Hi Joymon,
If your Nest Thermostat won’t turn on, the batteries could have drained or there could be a power issue.
If there’s a power issue, your thermostat’s battery will drain and it will turn off Wi-Fi, the display and other features to preserve battery life.
Before you begin
- Your thermostat should automatically turn on once it’s connected to your system, and your system is powered up or if you put in new batteries.
- During regular use, the screen may turn off if it doesn’t sense motion for a time. It will turn back on when it senses someone is nearby or when someone uses the app to control it.
- When batteries start to get low, the thermostat will turn off features like Wi-Fi and motion sensing to preserve battery life before it must turn off completely. You might need to tap the right side of the thermostat to wake it up.
- If there's a help message on your thermostat or in the app, follow the troubleshooting steps in Troubleshooting Nest thermostat error codes.
- Some systems, including heating-only, cooling-only, zone-controlled, and heat pump systems, require a C wire or the Nest Power Connector. Go to g.co/nest/cwire for details.
also try,
Remove the batteries and put them back in and
Replace your batteries
If these steps don’t resolve the problem, you should
contact a local Pro. The problem may be caused by an issue with your system.
Thanks
-From Arun Kumar S, Bronze Member.
