Wire issue on google nest

[Lmliace03]

Ok guy I have been at this for 2 hours now. I am getting a no power error m20 and e257. How can I get past this wiring issue?

Lisa 

[tajennifer]

Hi Lmliace03,

Thanks for posting. I apologize for the issue that you are experiencing with your thermostat. But don't worry I can help. In this case you see two different codes regarding the wiring configuration:

• M20: Missing Power Source

1. This code indicates that your thermostat might not be receiving proper power.
2. On your Nest Thermostat, navigate to Settings > Equipment > Wiring Info.
3. Check for wires listed as "gray." These wires aren't supplying voltage to your thermostat. Certain wires, like the C or R wire, are needed to provide continuous power. 

Here is how to Troubleshoot a "No power" alert on the Nest Thermostat article for more information regarding this help code.

• E257: Missing Y1 Wire

1. This code suggests your heat pump requires a Y1 wire for proper functionality.
2. Codes like this might appear if the thermostat wires weren't configured correctly within the Home app.
3. To resolve this, try resetting your thermostat and re-adding it to the Home app. 

Here is how to Troubleshoot Nest thermostat help codes article for more information regarding this help code.

Please let me know if you have questions regarding the steps to solve the issue. 

Regards,

Jenny