S1, S2 and Aux Wires

[paulfoster19]

I recently purchased the basic Google Nest Smart Thermostat, not knowing our downstairs unit apparently has a heat pump. I had easily installed this same model on our upstairs unit and assumed they were the same.

A quick call to Google helped me figured out why this one wasn’t compatible, and the tech said I could just tape the S1/S2 wires. After I got off the phone I realized that I don’t know the purpose of the white Aux-E wire, and where that would go in the new nest. 

Would purchasing the learning model accommodate the S1, S2 and Aux-E wires or would we be taping the sensor wires on all Nest thermostats? Where does the white Aux-E wire go in the nest?

 

[EdmondB]

Hello paulfoster19,

Thanks for verifying the type of HVAC system you have. This should be compatible with any type of Nest Thermostat. Check out this link for Nest thermostat compatibility.

The correct wiring configuration for that in the Google Nest thermostat is: 

1. Yellow wire on Y or Y1
2. Red wire on R or RH/RC
3. Green wire on G
4. White wire on W1/W
5. Blue wire on O/B
6. Brown wire on C

Take note S1 and S2 wires are sensors to provide temperature outside and since Nest uses Wifi connection to get its outside temperature no need to connect it. 

Let me know if you have more questions.

Thanks,
Edmond

[EdmondB]

Hi there,

I just wanted to follow up and see if you still need any help. Let me know if you have any additional questions from here.

Best,
Edmond

[Markjosephp]

Hello everyone,

Thanks for looking into this, Edmond.

@paulfoster19, 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 close this thread in 24 hours. 

Regards,

Mark