Control System Adjustment - Sullair 900XH Operators Manual And Parts Lists

Section 5
MAINTENANCE
Figure 5-3 Control System Components

CONTROL SYSTEM ADJUSTMENT

Refer to Figure 5-3, or control schematic (Figure 2-
3). Prior to adjusting the control system, it is neces-
sary to determine the desired operating pressure
range as well as the maximum pressure at which
the machine is to operate. This pressure must not
exceed the maximum operating pressure which is
stamped on the machine serial number plate. The
following explanation applies to a typical machine
with a desired operating range of 200 to 350 psig
(13.8 to 24.1 bar). This information will apply to a
machine with any other operating range except for
the stated operating pressure. For high pressure
machines, adjustment pressures are shown in
parenthesis.
1. Start the machine and let it warm-up with warm-
up valve in "start" position.
around connections.
36
2. Open service valve slightly and turn the warm-up
Check for leaks
3. For 200 psig (13.8 bar) machines turn the pres-
valve to "run" position. Slowly close the service
valve, watching the pressure gauge to insure the
unload pressure does not exceed 350 psig (24.1
bar) . If it does, the control regulator set screw
must be backed out until the compressor will
unload. With service valve closed, check and
adjust the pressure at the reducing regulator for
a 60 psig (4.1 bar) setting. With service valve
still closed, adjust the high pressure back pres-
sure regulator on 350 psig [25.5 bar] machines
to maintain a discharge pressure of 350 psig
(24.1 bar) . Machine speed must be 1400 RPM,
check instrument panel. Open the service valve
to load the compressor to maintain 350 psig
(24.1 bar) discharge pressure.
speed should be 1800 RPM on the instrument
panel.
Operating