Sullair LS-20S, Operator'S Manual And Parts List

Page: 16 / 102

Section 2
DESCRIPTION
10
AFTERCOOLER
MOISTURE
SEPARATOR
SUMP
TANK
BLOWDOWN
VALVE
MINIMUM PRESSURE/
CHECK VALVE
WATER-
COOLED
MACHINES
FLUID FILL
PLUG
FLUID LEVEL
SIGHT GLASS
Figure 2-4B Compressor Discharge System Diagram- Water-cooled Model
See Supervisor II module functional description for
further details on shutdown pressure levels.
All Sullair compressor models are equipped with a
high pressure shutdown protection to shut down the
compressor at 20 psig (1.4 bar). This prevents the
pressure relief valve from opening under routine
conditions, thereby preventing fluid loss through the
pressure relief valve. A temperature switch will shut
down the compressor if the discharge temperature
reaches 240
_
F (115
_
C).
WARNING
!
DO NOT remove caps, plugs, and/or other com-
ponents when compressor is running or pressur-
ized.
Stop compressor and relieve all internal pressure
before doing so.
Fluid is added to the sump via a capped fluid filler
opening, placed low on the tank to prevent overfilling
of the sump. A sight glass enables the operator to
visually monitor the sump fluid level
2.6 CONTROL SYSTEM, FUNCTIONAL DESCRIP-
TION
Ref er t o F igur es 2- 5A and 2- 5B . T he pur pos e of t he
compressor control system is to regulate the
amount of air being compressed to match the
amount of compressed air being used. The capac-
ity control system consists of a Sullicon Control ,
a butterfly valve (located on the compressor air in-
let), a pressure switch , pilot valve pressure reg-
ulator(s) and a control line filter . The functional
description of the control system is described below
in four distinct phases of operation. For explanation
purposes, this description will apply to a compressor
with an operating range of 100 to 110 psig ( 6.9 to 7.6
bar). A compressor with any other pressure range
would operate in the same manner except stated
pressures.
START MODE -- 0 TO 50 PSIG (0 TO 3.5 BAR)
When the Supervisor II Module “ I ” or “ ” pad is de-
pressed, the unit starts and the pressure quickly
rises from 0 to 50 psig (0 to 3.5 bar). The pressure
regulator(s) and the pilot valve(s) remain closed,
and the Sullicon Control and spiral valve are inop-
erative.The spring on the control holds the butterfly
valve fully open via its spring--loaded lever arm. The
minimum pressure valve (MPV) isolates the com-
pressed air from reaching the service line while
building enough backpressure (40--50 psig [2.8--3.5
bar]) to maintain adequate lubricant fluid flow. If the
optional Closed Inlet Start assembly is provided, a
spring--loaded, single acting pneumatic cylinder
holds the butterfly valve almost fully closed, mini-
mizing the compression load for special drivers (i.e.,
Wye--Delta electric motors) during the start--up
phase. After a pre--determined amount of time, a so-
lenoid valve energizes the pneumatic cylinder and
the butterfly valve is thus opened fully. All further
Sullicon Control operation takes place with the
pneumatic cylinder energized.