I am installing an Ecobee3 and have found that, while the common wire exists, it is not connect to the furnace. The wiring schematic for my specific furnace can be found in this PDF
There is no control board on this furnace so identifying the connections aren't as simple as they could be.
On my furnace, the current wiring is as follows:
- The 3 white wires from the low voltage field connection are joined with the single white wire going to thermostat.
- The green wire is connect to green going to thermostat.
- The red wire is connected to red going to thermostat.
- The blue wire is connected to yellow wire going to thermostat.
Here is a picture of the current wiring.
Do I connected the unused blue wire going to the thermostat, to the blue wire coming from the furnace? If so, what do I do with the yellow wire? Do I join all 3?