COMMERCIAL PACKAGED AIR-HANDLING UNIT
HVAC GUIDE SPECIFICATIONS
SIZE RANGE: 1,800 to 12,500 CFM, NOMINAL AIRFLOW 6 TO 25 TONS, NOMINAL COOLING
BRYANT MODEL NUMBERS: 524A-B (DIRECT-EXPANSION COIL), 524A-C (HIGH-CAPACITY 4-ROW DIRECT-EXPANSION COIL)
PART 1 — GENERAL
1.01SYSTEM DESCRIPTION
A.Indoor, packaged air-handling unit for use in commercial split systems. Unit shall have a multiposition design and shall be capable of horizontal or vertical installation on a floor or in a ceiling, with or without ductwork. (Only verti- cal units are to be applied without ductwork.)
B.Unit with direct-expansion coil shall be used in a refriger- ant circuit with a matching air-cooled condensing unit.
1.02QUALITY ASSURANCE
A.Coils shall be designed and tested in accordance with ASHRAE 15 Safety Code for Mechanical Refrigeration, latest edition.
B.Unit shall be constructed in accordance with ETL and ETL, Canada, standards and shall carry the ETL and ETL, Canada, labels.
C.Unit insulation and adhesive shall comply with NFPA-90A requirements for flame spread and smoke generation. Insulation shall contain an EPA-registered immobilized antimicrobial agent to effectively resist the growth of bacteria and fungi as proven by tests in accordance with ASTM standards G21 and 22.
D.Unit shall be manufactured in a facility registered to the ISO 9001:2000 manufacturing quality standard.
E.Direct-expansion coils shall be burst and leak tested at 435 psi.
1.03 DELIVERY AND STORAGE
Units shall be stored and handled per manufacturer’s recommendations.
PART 2 — PRODUCTS
2.01EQUIPMENT
Indoor mounted, draw-thru, packaged air-handling unit that can be used in a suspended horizontal configuration or a vertical configuration. Unit shall consist of forward- curved belt-driven centrifugal fan(s), motor and drive assembly, prewired fan motor contactor, factory-installed refrigerant metering devices (direct-expansion coil units), cooling coil, 2-in. disposable air filters, and condensate drain pans for vertical or horizontal configurations.
A.Base Unit:
1.Cabinet shall be constructed of mill-galvanized steel.
2.Cabinet panels shall be fully insulated with 1/2-in. fire-retardant material. Insulation shall contain an EPA-registered immobilized antimicrobial agent to effectively resist the growth of bacteria and fungi as proven by tests in accordance with ASTM standards G21 and 22.
3.Unit shall contain non-corroding condensate drain pans for both vertical and horizontal applications. Drain pans shall have connections on right and left sides of unit to facilitate field connection. Drain pans shall have the ability to be sloped toward the right or left side of the unit to prevent standing water from accumulating in pans.
4.Unit shall have factory-supplied 2-in. throwaway-type filters installed upstream from the cooling coil. Filter access shall be from either the right or left side of the unit.
B.Coils:
Coils shall consist of 3 rows (524A-B) or 4 rows (524A-C) of copper tubes with sine-wave aluminum fins bonded to the tubes by mechanical expansion. Suction and liquid line connections or supply and discharge connections shall be made on the same side of the coil.
1.Direct-expansion coils shall feature factory-installed thermostatic expansion valves (TXVs) for refrigerant control. The TXVs shall be capable of external adjustment. Coil tubing shall be internally rifled to maximize heat transfer.
2.High-Capacity Coil:
The high-capacity 4-row coil consists of 4 rows of 3/8-in. copper tubes with sine-wave aluminum fins bonded to the tubes by mechanical expansion. Coil tubing shall be internally rifled to maximize heat transfer. Suction and liquid line connections shall be made on the same side of the coil. Direct-expansion coils shall feature factory-installed thermostatic expansion valves (TXVs) for refrigerant control. The TXVs shall be capable of external adjustment.
C. Operating Characteristics: | | | |
Unit shall be capable of providing | | | cfm airflow at an |
external static pressure of | | | in. wg. |
D.Motor:
Fan motor of the size and electrical characteristics speci- fied on the equipment schedule shall be factory supplied and installed.
Motors rated at 1.3 through 3.7 hp shall have internal thermal overload protection. Motors rated at 5, 71/2, and 10 hp shall be protected by a circuit breaker.
E.Special Features:
1. Alternate Motor and Drive:
An alternate motor and/or medium-static or high- static drive shall be available to meet the airflow and external static pressure requirements specified on the equipment schedule.
2. External Paint:
Where conditions require, units shall be painted with an American Sterling Gray finish.
3. Hot Water Coil:
Coil shall be 2-row, U-bend coil with copper tubes and aluminum plate fins bonded to the tubes by mechanical expansion. Coil shall be mounted in a galvanized steel housing that shall be fastened to the unit’s fan deck for blow-thru heating operation. Coil shall have maximum working pressure of 150 psig.
4. Steam Distributing Coil:
Coil shall consist of one row of copper tubes with aluminum plate fins, and shall have inner steam dis- tributing tubes. Coil shall be mounted in a galvanized steel housing and shall be fastened to the unit’s fan deck for blow-thru heating operation. Coil shall have maximum working pressure of 20 psig at 260 F.
