Need help with 6 wire install for nest thermostat

[Krazykakes]

Im trying to install a nest learning thermostat and have 6 wires. I currently have a “U” black wire installed and dont know where that goes. 

[alejandom]

Hi @Krazykakes,

Installing a Nest Learning Thermostat with a black "U" wire can be a bit tricky because Nest thermostats typically don't use jumper wires like the "U" wire you mentioned. Here's how to approach the situation:

1. Identify Your Old Thermostat: The first step is to identify the model of your old thermostat. Knowing the model will help you understand the function of the "U" wire based on the wiring diagram for your specific thermostat. Consult the manual that came with your old thermostat or search online for the wiring diagram based on the model number.

2. Nest Thermostat Compatibility: Once you identify the "U" wire's function in your old thermostat, check the Nest website for compatibility information. Here's a link to the Nest thermostat compatibility checker: https://support.google.com/googlenest/answer/9246656?hl=en

If you have any other concern don't hesitate to let me know.

Regards,

Mario.