My furnace's control board. The "C" terminal has no connection to the thermostat in this picture. (The white wire on the C terminal goes to the A/C.) I connected the unused blue wire (bottom center) to the C terminal. The Nest now confirms the active "C" wire. I recently bought and installed a Nest Learning Thermostat to replace my old non-networked thermostat.
posted at 2012-08-30 11:41:54 US/Mountain
by David Simmons
tags: thermostat nest home automation electronics