Specifications
13
PIC III System Components (Fig. 11-14) — The
chiller control system is called PIC III (Product Integrated
Control III). See Table 2. The PIC III controls the chiller by
monitoring all operating conditions. The PIC III can diagnose a
problem and let the operator know what the problem is and
what to check. It promptly adjusts compressor speed to main-
tain leaving chilled liquid temperature. It can interface with
auxiliary equipment such as pumps and cooling tower fans to
turn them on when required. It continually checks all safeties to
prevent any unsafe operating condition. It also regulates the oil
heater and regulates the hot gas bypass valve, if installed. The
PIC III controls provide critical protection for the compressor
motor and control of the variable frequency drive.
The PIC III can interface with the Carrier Comfort
Network
®
(CCN) system if desired. It can communicate with
other PIC I, PIC II or PIC III equipped chillers and other CCN
devices, such as LEI (Local Equipment Interface).
The PIC III controls are housed inside the control center
enclosure. See Fig. 14. The component names are listed
below (also see Table 2):
INTERNATIONAL CHILLER VISUAL CONTROLLER
(ICVC) — The ICVC is the “brain” of the PIC III. This
module contains all the primary software needed to control the
chiller. The ICVC is the input center for all local chiller set
points, schedules, configurable functions, and options.
The ICVC has a stop button, an alarm light, four buttons for
logic inputs, and a backlight display. The backlight will
automatically turn off after 15 minutes of non-use. The func-
tions of the four buttons or “softkeys” are menu driven and are
shown on the display directly above the softkeys. The ICVC is
mounted on the Control Center door. See Fig. 2.
To change the contrast of the display, access the adjustment
on the back of the ICVC. See Fig. 11.
CHILLER CONTROL MODULE (CCM) — This module is
located on the control panel in the control center. The CCM
provides the input and outputs necessary to control the chiller.
This module monitors refrigerant pressure, entering and
leaving liquid temperatures and pressures, and outputs control
for the oil reclaim valve, oil heaters, and oil pump. The CCM is
the connection point for optional demand limit, automatic
chilled liquid reset, 4 to 20 mA kW output, remote temperature
reset, and refrigerant leak sensor.
VFD POWER MODULE — This module is located in the
control center (see Fig. 12). The A/C line I/O assembly exe-
cutes commands from the ICVC for functions such as starting
and stopping the condenser and evaporator liquid pumps, tower
fan and alarm contacts. The Standard I/O Option Assembly
monitors inputs such as remote start contact, spare safety, and
the high condenser pressure switch and provides the 4-20 mA
Head Pressure Reference Output.
VFD GATEWAY MODULE — The VFD Gateway Module
translates the protocols between the ICVC, CCM and VFD.
This module also contains logic capable of an independent
safety shutdown. It shuts down the chiller if communications
with the ICVC are lost. See Fig. 13 for power module compo-
nent locations.
OIL HEATER CONTACTOR (1C) — This contactor is lo-
cated on the control panel (Fig. 14) and operates the heater at
115 V. It is controlled by the PIC III to maintain oil temperature
during chiller shutdown.
Table 2 — Major PIC III Components and
Panel Locations
OIL PUMP CONTACTOR (2C) — This contactor is located
in the control panel (Fig. 14) and operates the oil pump. The oil
pump is controlled by the PIC III to provide oil pressure during
pre-lube and when the chiller is starting or running.
HOT GAS BYPASS CONTACTOR RELAY (3C)
(Optional) — This relay, located in the power panel, controls
the opening of the hot gas bypass valve. The PIC III energizes
the relay based on hot gas bypass algorithm settings.
VFD REFRIGERANT COOLING SOLENOID VALVE
(5C) — This solenoid is located on the VFD cooling line. The
VFD cooling solenoid regulates the amount of time refrigerant
is allowed to flow through the VFD cold plate to keep its
temperature within operating limits.
VAPORIZER HEATER CONTACTOR (6C) — This contac-
tor is located in the control panel (Fig. 14) and energizes the
surface mounted heater on the bottom of the vaporizer.
CONTROL TRANSFORMERS (T1, T2) — These transform-
ers convert incoming control voltage to 24 vac power for the
power panel contactor relays, CCM, ICVC, and 21 vac power
for the optional DataLINK™ or DataPort™ modules. Circuit
breakers CB-1A, CB-1B, CB-2A and CB-2B for the control
transformers are located above the CCM.
PIC III COMPONENT PANEL LOCATION
International Chiller Visual Controller
(ICVC) and Display
Control Center
Door
VFD Power Module Inside Control Center
Chiller Control Module (CCM) Control Panel
Oil Heater Contactor (1C) Control Panel
Oil Pump Contactor (2C) Control Panel
Hot Gas Bypass Relay (3C) (Optional) Control Panel
Control Transformers (T1, T2) Control Panel
Control Transformer Circuit Breakers
(CB-1A, CB-1B, CB-2A, CB-2B)
Control Panel
Temperature Sensors See Fig. 3 and 9
Pressure Transducers See Fig. 3 and 10
Vaporizer Heater Contactor (6C) Control Panel
CONTRAST
ADJUSTMENT
SCREW
Fig. 11 — ICVC Contrast Adjustment
a23-1625