The document describes the YORK YCIV R-134a Air-Cooled Screw Liquid Chillers, specifically Style A Models YCIV0157 to YCIV0397, 60 Hz (150 to 260 tons), available in E/V High Efficiency and S/P Standard Efficiency configurations. This manual provides detailed information for installation, operation, and maintenance.
The YCIV chillers are designed for water or glycol cooling and are intended for outdoor installation on building roofs or at ground level. They are shipped completely assembled with all interconnecting refrigerant piping and internal wiring, pressure tested, evacuated, and fully charged with refrigerant and oil. An operational test is performed to ensure correct refrigerant circuit operation. The unit structure is made from heavy-gauge galvanized steel with a "Champagne" baked-on enamel powder paint for corrosion resistance. All exposed power wiring is routed through liquid-tight, non-metallic conduit.
Function Description:
The YCIV chiller line combines modern screw compressor design with variable speed drive (VSD) technology for superior control and efficiency. The VSD allows the compressor speed to match the system load, resulting in precise chilled liquid control, minimized sound, maximum energy efficiency, and reduced cost of ownership. It also provides soft starts with no electrical inrush, reducing the required off-time between starts to 2 minutes. The chiller operates in ambient temperatures from 0°F to 125°F (-18°C to 52°C) and can reduce chiller capacity to 10% of full load without hot gas bypass.
The chiller consists of 2 or 3 screw compressors in separate refrigerant circuits, a single shell and tube DX evaporator, an air-cooled condenser, flash tanks, drain/feed valves, oil separators, and compressor mufflers. Oil cooling is achieved by routing oil from the oil separator through condenser coils.
Important Technical Specifications:
- Refrigerant: R-134a
- Compressors: Direct drive semi-hermetic rotary twin-screw MTS compressors (2 or 3 per chiller) designed for industrial refrigeration. Capacity control is stepless via VSD speed changes (10% to 100% of chiller capacity). Rotors are made from forged steel, and the 4-pole motor operates up to 6000 RPM.
- Evaporator: High-efficiency shell and tube type Direct Expansion Evaporator. Two-pass for 2-compressor chillers (liquid inlets/suction outlets at same end). Single-pass for 3-compressor chillers (liquid inlets at one end, suction outlets at opposite end, split flow). Design working pressure: 150 psig (10 bar) shell side, 235 psig (16 bar) tube side. Equipped with a thermostatically controlled heater for protection to -20°F (-29°C) ambient and 3/4 in. (19 mm) flexible closed-cell insulation. Water nozzles have grooves for mechanical couplings. A 300 psig (20.7 bar) waterside design working pressure option is available.
- Condenser: Fin and tube coils with seamless, internally enhanced, high-condensing coefficient, corrosion-resistant copper tubes and aluminum alloy fins. Design working pressure: 450 psig (31 bar). Multiple TEAO motor-driven fans provide vertical air discharge. Standard fan motors are high-efficiency, 6-pole, 3-phase, Class-“F,” current overload protected, totally enclosed type with double-sealed, permanently lubricated ball bearings.
- Flash Tank: Shell type refrigerant reservoir designed for 2-phase refrigerant, increasing system efficiency. Design working pressure: 450 psig (31 bar). Drain and Feed Valves are stepper motor valves controlled by a stand-alone controller based on suction superheat and liquid level (target 35%, faults at 87.5%).
- Oil System: External oil separators (no moving parts) mounted in the compressor discharge line. Oil (YORK “L” POE oil) flows from separator, through condenser for cooling, and back to compressor via a replaceable 0.5 micron oil filter. Max working pressure of oil separator: 450 psig (31 bar).
- Relief Valves: Two relief valves per refrigerant circuit: 325 psig on flash tank, 250 psig on suction line near evaporator.
- Variable Speed Drive (VSD): Liquid-cooled, transistorized, PWM inverter. Power Factor 95% at part or full load. Controls compressor speed to match load. Composed of AC to DC rectifier, DC link filter, DC to AC inverter, and output suppression network. Cooled by a propylene glycol loop.
- Control Panel: NEMA 3R (IP65) rated, powder-painted steel enclosure with hinged, latched, and gasket-sealed outer doors. Includes compressor VSD controls, chiller microprocessor controls, fan controls, and other chiller controls. Short Circuit Withstand Rating: 30,000 Amps (standard terminal block), up to 100,000 A (200/230 V) or 65,000 A (380/460 V) or 42,000 A (575 V) with circuit breaker option.
- Microprocessor and VSD Controls: Control starting, stopping, loading, unloading, safeties, and chilled liquid temperature. Includes brine chilling, thermal storage, run signal contacts, unit alarm contacts, chilled liquid pump control, automatic reset after power failure, and automatic system optimization.
- Display: Liquid crystal 2-line by 40-character display with backlighting, accessible through an access door. Displays parameters in English (°F and psig) or Metric (°C and bar).
- Keypad: Color-coded, 36-button, sealed keypad for complete system control.
Usage Features:
- Soft Starts: VSD provides soft starts with no electrical inrush.
- Capacity Control: Stepless VSD speed changes allow smooth capacity control between 10% and 100% of chiller capacity.
- Remote Control: Options for remote cycling, current limiting, temperature setpoint reset, and sound limit via user-supplied signals to the microprocessor.
- Generator Operation: Can operate on a generator if output voltage is maintained within specifications. Requires a minimum 10-second delay when switching power sources.
- Emergency Shutdown: Control panel fitted with a UNIT switch to stop the unit by removing 120VAC electrical supply from the inverter system.
- Sound Reduction Options: Available with Ultra Quiet Fans, Two-Speed Fans, Reduced Sound option (unlined compressor enclosure), and Low Sound option (acoustically lined compressor enclosure). SilentNight™ control option limits sound output based on time of day.
- Condenser Coil Protection: Options for pre-coated fin, post-coated epoxy dipped, or copper fin condenser coils for corrosion resistance.
- Protective Chiller Panels: Options for wire panels (full unit) or louvered panels (condenser coils only or full unit) for protection and visual screening.
- Evaporator Options: Double thick 1 1/2 in. insulation, raised face flange accessory, and opposite handed evaporator water connections.
- Flow Switch Accessory: Vapor proof SPDT, NEMA 3R switch (150 psig, 20°F to 250°F) or differential pressure switch (3 psig to 45 psig).
- Building Automation System Interface: Accepts 4 mA to 20 mA or 0 VDC to 10 VDC input for remote leaving chilled liquid temperature reset.
- Multi-unit Sequence Control: Separate sequencing control center for up to eight chillers in parallel.
- Service Isolation Valve: Suction isolation valve for each refrigerant circuit.
- Vibration Isolation: Options for elastomeric isolation, one-inch spring isolators, or two-inch seismic spring isolators.
Maintenance Features:
- Scheduled Maintenance: Daily checks by operator/customer, regular service inspections by qualified Service Engineer. Minor service every 3-6 months, major service annually.
- Refrigerant Charge: Units are shipped with a full charge. Leak testing is critical after charging, with an acceptable limit of 0.1 oz/year at DWP for R-134a.
- Oil Level Check: Compressor oil level should be between upper and lower sight glasses after 30 minutes of full load operation.
- Evacuation and Dehydration: Detailed procedures for system evacuation and dehydration to remove moisture and prevent acid formation. Requires high-resolution vacuum gauge and vacuum pump.
- Troubleshooting Guide: Comprehensive table outlining common problems, possible causes, and recommended actions.
- Recommended Spare Parts: List of recommended spare parts including fan motors, fan blades, dehydrator cores, compressor oil, various sensors, relay output boards, VSD logic boards, controller valves, SCR trigger boards, chiller control boards, and level sensors.
- Warranty: 18 months from shipment date for defects in workmanship and materials. Voided if non-YORK approved parts/refrigerants are used, equipment is misused, or scheduled maintenance is not performed.
To Next Page
Need help?
General
