Nest thetmostat power numbers

[Pillman]

My nest thetmostat has a lin value of 385(Y). What does the Y mean? 

[EduardoN]

Hi @Pillman,

Thank you very much for contacting this community! I understand your question about the "LIN" value of 385(Y) on your Nest Thermostat. I can tell you that the value shown as "LIN" is the Input Current. This represents the amount of current in milliamperes (mA) that the thermostat is using from your system to power the heating and cooling functions.

In this case, a reading of 385(Y) is very common for a Nest Thermostat when there is no C wire or Nest Power Connector present. It means the thermostat is drawing power from one of the wires when the system is not actively running for that wire's purpose—in this specific instance, the air conditioning.

Keep me posted.

Best regards,
Eduardo

[Pillman]

I have a C wire that reads PS:C-385 along with the lin 385(Y) and Vin 29.411V

[EduardoN]

Hi @Pillman,

Thank you very much for the information you provided regarding your thermostat's readings. I can now verify that this is an excellent sign, directly confirming you have a functional C wire and sufficient power for your thermostat. The C wire and high-voltage (Vin) readings mean you have all the necessary power components to use your Nest thermostat without needing a Nest Power Connector or worrying about the battery running out. For your information, PS:C-385 means the C wire is providing a constant electrical return path.

Keep me posted.

Best regards,
Eduardo