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learning nest 3rd gen with Mastertrol V-6

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A/c was fine on instal worked great. Switched to heat and e80 no power to y1...said might need C wire...bought google power connector to solve the problem and installed....no difference...anyone else experience this and solved it?

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  • Jamie Hall
    Jamie Hall Member Posts: 23,668
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    Pretty much everyone who has tried to tack a Nest onto an existing heating system has had some sort of similar trouble.

    You do need a C wire, and if you have both A/C and heat and the Nest is trying to switch back and forth, it can get very interesting.

    Try searching The Wall for threads referencing Nests or C wire...
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
  • douglashansen
    douglashansen Member Posts: 3
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    The google power connector was suppose to take care of that issue it connects to the c on the board. Did not work
  • ratio
    ratio Member Posts: 3,701
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    What does Nest tech support say?

    Does it work right if you switch it back to AC mode?

  • douglashansen
    douglashansen Member Posts: 3
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    yes...and google support had me check connections which I had done 20 times and sent me to Nest pro support so they could charge me 99 bucks to set up an appointment....for someone to come out to diagnose. No phone support that meant anything...
  • EBEBRATT-Ed
    EBEBRATT-Ed Member Posts: 15,847
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    @douglashansen

    You would not believe the quantity of Nest posts we get here on a daily basis.

    There are all kinds of work arounds like the one you tried that didn't work.

    The best way is to add a transformer and a RIB relay, probably $50 worth of parts. You have the new transformer power the Nest and have the Nest control the new relay. The new relay controls the heating and ac equipment.

    Nest's apparently take a lot of power to keep their battery charged so they don't play well with some controls with small transformers. Plus you can then get a new "C" wire off the new transformer.

    It's a foolproof fix as far as i know.

    Yo can try other fixes maybe they work and maybe they don't
    STEVEusaPA
  • ratio
    ratio Member Posts: 3,701
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    Say, are you replacing the master stat or a slave zone? IIRC (at least earlier) Mastertrol systems didn't use regular stats for the slaves. IIRC there are a few threads here about that, you should look through them to see if they match your issues (Use a google site search [add " site: forum.heatinghelp.com", the spaces are important] to your search terms, as the native search isn't all that great).

    If there's a schematic, post a pic of that, along with the model number of the controls.