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C wire & Aquastat L8148E with 3 zones

I would like to use 2 NEST thermostats on my boiler. I have a Honeywell Aquastat L8148E. I also have 3 Zones (valves are Honeywell V8043E1012) and will be using a NEST on only two of the Zones

I have currently 2 wires connected to the thermostats, both plain 'speaker' wire not colored wires.

Anyone care to help with getting 'C' Wire to the two NEST thermostats maybe with wire diagram ?
Thank-you
Royals

Comments

  • EdTheHeaterMan
    EdTheHeaterMan Member Posts: 4,913
    Do the zone valves have a separate transformer?
    Do the zone valves use the transformer in the L8148E?

    This will determine where to get the C wire from.
    Edward Young Retired HVAC Contractor & HYDRONICIAN Services first oil burner at age 16 P/T trainer for EH-CC.org
  • Royals
    Royals Member Posts: 13
    I am pretty sure the zone valves have separate transformer, outside the Aquastat, let me just confirm
  • Royals
    Royals Member Posts: 13
    So Yes i can confirm, there is an extrenal transformer, so from the external transformer, the yellow wire goes near the Zone valves, and is then spliced to the 3 zone valves one of their yellow wires (they have 2 yellow wires on each valve). The blue wire from the external transformer, goes to near the Zone valves and is spliced, to the 3 thermostats wires, then from there on to the 2nd yellow wire on their respective zone valves. The 2 RED wires from the Zone valves then go to Aquastat, one each to T and TV.
    Make any sense ?
    Royals
  • EdTheHeaterMan
    EdTheHeaterMan Member Posts: 4,913
    edited October 2022
    Then the C wire on the thermostat goes the the C of the zone valve transformer. diagram to follow
    Edward Young Retired HVAC Contractor & HYDRONICIAN Services first oil burner at age 16 P/T trainer for EH-CC.org
  • Royals
    Royals Member Posts: 13

    Then the C wire on the thermostat goes the the C of the zone valve transformer

    Thank-you , which wire would be the 'C' on the valves that i can connect the Themostat C wire to?
  • EdTheHeaterMan
    EdTheHeaterMan Member Posts: 4,913
    edited October 2022

    C on the valve is one of the yellow wires.
    W on the thermostat is the other yellow wire

    Thanks Jamie. I cleaned up the connections and added "wire nut dots"

    Edward Young Retired HVAC Contractor & HYDRONICIAN Services first oil burner at age 16 P/T trainer for EH-CC.org
    Peter_26
  • Jamie Hall
    Jamie Hall Member Posts: 20,416
    To add a note to @EdTheHeaterMan 's excellent diagrom (wish i could draw like that) -- there is no connection where the black/yellow vertical crosses the black horizontal...
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
    EdTheHeaterMan
  • Royals
    Royals Member Posts: 13


    C on the valve is one of the yellow wires.
    W on the thermostat is the other yellow wire

    Thanks Jamie. I cleaned up the connections and added "wire nut dots"

    Ed: I can't thank you enough. everything working like it should. The diagrams were perfect and I followed them easily.
    You're the best
    Royals
    EdTheHeaterMan