Automatic Soft Stop Amps Threshold; Chilled Water Recycle Mode - Carrier AquaEdge 19XRV series Operation, Maintenance And Installation Manual

QUANTITY CHECKED
STARTS IN 12 HOURS
COMP THRUST BRG TEMP
COMP MOTOR WINDING TEMP
COMP DISCHARGE TEMP
EVAPORATOR REFRIG TEMP
OIL SUMP TEMP
CONDENSER PRESSURE
PERCENT LINE VOLTAGE
PERCENT LINE VOLTAGE
ACTUAL GUIDE VANE POS
RECTIFIER TEMPERATURE
INVERTER TEMPERATURE
Certain conditions that occur during shutdown can change
this sequence.
• If the AVERAGE LINE CURRENT is greater than 5%
after shutdown, the oil pump and chilled water pump
remain energized and the alarm is displayed.
• The condenser pump shuts down when the CONDENSER
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 temperature,
the chilled water pump continues to run until the LEAVING
CHILLED WATER temperature is greater than the CON-
TROL POINT temperature, plus 5 F (2.8 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
signal 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
INCREASE DECREASE
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 pressing the
STOP button twice.
Table 9 — Prestart Checks
< 8 (not counting recycle restarts or auto restarts after power failure)
ALERT is cleared once RESET is pressed.
[COMP THRUST BRG TRIP] setting < [COMP THRUST BRG ALERT]
setting (SETUP1)
< [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) and > [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
< RECTIFIER TEMP OVERRIDE – 20 F (11.1° C)
< INVERTER TEMP OVERRIDE – 20 F (11.1° C)
The
softkey to set the SOFT STOP
REQUIREMENT
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 (refer to page 58).
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
defaults to 5 F (2.8 C). This value can be viewed or modified
on the SETUP1 table. The compressor will restart when the
chiller is:
• in LCW CONTROL and the LEAVING CHILLED WATER
temperature is greater than the CONTROL POINT plus the
(RECYCLE CONTROL) RESTART DELTA T.
• in ECW CONTROL and the ENTERING CHILLED WATER
temperature is greater than the CONTROL POINT plus the
(RECYCLE CONTROL) RESTART DELTA T.
Once these conditions are met, the compressor initiates a
start-up with a normal start-up sequence.
An alert condition may be generated if 5 or more recycle
start-ups occur in less than 4 hours. Excessive recycling can
reduce chiller life; therefore, compressor recycling due to
extremely low loads should be reduced.
To reduce compressor recycling, use the time schedule to
shut the chiller down during known low load operation period,
or increase the chiller load by running the fan systems. If the
hot gas bypass is installed, adjust the values to ensure that hot
gas is energized during light load conditions. Increase the
(RECYCLE CONTROL) RESTART DELTA T on the SETUP1
table to lengthen the time between restarts.
63
ALERT STATE IF FALSE
100
101
102
103
104
105
106
107
108
109
110
111
The chiller may