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Taco zone valve wiring

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Hello all,
I have 4 heating zones controlled by Taco zone valves. I noticed that one of the brown wires around the setup is not attached to anything, but it looks like it should be.

When I look closer at the wiring, I can't make much sense of it. I don't quite understand why the 4 valves would be wired differently.

I uploaded some pictures here https://imgur.com/a/MgLhItp

The left 2 valves have 2 reds and 1 white.
However, the right 2 valves have 1 red, 1 brown and 1 green.

There is 1 unattached brown wire that seems like it could have gone to the second from the right.

Does this wiring make sense to anyone given the provided info? Would love to learn more about it and potentially identify whether that brown wire needs to go anywhere. I can't say I've noticed any heating issues but I'm not sure it's running optimally.

Thanks

Comments

  • HomerJSmith
    HomerJSmith Member Posts: 2,511
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    The wiring is a mess. You can't know if the wiring is correct unless you know what the wire is connected to on the other end.
  • Tim McElwain
    Tim McElwain Member Posts: 4,629
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    We need more information as to what controls are on the boiler such as a relay stc.
  • Big Ed_4
    Big Ed_4 Member Posts: 2,831
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    The zone valve motor receives its power though a transformer , the thermostat is a switch controls the power to open the valve . In the zone valve there is an end switch to switch on the circulator and burner . On that type zone valve the two share the same common .

    There was an error rendering this rich post.

  • Dave H_2
    Dave H_2 Member Posts: 560
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    Not being able to see the other end of the wire makes it difficult to diagnose.
    Using a ZVC streamlines the wiring and makes troubleshooting later a little easier.
    Maybe this wiring diagram can help and if you are not sure where a wire goes or if there is power on it (some can be low voltage 24v, some can be high voltage, 120v) ask a professional to take a look.

    Dave H
  • tryingtobeaplumber
    tryingtobeaplumber Member Posts: 12
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    Thanks for the replies. I ended up finding an older picture that shows where the loose wire should go to.
    The system has 4 - 20/2 wires (1 for each thermostat) and 2 - 20/4 which come from the boiler controller. Only 3 of the four conductors from the boiler are used.
  • EBEBRATT-Ed
    EBEBRATT-Ed Member Posts: 15,839
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    @tryingtobeaplumber

    Remember electricity is color blind (like me). The wiring colors mean nothing. You could use all black wire or any other color. It's what it's connected to that counts. The colors confuse things sometimes.

    The attached may help
  • EdTheHeaterMan
    EdTheHeaterMan Member Posts: 8,167
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    Thanks for the replies. I ended up finding an older picture that shows where the loose wire should go to.
    The system has 4 - 20/2 wires (1 for each thermostat) and 2 - 20/4 which come from the boiler controller. Only 3 of the four conductors from the boiler are used.

    Is your problem resolved now? Not really sure from your statement (See above quote)

    As there is no picture of the transformer that powers the zone valves, It is difficult to tell you what to look for to resolve the problem. However here are some slides from my one day seminar that I used to teach. It goes thru the logic of how a zone valve operates.

    What a one zone might look like using the simplest heating appliance.

    How the transformer powers up the valve when the thermostat calls for heat

    How the valve does the thermostats job to turn on the boiler

    The complete wiring for one zone


    Edward Young Retired

    After you make that expensive repair and you still have the same problem, What will you check next?