York ZT SERIES Technical Manual

Contents

5167821-YTG-K-1118Johnson Controls Ducted Systems 14Guide specificationsGeneralYORK® Predator ® units are convertible single packages with a common footprint cabinet and common roof curb for all 3 through12.5 ton models. The units were designed for light commercial applications and can be easily installed on a roof curb, slab, orframe. All Predator ® units are self-contained and assembled on rigid full perimeter base rails allowing for 3-way forklift access andoverhead rigging. Every unit is completely charged with R-410A, wired, piped, and tested at the factory to provide a quick and easyfield installation. All units are convertible between side and down airflow. Independent economizer designs are used on side anddown discharge applications, as well as all tonnage sizes. Predator ® units are available in the following configurations: coolingonly, cooling with electric heat and cooling with gas heat. Electric heaters are available as factory-installed options or field-installedaccessories.DescriptionUnits shall be factory assembled, single package, (Elec/Elec, Gas/Elec), designed for outdoor installation. They shall have built in fieldconvertible duct connections for down discharge supply/return or horizontal discharge supply/return and be available with factory installedoptions or field installed accessories. The units shall be factory wired, piped and charged with R-410A refrigerant and factory tested prior toshipment. All unit wiring shall be both numbered and color coded. The cooling performance shall be rated in accordance with DOE andAHRI test procedures. Units shall be CSA certified to ANSI Z21.47 and UL 1995/CAN/CSA No. 236-M90 standards.Unit cabientUnit cabinet shall be constructed of galvanized steel with exterior surfaces coated with a non-chalking, powder paint finish, certifiedat a 750-hour salt spray test per ASTM-B117 standards. Indoor blower sections shall be insulated with up to 1” thick insulationcoated on the airside. Either aluminum foil faced or elastometric rubber insulation shall be used in the unit’s compartments and befastened to prevent insulation from entering the air stream. Cabinet doors shall be hinged with toolless access for easy servicing andmaintenance. Full perimeter base rails shall be provided to assure reliable transit of equipment, overhead rigging, fork truck accessand proper sealing on roof curb applications. Disposable 2-in. filters shall be furnished as standard and be accessible throughhinged access door. Fan performance measuring ports shall be provided on the outside of the cabinet to allow accurate airmeasurements of evaporator fan performance without removing panels or creating bypass of the coils. Condensate pan shall beslide out design, constructed of a non corrosive material, internally sloped and conforming to ASHRAE 62-B9 standards.Condensate connection shall be a minimum of ¾” I.D. female and be rigid mount connection.Indoor (evaporator) fan assemblyFan shall be a belt drive assembly and include an adjustable pitch motor pulley. Job site selected brake horsepower shall not exceedthe motors nameplate horsepower rating plus the service factor. Units shall be designed to operate within the service factor. Fanwheel shall be double inlet type with forward curve blades, dynamically balanced to operate smoothly throughout the entire range ofoperation. Design shall meet ASHRAE 90.1 single-zone variable supply air volume standard. Bearings shall be sealed and perma-nently lubricated for longer life and no maintenance. Entire blower assembly and motor shall be slide out design.Outdoor (condenser) fan assemblyThe outdoor fans shall be of the direct drive type, discharge air vertically, have aluminum blades riveted to corrosion resistant steel spiderbrackets and shall be dynamically balanced for smooth operation. The outdoor fan motors shall have permanently lubricated bearingsinternally protected against overload conditions and staged independently. A cleaning window shall be provided on two sides of the unitsfor coil cleaning.Refrigerant componentsCompressors:a. Shall be fully 2-stage, hermetic type, direct drive, internally protected with internal high-pressure relief and over temperatureprotection. The hermetic motor shall be suction gas cooled and have a voltage range of + or – 10% of the unit nameplatevoltage.b. Shall have internal spring isolation and sound muffling to minimize vibration and noise, and be externally isolated on adedicated, independent mounting.Coils:a. Evaporator coils shall have aluminum plate fins mechanically bonded to seamless internally enhanced copper tubes with alljoints brazed. Special Phenolic coating shall be available as a factory option.b. Evaporator coils shall be of the direct expansion, draw-through design.c. Condenser coils shall have Micro-Channel aluminum tube, aluminum fins.d. Condenser coils shall be of the draw-through design.