Nest thermostat compatible

[TheDweeb]

Hello, I am wondering if my existing wiring is compatible with the Nest. 

is the blue (B) wire common in my setup?

is the brown wire for O/B? It is currently not connected to anything.

The previous thermostat was a Trane T8411R

thanks in advance!

[CoolingWizard]

@TheDweeb , the absolute easiest way to verify if indeed, the blue wire attached to the  B Terminal is your common, you need to use a multimeter and with the power on, check for AC voltage between B and R terminals.  If your meter measures somewhere between 23 and 27 V of AC power, the B blue wire is indeed common.

The AC Cooling Wizard

[Patrick_Caezza]

@TheDweeb 

Many old Trane thermostats label the C wire as B in the Thermostat, and X2 is the emergency heat convection.

Your current thermostat is not fully compatible with the Google Nest Thermostat. Only the Nest Learning Thermostat, 3rd Gen, is fully compatible.

[Jenelyn_O]

Hi folks,

Thanks for reaching out. I hope you get the answer you're looking for. Please let us know if you still need help, as we'll be willing to assist you further.

I appreciate your help, @CoolingWizard and @Patrick_Caezza.

Best,
Jenelyn

[TheDweeb]

@CoolingWizard I will test this once I am able to get back into the home (being painted atm)

@Patrick_Caezza I will return mine for that one then, thanks!

[Jenelyn_O]

Hey TheDweeb,

That sounds like a plan! I'll just keep this thread open to ensure everything will be taken care of. Please keep us posted. 

Thanks,

Jenelyn

[Markjosephp]

Hi TheDweeb,

I'm checking back in — how's it going? Still need our help?

Regards,

Mark

[Jenelyn_O]

Hi folks,

We haven't heard from you in a while so we'll be locking this thread if there is no update within 24 hours. If you need assistance or want to discuss topics, feel free to start a new thread.

Thanks for your help, mark.

Best,

Jenelyn