Hi @EdwardT thanks for reaching out. I had a tech come in to solve the issue.
The problem was I wired the system a year ago following the old thermostat. I had no C power wire. The system worked fine for a year and had no issues. But a week ago this started blowing cold air instead of heat.
Turns out that I had the wiring wrong. I did not have a heat pump. So no brown wire connection. The tech was also surprised that the system was working fine for a year. Got the Blue wire hooked up and fixed the wiring. Now the system works fine.
The thing I learned from this experience is to make sure the wiring from your system matched the nest system and do not rely on the wiring form your old thermostat.
