Capacity Control System - Sullair 1600H User Manual

SECTION 2
2.5

CAPACITY CONTROL SYSTEM,

FUNCTIONAL DESCRIPTION
Refer to Figure 2-3 and Figure 2-4. The purpose of
the control system is to regulate the amount of air
intake in accordance with the amount of compressed
air demand. The control system consists of an inlet
valve, the high and low pressure regulators, the
pressure reducing regulator, the blowdown/running
blowdown valve, the Compass Controller, a START/
RUN selector switch, and the HIGH/LOW selector
switch.
S - 0 65
TART TO PSIG
Push OFF/ON/START switch to "N" position to
initialize the Compass Controller. Once the Compass
Controller says "READY" on LCD, press OFF/ON/
START switch to the "START" position. In the
"START" position, the inlet valve is held closed by the
springs in the inlet valve. The valve is cracked open
by vacuum in the compressor and is allowed to build
up to 65 psig (4.5 bar). The reason for keeping the
valve closed during start is to allow the engine to
warm up without being loaded by the compressor. Air
pressure is contained in the receiver tank by the
minimum pressure valve which has a set point of 65
psig (4.5 bar). At this point the valve opens allowing
the air to pass to the service valve. After engine has
warmed up the machine automatically transfers to
"RUN" mode.
L P - 80
OW RESSURE
)
BAR
With the HIGH/LOW switch in the "LOW" position,
and the controller in "RUN" mode, the service valve
can now be opened. Pressure from the 60 psig (4.1
(0 4.5 )
TO BAR
100 (5.5 6.9
TO PSIG TO
1600C LP USER MANUAL
bar) reducing regulator opens up the inlet valve and
the Compass Controller increases the engine speed
to full load (1800 rpm). As the demand for air
decreases, the Compass Controller commands the
engine to reduce speed to idle (1400 rpm) and the
inlet valve closes, where it stabilizes until the air
demand is required again. If the machine is not
marked with an "H" or "HH" it is a single pressure
machine and will not have a HIGH/LOW switch. The
machine will run as if it is in the "LOW" position.
H P - 80
IGH RESSURE
) "H"
BAR FOR MODELS OR
13.8 ) "HH"
TO BAR FOR
When the HIGH/LOW switch is switched to the
"HIGH" position, the low pressure regulator is
blocked off allowing the high pressure regulator to
take over control of the machine. The 60 psig (4.1
bar) reducing regulator fully opens the inlet valve and
the Compass Controller commands maximum speed
(1800 rpm) from the engine. As the pressure reaches
the set point of the system the high pressure
regulator cracks open and closes the inlet valve and
the Compass Controller returns the engine back to
idle, until a demand for air is seen.
S
HUTDOWN
The blowdown valve is normally closed. When the
compressor is shutdown, system pressure backs up
to the inlet valve causing the check spring in the inlet
valve to close the air inlet valve. This sends a
pressure signal to the blowdown valve causing it to
open and vent the pressure in the system. After the
pressure is vented, the blowdown valve spring
returns the blowdown valve to the closed position.
150 (5.5 10.3
TO PSIG TO
80 200 (5.5
TO PSIG
MODELS
25