Green wire is on "C" terminal on old thermostat. Customer has gas furnace

[sparkync]

I'm changing a "Honeywell thermostat" ( looks like), and there are 4 wires.  The furnace is "gas".  The green wire is on the "C" terminal.  I thought the green wire was normally the "fan" wire.  Do I still hook the green wire up the "C" terminal on the new "Nest" thermostat?  The instructions say it don't need a "common" wire, but the old thermostat has a "run" mode for the fan.  Looks like if I don't hook the green wire up, the "fan only" option would not work.

Thanks

[Ryan_G]

Hi sparkync,

Thanks for reaching out and we're sorry for the delay.

We don't recommend following the color coding for wires as the system may vary. If your system green wire is for the C (common) wire, we'll be using it to the C terminal on the Nest Thermostat. The good thing about having a C wire is for your Nest Thermostat to have a constant power to be able to function and be connected to the Wi-Fi all the time.

Regards,

Ryan

[MelbaDT]

Hey there, 

Checking back in should you have further questions here. Let us know by replying to this thread. 

Best, 

Melba

[MelbaDT]

Hi, 

We haven't heard from you in a while so we'll be locking this thread if there is no update within the day. If you have any new issues, updates or just a discussion topic, feel free to start a new thread in the Community.

Best, 

Melba