Sullair LS-32 Operator's Manual And Parts List page 20

Section 2
DESCRIPTION
the Sullicon Control, which starts partially closing
the inlet butterfly valve. The inlet butterfly valve pro-
vides modulation range from 50 to 40%. During this
period, the pressure rises approximately from 66 to
70 psig (4.1 to 4.8 bar). During this range, the spi-
ral valve remains in the full open position.
UNLOAD MODE - IN EXCESS OF 70 PSIG (4.8
BAR)
When a relatively small amount or no air is being
used, the service line pressure continues to rise.
When it exceeds 70 psig (4.8 bar), Supervisor
Controller de-energizes the solenoid valve allowing
line pressure to be supplied directly to the Sullicon
diaphragm keeping the inlet butterfly closed; the
spiral valve is in the fully open (minimum) position.
Simultaneously, the solenoid valve sends a pneu-
matic signal to the blowdown valve. The blowdown
valve opens the sump to the atmosphere. This
reduces the sump pressure to approximately 30
psig (2.1 bar) which results in low horsepower con-
sumption. The check valve in the air service line
prevents line pressure from returning to sump while
the compressor is running in the unloaded mode.
Both the spiral valve and the butterfly valve remain
in the unload position.
When the line pressure drops back to 60 psig (4.2
bar) due to an increase in the air demand,
14
Supervisor Controller energizes the solenoid valve
allowing the air pressure behind the Sullicon
Control to be vented through the solenoid valve
exhaust port. The blowdown valve closes, and the
inlet butterfly valve opens. Also the air pressure at
the spiral valve actuator diaphragm is reduced
through a vent hole at the spiral valve differential
pressure regulator, and a spring in the actuator
causes the spiral valve to return to the full load
(maximum) position.
AUTOMATIC OPERATION
For applications with varied periods of time when
there are no air requirements, Supervisor's Auto
mode allows the compressor to shut down (time
delayed) when no compressed air requirement is
present and restart as compressed air is needed.
LOAD/ NO LOAD OPERATION
If applications call for load/no load operation, mod-
ulation can be disabled in the Supervisor
Controller in the "Control Parameters" menu. If
TM
modulation is disabled, the unload pressure must
be reset to the rated load pressure of the machine.
For example, an LL model rated for 60 psig full load
operation and 70 psig unload must have the unload
pressure reset to 60 psig. This ensures that the
motor will not run in an overload condition.