FORM 160.77-O2
ISSUE DATE: 11/15/2011
SECTION 1 - YKEP CHILLER OVERVIEW
JOHNSON CONTROLS
9
1
of the mass owing through the primary and in-
creasing chiller capacity. Upon unloading, when
the economizer compressor PRV closed switch is
activated, signifying the economizer compressor
is completely unloaded, or the economizer satu-
ration temperature is 0.5 Degrees F above what
the target saturation temperature would be for
economizing mode, the economizer compressor
switches back to economizing operation. Then
the primary compressor control returns to fol-
lowing the chiller programmed leaving chilled
liquid temperature and the economizer compres-
sor is following its target economizer pressure as
described in (2) above.
A timing diagram of the compressors’ start sequence
and shutdown is shown in Figure 3 on Page 9.
FIGURE 3 - YKEP CHILLER OPERATION SEQUENCE TIMING DIAGRAM
LD16023
0 10 13 45 50 110
(0.17) (0.22) (0.75) (0.83) (1.83)
VANES
CLOSED
MAN. OIL
PUMP
DISABLED
AUTO ZEROING DIFFERENTIAL
OIL PRESSURE TRANSDUCERS
** VANES CLOSING - TIME
DEPENDENT ON INITIAL
VANE POSITION
OIL PRESSURE CHECK
OIL PUMP ON
"SYSTEM
COASTDOWN"
"SYSTEM
SHUTDOWN"
TIME IN SECONDS (MINUTES)
DISPLAY
MESSAGE
"SYSTEM RUN"
"SYSTEM PRELUBE"
** "VANES CLOSING
BEFORE
SHUTDOWN"
ENERGIZE (OPEN)
LIQUID GEAR COOLING
SOLENOID (PRIMARY COMPRESSOR)
RESTART AFTER
ANTI-RECYCLE
(FOR EM STARTERS, 30 MIN)
(FOR VSD STARTERS, 5 STARTS THEN 10 MIN)
240 SEC
(4 MIN)
K7
Q3
150 SEC
(2.5 MIN)
FLOW
SWITCH
BYPASS
START STOP
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