Wiring Question

Discussion in 'Irrigation' started by PineywoodsLawnCare, Sep 4, 2011.

  1. PineywoodsLawnCare

    PineywoodsLawnCare LawnSite Member
    Messages: 2

    I am troubleshooting an old system where none of the valves are coming on. The owner is having to manually turn them on to water his lawn. I checked the controller and there are 24 volts coming out of it. I cannot get an ohm reading at the controller when testing the resistance. My conclusion is that there is a break in common wire between the controller and valve 1. But I also get a 24 volt reading at the wires going into valve 1. My question is: could I still be getting a voltage reading at valve 1 even though the common wire could be broken somewhere in the ground? Could the common wire be grounded at the break in the ground?
  2. Wet_Boots

    Wet_Boots LawnSite Fanatic
    Messages: 50,404

    You could have a bad splice in the wiring that creates a high resistance. You can read the controller voltage through a fault like that, even though it doesn't allow enough current through to operate the solenoid.
  3. Sprinkus

    Sprinkus LawnSite Silver Member
    Messages: 2,305

    Sounds like a high resistance fault.
    Are you checking the voltage at the valve?
    Have you tried connecting a solenoid to the valve terminals at the controller to be sure that it will turn it on?
  4. PineywoodsLawnCare

    PineywoodsLawnCare LawnSite Member
    Messages: 2

    Wet_Boots: Thanks for your reply and help. The homeowner said that the wires were spliced when the system was installed some twenty years ago, so I'm thinking that this is where the faulty splice could potentially exist. Is there a tool that would be able to detect this weak spot in the underground wire?

    Sprinkus: Thank you for your advice, too. I checked the voltage at the controller and at the valve and both checked out okay. I didn't try connecting a solenoid at the controller, but will do so when I go out there next time.
  5. bcg

    bcg LawnSite Bronze Member
    from Tx
    Messages: 1,865

  6. Mike Leary

    Mike Leary LawnSite Fanatic
    Messages: 23,148

    How did you check the voltage at the valve? :dizzy:

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