Specifications

Unit-Mounted Wye-Delta Starter (Optional)
—
The 19XRT chiller may be equipped with a wye-delta
starter mounted on the unit. This starter is intended for use
with low-voltage motors (under 600 v). It reduces the start-
ing current inrush by connecting each phase of the motor
windings into a wye configuration. This occurs during the
starting period when the motor is accelerating up to speed.
Once the motor is up to speed, the starter automatically con-
nects the phase windings into a delta configuration. Starter
control, monitoring, and motor protection is provided by
Carrier’s Integrated Starter Module (ISM).
CONTROLS
Definitions
ANALOG SIGNAL — An analog signal varies in propor-
tion to the monitored source. It quantifies values between
operating limits. (Example: A temperature sensor is an ana-
log device because its resistance changes in proportion to
the temperature, generating many values.)
DISCRETE SIGNAL — A discrete signal is a 2-position rep-
resentation of the value of a monitored source. (Example: A
switch produces a discrete signal indicating whether a value
is above or below a set point or boundary by generating an
on/off, high/low, or open/closed signal.)
General — The 19XRT hermetic centrifugal liquid chiller
contains a microprocessor-based control center that moni-
tors and controls all operations of the chiller (see Fig. 7).
The microprocessor control system matches the cooling
capacity of the chiller to the cooling load while providing
state-of-the-art chiller protection. The system controls cool-
ing load within the set point plus the deadband by sensing
the leaving chilled water or brine temperature and regula-
ting the inlet guide vane via a mechanically-linked actuator
motor. The guide vane is a variable flow pre-whirl assem-
bly that controls the refrigeration effect in the cooler by
regulating the amount of refrigerant vapor flow into the com-
pressor. An increase in guide vane opening increases capac-
ity. A decrease in guide vane opening decreases capacity. The
microprocessor-based control center protects the chiller by
monitoring the digital and analog inputs and executing
capacity overrides or safety shutdowns, if required.
PIC II System Components — The chiller control
system is called PIC II (Product Integrated Control II).
See Table 1. The PIC II controls the operation of the chiller
by monitoring all operating conditions. The PIC II can di-
agnose a problem and let the operator know what the prob-
lem is and what to check. It promptly positions the guide
vanes to maintain leaving chilled water temperature. It can
interface with auxiliary equipment such as pumps and cool-
ing tower fans to turn them on when required. It continually
checks all safeties to prevent any unsafe operating condi-
tion. It also regulates the oil heater while the compressor is
off and regulates the hot gas bypass valve, if installed. The
PIC II controls provide critical protection for the compres-
sor motor and controls the motor starter.
The PIC II can interface with the Carrier Comfort Net-
work (CCN) if desired. It can communicate with other
PIC I or PIC II equipped chillers and other CCN devices.
The PIC II consists of 3 modules housed inside 3 major
components. The component names and corresponding con-
trol voltages are listed below (also see Table 1):
• control panel
— all extra low-voltage wiring (24 v or less)
• power panel
— 230 or 115 v control voltage (per job requirement)
— up to 600 v for oil pump power
• starter cabinet
— chiller power wiring (per job requirement)
Table 1 — Major PIC II Components and
Panel Locations*
PIC II COMPONENT
PANEL
LOCATION
Chiller Visual Controller (CVC) and Display Control Panel
Integrated Starter Module (ISM) Starter Cabinet
Chiller Control Module (CCM) Control Panel
Oil Heater Contactor (1C) Power Panel
Oil Pump Contactor (2C) Power Panel
Hot Gas Bypass Relay (3C) (Optional) Power Panel
Control Transformers (T1, T2) Power Panel
Temperature Sensors See Fig. 7.
Pressure Transducers See Fig. 7.
*See Fig. 5 and Fig. 7-11.
CHILLER VISUAL CONTROLLER (CVC) — The CVC is
the ‘‘brain’’ of the PIC II. This module contains all the op-
erating software needed to control the chiller. The CVC is
mounted to the control panel (Fig. 10) and is the input center
for all local chiller set points, schedules, configurable
functions, and options. The CVC 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 functions of the four buttons or ‘‘softkeys’’ are
menu driven and are shown on the display directly above
the softkeys.
The viewing angle of the CVC can be adjusted for opti-
mum viewing. Remove the 2 bolts connecting the control
panel to the brackets attached to the cooler. Place them in
one of the holes to pivot the control panel forward to back-
ward to change the viewing angle. See Fig. 10. To change
the contrast of the display, access the adjustment on the back
of the CVC. See Fig. 10.
Fig.6—Typical Starter External View
(Solid-State Starter Shown)
11