Nest Thermostat Wiring

[Ekavir]

I installed the thermostat and it works when in Cool mode but not in Heat mode. I'm suspecting the wiring is incorrect and have tried two possible mapping but neither worked. I've attached the wiring on my previous thermostat (Honeywell RTH221 1-WEEK PROGRAMMABLE THERMOSTAT). My furnace is a Ruud Silhouette II Gas Furnace. Can you please provide the wiring map that's appropriate for my furnace?

[laurentbourg]

Please post a picture of your Nest wire base connections

[Ekavir]

Where does the Blue wire attach to on the Nest Thermostat (Y, C, W, G, R, Ob) ? I've tried connecting to C and Ob but neither worked?

[laurentbourg]

Do you have a heat pump system?

[Ekavir]

No, there's no heat pump system.

[Ekavir]

I also traced the Blue wire back to the furnace and found it's not connected to anything. Only the White, Yellow, Green, Red wires are connected.

[laurentbourg]

Ok makes sense, I would not expect it to perform any function in your setup. You can ignore it. 

[Ekavir]

I connected the 4 wires to the appropriate Next labeled terminal (Yellow -> Y, White -> W, Green -> G and Red -> R) but still doesn't work.

[laurentbourg]

Please upload a picture of the wire diagram from google home. Settings -> Thermostat -> Wiring to make sure it is not setup as a heat pump and that it matches your physical diagram

[Ekavir]

 

 

[laurentbourg]

That’s what I thought, this is the wrong setup, it is configured as a heat pump, you need to update the wiring deleting the OB connection. 

[Ekavir · Accepted solution]

Good News! I noticed that the Google Home wire diagram was incorrect so I restarted the thermostat with only the 4 wires connected and voila!, it works! Here's the working wire diagram.

 

[laurentbourg]

Awesome that looks more like it. Please mark the answer as a solution when you get a chance so that we can close this thread. 

[Nasratullah]

I have only 4 wires , there’s no blue wire for auxiliary 

[Ekavir]

Is there a way I can troubleshoot the thermostat when not connected to the furnace?

[laurentbourg]

No, the wire base need be connected and the display on the wire base for being able to trouble shoot. You can emulate a furnace setup but that is too complex for us to setup on this thread. 

[Ekavir]

 I found the furnace schematic diagram.