E79 error after power outage

VRHRM — Wed, 24 Apr 2024 16:24:31 GMT

Hi there,

I have installed a new 3rd generation learning thermostat at my cottage a month ago and it has been giving me E79: no power to wire C after each power outage (we have had 2 of them in the past month) it has been very frustrating since the cottage is couple of hours away and I need to make the trip to reset the thermostat. I have been using nest thermostat at my house for more that 3 years and never had an issue after power outage. How can I resolve this?

Re: E79 error after power outage

moralesvicente — Sat, 27 Apr 2024 18:27:11 GMT

Hi VRHRM,

Thank you for posting in this community. I understand the inconvenience that you are having, but don’t worry I'm here to assist you. Of course E79 error code on your Nest thermostat indicates that it's not receiving continuous power, which is typically provided by the C wire. Here are some solutions you can try to resolve this issue:

First, make sure your system has power, Look for a switch labeled "furnace" or "AC" on your breaker box or fuse box.
Verify wiring connections, and ensure all the wires are securely fastened in the terminals on both the thermostat and your HVAC system's control board. Loose wires can sometimes interrupt the power supply.
Try to remove the c wire, isolate this wire and reboot the thermostat.

If the inconvenience persists, you can contact professional assistance.

Regards,

Daniel

topic Re: E79 error after power outage in Nest Thermostats

E79 error after power outage

Re: E79 error after power outage