Sullair ES-6 5H Operator's Manual And Spare Parts List page 13

Figure 2-2 Encapsulated Compressor System
2.6 CONTROL SYSTEM, FUNCTIONAL DESCRIP-
TION
The purpose of the compressor control system is to
maintain compressor capacity to meet the system
demand.
It consists of an inlet valve, pressure regulator
valve, solenoid valve, control lines and the mo-
tor start selector switch.
The selector switch has three settings: MANUAL/
START, OFF/RESET and AUTOMATIC START/
STOP.
MANUAL MODE
In the manual mode the ball valve should be closed
to isolate the pressure regulator. The compressor
motor will start and the air control solenoid will be
energized (closed.) During this time the inlet valve
is fully open due to inlet air flow, and the compres-
sor will start to deliver compressed air. When the air
demand is less than the rated flow for the compres-
sor, the service line pressure will rise to the pres-
sure switch cut---out setting. The system pressure
switch opens, interrupting the electrical power to
DESCRIPTION
the solenoid valve. The solenoid valve opens allow-
ing pressure to be applied to the inlet valve causing
the inlet valve to fully close. The compressor will
continue to run (unloaded) until the line pressure
drops to the low setting of the pressure switch--- ---
the pressure switch closes, reenergizing the nor-
mally open solenoid valve and allows the compres-
sor to load again.
MANUAL MODULATION CONTROL MODE
In the modulation control mode the ball valve
should be open to allow pressure to the pressure
regulator. The compressor motor will start and the
system pressure will rise until it reaches the set
point of the pressure regulator. The pressure regu-
lator will them begin to open allowing pressure to
be applied to the inlet valve. The pressure regula-
tor will modulate the inlet valve to match system de-
mand.
OFF/RESET MODE
The compressor motor, if running, will stop if the off/
reset position is selected. If the compressor during
normal running has a fault caused by either overload
or high discharge temperature, the compressor will
stop. After a fault has been cleared, the compressor
Section 2
7