Shutdown Sequence; Automatic Soft Stop Amps Threshold; Chilled Water Recycle Mode - Carrier AquaEdge 19XR series Start-Up, Operation And Maintenance Instructions Manual

QUANTITY CHECKED
STARTS IN 12 HOURS
COMP THRUST BRG TEMP
COMP MOTOR WINDING TEMP
COMP DISCHARGE TEMP
EVAP REFRIG LIQUID TEMP
OIL SUMP TEMP
CONDENSER PRESSURE
PERCENT LINE VOLTAGE
PERCENT LINE VOLTAGE
ACTUAL GUIDE VANE POS
Shutdown Sequence —
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 —
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
Table 9 — Prestart Checks
REQUIREMENT
< 8 (not counting recycle restarts or auto restarts after power failure)
ALERT is cleared once RESET is pressed.
< [COMP THRUST BRG ALERT] –10° F (5.6° C)
< [COMP MOTOR TEMP OVERRIDE] –10° F (5.6° C)
< [COMP DISCHARGE ALERT] –10° F (5.6° C)
< [EVAP REFRIG TRIPPOINT] + [REFRIG OVERRIDE DELTA T]
< 150° F (65.5° C) or <[EVAPORATOR REFRIG TEMP] + 50° F (27.8°
C)
< [COND PRESS OVERRIDE] –20 PSI (138 kPa) and
< 145 psi (1000 kPa)
< [Undervoltage Threshold]
> [Overvoltage Threshold]
Controls test guide vane calibration must be performed
Chiller shutdown begins if
The
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
the or
INCREASE DECREASE
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 —
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
66
ALERT STATE IF FALSE
100
101
102
103
104
105
106
107
108
109
screen on the ICVC.
softkey to set the SOFT
The chiller may
Use