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Zone Control Wiring

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Alan (California Radiant) Forbes
Alan (California Radiant) Forbes Member Posts: 4,074
edited January 2023 in THE MAIN WALL
Everyone has their own way of wiring, even on a controller where they provide you a terminal for every wire. This installer sent 24 volts (both "R" and "C", large red and blue wires) directly from the transformer to the thermostats and then a return wire from the thermostat to the "W" terminal.

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

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  • EdTheHeaterMan
    EdTheHeaterMan Member Posts: 8,153
    edited January 2023
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    Was there a picture to go with this?

    Everyone has their own way of wiring, even on a controller where they provide you a terminal for every wire. This installer sent 24 volts (both "R" and "C", large red and blue wires) directly from the transformer to the thermostats and then a return wire from the thermostat to the "W" terminal.

    Otherwise, It sounds like R to R w to W and C to C is what you would expect.
    Makes more sense with the photo.

    Edward Young Retired

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

  • Big Ed_4
    Big Ed_4 Member Posts: 2,813
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    Someone thought they can wire a nest :)

    There was an error rendering this rich post.

  • hot_rod
    hot_rod Member Posts: 22,327
    edited January 2023
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    Looks like an additional relay involved also 
    Does it work?
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
  • Big Ed_4
    Big Ed_4 Member Posts: 2,813
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    Maybe but why .... It would be simpler to rip the board out and hard wire

    There was an error rendering this rich post.

  • STEVEusaPA
    STEVEusaPA Member Posts: 6,505
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    Looks like they just basically mimicked what it looked like when it was wired without the zone control.

    There was an error rendering this rich post.

  • Alan (California Radiant) Forbes
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    hot_rod said:

    Looks like an additional relay involved also 
    Does it work?

    Not a relay. It's just a toggle switch for those who prefer toggles to unplugging a cord.

    This was installed by a company in California, early on in hydronics who were very good at marketing. They used large water heaters for DHW and radiant (via a HX), homemade expansion tanks, non-barrier tubing, non-ferrous pumps, no remote manifolds (all home runs to the mechanical room)..........
    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
  • mattmia2
    mattmia2 Member Posts: 9,828
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    Are you sure they didnt burn out some part of it
  • EdTheHeaterMan
    EdTheHeaterMan Member Posts: 8,153
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    Has this ever worked before the Nest Thermostats were installed? I think they used the correct T terminal for the W. And R is R where ever you pick it up from. Same for C... C is still C where ever you pick it up from.

    Looks like there is custom wiring in order to confuse their competitors. Kind of a guarantee that the customer comes back to the original installer for service. "If the competition can't figure it out, then I guess we need to call the guys that installed it"

    Sounds like Weil McLain parts. Can't use lower price generic off the shelf parts, Must use the Weil McLain part number or it won't work.

    Edward Young Retired

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

  • Alan (California Radiant) Forbes
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    There are no Nest or other wi-fi thermostats; simple setback ones that are not power stealing. Some installers like to power thermostats with a "C" wire so you don't have to change the batteries so often.
    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
    EdTheHeaterMan
  • Big Ed_4
    Big Ed_4 Member Posts: 2,813
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    I would recommend fusing the transformer

    There was an error rendering this rich post.

    EricPetersonAlan (California Radiant) Forbes