Product data

34
using a tapered fit, double keyway design. Gear
shaft shall be straight fit design.
3. Coupling guards shall be installed on both
couplings.
4. If the coupling is of a proprietary design, a spare
coupling and coupling shaft shall be supplied.
5. High speed coupling shall be balanced to the
requirements of AGMA 9000-C90 for the cate-
gory of “Normal System Sensitivity.”
F. Cooler and Condenser:
1. Cooler and condenser shall be in separate
shells. Heat exchangers shall be fabricated
with high performance copper tubing, steel
shell-and-tube sheets, and fabricated steel
waterboxes.
2. Tubing shall be copper, high-efficiency type
with integral internal and external fins. Tubes
shall be nominal ¾-in. OD with wall thickness
of 0.025 in. (0.635 mm) measured at the root
of the fin. Tubes shall be rolled into tube sheets
and shall be individually replaceable. End
sheets shall be double grooved for joint struc-
tural integrity. Cooler tubes shall be expanded
into intermediate support sheets. Intermediate
tube support sheet spacing shall not exceed
37 in. (940 mm).
3. Waterboxes shall be nozzle-in-head (NIH)
design with connections designed for 150 psig
(1034 kPa) maximum working pressure unless
otherwise noted. Nozzles shall have grooves to
allow use of victaulic couplings.
4. The vessel shall display an ASME nameplate
that shows pressure and temperature data
and the “U” stamp for ASME Section VIII,
Division 1.
5. Waterboxes shall have vents, drains, and cov-
ers to permit tube cleaning within the space
shown on the drawings. Suitable tapping shall
be provided in waterboxes and nozzles for con-
trol sensors.
6. Tubes shall be removable from either end of
the heat exchanger without affecting strength
and durability of the tube sheet and without
causing leakage in adjacent tubes.
7. The condenser shell shall include a FLASC
(Flash Subcooler) which cools the condensed
liquid refrigerant to a temperature that is below
the condensing temperature, thereby increas-
ing the refrigeration cycle efficiency.
8. The tube sheets of the cooler, condenser, and
economizer/storage vessel shall be bolted
together to allow for field disassembly and
reassembly.
9. Safety relief valves shall be installed on the
cooler.
10. Cooler shall be designed to prevent liquid
refrigerant from entering the compressor.
G. Interstage Flash Economizer/Storage Vessel:
1. Unit shall include an interstage flash econo-
mizer/storage vessel that shall be an integral
part of the chiller.
2. The vessel shall be large enough to hold the
entire refrigerant charge.
3. To improve part load performance, liquid refrig-
erant shall be metered from the condenser to
the cooler using a float-type metering valve to
maintain the proper liquid level of refrigerant in
the heat exchangers under both full load and
part load operating conditions. By maintaining a
liquid seal, bypassed hot gas from the condenser
to the cooler is eliminated. The float valve cham-
bers shall have bolted access covers.
4. Isolation valves shall be factory installed on the
condenser liquid line, cooler liquid line, and
economizer gas line. These valves shall allow
isolation of the refrigerant charge in the econo-
mizer/storage vessel during chiller service.
5. Safety relief valves shall be installed on the flash
economizer/storage vessel.
H. Thermal Insulation:
1. Chillers provided with insulation applied at the
chiller manufacture’s factory shall require the
waterbox and chilled water piping to be insu-
lated by the contractor.
2. Chillers provided with no insulation shall be
insulated at the job site per manufacturer’s
instructions.
3. Insulation shall be ¾-in. (19 mm) thick with
a thermal conductivity not exceeding
0.28 (0.0404 °C), shall conform
to UL Standard 94, and have classification 8-94
HBF.
I. Vibration Isolation:
1. Chiller manufacturer shall furnish isolator pads
for mounting equipment on a level concrete pad
surface.
2. If the equipment room floor is not level, the
chiller should be ordered with accessory sole-
plates, jacking screws, and leveling pads for field
installation.
J. Controls:
1. The chiller shall be provided with a factory
installed and wired microprocessor control
center with individually replaceable, modular
component construction. Components in-
cluded shall be the main processor/sensor
input/output module, power supply, starter
management module (located in starter cabi-
net), relay board, and temperature and
pressure (thermistor and transducer) sensors.
The control center includes a 16-line by
40-character liquid crystal display (LCD),
4 softkeys (function keys), a stop button, and
Btu
⋅
in.
hr
⋅
ft
2
⋅
°F
W
m
Guide specifications (cont)