Hi Sirwac,
Thanks for posting in the Google Nest Community forum. I'd like to know more about it. Could you please take a photo of the wires connected to your system's control board? This will help us to check if your system's wires are in the right connectors.
Go to the wiring Diagram and Technical Info. Take a photo of the diagram and power readings, then share it with us.
Best,
Jenelyn
