Product specifications

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B. The start-up date shall be certified by the Mechanical Contractor, and provided to the Manufacturer,
Engineer and Owner.
C. (Provide an optional extended four (4)-year warranty on the compressors only, 5 years total).
D. (During the warranty period, the equipment supplier shall furnish the services of an authorized service
agency for all labor associated with parts replacement or repair, and start-up of the refrigeration equipment
at the beginning of each cooling season. The equipment supplier shall also furnish the services of an
authorized service agent for one maintenance visit during winter months of operation, such times shall be
designated by the Owner.)
1.09 Maintenance
Maintenance of the chillers shall be the responsibility of the owner and performed in accordance with the
manufacturer’s instructions.
Part 2: Products
2.01 Tandem Scroll Compressor Air Cooled Water Chillers
2.02 Acceptable Manufacturers
A. Dunham-Bush, Inc.
B. (Approved equal)
2.03 General
A. Furnish and install as shown on the plans, air-cooled Tandem Scroll Compressor water chillers. Units shall
be Dunham-Bush Model ACDS-B or equal.
B. The units are to be completely factory assembled and wired in a single package complete with Tandem
Scroll Compressors, evaporator, condenser, starting control with safety and operating controls. The unit
is to be given a complete factory operating and control sequence test under load conditions and is to be
shipped with full operating charge of R-22 and full oil charge.
C. The units shall be built in accordance with all applicable national and local codes including the ANSI safety
code; the National Electrical Code and applicable ASME Code for Unfired Pressure Vessels.
2.04 Performance
The units shall be furnished as shown on capacity schedules and drawings. Unit performance shall be in accordance
with ARI Standard 550/590.
2.05 Construction
The unit will be designed for maximum corrosion protection being of heavy gauge, UL90 approved galvanized
steel construction. The base and legs shall be manufactured of 10 gauge galvanized steel channel. Frame members
are constructed of 12 gauge, galvanized steel.
2.06 Evaporator
Evaporator shall be direct expansion, shell and tube type. The shell shall be fabricated from carbon steel, with
enhanced inner fin construction inside seamless copper tubes. The tube sheets shall be heavy gauge copper in
welded head vessels. The tubes shall be brazed into the tubesheets. Water control baffles shall be copper. The
heads shall be constructed of carbon steel. Evaporators shall be designed, constructed and inspected to comply
with current ASME code for unfired pressure vessels. Shell side (water) design working pressure shall be minimum
200 PSIG and tube side (refrigerant) design working pressure shall be minimum 300 PSIG. A thermostatically
controlled electric resistance heater cable shall be wrapped around the shell to prevent freezing down to -20°F
(-28.9°C) outdoor temperature.
2.07 Condenser
The condenser coil is to be constructed of copper tubes and die formed aluminum fins having self-spacing collars.
Fins shall be mechanically bonded to the tubes. An integral sub-cooling loop shall be incorporated into the coil.
Condenser divider baffles shall fully separate each condenser fan section to control the airflow to maintain proper
head pressure control.
2.08 Fans
The fans shall be heavy duty, aluminum blade, direct drive propeller type. Motors shall be three phase (except for
low ambient option lead fan per circuit) with internal overloads and are to be permanently lubricated.
2.09 Compressor
A. The compressors shall be Tandem Scroll with suction and discharge manifolded and oil and gas equalization
provided. All compressors shall be 3500 RPM direct drive with an integral two-pole hermetic squirrel cage
motor. A dust-proof terminal box, located in an accessible location on the compressor, shall contain all
connection terminals.