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Join Date: Jan 2012
Posts: 12
CAL

01-22-12, 06:17 PM   #7 (permalink)  
Nest is compatible with 2 wire 24v systems that have only Rh and W and Nest Support thought that's what I had (and also what *I* thought I had) until A) We had a power outage, and the thermostat continued to work and B) I traced the wires from the thermostat all the way to the furnace, and noticed that they end at a small box right next to the pilot light. And there is no other wiring running into or out of the furnace.

As for my existing wiring—currently there are only the two millivolt Rh and W wires running to the stat, but I do have the ability to easily run as many extra wires to the stat as needed, so that's not an issue. The wiring is very accessible.