Mysterious wiring problem

Discussion in 'Zone Talk' started by Central Irrigation, Aug 12, 2019.

  1. Central Irrigation

    Central Irrigation LawnSite Member
    Messages: 18

    Took over servicing an apartment complex last year and have been dealing with its wiring nightmares ever since.

    Basic rundown: two 13 strands left controller and spliced into 39 single strand wires. I have already remedied that situation. Now each single strand has it's own wire in the controller.

    Most zones comprise of multiple valves, some as many as 5 valves.

    Zone 8 has 3 valves all wired in series on one wire
    Zone 20 has 2 valves all wired in series on one wire
    Zone 27 has 3 valves all wired in series on one wire

    Zone 8 and 20 activate as expected.

    The problem; when I activate zone 27, I get the valves I want, plus one valve from zone 8 and also one valve from zone 20. Zone 27 activates 5 valves in total.

    For the life of me I cannot figure out how this possible. No known doublers. No known add-a-zones. Somehow these wires are all tied together, but why wouldn't zone 8 or 20 activate the valves of zone 27 then?:dizzy:
     
  2. Delmarva Keith

    Delmarva Keith LawnSite Senior Member
    Messages: 753

    When you say wired in series, did you mean parallel? Series wired valves are not anything I’m familiar with and my first thoughts are that’s not the way to do it. Any controller should be able to open two valves in wired in parallel and maybe three. What type of controller is it? If it can’t, a separate transformer and some ice cube relays would seem the way to go.

    My only other thought is to ring out the wires checking for continuity and any short or low impedance path to any other wire one at a time. Tedious and requires an assistant but what you’re describing is weird enough that it seems worth doing.

    Here’s my best guess with the info so far — you have a short somewhere. Because of all of the combinations of valves in series, there is insufficient voltage to open all of the valves of the shorted zones, so the ones that will pull in with the reduced voltage across each (reduced across each valve as a result of being wired in series) do open and the behavior changes based on which combinations are powered and defies explanation. Just a guess but I got nothing better at the moment.
     
  3. OP
    OP
    Central Irrigation

    Central Irrigation LawnSite Member
    Messages: 18

    My understanding of series is multiple selonoids daisy chained on an individual zone wire. Parallel referring to two or more selenoids each having their own wire but sharing the same power supply. A double tap if you will.

    I have no doubt that the wiring of these zones resembles that of a backwood's family tree. A set of series and paralleled circuits, cleverly (or not so cleverly) designed so as to trick the controller into not throwing a fault code.

    Some troubleshooting from today yielded that one of the valves of zone 27 is being fed voltage from both sides. The few hours I had today were tracing out the wire path and marking potential splice points.

    It is funny though, my valve actuator will light up both good and short at the same time, and activate all 5 valves on zone 27. The Rainbird LXME and my Eicon are unaffected by it.

    Alot of splices are going to be dug up soon!
     
    Delmarva Keith likes this.
  4. jdmccay

    jdmccay LawnSite Member
    Messages: 20

    This is why we put splices in boxes. Let me say it louder for the folks in the back. THIS IS WHY WE PUT SPLICES IN BOXES!

    also, what was their reasoning for running multiple zones on one wire? Were they trying to fit into a watering window, or were they too cheap to get a clock with enough slots for all the zones?
     
  5. Delmarva Keith

    Delmarva Keith LawnSite Senior Member
    Messages: 753

    Sounds like a rats nest. The good news seems to be there are enough wires to wire things correctly.

    I’m still not familiar with wiring valves in series (the daisy chain you describe). It strikes me as a technique that might allow a tech to get things working and go home early as a matter of luck, but one day when a valve needs to be replaced and the new valve has a slightly different solenoid, or the clock is replaced with something new, nothing works anymore. Just bad practice as far as I can figure.

    If a set of zone valves have one wire in and one wire out, that adds up to two wires for that zone in the pit. Why would they not have used the two wires to wire it correctly? Or if they’re daisy chained across multiple locations, there still has to be a common wire in addition to the single zone wire I’d think (did they really run just a single wire in and out of multiple pits? If so, I’d submit a bid to rewire or walk away from what seems to me to be a never ending string of callbacks). Series wiring valves seems like a complete hack job but I learn something new everyday so who knows. :)

    The next question that rattles through my brain (there are more, but here’s the next one), assuming there are a sufficient number of wires so those multivalve zones can be wired “correctly” (valves in parallel with a relay and even separate transformer at the clock if needed), what is the gauge of the existing wires and is it sufficient to avoid excessive voltage drop running three valves instead of the usual one? You might end up having to bury a bunch of new wire even if it can be wired to “work” on the existing.
     
  6. magna111

    magna111 LawnSite Senior Member
    from NJ
    Messages: 487

    0AB540F2-46C8-4BD8-B99B-4BE224FBECDD.jpeg
    Series means if the zone wire was green, the wire would come from the clock, green would go into the solenoid, green out of the solenoid, and green on to the next valve. So if you had 3 valves wired in series, the first 2 valves on the series would wire in and out on the zone wire, and the last valve would wire in on the zone wire and out the common back to the clock. Parallel would be when each valve goes from the zone wire to the common, even if the zone wire continues to another valve down the line. Make sense?

    Editing to add that I’ve never seen valves wired in series in 20 years, not that it isn’t or hasn’t been done.
     
  7. OP
    OP
    Central Irrigation

    Central Irrigation LawnSite Member
    Messages: 18

    My mistake. My understanding of series and parallel was wrong. They are in fact wired parallel. Each selenoid is connected to common sharing a single zone wire.

    As to why they did this, it's anyone's guess. From what I've been told, the system started life as a well system. Perhaps they had more water than planned and needed to combine zones to prevent cycling. The system dates back 30 years. Perhaps two 12 zone controllers is all they had.

    When running new wire from controller to the first two wire splices, I did discover that all these multiple valve zones was in fact intentional, and done at the time of install.

    As far as having extra wire...doubtful. All the single strand installs I've been a part of only run enough wire that is necessary. Seldom is there ever spare wires run. The splices near the controller did, however yield 3 open wires. The question that I have yet to answer is whether or not they go the direction I want them to go, and if they will be any good once they get there. Unfortunately, I'm forced to use this afflicted zone 27 wire as it is the only wire available at the valves. Once I get the wire "T's" dug up I'll have more info to go on

    The voltage coming from both sides of the valve has me perplexed. Almost like someone connected the ends of two zone wires together.

    14 gauge wire to answer your question

    I'll have to snap a photo of the zone layout.
     
    Last edited: Aug 14, 2019
  8. OP
    OP
    Central Irrigation

    Central Irrigation LawnSite Member
    Messages: 18

    20190820_095414.jpg 20190820_095645.jpg

    The valves that activate with zone 27 are the zone 8valve near building 17 and zone 20 valve near building 11.

    Zone 20-b11 zone wire is wired through to feed valve20-b16. Zone 27 backfeeds voltage to activate valve 20-b11. I have yet to locate valve 20-b16. Although valve 20-b16 is unaffected by zone27.

    Thoughts?
     
  9. jdmccay

    jdmccay LawnSite Member
    Messages: 20

    I almost wonder if the control wire for zone 27 is spiced in with the common on the other two zones. Do you have one or multiple common wires at the clock? Maybe try sending a tone through the control wire for 27 and see if the signal is coming through the control wire of the other two or through the common. That's the only thing that makes sense me. Otherwise if the control wires were spliced together 27 would activate when you turned on the other 2 as well.
     
  10. jdmccay

    jdmccay LawnSite Member
    Messages: 20

    Oooooor.... By this point it might be more time effective to just trench a new wire... Just a thought
     

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