Hi @MM2008,
Thanks for posting in the community. I understand you're upgrading from your Nest Thermostat (2nd Gen) to a newer Nest Thermostat (Gen 4), and you're wondering if you can use the same wiring connections. This is a common and important question when upgrading, and I'm here to help clarify!
Generally, if the new Nest Thermostat's base has the same labeled ports (e.g., R, W, Y, G, C, O/B, etc.) as your Nest Thermostat (2nd Gen) base, you can typically plug the wires into their corresponding lettered slots. Nest products are designed to make upgrades as straightforward as possible where wiring is concerned.
For detailed guidance specific to your new thermostat, and to ensure a smooth setup, I highly recommend following the steps in our official Help Center article: Get started with your Nest Thermostat and Nest Learning Thermostat (4th gen).
This article provides comprehensive instructions that will walk you through the setup process, including confirming your wiring.
If you have any further questions as you're setting up your new Nest Thermostat, or if you encounter any issues, please don't hesitate to reply back to us. If you're still having trouble with the wiring, please try to attach a picture of your current wiring setup when you respond, as that can be incredibly helpful for us to see your specific connections!
Regards,
Kevin
