Pressure Regulator Adjustment; Compressors With Optional Spiral Valve; Shaft Coupling Maintenance - Sullair LS20 Operator's Manual And Parts List

Section 10
MAINTENANCE
Figure 10-4 Pressure Switch (P/N 040694)
decrease the setting.
3. To set the regulator, continue closing the service
valve until the line pressure is 102 psig (7.0 bar).
At this point regulator should pass a signal to the
inlet valve to start closing it. If the line pressure
keeps on rising or if the modulation does not
begin, adjust the regulator as described above.
After adjustment, line pressure should be
approximately 102 psig (7.0 bar) and 1.00 in. Hg
(2.54 cm Hg.) vacuum below the inlet.
4. Next, close the service valve; line pressure will
start rising. When line pressure reaches 110
psig (7.6 bar), the inlet valve will be closed to its
maximum position. The inlet vacuum at this
point will be around 25 in. Hg (63.5 cm Hg.). The
machine should unload at this point.
5. Open the service valve so the line pressure is
100 psig (6.9 bar). Machine is now set for oper-
ation. Recheck the unload pressure by closing
of the service valve. Machine should unload via
the pressure switch at 110 psig (7.6 bar).
After the control pressures have been adjusted, the
"unloaded" sump pressure should be checked. It
will be necessary to shut the compressor down,
remove the pressure switch cover, and disconnect
one of the two lead wires that are connected to the
micro-switch (contact block). In order to have a cor-
rect reading, the air system to which the compres-
sor is connected must be pressurized to at least 80
psig (5.5 bar). After disconnecting the lead, tape the
52
exposed wire with electrician's tape to make sure
that it does not come in contact with any metallic
surface.
DO NOT touch the electrical contacts, terminal or
leads with any metallic object. Severe electrical
shock may occur.
With the lead taped, you may start the compressor
again. Allow the sump pressure to stabilize.
The sump pressure should read 15 to 20 psig (1.0
to 1.4 bar).
Once this is checked, shut the compressor down
once again and reconnect the taped lead and
replace the pressure switch cover. At this time, start
the compressor and cycle the Control System sev-
eral times and re-check all pressure settings and
adjustments.
DO NOT touch the pressure switch, electrical con
with any part of the body or any un-insulated
metallic object. Severe electrical shock may
occur.

PRESSURE REGULATOR ADJUSTMENT

Start the compressor and adjust the service valve to
maintain service air pressure approximately at five
(5) psi over rated pressure. Turn the inlet valve reg-
ulator adjusting screw until air just begins to escape
from the control air orifice (located at the bottom of
the regulator.). Lock the adjusting screw in place
with the locknut. The regulator is now properly set.
COMPRESSORS WITH OPTIONAL SPIRAL
VALVE
Start the compressor and adjust the service valve to
maintain service air pressure approximately at five
(5) psi over rated pressure. Turn the inlet valve reg-
ulator adjusting screw until air just begins to escape
from the control air orifice (located at the bottom of
the regulator.). Lock the adjusting screw in place
with the locknut.
Readjust the service valve to maintain service air
pressure approximately one (1) psi over rated pres-
sure. Turn the spiral valve regulator adjusting screw
until air just begins to escape from the control air
orifice (located at the bottom of the regulator.). Lock
the adjusting screw in place with the locknut. The
regulators are now properly set.

SHAFT COUPLING MAINTENANCE

Refer to Figure 10-5. The compressor unit and
motor are rigidly connected via a rigid adapter
piece, thus the shafts are maintained in proper