Nest Thermostat installed and was working. Now there is E79 error.

[Rcornette41]

I recently had a nest 3rd generation Thermostat installed and was working for 3 weeks. The device was unlinked from my nest account and I went to add it back in. I removed the Thermostat head to scan the qcode on the back and then plugged it back in. When i did that it said that a wiring configuration had changed. It said no power to Common wire. I have verified power on the Rc/Rh and Common wire and am getting 24v. I checked at the air handler and the compressor outside and getting 2v on the wires as well. Any thoughts?

[EdwardT]

Hi Rcornette41,

Thanks for reaching out. I'm sorry to hear that you're having an issue with your Nest Thermostat. I'd love to know more about this and I have a few questions:

• How is your Nest Thermostat wired?
• Have you tried reseating the C wire?
• What is the power reading of your Nest Thermostat?

Looking forward to your response.

Thanks,

Edward

[EdwardT]

Hi Rcornette41,

I wanted to follow up and see if you are still in need of any help. Please let me know if you are still having any trouble from here, as I would be happy to take a closer look and assist you further.

Thanks,

Edward

[EdwardT]

Hi Rcornette41

I'm just checking in to make sure that you've seen our response. Please let us know if you have any other questions or concerns as I will be locking this in 24 hours.

Thanks,

Edward