5
JOHNSON CONTROLS
Guide Specifications -
continued
ANSI/AwwA C-606 grooves shall be provided. water
Boxes shall be designed for 150 psig (1034 Kpa) design
working pressure and be tested at 225 psig (1551 Kpa).
Vent and drain connections with plugs shall be provided
on each water box.
Refrigerant System
The YS chiller is equipped with a refrigerant metering
device consisting of a fixed orifice and solenoid valve
controlled via the OptiView Control Center. This control
ensures proper refrigerant flow to the evaporator over a
wide range of operating conditions, including thermal stor-
age applications and chilled water reset. Valve operation
is programmable and can be customized for a specific
application via the OptiView Control Center keypad.
The condenser shell shall be capable of storing the entire
system refrigerant charge during servicing. Isolation from
the rest of the system shall be by manually operated isola-
tion valves located at the inlet and outlet of the condenser.
Additional valves shall be provided to facilitate removal of
refrigerant charge from the system.
OPTIVIEw CONTROL CENTER
General –
The chiller shall be controlled by a stand-alone
microprocessor based control center. The chiller control
panel shall provide control of chiller operation and monitor-
ing of chiller sensors, actuators, relays and switches.
Control Panel –
The control panel shall include a 10.4-
in. diagonal color liquid crystal display (LCD) surrounded
by “soft “ keys which are redefined based on the screen
displayed at that time. This shall be mounted in the middle
of a keypad interface and installed in a locked enclosure.
The screen shall detail all operations and parameters,
using a graphical representation of the chiller and its
major components. Panel verbiage shall be available in
other languages as an option with english always avail-
able. Data shall be displayed in either english or Metric
units. Smart Freeze point protection shall run the chiller
at 36°F (2.22°C) leaving chilled water temperature, and
not have nuisance trips on low water temperature. The
sophisticated program and sensor shall monitor the chiller
water temperature to prevent freeze-up. when needed,
Hot Gas Bypass is available as an option. The panel shall
display countdown timer messages so the operator knows
when functions are starting and stopping. every program-
mable point shall have a pop-up screen with the allowable
ranges, so that the chiller can not be programmed to
operate outside of its design limits.
The control panel shall be provided with a thermal ice
storage control mode to enhance system performance
during ice building operation. In the thermal storage control
mode, the chiller shall stay at 100% load until the setpoint
shutdown temperature is reached. To add greater operat-
ing flexibility and eliminate unnecessary chiller cycling,
two different Low water (Liquid) Temperature Restart
Thresholds shall be programmable, one for the ice mode
and one for the standard cooling mode. The chiller shall
have the capability to remain in the standard control mode
for temperatures between 20 to 70°F (-6.7 to 21.1°C) for
applications involving a process cooling duty that requires
leaving chilled liquid temperature setpoint control.
The chiller control panel shall also provide:
1. System operating information including:
a. Return and leaving chilled water temperature
b. Return and leaving condenser water temp.
c. evaporator and condenser saturation temp.
d. Oil pressure at compressor and oil filter
differential
e. percent motor current
f. evaporator and condenser saturation temp.
g. Compressor discharge temperature
h. Oil temperature
i. percent slide valve position
j. Operating hours
k. Number of unit starts
2. Digital programming of setpoints through the univer-
sal keypad including:
a. Leaving chilled water temperature
b. percent current limit
c. pull-down demand limiting
d. Six-week schedule for starting and stopping the
chiller, pumps and tower
e. Remote reset temperature range
3. Status messages indicating:
a. System ready to start
b. System running
c. System coastdown
d. System safety shutdown-manual restart
e. System cycling shutdown-auto restart
f. System prelube
