2,781

    I've run lots of pressure switches at the pump w/o problems. A pressure tank is just storage and location isn't that important. The garage or shed on the other side of the property works just fine. BUT, the switch has to be set properly and work properly, or your gonna be buying a brand spanking new pump.
     
  7. Dirty Water

    Dirty Water LawnSite Fanatic
    Posts: 6,799

    The way I look at is that any line between the pressure tank and the pump is simply just adding capacity to the pressure tank.

    How many GPM is this pump rated for, how many GPM of water is actually being used. This is the real question.
     
  8. Bigred350

    Bigred350 LawnSite Senior Member
    Posts: 772

    Why dont you take the pressure switch and tank off. ANd install a pump start relay and let the timer turn the pump on. Thats how we do it on a centrifical pump.
     
  9. Dirty Water

    Dirty Water LawnSite Fanatic
    Posts: 6,799


    Perhaps the mainline has quick connects or hydrants on it?
     
  10. Midlo Snow Maker

    Midlo Snow Maker LawnSite Member
    Posts: 183

    same problem different setting you need a bigger spread.
     

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