the SL6200  control board can manage 1 compressor frequency conversion system (with Deep Blue SL8335 frequency conversion drive module), can manage 1 set of heaters, blower PWM control, and can manage 1 humidifier. 
1. NO is the normally open contact of the relay, NC is the normally closed contact of the relay, and COM is the common terminal.
2. the rated index of the relay refers to the resistive load carrying capacity, which should be derated by at least 30% in actual engineering applications.
3. the terminal load capacity is 10A, which is limited by the size and quantity of the relay.