Electrical troubleshooting

Discussion in 'Irrigation' started by greenone, May 11, 2006.

  1. greenone

    greenone LawnSite Member
    from ontario
    Posts: 13

    I am currently servicing a 23 zone system. I was unable to open the last 6 zones of the system using the controller. I checked to ensure there was water to the zones by opening them manually. I checked the area and was unable to locate any disturbance on the ground. Also, the blueprints show that the mainline was buried with the wire(s), therefore if the main was struck by a shovel, I would have seen a waterfall.

    Any suggestions on how to best isolate the wiring fault? I checked the controller with a muti-meter and observed a 24v reading to the affected zones. Of course, the valves have numerous wires and I have located a reading of 8v on the common wire for the last valve that is working properly. Do you think the wire has been split?

    Any help would be appreciated.

    Anyone recommend the valve/seloniod tester thats on the market? Looks like a neat tool, wondering if it is worth the $80.
     
  2. jirrigation

    jirrigation LawnSite Member
    Posts: 27

    Disconnect the 6 wires of the zones that arent working from the controller as well as the common and measure the resistance across the common and each wire one at a time. You should be getting something from around 20-80 ohms, depending on the brand of solenoid and age.

    Go to the valve box just before the first one that doesnt turn on and make sure the common that continues to the not working valve box is connected properly. If the common makes a good contact there go to the first valve box that isnt working and make sure the common is connected properly there as well. From your explanation is sounds like its simply a bad connection in the common somewhere.
     
  3. PurpHaze

    PurpHaze LawnSite Fanatic
    Posts: 5,496

    If the controller has no problems then I'd bet on a disruption of the common wire also. Make sure that the common is properly connected at the first of the six valves in sequence. If all is good at the valve end then the common has most likely been lost somewhere between the last good working valve and the first non-working valve. To confirm that all the wiring hasn't been disrupted you could run a common wire above ground between the good valve and the bad valve. You could also use a 501 locator and ground fault indicator in order to locate the problem.
     
  4. Critical Care

    Critical Care LawnSite Bronze Member
    Posts: 1,654

    Or, suspecting a bad ground, temporarily switch one of the positive valve wires over to serve as the ground for the other valves. Just remember to switch it over at the controller too.
     
  5. greenone

    greenone LawnSite Member
    from ontario
    Posts: 13

    Thanks for the help folks. Any thoughts on those valve/selonoid testers?
     
  6. PurpHaze

    PurpHaze LawnSite Fanatic
    Posts: 5,496

    Never really used them. I use another solenoid as a tester.
     
  7. Station master works okay.....I prefer to use an Ohm Meter actually..old school I guess.
     

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