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General
The units shall be dedicated downflow or
horizontal airflow. The operating range
shall be between 115 F and 0 F in cooling
as standard from the factory for all units.
Cooling performance shall be rated in
accordance with ARI testing procedures.
All units shall be factory assembled,
internally wired, fully charged with HCFC-
22 and 100% run tested to check cooling
operation, fan and blower rotation and
control sequence before leaving the
factory. Wiring internal to the unit shall be
numbered for simplified identification.
Units shall be UL listed and labeled,
classified in accordance to UL 1995/CAN/
CSA No. 236-M90 for Central Cooling Air
Conditioners. Canadian units shall be
CSA Certified.
Casing
Unit casing shall be constructed of zinc
coated, heavy gauge, galvanized steel.
All components shall be mounted in a
weather resistant steel cabinet with a
painted exterior. Where top cover seams
exist, they shall be double hemmed and
gasket sealed to prevent water leakage.
Cabinet construction shall allow for all
maintenance on one side of the unit.
Service panels shall have handles and
shall be removable while providing a
water and air tight seal. Control box
access shall be hinged. The indoor air
section shall be completely insulated
with fire resistant, permanent, odorless,
foil faced glass fiber material. The base
of the unit shall have provisions for
crane lifting.
Filters
Two inch, throwaway filters shall be
standard on all size units. Two inch "high
efficiency", and four inch "high
efficiency" filters shall be optional.
Compressors
™
Scroll compressors have a
Trane 3-D
simple mechanical design with only
three major moving parts. Scroll type
compression provides inherently low
vibration. The 3-D Scroll provides a
completely enclosed compression
RT -PRC007-EN
Mechanical
Specifications
chamber which leads to increased
efficiency. Exhaustive testing on the 3-D
Scroll, including start up with the shell
full of liquid, has proven that slugging
does not fail involutes. Direct-drive, 3600
rpm, suction gas-cooled hermetic motor.
Trane 3-D Scroll compressor includes
centrifugal oil pump, oil level sightglass
and oil charging valve. Each compressor
shall have crankcase heaters installed,
properly sized to minimize the amount of
liquid refrigerant present in the oil sump
during off cycles.
Refrigerant Circuits
Each refrigerant circuit shall have
independent thermostatic expansion
devices, service pressure ports and
refrigerant line filter driers factory-
installed as standard. An area shall be
provided for replacement suction line
driers.
Evaporator and Condenser Coils
Condenser coils shall have
3
/
" copper
8
tubes mechanically bonded to lanced
aluminum plate fins. Evaporator coils
1
shall be
/
" internally finned copper
2
tubes mechanically bonded to high
performance aluminum plate fins. All
coils shall be leak tested at the factory to
ensure pressure integrity. All coils shall
be leak tested to 200 psig and pressure
tested to 450 psig. All dual circuit
evaporator coils shall be of intermingled
configuration. Sloped condensate drain
pans are standard.
Outdoor Fans
The outdoor fan shall be direct-drive,
statically and dynamically balanced,
draw through in the vertical discharge
position. The fan motor(s) shall be
permanently lubricated and have built-in
thermal overload protection.
Indoor Fan
Units shall have belt driven, FC,
centrifugal fans with fixed motor
sheaves. All motors shall be circuit
breaker protected. All indoor fan motors
meet the U.S. Energy Policy Act of 1992
(EPACT).
Electric Heaters
Electric heat shall be available for factory
installation within basic unit. Electric
heater elements shall be constructed of
heavy-duty nickel chromium elements
internally delta connected for 240 volt,
wye connected for 480 and 600 volt.
Staging shall be achieved through the
rooftop refrigeration module (RTRM).
Each heater package shall have
automatically reset high limit control
operating through heating element
contactors. All heaters shall be
individually fused from factory, where
required, and meet all NEC and CEC
requirements. Power assemblies shall
provide single-point connection. Electric
heat shall be UL listed or CSA certified.
Gas Heating Section
The heating section shall have a drum
and tube heat exchanger(s) design with
primary and secondary surfaces of
corrosion resistant aluminized steel or
optional stainless steel.
A forced combustion blower shall
supply premixed fuel to a single burner
ignited by a pilotless hot surface ignition
system. In order to provide reliable
operation, a negative pressure gas valve
shall be used that requires blower
operation to initiate gas flow. On an
initial call for heat, the combustion
blower shall purge the heat exchanger(s)
45 seconds before ignition. After three
unsuccessful ignition attempts, the entire
heating system shall be locked out until
manually reset at the thermostat. Units
shall be suitable for use with natural gas
or propane (field installed kit) and also
comply with California requirements for
low NOx emissions. All units shall have
two stage heating.
Controls
Unit shall be completely factory wired
with necessary controls and terminal
block for power wiring. Units shall
provide an external location for mounting
fused disconnect device. ReliaTel controls
73
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