Nest Thermostat (C) wire N260 error

[WLF]

Purchased 3 Nest Thermostats and they are compatible with my HVAC system.

I'm having the N260 issue with 2 of the thermostats...stating that the Common (C) wire is needed.

The 3rd is good and have no error indication.

Why does 2 of the 3 require the (C) wire and not the 3rd?

All the wiring is the same (Y), (W), (G) and (R)

I need help explaining this problem.

Any assistance and information is greatly appreciated.

Thank you.

[Jeff]

Hi everyone,

In an effort to keep content fresh on the forums here and prioritize current issues, I'm going to go ahead and close up this thread. If you have any outstanding issues from this post or any other problems, please feel free to open up a new discussion.

Thanks,
Jeff