Thanks for reaching out to the Google Nest Community.
What type of Nest thermostat do you have? Has it worked with this HVAC system before? If yes, were there recent changes made before this started happening? I suggest that you go through the suggested troubleshooting guide here to check on your thermostat wires: https://bit.ly/3qjt7Si
I haven't heard from you in a while so I'll be locking this thread if there is no update within the day. If you have any new issues, updates or just a discussion topic, feel free to start a new thread in the community.
