GENERAL
All chillers are factory run-tested to confirm proper operation. Units are checked on a computer-based test stand at typical ambient and water conditions and control operation is monitored. Units ship with a full operating charge of refrigerant and oil.
Units are constructed of 14-gauge welded galvanized steel frame with 14 and 16-gauge galvanized steel panels and access doors. Unit surface is phosphatized and finished with an air- dry paint.This air-dry paint finish is durable enough to withstand a 1000- consecutive-hour salt spray application in accordance with standard ASTM B117.
Evaporator
Braze plate construction designed to withstand a waterside working pressure of 300 psig and a refrigerant side working pressure of 225 psig. It has one water pass. Etched foil heaters protect the evaporator to an ambient of -20°F.
Flow Switch
This factory supplied item indicates the loss of evaporator flow and ships with the unit for field installation.
Strainer (with installation hardware)
The strainer is required to prevent collection of particles within the evaporator.
Condenser
Air-cooled condenser coils have configurated aluminum fins mechanically bonded to seamless copper tubing and integral subcooling circuits. Condensers are factory leak- tested with air underwater at 425 psig air pressure.
Direct-drive vertical discharge condenser fans are statically and dynamically balanced.Three-phase condenser fan motors with permanently lubricated ball bearings and three-phase thermal overload protection. Optional low ambient units start and operate to 0°F with electronic damper assemblies for head pressure control.
Decorative grilles provide protection from exterior damage to coil surface and
other interior unit components. Grilles are factory mounted, louvered, galvanized steel mesh panels finished with an air-dry paint. Grilles will cover all open ends of units.
Compressors
Trane 3-D Scroll compressors have simple mechanical design with only three major moving parts. Scroll type compression provides inherently low vibration.The 3-D Scroll provides a completely enclosed compression chamber which leads to increased efficiency. Exhaustive testing on the 3-D Scroll, including start up with the shell full of liquid, has proven that slugging does not fail involutes. Direct-drive, 3600 rpm, suction gas-cooled hermetic motor. Trane 3-D Scroll compressor includes centrifugal oil pump, oil level sight glass and oil charging valve. Each compressor shall have crankcase heaters installed, properly sized to minimize the amount of liquid refrigerant present in the oil sump during off cycles.
Refrigerant Circuits and Capacity Modulation
Twenty to 30-ton sizes have a single refrigerant circuit. Forty to 60-ton sizes have dual refrigerant circuits. Each refrigerant circuit has twoTrane 3-D Scroll compressors, piped in parallel, with a passive oil management system. Passive oil management system maintains proper oil levels within compressors and has no moving parts. Each refrigerant circuit includes a liquid line solenoid valve, filter drier, liquid line sight glass with moisture indicator, thermostatic expansion valve, and service valves (liquid and discharge). Capacity modulation is achieved by turning compressors on and off.Twenty to 30-ton sizes have two capacity stages. Forty, 50 and 60-ton sizes have four capacity stages.The standard leaving chilled water temperature range is 40°F to 50°F. Options are available for leaving chilled solution temperature ranges from 20° to 29°F, 30° to 39°F, and 51° to 65°F.
Unit Controls
Compressor contactors and unit controls are in a weather tight enclosure with knockouts for jobsite installed wiring.The
unit controller shall be suitable to control leaving chilled solution temperature for comfort or process applications, automatic compressor sequencing, condenser fan sequencing, load limiting and anti-recycle functions. Failure protections include loss of chilled solution flow, chiller freeze protection, chilled solution flow interlock, head pressure control, pump down control, low ambient start, hot start control, and low ambient lockout. Leaving and entering solution temperature sensor is factory installed. Controls include auto/stop switch, a leaving water temperature set point adjustment, a DeltaT adjustment viewable through the unit Human Interface digital display.
Unit Controller
DDC microprocessor controls shall be provided to control all unit functions.The control system shall be suitable to control comfort and process applications.The controls shall be factory-installed and mounted in the main control panel. All factory-installed controls shall be fully commissioned (run tested) at the factory.The unit shall have a Human Interface Panel with a 16 key keypad, a 2 line X 40 character clear English display as standard to provide the operator with full adjustment and display of control data functions.The unit controls shall be used as a stand-alone controller, or as part of a building management system involving multiple units.
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The unit shall be equipped with a complete microprocessor control system.This system shall consist of temperature and pressure (thermistor and transducer) sensors, printed circuit boards (modules), and a unit mounted Human Interface Panel. Modules (boards) shall be individually replaceable for ease of service. All microprocessors, boards and sensors shall be factory mounted, wired and tested.
The microprocessor boards shall be stand-alone DDC controls not dependent on communications with an on-site PC or a Building Management Network.The microprocessors shall be equipped with onboard diagnostics, indicating that all