Product data
Guide specifications
Packaged Hermetic Screw Liquid Chiller
SizeRange:150to360Tons(530to1270kW)—60Hz
130to300Tons(460to1060kW)—50Hz
Carrier Model Number: 23XL
Part 1 — General
1.01 SYSTEM DESCRIPTION
A. Microprocessor-controlled liquid chiller using a twin
rotor, 3550 rpm (60 Hz) or 2960 rpm (50 Hz), di-
rect drive, semi-hermetic, screw compressor using re-
frigerant HCFC-22 or HFC-134a. Chillers using
CFC refrigerants such as CFC-11, CFC-12, or CFC/
HFC-500 shall not be acceptable.
If a manufacturer proposes a liquid chiller using
HCFC-123 refrigerant, then the manufacturer shall
include in the chiller price:
1. A vapor activated alarm system consisting of all
alarms, sensors, safeties, and ventilation equip-
ment as required by ANSI/ASHRAE Standard 15
Safety Code for Mechanical Refrigeration (latest
edition) with the quotation. System shall be ca-
pable of responding to HCFC-123 levels of
10 ppm Allowable Exposure Limit (AEL).
2. External refrigerant storagetank and pumpoutunit.
3. High efficiency purge unit.
4. Back-up relief valve to rupture disc.
5. Chiller pressurizing system to prevent leakage of
non-condensables into chiller during shutdown
periods.
6. Plant room ventilation.
1.02 QUALITY ASSURANCE
A. Chiller performance shall be rated in accordance with
ARI Standard 550 (latest edition).
B. Equipmentand installation shall be in compliance with
ANSI/ASHRAE 15 (latest edition).
C. Cooler and condenser shall include ASME ‘‘U’’
stampandnameplate certifyingcompliance withASME
Section VIII, Division 1 code for unfired pressure
vessels.
D. Chillershall be manufactured in a facility that has been
registered by UL to the ISO 9000 Series Standards
for quality.
E. Chiller shall be designed and constructed to meet UL
and UL of Canada requirements and shall have labels
appropriately affixed.
F. Each compressor assembly shall undergo a mechani-
cal run-in test to check proper operation of compo-
nents and to verify that vibration levels, oil pressures/
temperatures, and efficiencies are within acceptable
limits. Each compressor assembly shall be pneumati-
cally proof tested at 405 psig (2792 kPa) and leak
tested with a tracer gas at 225 psig (1551 kPa).
G. Both cooler and condenser shall be proof tested at
375 psig (2586 kPa) on the refrigerant side and leak
tested with a refrigerant tracer gas at 300 psig
(2068 kPa). The water side of each heat exchanger
shall be hydrostatically tested at 1.5 times rated work-
ing pressure.
H. The entire chiller assembly shall be leak tested with a
refrigerant tracer gas at 300 psig (2068 kPa).
I. Prior to shipment, the chiller automated controls shall
be tested under power to verify proper wiring and
ensure correct controls operation.
1.03 DELIVERY, STORAGE AND HANDLING
A. Unit shall be stored and handled in accordance with
manufacturer’s instructions.
B. Unit shall be shipped with all refrigerant piping and
control wiring factory installed.
C. Unit shall be shipped charged with either refrigerant
HCFC-22, refrigerant HFC-134a, or a nitrogen hold-
ing charge, and oil as specified on the equipment
schedule.
D. Unit shall be shipped with firmly attached labels that
indicate the name of the manufacturer, chiller model
number,chiller serialnumber, andtherefrigerant used.
1.04 WARRANTY
Warranty shall include parts and labor for one year
after start-up or 18 months from shipment, which-
ever occurs first.
Part2—Products
2.01 EQUIPMENT
A. General:
Factoryassembled, single piece, liquid chillershall con-
sist of compressor, motor, lubrication system, cooler,
condenser,initial oiland refrigerant operating charges,
microprocessor control system, and documentation
requiredprior to start-up.Anoptional compressor mo-
tor starter can be mounted on the chiller, wired, and
tested by the chiller manufacturer.
B. Compressor:
1. One positive displacement field-serviceable heli-
cal, rotary, semi-hermetic, twin rotor-type com-
pressor.Compressor section joints shall be sealed
using O-rings instead of gaskets to reduce the oc-
currence of refrigerant leakage.
2. The compressor casing shall be cast-iron with de-
sign pressure rating of 300 psig (2068 kPa) or
higher.
3. The compressor/motor shall be designed to op-
erate at 3550 rpm (60 Hz) or 2960 rpm (50 Hz)
input speed.
4. Bearings shall be pressure lubricated rolling ele-
ment type, AFBMA Class 5 or superior.
5. Capacity control shall be via a hydraulically acti-
vated slide valve located below rotating screw
rotors.
6. Discharge oil separation shall be accomplished
external to the compressor casing. Oil separator
and return system shall be designed to ensure
that oil is adequately returned to the compressor
and does not collect in the heat exchangers.
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