General; Purpose Of Controls - Sullair LS20T Operator's Manual And Parts List

6.1 GENERAL

While Sullair has built into this compressor a com-
prehensive array of controls and indicators to
assure you that it is operating properly, you will
want to recognize and interpret the reading which

6.2 PURPOSE OF CONTROLS

CONTROL OR INDICATION
FLUID LEVEL SIGHT GLASS
SEPARATOR RETURN LINE SIGHT
GLASS
FLUID STOP VALVE
DISCHARGE CHECK VALVE
THERMAL VALVE
MINIMUM PRESSURE/CHECK VALVE
PRESSURE RELIEF VALVE (SUMP)
PRESSURE RELIEF VALVE (INTER-
STAGE)
INLET POPPET VALVE
PRESSURE REGULATOR (INLET POP-
PET VALVE)
PRESSURE REGULATOR (UNLOAD)
will call for service or indicate the beginning of a
malfunction. Before starting your Sullair compres-
sor, read this section thoroughly and familiarize
yourself with the controls and indicators - their pur-
pose, location and use.
PURPOSE
Monitors fluid level in the sump. Proper level should fill the
sight glass. Check level when the compressor is shut down.
DO NOT OVERFILL.
Used to indicate fluid flow in the return lines. When the com-
pressor is running at full load, fluid flow should be visible in
this sight glass. There may be little or no flow when the com-
pressor is running unloaded, but a sluggish flow at full load
indicates a need to clean the return line strainer.
Cuts off flow of fluid to compressor unit at compressor shut-
down and allows flow of fluid to the unit on startup.
Cuts off the reverse flow of air/fluid mixture through compres-
sor discharge system at compressor shutdown.
Regulates flow of fluid to and around the cooler. Designed to
maintain a minimum operating temperature of 250ºF (121ºC).
Also used for fast warm-up on startup.
Maintains minimum of 170 psig (11.7 bar) in the compressor
sump. Valve piston restricts receiver air discharge from
receiver/sump when pressure falls to 160 psig (11 bar).
Prevents line pressure backflow into the sump during unload
conditions and after shutdown.
Opens sump pressure to the atmosphere should pressure
inside the sump becomes too high (600 psig [41.4 bar]).
Operation of this valve indicates that there is a mechanical or
electrical malfunction.
Opens interstage of compressor to atmosphere should the
pressure become too high (200 psig [13.8 bar]). Operation of
this valve indicates unit pressurization during shutdown.
Causes may be plugged control lines, faulty discharge check
valve, or faulty fluid stop valve.
Regulates the amount of air allowed to enter the air inlet
valve. This regulation is determined by the amount of air
being used at the service line.
Opens a pressure line between the sump and inlet poppet
valve allowing to regulate air delivery according to the air
demand.
Opens a pressure line between the sump and the inlet poppet
valve to regulate the unload pressure.
Section 6
OPERATION
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