Swift Restart; Cooling Tower Control; Head Pressure Control; Ice Build Option - Carrier PIC 5+ User Manual

5.20 - Swift Restart

This function is designed for data center application, and it
allows the chiller to be restarted swiftly to meet the building
load requirements.
To enable this function, the "auto restart option" point in
CONF_OPT table should be set to "ENABLE" .
The water flow verification time, oil prelube time and other
delays will be decreased accordingly. If the control system
and oil system are equipped UPS (uninterrupted power
supply), the startup time will be decreased accordingly.

5.21 - Cooling Tower Control

If "water pressure option" in CONF_OPT table is ENABLED,
there will be another optional hydraulic control I/O board
in the PIC 5+ control system to allow PIC 5+ control the
water pumps and cooling tower fans (high speed and low
speed).
The cooling tower fans are controlled by the pressure
difference between condenser and evaporator and entering
water temperature of condenser, the objective is to maintain
the entering condenser water temperature is the optimal
range.

5.22 - Head Pressure Control

If the chiller system is equipped with head pressure control
valve, and head pressure valve option in CONF_OPT table
is ENABLED, then PIC 5+ control system will control the
opening of head pressure valve to maintain the pressure
difference between condenser and evaporator. The output
of this valve is 4-20mA type.
Before using this function, the appropriate configurations
should be in place. They are pressure difference value for
20mA and pressure difference for 4mA.
The head pressure valve should be in fully closed position
when chiller is in OFF mode.

5.23 - Ice Build Option

PIC 5+ control provides ice build option based on efficiency
improving point,.
"ice build option" in CONF_OPT table should be set to
ENABLED to make ice build active, and another two
configurable parameters should be configured.
Ice_recy indicates whether recycle option is enabled in ice
build mode or not.
Ice_term indicates how the ice build is terminated. There are
three types, temperature, dry contact or combined temperature
and dry contactor.

5.24 - Time Schedule

PIC 5+ control provides three schedules, they are:
Local schedule, Ice build schedule and Network schedule
There are 8 time segments in each schedule, if there is an
overlap on the two time segments, then occupied time
segment takes the high priority.
There are 16 holiday time segments in Holiday Menu, and
each time segment is determined by three parameters, month,
start date and holiday days. The controller will be in
unoccupied mode when holiday is active.
PIC 5+ also provides Daylight Saving function. Broadcast
Menu, enable this function and set the Daylight Saving start
time and end time.

5.25 - Black Box

The black box task continuously stores operation parameters
in the memory every 5 seconds. Reporting of chiller
operation alarm would trigger the controller to generate a
collection of the records. Each collection contains up to 180
records (15 minutes) which consist of 168 records (14
minutes) before the alarm and 12 records (1 minute) after.
Each record is associated with a time stamp. These collections
are saved as csv files. 20 files can be stored in total.
The black box file can be uploaded with Carrier S-Service
tool. Once the upload is done, the original files saved in
controller will be erased.

5.26 - Pressure Transducer Calibration

When pressure transducer calibration is performaned,
entering value shall result in a recalculation for the slope and
intercept of the 2 values. Thereafter, the new slope and
intercept values shall be used for voltage ratio to pressure
conversions.
• Step 1: Set CALIBRATION ENABLE for certain
pressure transducer
• Step 2: Put the transducer at atmosphere and enter 0
PSIG (0 kPa) to CALIB PRESS1
• Step 3: Give the transducer a known pressure (100-250
PSI (690-1700 kPa)) via Tool and enter this pressure to
CALIB PRESS2
• Step 4: Recalculate calibrated Slope and Intercept

5.27 - Temperature Sensor Calibration

The four water temperature sensors can be calibrated per
the following steps:
• Step 1: Place the temperature sensor at 32 °F (0 °C)
Drop each temperature sensor in a 32 °F (0 °C) water
solution.
• Step 2: Read the sensor raw temperature in maintenance
screen
Go to maintenance screen, read the corresponding sensor
raw temp
Calculate the offset to be applied = 32 - sensor raw temp
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