The suction control valve open/close valve operates in either fully open or fully closed position on compressor working at load / idling. The proportional control valve and open/close valve work not only at completely open or completely closed, but operates at different positions depending on the amount of air used. This allows the compressor to work more regularly. In proportional control valve operation, the compressor produces as must air as is consumed, and thus 10% energy savings are made.
At times where the air consumption is very low or none, the compressor works at idle or automatic waiting mode just as in the load/idle working order.