12 pin screw terminal pin assignment:
Pin 1 : Thermistor 1 input
Pin 2 : Thermistor 1 input
Pin 3 : Thermistor 2 input
Pin 4 : Thermistor 2 input
Pin 5 : Relay 1 NO (normally open)
Pin 6 : Relay 1 COM
Pin 7 : Relay 2 NO (normally open)
Pin 8 : Relay 2 COM
Pin 9 : Relay 3 NO (normally open)
Pin 10: Relay 3 COM
Pin 11: 24VAC input
Pin 12: 24VAC input (GND)
4 pin serial communication connector pin assignment:
Pin 1 : 24VAC
Pin 2 : Serial communication signal 1
Pin 3 : Serial communication signal 2
Pin 4 : 24VAC (GND)
