Wiring NEST Learning Thermostat for AC - Power

[Plasola]

I just installed my new Next Learning Thermostat 3rd Gen and the power keeps running low and eventually totally drained. After extensive reading and research and reading the post about wiring and power issue in the community, Someone smarter than me directed me to the Fan/Humidity control box located in my attic where the main AC unit is located.  I have a RobertShaw, Model 3100 series (?) thermostat that runs on battery.  I found that certain wire in the wiring was not connected and only the Rc, Y1, Y/O and G were. Which meant, at least for my unit, the blue wire was not. I connected the blue wire to the C port on both the thermostat and the fan/humidity control box in the attic and that seem to have solved my battery/power issue.  I hope this helps. @Link to members

[moralesvicente]

Hey Plasola, 

Welcome! I’m happy you're checking us out in this community. Thank you for taking the time to post this informative content. Your tips will be valuable to many people.

Of course, if you encounter problems after installing your Nest thermostat, connecting a C wire might be the solution. The C wires that provide constant power to your device are commonly blue; however, it's important to note that the color can vary depending on your HVAC system. 

If your system can’t deliver consistent power to your thermostat to keep its battery charged correctly or you are experiencing some troubles regarding cooling or heating, please check out this article: Learn about the common C wire. I know this information will be useful.

Thank you for sharing your tips and assisting others.

Regards

Daniel.