Low Battery message won't go away

[Carly1028]

About a week ago I got a notification that my Nest thermostat had a low battery.  The message code was N261 - low power to C wire.  The C wire is connected though.  Our old thermostat was ancient and none of the wires were labeled when we installed the Nest.  We have green, red, white and blue wires.  The blue wire was the only wire that made sense to connect it as the C wire.  We adjusted the blue wire to make sure it wasn't loose, and I replaced the batteries in the Nest this morning.  I'm still getting an error message that the batteries are very low.  The N261 error has been gone for a few days though.  Why would I still be getting a very low battery message even though the batteries were replaced and the C wire is connected?  The system is still heating correctly but I'm about ready to throw this Nest thermostat out the window with all of the troubleshooting I've had to do!

[Markjosephp · Accepted solution]

Hello Carly1028,

Thank you for taking the time to let us know about your inquiry. I'd be happy to take a look into this for you.

With this message code you're getting, it means that the thermostat received low power and can be fixed with a proper installation. To isolate:

• Could you share a photo of your thermostat's wiring?
• Did you update the wiring after installing the C wire?
• Gather the power readouts in the "Wiring info" section under the Equipment settings.

I'll look forward to your response.

Regards,

Mark

[EmersonB]

Hello everyone,

@Carly1028 how's it going with your Nest Thermostat? We would appreciate it if you could share with us the information that we're asking above. Let us know if you have more questions in mind.

I appreciate the help, Mark.

Best, 
Emerson

[EmersonB]

Hi Carly1028,

Just one quick final check in here since activity has slowed down. We'll be locking the thread in the next 24 hours, but if you still need help, I would be happy to keep it open. If there's more we can do, just let me know.
 
Thanks,
Emerson