E72 code out of the blue

[Doctortlc]

I am getting an E72 error code after a couple years of consistent use. I would have posted to one of the other conversations regarding this subject, but for some reason I was blocked from doing so. I followed directions from those posts: checked wires, checked fuse box, checked filters and the doors... however, the nest will not stay charged long enough to re-attach it to the app. The nest will not recognize the wifi or the sensor. 

It has been -10 to 6° here and I had no choice but to go get a thermostat from the store because I couldn't go without heat. The heat worked with the manual thermostat. 

What other help can I receive or do I have a faulty thermostat?

Thanks

[Jenelyn_O]

Hi Doctortlc,

Thanks for reaching out in the Google Nest Community forum and for being a step ahead of us. I'm sorry for the trouble this may have caused you. I'd like to take a closer look at it. 

The E72 code means that your thermostat didn't detect any power wire at all. Your system might not provide enough power or any power to either the thermostat or a specific wire (so the thermostat can’t complete a circuit and shows the code). A few questions: in what country are you located? Did you recently experience any power outage in your area? Do you have an energy savings box? Some utility companies install boxes that cut off the power during high-demand (peak) times.

Please provide your thermostat's power readings. You can follow the guide below:

1. Go to your thermostat Quick View menu.
2. Go to Settings.
3. Look for Technical Info.
4. Select Power.

Keep me posted.

Best,

Jenelyn