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RLC-PRC005-E4
Mechanical Specifications
General
Units are leak- and pressure-tested at
24.5 bars [350 psi] high side and 14 bars
[200 psi] low side, and then evacuated
and charged. Packaged units ship with a
full operating charge of oil and
refrigerant. Unit panels, structural
elements, and control boxes are
constructed of 1.5 to 3 mm [11 to 16
gauge] galvanized sheet metal and
mounted on a welded structural-steel
base. Unit panels and control boxes are
finished with baked-on powder paint,
and the structural-steel base is finished
with an air-dry paint RAL 1019.
Evaporator
The evaporator is a tube-in-shell heat
exchanger design, with internally-finned
copper tubes roller-expanded into the
tube sheet. The evaporator is designed,
tested, and stamped in accordance with
the appropriate pressure-vessel code
approval. The evaporator is designed for
a waterside working pressure of 14
bars[200 psi]. Water connections are
grooved pipe for Victaulic couplings.
Each shell includes a vent, a drain, and
fittings for temperature control sensors,
and is insulated with 19mm [3/4 inch]
Armaflex II (or equivalent) insulation
(K=0.26). Optional evaporator heaters
with thermostats are provided to protect
the evaporator from freezing at ambient
temperatures down to -25°C [-13°F].
Condenser and Fans
Air-cooled condenser coils have
aluminum fins mechanically bonded to
internally-finned seamless copper
tubing. The condenser coil has an
integral subcooling circuit. Condensers
are factory proof- and leak-tested at 35
bars [500 psi]. Direct-drive vertical-
discharge airfoil
ZephyrWing
condenser
fans are dynamically balanced. Three-
phase condenser fan motors with
permanently-lubricated ball bearings
are provided. Standard units will start
and operate from -4 to 46°C [25 to
11 5°F] ambient.
Compressor and Lube Oil System
The helical-rotary compressor is semi-
hermetic, direct drive, 3000 rpm, with
capacity-control slide valve, a
load/unload valve, rolling element
bearings, differential refrigerant
pressure oil pump, and oil heater. The
motor is a suction-gas-cooled,
hermetically sealed, two-pole squirrel-
cage induction motor. Oil separator and
filtration devices are provided separate
from the compressor. Check valves in
the compressor discharge and lube oil
system, and a solenoid valve in the
lube system, are provided.
Refrigeration Circuits
Each unit has two refrigerant circuits,
with one helical-rotary compressor per
circuit. Each refrigerant circuit includes
a removable-core filter drier, liquid-line
shutoff valve, liquid-line sight glass with
moisture indicator, charging port, and
an electronic expansion valve. Fully
modulating compressors and electronic
expansion valves provide variable
capacity modulation over the entire
operating range. (Optional compressor
discharge and suction service valve).
Unit Controls
All unit controls are housed in a
weather-tight enclosure, with
removable plates to allow for customer
connection of power wiring and remote
interlocks. All controls, including
sensors, are factory-mounted and -
tested prior to shipment.
Microcomputer controls provide all
control functions including startup and
shutdown, leaving-chilled-water
temperature control, compressor and
electronic expansion-valve modulation,
fan sequencing, anti-recycle logic,
automatic lead/lag compressor starting,
and load limiting. The unit control
module, utilizing the Adaptive Control
™
microprocessor, automatically takes
action to avoid unit shutdown due to
abnormal operating conditions
associated with low refrigerant pressure,
high condensing pressure, and motor
current overload. Should the abnormal
operating condition continue until a
protective limit is violated, the unit will
be shut down. Unit protective functions
include loss of chilled-water flow,
evaporator freezing, loss of refrigerant,
low refrigerant pressure, high refrigerant
pressure, reverse rotation, compressor-
starting and -running overcurrent, phase
loss, phase imbalance, phase reversal,
and loss of oil flow. A digital display
indicates chilled-water set point and
leaving-chilled-water temperature as
standard, while current-limit set point,
evaporator and condenser refrigerant
pressures, and electrical information are
an option. Both standard and optional
displays can be viewed on the unit
without opening any control panel
doors. Standard power connections
include main three-phase power to the
compressors, condenser fans, and
control power transformer, and optional
connections are available for the 230
volt single-phase power for freeze
protection on the evaporator heaters.
Starters
Starters are housed in a weather-tight
enclosure with hinged doors to allow for
customer connection of power wiring.
Wye-Delta closed transition starters (33
percent of LRA inrush) are standard. An
optional Wye-Delta closed transition
starter (33 percent of LRA inrush) is
available on 400/3/50 volt units.