Converting from Carrier to Nest

[jennG29]

My old system has four wires that went to labels RS-(green wire), RS+ (blue wire), VG (white wire), and V+ (red wire). I have no idea how to connect it to my Nest thermostat.

[Markjosephp]

Hello jennG29,

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

It appears that your existing thermostat doesn't have the standard thermostat terminals. The RS terminals are usually for remote sensors, which Nest Thermostats don't use. To check your system compatibility with the Nest. Can you share with us a photo of your thermostat's wiring and your HVAC system control panel showing how the wires are being labeled? Also, tell us the make and model of it.

I'll look forward to your response.

Regards,
Mark

[jennG29]

Thanks so much for the response. My thermostat is Carrier and the model is a Comfort Zone II. I took a picture of it but can't find an option on here that allows me to attach it. 

[Markjosephp]

Hey there,

Thanks for the speedy reply! To insert an image in a post:

1. Hit reply to this post or your post and tap the camera icon.
2. Click Insert Image.
3. Choose an image source location.
4. Follow the on-screen instructions.

Best,
Mark

[jennG29]

Apologies for the delay. The problem was that I was trying to add an image from my phone but I can only do it from my laptop.

[zoeuvre]

Hi folks,

@jennG29, I’m sorry to hear about your Nest Learning Thermostat situation. RS-, RS+, VG, and V+ are non-standard thermostat labels which means that your system is proprietary. Proprietary systems aren’t compatible with Google Nest Thermostats. However, some proprietary systems can be rewired by a pro installer to be compatible.

Let us know if you have any other questions.

I appreciate your help, Mark. 

Thanks, 
Zoe

[jennG29]

I was afraid that might be the case. That makes me so sad, I really enjoy my Nest products. I will reach out to a pro installer to see if I can get at least one of my two nest thermostats back in use. 

[zoeuvre]

Hi jennG29, 

It sounds like a plan! and I definitely understand your disappointment with this, but you may still reach out to our pro installers like you've decided to better assist you with your system's compatibility with our Nest Thermostat. If you come across other information you'd like to pass along or have more questions, feel free to create a new post along with your thermostat's wiring setup.

All the best,

Zoe