Wiring compatibility

[sanbsetty]

Hi, 

Attached current wiring of my first floor unit. I successfully replaced the upstairs thermostat to nest as it was straight forward.

I understand that Rh Rc connection is not required. 

But, I do not understand the orange wire between B/C and Aux2 

How does this wire translate to Nest?

Appreciate any advice 

 

[Markjosephp]

Hello sanbsetty,

Thanks for reaching out to the Google Nest Community Forum. I'd be happy to take a look at this for you.

The Nest Thermostats don't require jumper wires, so you no longer have to connect them. But to be sure, is your system a conventional unit only with Heating and cooling and not a Heat Pump? If so, here's how you should wire your Nest Thermostat:

• White wire > W/W1 terminal (Heat)
• Green wire > G terminal (Fan)
• Yellow wire > Y/Y1 terminal (Cool)
• Blue wire > C terminal (24-volt common)
• Red wire > Rh terminal (Power)

Let me know if you have more questions.

Regards,
Mark

[Markjosephp]

Hey there,

I wanted to follow up and see if you are still in need of any help. Please let me know if you are still having any trouble from here, as I would be happy to take a closer look and assist you further.

Thanks,

Mark

[sanbsetty]

Hi Mark, thank you for your reply.

I am looking specifically at the black wire to Aux2 and the orange wire from B/C.

I spoke to a ac technician and he thinks it could be to control the air vent. As our a/c is a single stage system. 

[Markjosephp]

Hi sanbsetty,

Got it! I'm sorry for the late reply. With that said, the Black wire goes to the W2/Aux terminal, leaving the orange jumper wire disconnected in the Nest Thermostat.

Let me know if you have more questions.

Best regards,
Mark

[Markjosephp]

Hello sanbsetty,

Checking back in — how's it going with the installation? Still need our help?

Thanks,

Mark

[sanbsetty]

I connected the black wire to * and AC is working fine, not sure why you suggested it should go to W2/Aux 

[Markjosephp]

Hello there,

This depends on the Nest Thermostat model you have; if you have the Nest Learning Thermostat, it should go to the W2/Aux unless it's emergency heating. But if you have the Nest Thermostat E or the Nest Thermostat 2020, it'll go to the *O/B terminal. But I'm glad to hear it was sorted out.

Let us know if you have any other concerns or questions. Otherwise, feel free to create a new thread to open a new topic.

Regards,
Mark

[sanbsetty]

From the AC tech I was told the black wire could be for humidity control and I have Nest learning thermostat. Does that mean I should change the black wire to W2/aux instead of * ?

[Markjosephp]

Hi sanbsetty,

Got it! Thanks for letting me know. For HVAC accessories such as humidifiers or dehumidifiers, they will be connected to the * terminal. But right now, leave the wires as they are for the configuration and let me know if I can help out with anything else.

Best,
Mark

[Jenelyn_O]

Hi there,

Chiming in —  I just want to check if you managed to see the response above. Please let us know if you still have questions or concerns, as we'll be willing to assist you further. 

I appreciate the help, Mark.

Thanks,

Jenelyn

[sanbsetty]

Hi Jenelyn

I think I managed to get the thermostat working. Thank you 

[Jenelyn_O]

Hey sanbsetty,

Thanks for the update. I'm glad to hear that your Nest Thermostat is working now. Please feel free to let us know if you have any questions or concerns in the future by creating a new thread, as we'll be willing to assist you.

Cheers,

Jenelyn