E79 Error message persist even after recheck of wires. What's the solution?

[JLewis18]

I'm installing a refurbished Nest thermostat and I'm getting this E79 error message.  I've rechecked the wires, made sure they're connected properly.  How do I get rid of this E79 message?

[maedacortez]

Hi JLewis18,

Thanks for reaching out about the error code E79 on your Nest thermostat. I understand how frustrating it can be when your thermostat isn't working properly.

The error code typically indicates an issue with the C wire. To help you get things back up and running quickly, I've included a link to our troubleshooting guide for Nest thermostat error codes here.

I will look forward to your response.

Regards,

Manuel

[JLewis18 · Accepted solution]

I checked the troubleshooting, checked the wires then got an E73 message - no connection to the Rh wire.   The thermostat is also Offline.