Won’t turn on AC

[Billdash]

I have installed the thermostat twice now. In between, I reinstalled my old thermostat to be 100% sure my AC unit is running well (it is). My issue is that I install the Nest using what I think are the right wires, but the Nest won’t turn on my AC. The heat will turn on and the fan blows but not the AC. I thought I had an issue with the O and B wire (I think mine is B since there is an orange wire not used and the brown wire is in the O/B slot on the old thermostat but it’s still not working. Would appreciate advice!

 

 

[Patrick_Caezza]

The first thing you need to do is clean up those wires, they have to be straight and have shinny bright copper showing with no nicks or dings.

You appear to have the wires in the correct location, but how did you identify them when the app asked you to select the wires that are in use? You should select these I believe.

Y/Y1, G/G1, C, O/B, Other, and R

Other is for the white wire which is AUX, not W2

[Billdash]

Hi Patrick. Appreciate the reply. I removed the device, reset it, and reinstalled. I chose the wires you suggested (Other) and got the same result. When the AC is supposed to turn on, only the fan blows. There is one other wire in the bunch - and orange one that is not connected, by the way (and not used with the prior thermostat). I chose O when asked between O and B also. 

any suggestions?  Again, very much appreciate your help. 

[Billdash]

Got lucky and my pest control guy used to do hvac. Had him look at it. Confirmed I had a Rheem unit that works off of a B configuration. Never changed a wire physically from what I had installed. Just reconfigured with R C G W and O/B

[Ryan_G]

Hey Billdash,

Thanks for sharing this here at the Google Nest Community.

It's great to hear that you were able to configure the right OB wire orientation to get your AC going, thanks to your pest control guy too.

It looks like this has been resolved but we'll give it a couple of days and let us know how it goes by replying to this thread.

Thank you for your help too, Patrick_Caezza.

Best regards,

Ryan

[Patrick_Caezza]

Ya, since your original thermostat had the O/B label you should have chosen the O/B option in the setup. 

I need to remember to start telling people what wires to select in the Google Home app when they are setting up the Google Nest thermostat since it doesn't do it automatically as the other Nest thermostats do.

[MelbaDT]

Hey folks, 

Thanks again for your answer, Patrick_Caezza. 

We haven't heard from you in a while so I'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