Specifications

58
NOTE: The 19XRV units are not available with factory-
installed chilled water or condenser water flow devices (avail-
able as an accessory for use with the CCM control board).
If the water/brine temperature is high enough, the start-up
sequence continues and checks the guide vane position. If the
guide vanes are more than 4% open, the start-up is delayed
until the PIC III closes the vanes. If the vanes are closed and
the oil pump pressure is less than 4 psi (28 kPa), the oil pump
relay energizes. The PIC III then waits until the oil pressure
(OIL PRESS VERIFY TIME, operator-configured, default of
40 seconds) reaches a maximum of 18 psi (124 kPa). After oil
pressure is verified, the PIC III waits 40 seconds, and the VFD
energizes to start the compressor.
Compressor ontime and service ontime timers start, and the
compressor STARTS IN 12 HOURS counter and the number of
starts over a 12-hour period counter advance by one.
Failure to verify any of the requirements up to this point will
result in the PIC III aborting the start and displaying the appli-
cable pre-start mode of failure on the ICVC default screen. A
pre-start failure does not advance the STARTS IN 12 HOURS
counter. Any failure after the VFD has energized results in a
safety shutdown, advances the starts in 12 hours counter by
one, and displays the applicable shutdown status on the ICVC
display. The minimum time to complete the entire prestart
sequence is approximately 185 seconds.
Shutdown Sequence — Chiller shutdown begins if
any of the following occurs:
• the STOP button is pressed 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 net-
work or the ICVC
When a stop signal occurs, the shutdown sequence first
stops the compressor by deactivating the VFD output to the
motor. A status message of “SHUTDOWN IN PROGRESS,
COMPRESSOR DEENERGIZED” is displayed, and the
compressor 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
temperature is greater than or equal to 115 F (46.1 C) and
the CONDENSER REFRIG TEMP is greater than the
CONDENSER 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, 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 — The 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 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 pressing the
STOP button twice.
A—START INITIATED: Pre-start checks are made; evaporator pump
started.
B—Condenser water pump started (5 seconds after A).
C—Water flows verified (30 seconds to 5 minutes maximum after B).
Chilled water temperatures checked against control point. Guide
vanes checked for closure. Oil pump started; tower fan control
enabled.
D—Oil pressure verified (15 seconds minimum, 300 seconds maximum
after C).
E—Compressor motor starts; compressor ontime and service ontime
start, 15-minute inhibit timer starts (10 seconds after D), total com-
pressor starts advances by one, and the number of starts over a
12-hour period advances by one.
F—SHUTDOWN INITIATED — Compressor motor stops; compressor
ontime and service ontime stop, and 1-minute inhibit timer starts.
G—Oil pump and evaporator pumps deenergized (60 seconds after F).
Condenser pump and tower fan control may continue to operate if
condenser pressure is high. Evaporator pump may continue if in
RECYCLE mode.
O/A — Restart permitted (both inhibit timers expired: minimum of 15 min-
utes after E; minimum of 1 minute after F).
Fig. 27 — Control Sequence
a19-765
INCREASE
DECREASE