Mechanical Specifications

General

The units shall be convertible airflow. The operating range shall be between 46°C and –18°C (115°F and 0°F) in cooling as standard from the factory for all units. All units shall be factory assembled, internally wired, fully charged with R-22, and 100 percent run tested to check cooling operation, fan and blower rotation and control sequence, before leaving the factory. Wiring internal to the unit shall be colored and numbered for simplified identification.

Casing

Unit casing shall be constructed of zinc coated, heavy gauge, galvanized steel. Exterior surfaces shall be cleaned, phosphatized, and finished with a weather-resistant baked enamel finish. Cabinet construction shall allow for all maintenance on one side of the unit. Service panels shall have lifting handles and be removed and reinstalled by removing only a single fastener while providing a water and air tight seal. All exposed vertical panels and top covers in the indoor air section shall be insulated with cleanable foil faced, fire- retardent permanent, odorless glass fiber material. The base of the unit shall be insulated with 13mm, 16 kg (1/2 inch, 1 pound) density foil-faced, closed-cell material. All insulation edges shall be either captured or sealed.The unit’s base pan shall have no penetrations within the perimeter of the curb other than the raised 29mm (11/8 inch) high downflow supply/return openings to provide an added water integrity precaution, if the condensate drain backs up. The base of the unit shall have provisions for forklift and crane lifting, with forklift capabilities on three sides of the unit.

Unit Top

The top cover shall be one piece, or where seams exist, double hemmed and gasket sealed to prevent water leakage. The ribbed top adds extra strength and prevents water from pooling on unit top.

Filters

25 mm (1 inch), throwaway filters shall be standard on all 5 ton units.. The filter rack can be converted to two inch capability. 50 mm (2 inch) filters shall be factory supplied on all 6-10 ton units. Optional 50 mm (2 inch) pleated media filters shall be available.

Compressors

All units shall have direct-drive, hermetic, scroll type compressors with centrifugal type oil pumps. Motor shall be suction gas-cooled and shall have a voltage utilization range of plus or minus 10 percent of unit nameplate voltage. Internal overloads shall be provided with the scroll compressors. .

Refrigerant Circuits

Each refrigerant circuit shall have independent fixed orifice or thermal expansion devices, service pressure ports, and refrigerant line filter driers factory-installed as standard. An area shall be provided for replacement suction line driers.

Evaporator and Condenser Coils Internally finned, 8mm (5/16 inch) copper tubes mechanically bonded to a configured aluminum plate fin shall be standard. Coils shall be leak tested at the factory to ensure the pressure integrity.The evaporator coil and condenser coil shall be leak tested to 1,375 kPa (200 psig) and pressure tested to 3,100 kPa (450 psig). The condenser coil shall have a patent pending 1 + 1 + 1 hybrid coil designed with slight gaps for ease of cleaning. A reversible, removeable, double sloped condensate drain pan with provision for through the base condensate drain is standard.

Outdoor Fans

The outdoor fan shall be direct-drive, statically and dynamically balanced, draw-through in the vertical discharge position. The fan motor shall be permanently lubricated and shall have built-in thermal overload protection.

Indoor Fan

All units shall be belt driven. Units with belt-drive shall have an idler-arm assembly for quick-adjustment of fan belts and motor sheaves. All motors shall be thermally protected. Oversized motors shall be available for high static application.

Controls

Unit shall be completely factory wired with necessary controls and contactor pressure lugs or terminal block for power wiring. Unit shall provide an external location for mounting a fused disconnect device. Microprocessor controls shall be provided for all 24 volt control functions. The resident control algorithms shall make all heating, cooling, and/or ventilating decisions in response to electronic signals from sensors measuring indoor and outdoor temperatures. The control algorithm maintains accurate temperature control, minimizes drift from set point, and provides better building comfort. A centralized microprocessor shall provide anti-short cycle timing and time delay between compressors to provide a higher level of machine protection.

Defrost Controls

Adaptive demand defrost shall be provided to permit defrost wherever coil icing conditions begin to significantly reduce unit capacity.

PKGP-PRC004-EN