I am trying to troubleshoot a dual-energy heating installation. I found this diagram from the electrical company. The terminals below the meter face are labeled O, N, F, 12, and VCA. 12 I think is 12 volts, VCA is alternating current. These are in French so I'm guessing O, N and F are as well. If it helps: two of these terminals should act like a thermostat and close the circuit at a certain temperature (not sure which two,that's what I'm trying to troubleshoot). I'm not sure what the third one does.

  • Where are you on this planet? Commented Dec 11, 2018 at 4:53
  • Quebec; the English language diagrams often don't translate the abbreviations
    – Michael C
    Commented Dec 11, 2018 at 9:29

1 Answer 1


The answer awoke me at 4am: It's a three way switch. N = Neutre (neutral). O = Ouvert (Open, this circuit is open in the diagram), F = Fermé (Closed, this circuit is closed in the diagram).

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