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Electrical Troubleshooting / "Crossed" Wires

Discussion in 'Irrigation' started by jb925, Sep 19, 2013.

  1. jb925

    jb925 LawnSite Member
    Posts: 5

    Went out to a commercial site where station number 5 was not turning on.
    I turned on station 5, manually from the timer, to find that station 3 was turning on. I moved on to turning on stations 3 and 4, and again, station 3 was turning on.

    I connected a toner to station wire 5, at the valve, and found that the wire connected to wire terminal 5 was the loudest. Did the same for station 4, and again, the loudest wire was the wire connected to wire terminal 4. Proceeded to tone station wire 3 and found that I was getting loud tones from multiple wires.

    Moved on to the mutimeter to see what I could find. Manually turned on station 3 and found (at the timer wire terminals):
    Station 3: 26 volts
    Station 4: 16 volts
    Station 5: 16 volts
    Station 8: 16 volts
    Station 10: 16 volts
    Station 11: 16 volts
    Station 12: 16 volts

    I removed station wire 5 from the terminal and touched one lead onto the terminal, nothing. Removed the lead from the terminal and touched the wire and found 16 volts coming FROM THE WIRE.

    Moved on to manually turning on station 4 and I got 26 volts from terminal 4, yet again, 16 volts coming from stations 3, 5, 8, 10, 11, 12. I am getting the proper voltage for the station I manually turn on, but the rest are returning 16 volts.

    I disconnected station wire 3 from the terminal and found that even though the wire was disconnected, when the other stations in question were manually turned on, here was station 3 turning on still.

    In valve boxes for valves 3 and 5, I found a red wire that came up under the valve, into the box where it was coiled, and leaves the box without any kind of connection to the solenoids.

    I also used a valve activator to test the solenoid and all stations in question turn on as they should when using the valve activator.

    Ive heard this referred to as "crossed" wires, where a station wire is making contact with one or more other station wires and causes this type of problem.

    Anyone have any thoughts or suggestions?
    I tried searching the forum but no luck.
    Thank you.
     
  2. 1idejim

    1idejim LawnSite Fanatic
    Posts: 8,824

    You did all of that without first measuring the resistance of all of the zones, when you would have kqnown that you have a direct short. Quick guess is that the DMM would have measured 0 - 8 ohms on the valves that were running concurrently.
    Posted via Mobile Devicelook in the direction of the common.
     
    Last edited: Sep 19, 2013
  3. jb925

    jb925 LawnSite Member
    Posts: 5

     
  4. 1idejim

    1idejim LawnSite Fanatic
    Posts: 8,824

     
  5. 1idejim

    1idejim LawnSite Fanatic
    Posts: 8,824

    Digital Multi Meter
    Posted via Mobile Device
     
  6. Stillwater

    Stillwater LawnSite Platinum Member
    Posts: 4,796

    MMMID
    Posted via Mobile Device
     
  7. jb925

    jb925 LawnSite Member
    Posts: 5

    Your saying that I will more than likely have low resistance at the problematic stations? From what I understand, this is telling me there is a short in the field wiring?

    Still searching for clarification. As you can see my knowledge on electricity is a bit limited.

    Thank you!
    Posted via Mobile Device
     
  8. jb925

    jb925 LawnSite Member
    Posts: 5

    MMMID?
    Posted via Mobile Device
     
  9. Stillwater

    Stillwater LawnSite Platinum Member
    Posts: 4,796

    Just trying to inject a little humor
    Posted via Mobile Device
     
  10. 1idejim

    1idejim LawnSite Fanatic
    Posts: 8,824

    Begin with your resistance measurements. Document them and then do the same with your voltage measurements. Measure both static and dynamic voltage.

    Measure the dynamic first and then remove all of the zone wires for you static measurements. Reconnect one of the problematic wires and measure the vacant terminals while running the zone. If there is no voltage on the vacant terminals, the controller is prolly ok

    I would measure a few other things but, that's me.
    Posted via Mobile Device
     

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