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ZVC-406 Extra 24V terminals...

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john p_2
john p_2 Member Posts: 367
in Gas Heating
Having an issue with how to land 18 gauge wires at the (4) spare 24 terminals. Can someone please tell me how to land these? I have unscrewed them all the way but cannot seem to push the wire to where you'd expect it to land under the screw for some reason. Help please
MikeL_2
«1

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  • GW
    GW Member Posts: 4,692
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    Are there other wires you can fiddle with to try and figure it out? Once in a while I get “jammed” too. It’s frustrating
    Gary Wilson
    Wilson Services, Inc
    Northampton, MA
    gary@wilsonph.com
  • john p_2
    john p_2 Member Posts: 367
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    Originally was trying to land wire on right side of terminal, with no luck. Had success landing them on the left side, same side as the yellow wires land
  • GW
    GW Member Posts: 4,692
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    Yes correct, looks like you’re done
    Gary Wilson
    Wilson Services, Inc
    Northampton, MA
    gary@wilsonph.com
  • john p_2
    john p_2 Member Posts: 367
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    Thanks
  • kcopp
    kcopp Member Posts: 4,432
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    I actually don't think they were designed to go on the right hand side.
  • john p_2
    john p_2 Member Posts: 367
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    Kcopp, I agree. Thats where I first thought they went. But will tell you it was not easy to get the wires on the left side. Very poor design, no room at all.
  • Alan (California Radiant) Forbes
    Alan (California Radiant) Forbes Member Posts: 4,002
    edited May 2020
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    I don't think they were designed to have ANY wires added. If you want 24 volts, add a transformer instead of endangering your zone valve control, especially one that has a difficult-to-remove transformer. If you make a mistake and fry the transformer............do I need to elaborate?
    8.33 lbs./gal. x 60 min./hr. x 20°ΔT = 10,000 BTU's/hour

    Two btu per sq ft for degree difference for a slab
  • john p_2
    john p_2 Member Posts: 367
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    Yes, understood. I gave up on it because it was so difficult and thinking about it, I needed to supply four new stats w/24 volts and didn't feel comfortable trying to feed them from those transformers. Thanks
  • john p_2
    john p_2 Member Posts: 367
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    I'm trying to switch to all wifi stats (4) in the house. All existing stats were wired with 16 or 18/7 and have at least one unused wire. I need a diagram how to power these up if I add a new transformer keeping in mind I already have two wires going to TT terminals in my ZVC406.
    I have decided to use Honeywell Lyric 5+ thermostats.
  • SuperTech
    SuperTech Member Posts: 2,160
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    You could just replace your zone valve control. Tekmar and others make zone valve control panels that have a common wire terminal for each thermostat.
  • HVACNUT
    HVACNUT Member Posts: 5,834
    edited May 2020
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    You've got 6 zone valves, 4, 24v powered thermostats, internal switching, and 80 va. Get the calculator.

    Contact Taco. If you use 2 thermostats per transformer, I would think it would be ok. With room to spare.

    If Taco abides, I would use one wire under each terminal screw as a lead for external splices.

    Weird that Taco provides 24v terminals on the SR zone boards at the thermostat connections and a separate 24v output terminal block. Maybe there's a reason they don't on the ZVC. But the newest Revision I believe is from 2006, so who knows?
  • SteveSan
    SteveSan Member Posts: 234
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    Hi John, attach is a wiring diagram for an external transformer for your old zvc406. If you need assistance please contact Taco Tech Support @ 401-942-8000. We are here Mon-Fri 8am-5pm EST.
    rick in Alaska
  • john p_2
    john p_2 Member Posts: 367
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    Wow, thanks so much Steve. No my dilemma is how to neatly bring the 24V wires to/from stats & transformer
  • SteveSan
    SteveSan Member Posts: 234
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    If you are just looking for a "c" terminal on the old zvc, you would run the common wire down to the #1 zone valve terminal. So it will share the #1 from the zone valve as well
  • SteveSan
    SteveSan Member Posts: 234
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    Forgot to attach wiring C to old zvc control. Second diagram on the page
    SuperTech
  • john p_2
    john p_2 Member Posts: 367
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    That is exactly what I was looking for thanks Steve. Bur now let me tell you that I just ordered a new ZVC406-4 6 zone valve control panel (the one w/indicator lights in front, not on the side) as I have a relay that is bad. Will I see a "C" common wire location on the drawing that comes with the panel?
  • HVACNUT
    HVACNUT Member Posts: 5,834
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    > @john p_2 said:
    > Wow, thanks so much Steve. No my dilemma is how to neatly bring the 24V wires to/from stats & transformer


    No dilemma. If I were in your shoes I'd be on the phone to the service department of the company that installed the system. It certainly looks like they're capable.
  • john p_2
    john p_2 Member Posts: 367
    edited May 2020
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    HVACNUT - I installed it all.
  • SteveSan
    SteveSan Member Posts: 234
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    With your new ZVC406-4 you will have at the T-stat connection your R-W-C terminals on the top. http://apps.taco-hvac.com/uploads/FileLibrary/102-397.pdf
    SuperTechjohn p_2
  • HVACNUT
    HVACNUT Member Posts: 5,834
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    > @john p_2 said:
    > HVACNUT - I installed it all.

    Nice work!
    You said there's at least one extra wire at each thermostat so what's the issue?
  • john p_2
    john p_2 Member Posts: 367
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    HvacNut- no issue now that I know where to land the "C" wire...I hope to get to it tonite
  • john p_2
    john p_2 Member Posts: 367
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    SteveSan, just wired the first & easiest stat which is in the garage. Easiest cause it is heat only and worked great. One issue that I forgot to mention is now after initially trying to land the "C" wires on those four terminals shown in my pics the Taco PC700-2 is now reading outdoor temp thats not correct, off by 15° to the low side. Any ideas?
  • SteveSan
    SteveSan Member Posts: 234
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    There should be an ohms chart on the instruction sheet. Ohm out the sensor to see if it is reading the correct temp.
    http://apps.taco-hvac.com/uploads/FileLibrary/PC700-2(102-097).pdf
  • john p_2
    john p_2 Member Posts: 367
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    So I've tested the temp sensor on my PC-700 and see 2.65 on my meter. The PC 700 displays an outdoor temp of 45° and Weather Channel phone app says real time outdoor temp is 62°. I installed a fresh battery in my meter to be sure it was accurate, now what?
  • HVACNUT
    HVACNUT Member Posts: 5,834
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    You need to know what type resistor. Anything in the manual?
    If it's a 10K, then it thinks it's 137°. And it would be wrong.
  • john p_2
    john p_2 Member Posts: 367
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    HVACNut all I see in the paper work is outdoor sensor M2036
  • Alan (California Radiant) Forbes
    Alan (California Radiant) Forbes Member Posts: 4,002
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    "The wires from the sensor must not be connected to the control
    while the test is performed."

    Looks like a 10K sensor.


    8.33 lbs./gal. x 60 min./hr. x 20°ΔT = 10,000 BTU's/hour

    Two btu per sq ft for degree difference for a slab
  • john p_2
    john p_2 Member Posts: 367
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    Thanks Alan, I will recheck it tomorrow.
  • HVACNUT
    HVACNUT Member Posts: 5,834
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    Good save @Alan (California Radiant) Forbes . Step 1, remove wires.

    The resistance chart is on page 7.
  • john p_2
    john p_2 Member Posts: 367
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    So here is the ohm reading with multimeter set at 20k and wires diconnected at the sensor....Multimeter displays 16.72
    Outdoor temp 72° F
    PC700-2 displaying 57°F
  • HVACNUT
    HVACNUT Member Posts: 5,834
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    The ohm reading is correct according to what the display is reading.

    Are you able to check actual outdoor temp at the sensor location? North side in the shade?
  • john p_2
    john p_2 Member Posts: 367
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    HvacNut...I'm sure I could come up with some sort of thermometer but are you suggesting the15° difference between the Weather app display temp for my town and the display temp on the the PC700 is not accurate? I believe it might be a degree or two off but more than that, I seriously doubt it.
    The sensor is located on the north side of the house, in shade.
  • HVACNUT
    HVACNUT Member Posts: 5,834
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    No. The sensor is telling the PC700 its 57°. Its wrong.
    At 72°, the reading should be approximately 11,305. You need a new sensor.
  • john p_2
    john p_2 Member Posts: 367
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    Ok, cool we agree on that. Pretty expensive for a little sensor. Oh well....
  • john p_2
    john p_2 Member Posts: 367
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    Finally got a chance to replace both my zone control panel and outdoor temp sensor. But now I have a display on my Taco PC700-2 that I've never seen before....the "WWSD" I've never seen this prior to changing the outdoor sensor. I know the system design is for that to be set at 70° because all settings were recorded in the PC700 paperwork
  • STEVEusaPA
    STEVEusaPA Member Posts: 6,506
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    WWSD is warm weather shut down. If enabled it won't allow a zone valve to open/boiler to file when any zone calls, when the temperature is at or above the WWSD setpoint.
    steve
  • john p_2
    john p_2 Member Posts: 367
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    STEVEusaPA, thanks so much.
  • john p_2
    john p_2 Member Posts: 367
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    SteveSan,
    Installed the new Taco PC700 temp sensor & the Taco zone control panel, love it with "C" wire connections.

    Also installed a thermostat termination box due to some short wires - previously had just an electrical junction box but changed it out to a custom black plastic box w/aluminum as a back plate to mount the new terminals to.

    Started installing the remaining Wifi stats, should be complete soon - see attached photos. Thanks for the help

    STEVEusaPASteveSan
  • STEVEusaPA
    STEVEusaPA Member Posts: 6,506
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    Looks great! Nice workmanship.
    steve
  • Wellness
    Wellness Member Posts: 141
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    Nice finishing detail on the coiled thermostat wire leading to the Taco zone valve and, also, black wire looms.

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