Older Nest Thermostat

[BusterH]

I just replaced an older t-stat with an old ((10 years??) Nest learning stat.  Green light at top blinks, but nothing else happens.  Web says “check batteries”, but my unit does not have any batteries.  It does have a little USB port in the back though??  Any thoughts?

[AxelD]

Hi BusterH,

Thanks for posting in the Community! Sorry to hear that you’re getting the “Check batteries” error on your Nest Learning Thermostat. No worries, help is here! I’d like to ask some questions to gather more information:

1. Have you tried charging the device with a USB cable?
2. Can I get a photo of your old and current wiring configuration?
3. Do you have a C-wire connected?

Keep me posted.

Regards,

Axel.