Nest Pro Thermostat installation

[jayme76]

I bought a Nest 3rd Gen Learning thermostat after going through customer service and being assured it was compatible with my current system. I'm now trying to install but unsure of the wiring. I have a Bryant 2 zone with wiring attached pic. Not sure how to go about this but was assured it would work...

[CoolingWizard]

Your system using a digital communication and not a conventional HVAC control. This system, as wired, is not compatible with the Nest or any other conventional thermostat. It is possible to rewire your system and convert it back to conventional 24VAC control.

AC Cooling Wizard

[Ryoerger]

My thermostat base looks exactly like the one shown above. However, I have a white, blue, green and red wire bundle coming out of wall. The red is connected to the far right (V+) terminal and the green wire is connected to the second terminal in from the right (VG) terminal. Is this compatible with nest? Thx!

[CoolingWizard]

@Ryoerger , sadly conventional thermostats use 24Vac power to control the equipment.  These proprietary digital thermostats use a communications protocol that is digital in form. Most manufacturers of HVAC equipment provide both types of control.  Inside the air handler there are two separate control interfaces. One is for digital communications and the second uses the conventional R, C, Y, G , W, O wires.  you can switch to the conventional interface but to achieve this you have to go to your air handler and find the R,C,Y,G,W and O terminals and re-home the wires.   You will have to re-home the wires going to the outdoor unit as well.  Going outside is Y wire and C. If you have a heat pump you will have an O wire and possibly a Y2 wire. The Y2 is in heat pumps and air handlers that are heat pump ready. 

AC Cooling Wizard

[Ryoerger]

Ok. That was very helpful and the basic concept. I think this is one of those things I’ll hire the installer of my system to handle, to ensure it gets done right - unless someone can provide me a schematic for my specific system.

[CoolingWizard]

@Ryoerger , if you can provide me the make and model number of your indoor and outdoor units, I can check the IOM and provide you the desired schematic. 

AC Cooling Wizard

[Ryoerger]

 

[Ryoerger]

Any luck Cooling Wizard?

[CoolingWizard]

@Ryoerger , sorry for the delay. I think your condenser model number is GSC130301-AD. Here is the wiring schematic for that unit. 

The part number CAPF303006AA is actually the Goodman 2.5 Ton Evaporator coil.

AC Cooling Wizard

[Jenelyn_O]

Hi folks,

Thanks for posting in the Google Nest Community forum. I'm sorry for the delay. 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 your help, @CoolingWizard.

Best,

Jenelyn

[Jenelyn_O]

Hi there,

I wanted to follow up if you still need help. Please let me know if you’re still having any concerns or questions from here, as I would be happy to take a closer look and assist you further.

Thanks,

Jenelyn

[jayme76]

Jenelyn,

Thanks for following up - I ended up returning the thermostat as it wasn't going to work. My only feedback is that the phone "expert" and specialist from Google should have been able to identify this in the first place as I did my due diligence and took the time (probably an hour on phone email etc) trying to verify the thermostat would work for my system - took pics etc. and someone on this forum identified it in a lot less time. That's frustrating to me.

[Jenelyn_O]

Hi jayme76,

Thanks for sharing your feedback. I'm sorry for the time that was lost and for the trouble this has caused you. Ensure that we'll take note of your feedback. Please let us know if you still have questions or concerns, as we'll be willing to assist you further. Otherwise, I'll be locking this thread after 24 hours.

Regards,

Jenelyn