Fresh Air Temperature Sensor "T0" is in Open Circuit or Has Short Circuited
The fresh air temperature sensor with the designation "T0" at the air handler is reading that the temperature around the unit is either outside of safe operating limits or the sensor has shorted out.
Error at Start Up or During Normal Operation
- Check the air inlet temperature of the air handler with a standalone thermometer. Record the temperature and reach out to the manufacturer for additional troubleshooting or part replacement.