Well Pump trouble

Discussion in 'Irrigation' started by Dirty Water, Jan 30, 2007.

  1. Dirty Water

    Dirty Water LawnSite Fanatic
    Messages: 6,794

    We installed a system a few weeks ago that is having some odd issues.

    The pump outputs about 15 GPM. The issue is (I believe) that the pressure switch is set totally wrong.

    At the moment, the switch kicks the pump on at 30 PSI, and kills the pump at 120 PSI. I usually set them for 70/30, so I was really surprised when I got a 120 PSI pressure reading when I went to nozzle up the heads.

    There is a 300 gallon pressure tank. The issue is that if the pump is off, there is no way the heads use enough water to bring the pressure back down, I have to open a outside hydrant for around 5 minutes before the pump kicks on again.

    I'm pretty sure that if I reset the pressure switch to a smaller gap between starting and stopping settings the problem will go away, but I thought I'd post it on here, I couldn't get to the switch today as it was in a locked garage.

    Complicating things is the fact that the well pumps tons of sediment (we installed a filter on our lines), the 1" service line to the house has an inner diameter of about 1/2" because of buildup. I'm wondering if the pressure switch is so plugged up its making it behave weird.

    Any ideas?
  2. Wet_Boots

    Wet_Boots LawnSite Fanatic
    Messages: 50,369

    Pressure switches can and do get gummed up with crud. Even rust from years of galvanized pipe can do it. You can clean the supply side of a Square-D pressure switch.
  3. Repairs

    Repairs LawnSite Member
    Messages: 113

    Sounds like time for a new switch. I vote no for cleaning a old switch. Too fast to pop a new one on. JW
  4. Mad Estonian

    Mad Estonian LawnSite Senior Member
    Messages: 280

    That's quite a striking new avatar there Wet Boots. Or is that Wet Booties?:)
  5. Wet_Boots

    Wet_Boots LawnSite Fanatic
    Messages: 50,369

    I would also install a new switch, but cleaning a 1/4" nipple feeding an old one, while leaving the wiring intact, involves some dismantling of the old switch anyway, so it's kind of a freebie. Clearing a clog might make all the difference. If not, move on to the replacement.
  6. Hank Reardon

    Hank Reardon LawnSite Senior Member
    Messages: 599

    Gang a couple of zones to drop the pressure enough to get into the pump? Just guessing...
  7. Dirty Water

    Dirty Water LawnSite Fanatic
    Messages: 6,794

    Its the huge pressure tank thats killing me. It keeps the pump from kicking back until its nearly bled out, yet it doesn't supply enough pressure to make the heads look good. I think the amount of buildup in the lines are causing false pressure readings outside too.

    Its an odd deal. I'll probably play with the existing switch a bit, and then get frusterated and tear it out :)

    I installed a Rusco spindown strainer on the line, and it went from clear to murky brown in about 20 seconds after turning the water back on...Its the worst well I've ever seen.
  8. bicmudpuppy

    bicmudpuppy LawnSite Silver Member
    Messages: 2,781

    well, pump, and switch are new or existing when you installed? Second, if you have enough pump, why not shoot for closer to 50psi on the short side. Last, a $15 pressure switch isn't worth your time even in January to have these kind of headaches. I like 40-50psi range on a switch, your talking about 90. I have never seen a switch that allowed that kind of swing unless something was wrong with it.
  9. speedbump

    speedbump LawnSite Member
    Messages: 117

    I agree with bicmudpuppy. You didn't say what kind of switch or pump this system has, so troubleshooting is kind of a guessing game.

    If this is a Square D Switch or a copy of one, you won't ever get that kind of a swing in pressure. It's impossible to get it to that high of pressure without locking the springs down to the plate so it can't move. That means compressing the springs completely closed.

    I'm not sure what you mean by having to open a faucet to get the pump back on. If it takes a long time, that's a good thing. At least you won't cycle the motor to death.

    I am not familiar with the filter you mentioned, but I am going to assume it's an in line filter which in my opinion ain't worth two cents especially for irrigation. You didn't put this filter between the pump and pressure switch did you???

  10. Wet_Boots

    Wet_Boots LawnSite Fanatic
    Messages: 50,369

    A clogged inlet to a pressure switch, even a good one, could produce this sort of problem. If it looks like something that could occur again, I'd use two nipples and a union for connecting the pressure switch, so cleanouts could be done without disturbing the wiring.

    And yes, once the pressure switch operation looks trustworthy, raise the minimum pressure to the 50 psi neighborhood.

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