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C wires, Nests, and Gremlins
A sort of plaintive comment here. And yes, I've tried to get helpful information from Nest. Good luck with that.
Does anyone have access to how a Nest is actually wired up? Inside? I've been following the "Help C Wire" thread pretty carefully, and folks have come up with answers -- the relay, particularly -- which really ought to have worked. There are other problems with that install.
But. What does actually happen to the helpfully designated terminals inside that contraption? Is C actually a common ground to everything? What powers the nitwits computer and battery? Rc? Rh? Either? Both? What happens on a call for heat? No relays, I suppose... is Rc isolated from Rh unless there is an external jumper? What about the other terminals?
And so on.
I regard the thing as a first class, if very clever, kludge. But they seem to sell a lot of them, and it would be helpful to us who feel impelled to help the victims to know what really happens inside...
Br. Jamie, osb
Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England.
Hoffman Equipped System (all original except boiler), Weil-Mclain 580, 2.75 gph Carlin, Vapourstat 0.5 -- 6.0 ounces per square inch