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Installing a Nest Thermostat for heating with an ARGO 6P Zone controller

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gjlian
gjlian Member Posts: 4
in Thermostats and Controls
Replacing a Honeywell 2 wire thermostat with a Nest "Smart" thermostat is causing chattering of the relays. I've been reading forums and called both Nest as well as ARGO for advice. Nest simply told me to run a 3rd wire to the common terminal on the Nest which is a major hassle in an old house. I've also read about installing a local 24 volt power source near the Nest thermostat which is clunky in my opinion. Any thoughts or ideas are welcome. Thanks

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  • NY_Rob
    NY_Rob Member Posts: 1,370
    edited November 2018
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    I had to pull new t-stat cables when I when from old 2-wire stats to modern programmable stats. It was a pain pulling new wires, but better than running a wall-wart transformer to each t-stat for power.

    You can temporarily run any of the new stats off local 24vac transformers till you can pull new cables back to your boiler.


    Ironically... when I upgraded to a mod-con boiler, I went back to simple 2-wire t-stats again ;)
  • Jamie Hall
    Jamie Hall Member Posts: 23,289
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    As @NY_Rob says -- take your pick. Or pick one of the battery powered, programmable Honeywells, if you don't need internet connectivity.
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
    SuperTech
  • hot_rod
    hot_rod Member Posts: 22,143
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    Or get an Add a Wire kit. I think Ecobee includes that kit with some of there stats.


    https://smartthermostatguide.com/c-wire-venstar-add-a-wire-adapter-review/
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
    SuperTech
  • NY_Rob
    NY_Rob Member Posts: 1,370
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    @hot rod ....

    I looked it to that "add a wire kit" and stopped where it stated "Cannot be used as "R" power or "C" common wire. "

    If you look at the Q&A on Amazon it states:
    "Unfortunately this cannot be used to turn 2 wires into 3. It is specifically designed for 4-5 or 5-6 situations."
  • gjlian
    gjlian Member Posts: 4
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    Thanks for all the posts. I'm planning on installing an ARGO IR 882 (isolation relay) alongside the ARGO 6P this weekend. I'm told this will solve the problem. Total cost - $65 for IR 882 + $20 for 120/24 v transformer needed to power the relay. I will post the results on Monday in case anyone is interested.
  • NY_Rob
    NY_Rob Member Posts: 1,370
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    ^ Will the ARGO IR 882 supply power needed for your Nest over the existing 2 wires? I would contact them to be sure.
  • hot_rod
    hot_rod Member Posts: 22,143
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    NY_Rob said:

    @hot rod ....

    I looked it to that "add a wire kit" and stopped where it stated "Cannot be used as "R" power or "C" common wire. "

    If you look at the Q&A on Amazon it states:
    "Unfortunately this cannot be used to turn 2 wires into 3. It is specifically designed for 4-5 or 5-6 situations."

    Good to know, someone suggested there is a kit that can add a common. Maybe wi fi? Is that what Ecobee uses?
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
  • gjlian
    gjlian Member Posts: 4
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    I did speak to ARGO and yes they said it should work. I have a back up plan in case it doesn't but I'm cautiously optimistic at this point.
  • NY_Rob
    NY_Rob Member Posts: 1,370
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    I hope you will post back with results.....
  • gjlian
    gjlian Member Posts: 4
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    The ARGO isolation relay worked like a charm ! No more chatter :)
    NY_Rob
  • tjmagalhaes
    tjmagalhaes Member Posts: 1
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    Gjlian, I have the same issue. Can you post a photo of the final wiring at the argo boards?

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