Net Thermostat C wire voltage

[Talen]

While installing 4th Gen Net thermostat, I keep getting a C wire no power error. Use a meter to measure, my C to R voltage is 20 volts, while other wires are at 24 volts. What is the minimum voltage requirement for C wire for Net Thermostat to work? The same wiring have no problem with other thermostat and this is a new built house. Thank you.

[SoriaD_]

Hello @Talen 

Thanks for reaching out to our Nest Community. Don't worry, Im here to help you with your C wire on your Nest Thermostat.

Apologize for all the inconvenience; let me give you a hand to find an answer for this situation. 
 

The normal readout should be somewhere between 20 and 30 V (24 V is most common). 
Mentioned this, I suggest first checking if the C wire is correctly connecting on your base and checking if all the system is full on. 

Then please test one more time. If the message persists, you can tell me if you have a specific code message (E22, E23, E24, etc.).
Also, you can share with me the information located in Settings>Equipment>Power info.

With these details, we can determine the possible solution for your situation.

Feel free to keep us posting; I'm happy to assist you.

Best regards,
Douglas.