E79

[DRT]

Installed a nest third generation learning thermostat. Receiving an error code e- 79 telling me there’s no power to the C wire. When checking with a multi meter both R and c are measuring voltage. Have re-checked connections and made sure copper wire is clean and straight going into the terminal.

[Ryan_G]

Hey Murfee,

Thanks for reaching out and I'm sorry for the delayed response.

Since you've already checked the wire is clean and properly connected to the terminal, the error you're getting could be resolved by checking your HVAC system power. First, make sure the power to your system is on. The power switch will usually be in your breaker box or fuse box, but in some homes it will look like a light switch near the heating or cooling equipment. 

Note: Make sure to turn off your HVAC power switch before touching any wire.

Let me know how it goes.

Regards,

Ryan