Compatability

[JaneDawson]

Trying to replace a 1997 CommandAire geothermal thermostat with a Nest Learning Thermostat.  We have an F wire that I don't know what is for and its not on the compatibility checker. Also have y2, w1, w2, O, C and R.    Any ideas in the F? 

[JaneDawson]

Photo of  thermostat 

[Houptee]

Probably F is for the fan so it would go to G.

Looks like they used the green wire (which is usually the G fan wire) for 2nd stage heat on W2

So just match everything up but put F to G and it should work.

[aatienza]

Hey JaneDawson,

Checking in — we hope you've got the answer you're looking for. Let us know if you have more questions in mind.
 

I appreciate the help, Houptee.

Thanks,
Archie

[Markjosephp]

Hello folks,

Thanks for assisting, Archie.

@JaneDawson, I wanted to see if you had a chance to install your Nest Learning Thermostat. Please let us know if you have any other questions or concerns.

Regards,

Mark

[Markjosephp]

Hello JaneDawson,

I'm checking in to make sure that you've seen our response. Please let us know if you have any additional questions or concerns before we lock this thread in 24 hours.

Thanks,

Mark