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SECTION 15650
CHILLERS
PART I - GENERAL
1.01
WORK INCLUDED
A.
1.02
1.03
Extent of work shall be as indicated on Drawings and provisions of this section, including
schedules and equipment lists associated with either Drawings or this section.
QUALITY ASSURANCE
A.
Manufacturers: Firms regularly engaged in manufacturer of chillers and accessory
equipment of type and sizes required, whose products have been in satisfactory use in
similar service for not less than five (5) years.
B.
UL and NEMA Compliance: Provide electric motors and electrical components required
as part of chiller equipment, which have been listed and labeled by Underwriters
Laboratories and comply with NEMA standards.
C.
NEC Compliance: Comply with National Electrical Code (ANSI/NFPA 70) as applicable
to installation and electrical connections of ancillary electrical components of chillers and
accessory equipment.
SUBMITTALS
A.
Product Data: Submit manufacturer's chiller and accessory equipment specifications,
installation and start-up instructions, and capacity and ratings, with selection points
clearly indicated.
B.
Maintenance Data: Submit maintenance data and parts lists for each item of chiller and
accessory equipment. Include "trouble- shooting" maintenance guides. Include this data
in maintenance manual.
PART II - PRODUCTS
2.01
WATER-COOLED CHILLER
A.
Furnish and install factory-assembled York, Trane, or equal water-cooled screw
compressor water cooled centrifugal liquid chilling packages using Refrigerant R-22, R123 or R-134a. Model, size, and quantity, shall be as listed on the Drawings.
B.
Performance shall be certified in accordance with ARI Standard 550-90. Only chillers
that are listed in the ARI Certification Program for Centrifugal and Rotary Screw Water
Chillers are acceptable.
C.
Each unit shall be completely factory-packaged including evaporator, condenser,
subcooler, oil separator, compressor, open motor, lubrication system, micro-computer
control center, solid state starter with non-fused disconnect switch and all interconnecting
unit piping and wiring. Refrigerant shall be R-22, R-123 or R-134a, shipped inside the
unit.
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D.
The compressor shall be an open-drive, rotary-screw type or semi hermetic centrifugal.
The compressor housing shall be of cast iron, precision machined to provide minimal
clearance for rotors. The rotors shall be manufactured from forged steel and use
asymmetric profiles operating at a maximum speed of 3570 RPM. The compressor shall
incorporate a complete anti-friction bearing design to reduce power and increase
reliability; four separate cylindrical roller bearings to handle radial loads; and two fourpoint angular contact ball bearings to handle axial loads. The compressor shall have an
internal oil reservoir to assure a constant supply of oil to the bearings at all times. A
spring actuated positive seating check valve shall be incorporated in the compressor
housing to prevent rotor backspin during shutdown. The shaft seal shall be a spring
loaded carbon ring with precision lapped collar cooled by low pressure oil.
E.
Capacity control shall be achieved by use of a slide valve or in case of centrifugal unit
limit demand load to provide fully modulating control from 100% to 10% of full load. The
slide valve shall be actuated by oil pressure, controlled by external solenoid valves
through the microcomputer control center. The unit shall be capable of operating with
lower temperature cooling tower water during part-load operation in accordance with ARI
Standard 550-90. If the unit cannot operate at the minimum load, the manufacturer shall
provide a hot-gas-bypass system to allow operation at 10% load, and advise the
minimum load and power input of the unit at the point hot-gas-bypass is actuated.
F.
The motor shall be two-pole, continuous duty, squirrel cage induction type, and shall
have an open drip proof enclosure. Motor full-load amperes at design conditions shall
not exceed motor nameplate (FLA). Motor shall be designed for use with the starter type
specified. Motor shall be factory-mounted and directly connected to the compressor to
provide compressor/motor alignment.
G.
An adequate supply of oil shall be available to the compressor at all times. During
startup and coastdown, this shall be achieved by oil reservoirs in the compressor, or by
prelube and postlube oil pump operation. During operation, oil shall be delivered by
positive system pressure differential or full-time operation of an oil pump. An oil reservoir
shall be located in the compressor to lubricate bearings in the case of a power failure.
H.
An immersion oil heater shall be provided, temperature actuated, to effectively remove
refrigerant from the oil. An external replaceable-cartridge, oil filter shall be provided,
along with manual isolation stop valves for ease of servicing. An oil eductor shall be
provided to automatically remove oil which may have migrated to the evaporator and
return it to the compressor. The oil separator shall be of a horizontal design with no
moving parts, and shall provide effective oil separation before the refrigerant enters the
heat exchangers. A refrigerant-cooled oil cooler shall be provided to allow operation of
the chiller over the full range of operating conditions.
I.
Evaporator shall be of the shell-and-tube, flooded type designed for 300 psig working
pressure on the refrigerant side, and be tested at 450 psig. Shell shall be fabricated from
rolled carbon steel plate with fusion welded seams; have carbon steel tube sheets, drilled
and reamed to accommodate the tubes; and intermediate tube supports spaced no more
than four feet apart. The refrigerant side shall be designed, tested and stamped in
accordance with the ASME Boiler and Pressure Vessel Code, Section VIII-Division 1.
Tubes shall be high-efficiency, internally enhanced type. Each tube shall be roller
expanded into the tube sheets providing a leakproof seal and be individually replaceable.
Water velocity through the tubes shall not exceed 12 FPS. Liquid level sight glasses
shall be located on the side of the shell to aid in determining proper refrigerant charge.
The evaporator shall have a refrigerant relief device to meet the requirements of the
ASHRAE 15 Safety Code for Mechanical Refrigeration.
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J.
Water boxes shall be removable to permit tube cleaning and replacement. Stub out
water connections having Vitaulic grooves shall be provided. Water boxes shall be
designed for 150 psig design working pressure and be tested at 225 psig. Vent and drain
connections with plugs shall be provided on each water box.
K.
Condenser shall be of the shell-and-tube type, designed for 300 psig working pressure on
the refrigerant side and be tested at 450 psig. Shell shall be fabricated from rolled
carbon steel plate with fusion welded seams; have carbon steel tube sheets, drilled and
reamed to accommodate the tubes; and intermediate tube supports spaced no more than
four feet apart. A refrigerant subcooler shall be provided for improved cycle efficiency.
The refrigerant side shall be designed, tested and stamped in accordance with the ASME
Boiler and Pressure Vessel Code, Section VIII-Division 1. Tubes shall be high-efficiency,
internally enhanced type. Each tube shall be roller expanded into the tube sheets
providing a leakproof seal and be individually replaceable. Water velocity through the
tubes shall not exceed 12 FPS. The condenser shall have refrigerant relief devices to
meet the requirements of the ASHRAE 15 Safety Code for Mechanical refrigeration.
L.
Water boxes shall be removable to permit tube cleaning and replacement. Stubout water
connections having Victaulic grooves shall be provided. Water boxes shall be designed
for 150 psig working pressure and be tested at 225 psig. Vent and drain connections
with plugs shall be provided on each water box.
M.
Refrigerant flow to the evaporator shall be metered by a single fixed orifice with no
moving parts.
N.
The condenser shell shall be capable of storing the entire system refrigerant charge
during servicing. Isolation from the rest of the system shall be by manually operated
isolation valves located at the inlet and outlet of the condenser. Additional valves shall
be provided to facilitate removal of refrigerant charge from the system.
O.
Each unit shall be furnished complete with a microcomputer control center in a locked
enclosure, factory-mounted, wired and tested. The control center shall include a 40character alphanumeric display showing all system parameters in the English language
with numeric data in English units.
P.
Digital programming of essential setpoints through a color coded, tactile-feel keypad shall
include: leaving chilled water temperature, percent current limit, pulldown demand
limiting, seven-day timeclock for starting and stopping chiller, pumps and tower (complete
with holiday schedule), and remote reset temperature range.
Q.
All safety and cycling shutdowns shall be annunciated through the alphanumeric display
and consist of day, time, cause of shutdown and type of restart required. Safety
shutdowns shall include: high condenser pressure, low oil pressure at compressor,
clogged oil filter, high oil temperature, high oil pressure, high compressor discharge
temperature, low evaporator pressure, motor controller fault and sensor malfunction.
Cycling shutdowns shall include: low water temperature, cooler/condenser waterflow
interruption, power fault, internal timeclock and anti-recycle.
R.
System operating information shall include: return/leaving chilled water temperatures,
return/leaving condenser water temperatures (optional), evaporator/condenser refrigerant
pressures, oil pressures at compressor and oil filter differential, percent motor current,
evaporator/condenser saturation temperatures, compressor discharge temperature, oil
temperature, percent slide valve position, operating hours and number of compressor
starts.
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S.
Security access shall be provided to prevent unauthorized change of setpoints and to
allow local or remote control of the chiller.
T.
The chiller shall be provided with an RS232 port to output all system operating data and
shutdown/cycling messages to a field-supplied printer. The control center shall be
programmable to provide data logs to the printer at a set time interval.
U.
Control center shall be able to interface with a Metasys building automation system to
provide remote chiller start/stop, reset of chilled water temperature, reset of current limit
and status messages indicating chiller is ready to start, chiller is operating, chiller is
shutdown on a safety requiring reset and chiller is shutdown on a recycling safety.
V.
The chiller manufacturer shall furnish a reduced-voltage solid-state starter for the
compressor motor. Starter shall be factory-mounted and wired on the chiller. The started
shall provide, through the use of silicon controlled rectifiers, a smooth acceleration of the
motor without current transitions or transients. The started enclosure shall be NEMA 1,
with a hinged access door with lock and key. Electrical lugs for incoming power wiring
shall be provided.
W.
Protective devices shall include: phase rotation protection, single-phase failure
protection, momentary power interruption protection, and high/low line voltage protection.
Starter shall include: three leg sensing overloads, 120-volt control transformer for all unit
controls, and a non-fused disconnect switch. Three-phase voltage and current readings
shall be coordinated with the unit control center, with digital readout on the display.
X.
The chiller manufacturer shall include the services of a factory-trained, field service
representative to supervise the initial startup and concurrent operator instruction.
Y.
Chillers shall be warranted for two (2) year parts and labor warranty ending thirty (30)
months from shipment or twenty-four (24) months from start-up, whichever occurs first.
Z.
Insulation shall be ¾” thick flexible closed cell plastic factory applied with vapor-proof
cement to cooler shell and tube sheets, oil cooler, refrigerant liquid distribution piping,
suction connection, and auxiliary tubing as necessary. Insulation of cooler water box end
plates and water nozzles will be furnished and installed as required under Specification
Section 15250 "Mechanical Insulation." Insulation shall be provided with a final coat of
factory applied vinyl paint.
PART III - EXECUTION
3.01
INSTALLATION OF CHILLERS AND ACCESSORIES
A.
Install chillers and accessories as indicated, in accordance with manufacturer's
installation instructions and in compliance with applicable codes. Units supplied shall not
exceed the length of specified unit.
B.
An instruction manual completely describing installation, operation, and maintenance of
the specific chiller being furnished, with details of all modifications, shall be provided with
the unit. Copies of the chiller inspection and operational test reports shall be submitted
with the manual.
C.
Supervision of start-up and instruction of operating staff shall be provided by factorytrained personnel. The local representative in which area the chiller is installed shall
have factory-trained service personnel available on a 24-hour basis, seven days a week
for emergency service.
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3.02
CARE AND CLEANING
A.
3.03
OPERATION TEST
A.
3.04
Repair or replace broken, damaged, or otherwise defective parts, materials, and work.
Leave entire work in condition satisfactory to University's Representative. At completion,
carefully clean and adjust equipment installed as part of this work. Leave systems and
equipment in satisfactory operating condition.
Test each piece of equipment to show that it will operate in accordance with indicated
requirements.
CLEANING UP
A.
Upon completion of Work remove materials, equipment, apparatus, tools, and the like,
and leave premises clean, neat, and orderly.
END OF SECTION 15650
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