Sullair ES-6 SERIES User Manual page 14

Section 2 - DESCRIPTION
demand.
It consists of an inlet valve, pressure regulator
valve, solenoid valve, control lines and the motor
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
compressor will start to deliver compressed air.
When the air demand is less than the rated flow for
the compressor, the service line pressure will rise
to the pressure switch cut-out setting. The system
pressure switch opens, interrupting the electrical
power to the solenoid valve. The solenoid valve
opens allowing 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 normally open solenoid valve and
allows the compressor 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
regulator will them begin to open allowing pressure
to be applied to the inlet valve. The pressure
regulator will modulate the inlet valve to match
system demand.
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 can not be restarted
unless the Off/Reset mode is selected on the
selector switch, prior starting in any other mode of
operation.
8
AUTOMATIC MODE
In the automatic mode
compressor operates the same as in the manual
mode except that when the pressure switch
unloads the machine the compressor motor will
stop. The motor will automatically restart when the
line pressure drops to below the set-point of the air
pressure switch. If the compressor is equipped with
a wye-delta starter, the compressor will not restart
until the compressor sump pressure drops to the
minimum set-point on the sump pressure switch. It
is not recommended to open the pressure
regulator ball valve for the automatic mode of
operation.
2.7 INSTRUMENTATION, FUNCTIONAL
DESCRIPTION
Due to the simplicity of the ES-6 Series
compressor, the only instrumentation necessary is
a line pressure gauge which is located on the left
side of the electrical control center and a discharge
temperature gauge which is located on the right
side of the electrical control center. The line
pressure gauge reads plant air system pressure
only.
NOTE
At compressor shutdown, the sump
pressure is released to atmosphere
through the solenoid valve. The line
pressure gauge will continue to read
system pressure.
ES-6 USER MANUAL
of operation, the