1. Outdoor sensor not connected
2. Outdoor sensor wiring
3. Faulty sensor
1. The Trinity Lx is factory set with Outdoor Reset enabled. Connect outdoor sensor or disable Outdoor Reset.
2. Check wiring of outdoor sensor. Wires should connect to Low Voltage barrier terminals 11 & 12.
3. Check sensor. Should be free of ice and snow. Check resistance of sensor and compare to thermistor resistance chart.