Nest E79 Error Code (How to fix instructions)
In this video we explain in step-by-step instructions how we are fixing the E79 Error Code on our Nest Thermostat. This Nest Thermostat is of the 3rd generation.
First we are entering the Settings menu, going to Equipment. Here we find the equipment wiring detail, which the Nest was able to detect. We see that many wire-descriptions are grayed out, and also the 'C' port is marked in red. This indicates that we are not getting sufficient power over the 'C' / 'Rc' ports. In our case the power external 24 volt AC power supply is burned out and we need to replace it.
We install a new power supply with the same specifications and wire it up correctly - not forgetting the bridge between the 'Rc' and 'Rh' ports.