Sullair LS-200S Operator's Manual And Parts List page 22

Section 2
DESCRIPTION
Figure 2-5E Control System Diagram- UNLOAD
returned back internally to the suction end of the
compressor unit. Now the compressor is fully com-
pressing only that amount of air, which is being
used. As air demand keeps dropping further, the
spiral valve keeps opening more and more until all
the bypass ports are fully open. At this point, the
spiral valve has moved into the unload (minimum)
position.
The spiral valve provides a modulation range from
16
100 to 50%. During this period, the pressure rises
approximately from 100 to 105 psig (6.9 to 7.2 bar).
As the air pressure exceeds 105 psig (7.2 bar), the
differential pressure regulator controlling the inlet
poppet valve starts opening and forcing the poppet
closed, thus throttling inlet air flow to the compres-
sor. The inlet poppet valve provides a modulation
range from 50 to 40%. During this period, the pres-
sure rises approximately from 106 to 110 psig (7.3