Specifications

Catalog WSC/WDC-4 81
PART 2 — PRODUCTS
2.1 ACCEPTABLE MANUFACTURERS
A. McQuay International
B. (Approved Equal)
2.2 UNIT DESCRIPTION
Provide and install as shown on the plans a factory-assembled, factory charged, and factory run-
tested water-cooled packaged chiller. Each unit shall be complete with a single-stage hermetic
centrifugal compressor with lubrication and control system, factory mounted starter, evaporator,
condenser, refrigerant control device and any other components necessary for a complete and
operable chiller package.
2.3 DESIGN REQUIREMENTS
A. General: Provide a complete water-cooled hermetic centrifugal compressor water-chilling
package as specified herein. Machine shall be provided according to referenced standards
Section 1.2. In general, unit shall consist of a compressor, condenser, evaporator,
lubrication system, starter and control system.
Note: Chillers shall be charged with a refrigerant such as R-134a, not subject to the
Montreal Protocol and the U. S. Clean Air Act.
B. Performance: Refer to schedule on the drawings. The chiller shall be capable of stable
operation to ten percent of full load with standard ARI entering condensing water relief
without the use of hot gas bypass.
C. Acoustics: Sound pressure levels for the complete unit shall not exceed the following
specified levels. Provide the necessary acoustic treatment to chiller as required. Sound
data shall be measured according to ARI Standard 575-87. Data shall be in dB. Data shall
be the highest levels recorded at all load points. Test shall be in accordance with ARI
Standard 575.
Octave Band
63 125 250 500 1000 2000 4000 8000 dba
____ ____ ____ ____ ____ ____ ____ ____ ____
2.4 CHILLER COMPONENTS
A. Compressor:
1. Unit shall have a single-stage hermetic centrifugal compressor. Casing design
shall ensure major wearing parts, main bearings, and thrust bearings are
accessible for maintenance and replacement. The lubrication system shall protect
machine during coast down period resulting from a loss of electrical power.
2. The impeller shall be statically and dynamically balanced. The compressor shall
be vibration tested and not exceed a level of 0.14 IPS.
3. Movable inlet guide vanes actuated by an internal oil pressure driven piston shall
accomplish unloading. Compressors using an unloading system that requires
penetrations through the compressor housing or linkages, or both that must be
lubricated and adjusted are acceptable provided the manufacturer provides a five-
year inspection agreement consisting of semi-annual inspection, lubrication, and
annual change out of any compressor seals. A statement of inclusion must
accompany any quotations.
4. If the compressor is not equipped with guide vanes for each stage and movable
discharge diffusers, then furnish hot gas bypass and select chillers at 5% lower
kW/ton than specified to compensate for bypass inefficiency at low loads.
B. Lubrication System: The compressor shall have an independent lubrication system to
provide lubrication to all parts requiring oil. Provide a heater in the oil sump to maintain
oil at sufficient temperature to minimize affinity of refrigerant, and a thermostatically
controlled water-cooled oil cooler. Coolers located inside the evaporator or condenser are
not acceptable due to inaccessibility. A positive displacement oil pump shall be powered
through the unit control transformer.