C wire suddenly stopped being detected

[mathewr]

I have 2 nest thermostats connected via 2 separate nest power connectors. Both connected to same relay. One of them suddenly stopped working saying no power. I checked the wires, reset the thermostat and even got a new nest power connector. But no change. The thermostat without power is not detecting the W wire. It detects R but not W.

[mathewr · Accepted solution]

So the problem seems to be with the thermostat itself as I swapped the two thermostats and the faulty one still gives the same message at the other location- which tells me that the wires and connections are ok. Time for a new thermostat I guess as this is older than 2 years 

[EduardoN]

Hi @mathewr,

Thanks for contacting this community! I understand you have two Nest Thermostats, each connected to its respective Nest Power Connector. One of your thermostats is reporting no power and isn't detecting the W wire. I really appreciate that you've already performed several troubleshooting steps, including checking the wires, resetting the thermostat, and even trying another Nest Power Connector. Don't worry, I'm here to help you!

You performed a display swap between your two thermostats, but the faulty one still showed the same error on the working base. Because of this, the team would like to learn more about this behavior. When you get a chance, please fill out this form and let us know when you’re finished. We’ll have someone reach out to you via email from there.

Keep me posted.

Best regards,
Eduardo