C138SE 3 Phase Defrost and deice logics.
Anti short cycle timer.
Delay for Indoor fan operation in Heat mode.
Delays between stage operations.
Random start delay.
High Head pressure protection.
Minimum compressor run time.
USD = Unit Shut Down input with random start delay. Diagnostic indications.
Optional: 0-10v valves control (of to 2 valves).
RS 485 communication port.