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The schedules also can be overridden to keep the chiller in
an occupied state for up to 4 hours, on a one time basis. See the
Time Schedule Operation section, page 27.
Figure 22 shows a schedule for a typical office building
with a 3-hour, off-peak, cool-down period from midnight to
3 a.m., following a weekend shutdown. Holiday periods are in
an unoccupied state 24 hours per day. The building operates
Monday through Friday, 7:00 a.m. to 6:00 p.m., and Saturdays
from 6:00 a.m. to 1:00 p.m. This schedule also includes the
Monday midnight to 3:00 a.m. weekend cool-down schedule.
NOTE: This schedule is for illustration only and is not
intended to be a recommended schedule for chiller operation.
Whenever the chiller is in the LOCAL mode, it uses Occu-
pancy Schedule 01 (OCCPC01S). When the chiller is in the
ICE BUILD mode, it uses Occupancy Schedule 02 (OC-
CPC02S). When the chiller is in CCN mode, it uses Occupan-
cy Schedule 03 (OCCPC03S). The default setting for both LO-
CAL and CCN schedules is OCCUPIED all of the time.
The CCN SCHEDULE NUMBER is configured on the
NET_OPT display screen, accessed from the EQUIPMENT
CONFIGURATION table. See Table 3, Example 16.
SCHED-
ULE NUMBER
can be changed to any value from 03 to 99. If
this number is changed on the NET_OPT screen, the operator
must go to the ATTACH TO NETWORK DEVICE screen to
upload the new number into the SCHEDULE screen. See
Fig. 21.
Safety Controls —
The PIC II monitors all safety control
inputs and, if required, shuts down the chiller or limits the
guide vanes to protect the chiller from possible damage from
any of the following conditions:
• high bearing temperature
• high motor winding temperature
• high discharge temperature
• low discharge superheat*
• low oil pressure
• low cooler refrigerant temperature/pressure
• condenser high pressure or low pressure
• inadequate water/brine cooler and condenser flow
• high condenser water pressure drop (optional)
• high, low, or loss of voltage
• ground fault
• voltage imbalance
• current imbalance
• excessive motor acceleration time
• excessive starter transition time
• lack of motor current signal
• excessive motor amps
• excessive compressor surge
• temperature and transducer faults
*Superheat is the difference between saturation temperature
(CONDENSER REFRIGERANT TEMPERATURE) and
sensible temperature (COMPRESSOR DISCHARGE TEM-
PERATURE). The high discharge temperature safety mea-
sures only sensible temperature.
Faults or protective devices within the optional VFD can
shut down the chiller.
If the PIC II control initiates a safety shutdown, it displays
the reason for the shutdown (the fault) on the ICVC display
screen along with a primary and secondary message, energizes
an alarm relay in the starter, and blinks the alarm light on the
control panel. The alarm is stored in memory and can be
viewed on the ALARM HISTORY and ISM_HIST screens on
the ICVC, along with a message for troubleshooting. If the
safety shutdown was also initiated by a fault detected in the
motor starter, the conditions at the time of the fault will be
stored in ISM_HIST.
To give more precise information or warnings on the
chiller’s operating condition, the operator can define alert lim-
its on various monitored inputs in the SETUP1 screen. A par-
tial list of protective safety and alert limits is provided in
Table 6. A complete list of alarm and alert messages is provid-
ed in the Troubleshooting Guide section on page 99.
Pump and Fan Control —
The Carrier PIC controls
are designed to control when cooler and condenser water
pumps and tower fans are turned on and off. This is accom-
plished through a series of relay contacts on the ISM within the
starter or optional VFD, and interface terminals are provided at
ISM terminal strip J9 (refer to the Carrier Installation Instruc-
tions and certified drawings). If primary control of water
pumps and tower fans is provided by customer-installed devic-
es, a parallel means for the Carrier controls to independently
operate the pumps must also be provided to protect against
freeze-up.
Shunt Trip (Option) —
A main circuit breaker shunt
trip device is provided standard as a safety trip with all unit-
mounted starters, and is optional on other starters and some
VFDs. When a shunt trip is provided, it is wired from an output
on the ISM to the associated coil on the shunt trip equipped
motor circuit breaker. The shunt trip is activated by ISM logic,
based on values entered in the ISM_CONF table, under any of
the following conditions:
• Motor locked rotor amps limit exceeded
• Starter locked rotor amps rating exceeded
• Ground fault or phase-to-phase current fault limit
exceeded (when that option is included)
• Significant motor current detected more than 20 seconds
after a shutdown or otherwise when the chiller is off
• 1M and 2M auxiliary contacts closed when the chiller is
off.
In addition, starters may be designed to shunt trip based on
other starter-specific conditions or features. For example, Ben-
shaw solid-state starters include several such protective cir-
cuits. The shunt trip is also activated if
EVAPORATOR PRES-
SURE
drops below 0 psig (0 kPa). The Shunt Trip feature can
be tested using the Control Test feature.
Function Loss Trip —
The Function Loss Trip device
is provided standard as a safety trip with all unit-mounted
VFDs. When provided, the function loss trip is wired from an
output on the ISM to the VFD regulator board on the function
loss terminal. The function loss trip is activated by ISM logic,
based on values entered in the ISM _ CONF table.
CAUTION
If compressor motor overload occurs, check the motor for
grounded or open phases before attempting a restart.
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 ...