Living Room


This shows what my wiring looks like in the living room and garage. I had a Honeywell Thermostat that I want to replace with an Ecobee 3, is it possible to use the C terminal for this?

The red wire broke when I popped the Honeywell from the wall. There is also a blue wire that is unused on both ends.

  • Can you move the left-hand red wire out of the way in the shot of the furnace board and take a new photo? – ThreePhaseEel Oct 11 '16 at 0:40
  • In the second photo (furnace control board), what is the label on the furthest left terminal? – Tester101 Oct 11 '16 at 10:08
  • It is labeled C, forgot to add that part. – Wayne In Yak Oct 11 '16 at 13:19

I'm assuming the terminal on the end is C, though the label is blocked in the photo.

enter image description here

If it is marked C, then the installation is simple.

  1. Connect the unused blue wire to the terminal marked C in the furnace/air handler.
  2. Connect the other end of the unused blue wire to the C terminal on the thermostat.

If that is not a C terminal. Please post the make and model number of the furnace/air handler, and/or a schematic for the unit.

  • It is a C terminal on the end, forgot to mention that. I was guessing that is all I would need to do but wanted to double-check. I'll test it out here. and see how it goes. Thanks – Wayne In Yak Oct 11 '16 at 13:19

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