
66
Table 9 — Prestart Checks
Shutdown Sequence —
Chiller shutdown begins if
any of the following occurs:
• the STOP button is pressed continuously for at least one
second (the alarm light blinks once to confirm the stop
command)
• a recycle condition is present (see Chilled Water Recycle
Mode section)
• the time schedule has gone into unoccupied mode
• the chiller protective limit has been reached and chiller is
in alarm
• the start/stop status is overridden to stop from the CCN
network or the ICVC
When a stop signal occurs, the shutdown sequence first
stops the compressor by deactivating the start relay (1CR). A
status message of “SHUTDOWN IN PROGRESS, COM-
PRESSOR DEENERGIZED” is displayed, and the compres-
sor ontime and service ontime stop. The guide vanes are then
brought to the closed position. The oil pump relay and the
chilled water/brine pump relay shut down 60 seconds after the
compressor stops. The condenser water pump shuts down at
the same time if the
ENTERING CONDENSER WATER
tem-
perature is greater than or equal to 115 F (46.1 C) and the
CONDENSER REFRIG TEMP
is greater than the
CONDENS-
ER FREEZE POINT
plus 5 F (–15.0 C). The stop-to-start timer
now begins to count down. If the start-to-start timer value is
still greater than the value of the start-to-stop timer, then this
time displays on the ICVC.
Certain conditions that occur during shutdown can change
this sequence.
• If the AVERAGE LINE CURRENT is greater than 5%
after shutdown, or the starter contacts remain energized,
the oil pump and chilled water pump remain energized,
the SHUNT TRIP relay is energized, and the alarm is
displayed.
• The condenser pump shuts down when the
CON-
DENSER PRESSURE
is less than the
COND PRESS
OVERRIDE
threshold minus 3.5 psi (24.1 kPa) and the
CONDENSER REFRIG TEMP
is less than or equal to the
ENTERING CONDENSER WATER
temperature plus
3
F (–1.6
C).
• If the chiller shuts down due to low refrigerant tempera-
ture, the chilled water pump continues to run until the
LEAVING CHILLED WATER
temperature is greater than
the
CONTROL POINT
temperature, plus 5
F (3
C).
Automatic Soft Stop Amps Threshold —
The
soft stop amps threshold feature closes the guide vanes of the
compressor automatically if a non-recycle, non-alarm stop sig-
nal occurs before the compressor motor is deenergized.
Any time the compressor is directed to STOP (except in the
cases of a fault or recycle shutdown), the guide vanes are
directed to close, and the compressor shuts off when any of the
following is true:
• AVERAGE LINE CURRENT (%) drops below the SOFT
STOP AMPS THRESHOLD
• ACTUAL GUIDE VANE POSITION drops below 4%
• 4 minutes have elapsed
• the STOP button is pressed twice
If the chiller enters an alarm state or if the compressor enters
a RECYCLE mode, the compressor deenergizes immediately.
To activate the soft stop amps threshold feature, scroll to the
bottom of OPTIONS screen on the ICVC. Use
the
or
softkey to set the
SOFT
STOP AMPS THRESHOLD
parameter to the percent of amps
at which the motor will shut down. The default setting is 100%
amps (no soft stop). The range is 40 to 100%.
When the soft stop amps threshold feature is being applied,
a status message, “SHUTDOWN IN PROGRESS, COM-
PRESSOR UNLOADING” displays on the ICVC.
The soft stop amps threshold function can be terminated and
the compressor motor deenergized immediately by depressing
the STOP button twice.
Chilled Water Recycle Mode —
The chiller may
cycle off and wait until the load increases to restart when the
compressor is running in a lightly loaded condition. This cy-
cling is normal and is known as “recycle.” A recycle shutdown
is initiated when any of the following conditions are true:
•
LEAVING CHILLED WATER
temperature (or
ENTERING
CHILLED WATER
temperature, if the
ECW CONTROL
OPTION
is enabled) is more than 5° F (2.8° C) below the
CONTROL POINT
.
•
LEAVING CHILLED WATER
temperature (or
ENTERING
CHILLED WATER
temperature, if the
ECW CONTROL
OPTION
is enabled) is below the
CONTROL POINT
, and
the chilled water temperature difference is less than the
(RECYCLE CONTROL)
SHUTDOWN DELTA T
(config-
ured in the EQUIPMENT SERVICE/SETUP1 table).
• the
LEAVING CHILLED WATER
temperature is within
3
F (1.7
C) of the
EVAP REFRIG TRIPPOINT
.
NOTE: Recycle shutdown will not occur if the CONTROL
POINT has been modified (e.g., by a chilled water reset input)
within the previous 5 minutes of operation. Also, chilled water
recycle logic does not apply to Ice Build operation.
When the chiller is in RECYCLE mode, the chilled water
pump relay remains energized so the chilled water temperature
can be monitored for increasing load. The recycle control uses
RESTART DELTA T
to check when the compressor should be
restarted. This is an operator-configured function which de-
faults to 5
F (3
C). This value can be viewed or modified on
QUANTITY CHECKED
REQUIREMENT
ALERT STATE IF FALSE
STARTS IN 12 HOURS
< 8 (not counting recycle restarts or auto restarts after power failure)
ALERT is cleared once RESET is pressed.
100
COMP THRUST BRG TEMP
< [COMP THRUST BRG ALERT] –10° F (5.6° C)
101
COMP MOTOR WINDING TEMP
< [COMP MOTOR TEMP OVERRIDE] –10° F (5.6° C)
102
COMP DISCHARGE TEMP
< [COMP DISCHARGE ALERT] –10° F (5.6° C)
103
EVAP REFRIG LIQUID TEMP
< [EVAP REFRIG TRIPPOINT] + [REFRIG OVERRIDE DELTA T]
104
OIL SUMP TEMP
< 150° F (65.5° C) or <[EVAPORATOR REFRIG TEMP] + 50° F (27.8°
C)
105
CONDENSER PRESSURE
< [COND PRESS OVERRIDE] –20 PSI (138 kPa) and
< 145 psi (1000 kPa)
106
PERCENT LINE VOLTAGE
< [Undervoltage Threshold]
107
PERCENT LINE VOLTAGE
> [Overvoltage Threshold]
108
ACTUAL GUIDE VANE POS
Controls test guide vane calibration must be performed
109
INCREASE
DECREASE
Summary of Contents for AquaEdge 19XR series
Page 69: ...69 Fig 33 19XR Leak Test Procedures a19 1625 ...
Page 154: ...154 Fig 64 Benshaw Inc Wye Delta Unit Mounted Starter Wiring Schematic Low Voltage a19 1873 ...
Page 161: ...161 Fig 69 Typical Low Voltage Variable Frequency Drive VFD Wiring Schematic 575 v ...
Page 162: ...162 Fig 69 Typical Low Voltage Variable Frequency Drive VFD Wiring Schematic 575 v cont ...
Page 186: ...186 APPENDIX B LEAD LAG WIRING 19XR Lead Lag Schematic Series Cooler Flow a19 1655 ...
Page 187: ...187 APPENDIX B LEAD LAG WIRING cont 19XR Lead Lag Schematic Parallel Cooler Flow a19 1717 ...