Air-Cooled Condensers
HVAC Guide Specifications
Size Range: 5 to 20 Tons
Carrier Model Number: 09AZ
Part 1—General
1.01 SYSTEM DESCRIPTION
Outdoor mounted, packaged air-cooled remote condenser. Unit shall discharge condenser air vertically or horizontally as shown on contract drawings.
1.02 QUALITY ASSURANCE
A. Units shall be rated using refrigerant R-22, R-410A or R-134a. Ratings shall be listed at a minimum (5°F subcooling) and optimum (15°F subcooling) refrigerant charge and in accordance with AHRI Standard 460, latest edition. Units shall be rated with 50XCR units of the same nominal size and listed in AHRI directory. 50XCR units are also rated for R-410A refrigerant.
B. Unit shall be designed to conform to ANSI/ASHRAE 15, latest revision safety code, andUL Standard 1995, and shall be UL listed under both American and Canadian Standards.
C. Coils shall be leak tested at 450 psig and unit operation shall be tested at the factory.
1.03 DELIVERY, STORAGE, AND HANDLING
Units shall be stored and handled according to manufacturer’s recommendations.
Part 2—Products
2.01 EQUIPMENT
A. General:
Outdoor mounted, packaged, air-cooled remote condenser. Factory-assembled unit shall consist of condenser coil, fan(s) and motor(s), mounting legs, factory wiring, piping and controls, and a shipping charge of dry nitrogen.
B. Unit Cabinet:
1. Cabinet shall be constructed of minimum18 gage corrosion-resistant zinc-coated galvanized steel and are capable of withstanding Federal method Standard No. 141 (Method 6061) 500-hour salt spray test. (Optional heavy gage embossed aluminum shall be available.)
2. Two-fan units shall be divided by full width baffles to separate individual fan sections and prevent air bypass and provide additional casing rigidity.
3. Unit sizes 10 ton and larger shall be furnished with lifting holes to aid in rigging.
4. Unit sizes 5 ton to 71/2 ton shall have minimum 12 gage galvanized steel mounting legs, 15 in. high, and mounting rails. Legs shall be shipped with the unit for field assembly. Headers are to be arranged for horizontal or vertical airflow.
5. Unit sizes 10 ton to 20 ton shall have minimum 10 gage galvanized steel legs, 18 in. high, and 12 gage base rail.
6. Unit sizes 10 to 20 ton shall be factory arranged for vertical or horizontal airflow as required. Headers shall have proper arrangement and connection locations for correct refrigerant and oil return for the requiredairflow.
C. Fans:
Fans shall be propeller type, direct driven by weatherproof motors, and dynamically balanced. Discharge side shall be protected by corrosion-resistant fan guards constructed of vinyl coated close-mesh steel wire. Fans shall have dual square head set screws spaced 90 degrees apart which seat onto one flat and one keyway on the motor shaft.
D. Coils:
Coils shall use 3/8-in. OD copper tubes with staggered aluminum fin (or optional copper tube with copper fin, or be coated with polyester or e-coat flexible fin treatment as required) and galvanized steel tube sheets. Fins shall be bonded to tubes by mechanical expansion. Hot gas and liquid connections shall be made from the same end. Coil circuiting shall be single, 5 and 71/2 ton (100% capacity) or dual, 10 to 20 ton (50/50% capacity) circuit with a final pass subcooling circuit. Fins shall not exceed 14 fins per inch.
1. Copper-fin coils shall be constructed of copper-fins mechanically bonded to copper-tubes and copper tube sheets. Galvanized steel tube sheets shall not be acceptable. A polymer strip shall prevent coil assembly from contacting sheet metal coil pan to minimize potential for galvanic corrosion between the coil and pan. All copper construction shall provide protection in moderate coastal environments.
2. E-coated aluminum-fin coils shall have a flexible epoxy polymer coating uniformly applied to all coil surface areas without material bridging between fins. Coating process shall ensure complete coil encapsulation. Color shall be high gloss black with gloss requirements of 60° of 65 to 90% per ASTM D523-89. Uniform dry film thickness from 0.8 to 1.2 mil on all surface areas including fin edges. Superior hardness characteristics of 2H per ASTM D3363-92A and cross hatch adhesion of 4B-5B per ASTM D3359-93. Impact resistance shall be up to 160 in./lb (ASTM D2794-93). Humidity and water immersion resistance shall be up to a minimum of 1000 and 250 hours respectively (ASTM D2247-92 and ASTM D870-92). Corrosion durability shall be confirmed through testing to no less than 1000 hours salt spray per ASTM B117-90. Coil construction shall be aluminum-fins mechanically bonded to copper tubes.
3. E-coated copper-fin coils shall have a flexible epoxy polymer coating uniformly applied to all coil surface areas without material bridging between fins. Coating process shall ensure complete coil encapsulation. Color shall be high gloss black with gloss requirements of 60° of 65 to 90% per ASTM D523-89. Uniform dry film thickness from 0.8 to 1.2 mil on all surface areas including fin edges. Superior hardness characteristics of 2H per ASTM D3363-92A and cross hatch adhesion of 4B-5B per ASTM D3359.93. Impact resistance shall be up to 160 in./lb (ASTM D2794-93). Humidity and water immersion resistance shall be up to a minimum of 1000 and 250 hours respectively (ASTM D2247-92 and ASTM D870-92). Corrosion durability shall be confirmed through testing to no less than 1000 hours salt spray per ASTM B117-90. Coil construction shall be copper-fins mechanically bonded to copper-tubes with copper tube sheets. Galvanized steel tube sheets shall not be acceptable. A polymer strip shall prevent coil assembly from contacting sheet metal coil pan to maintain coating integrity and minimize corrosion potential between the coil and pan.
E. Motors:
Motors shall be weatherproof and inherently protected to operate at the specified electrical characteristics. Motor shall have permanently lubricated ball bearings. When required by environmental conditions, optional TEAO (totally enclosed, air over) motors shall be used. Motors shall be factory wired to weatherproof NEMA 3R control box on opposite header end of unit. When required by specifications, low-sound motors shall be provided.
F. Operating Characteristics:
Unit shall be capable of rejecting the required heat at the required cfm and be capable of operating at moderate ambient temperatures with standardfactory-supplied fan cycling and at reduced ambient temperatures with optional fan cycling or motor speed control.
G. Electrical Characteristics:
All electrical power wiring shall enter the unit cabinet at a single location. Fan motor contactors shall be provided and wired to condenser fans. Control circuit is 24 v and control wiring shall enter the unit control box at one connection only.
H. Special Features:
Units shall be furnished with optional factory- mounted or field-installed special features (as required by application).
1. Embossed aluminum cabinet shall be provided for enhanced appearance and corrosionprotection.
2. Extended 30-in. mounting legs for unit sizes 10 ton and larger.
3. Low sound condenser-fan motors shall befurnished for lower condenser-fan soundapplications.
4. Fan cycling (two-fan units only) shall include temperature actuated fan cycling switch, fan contactors, and low voltage terminal strip.Factory-mounted control cycles one fan in response to entering air-temperature to maintain head pressure.
5. Fan motor speed control shall be provided to allow operation up to –20°F. Factory mounted controller modulates the speed of the lead condenser fan in response to discharge head pressure. Fan cycling control and contactors provided wired with controls. Control shall include all components of fan cycling control and a single-phase motor qualified for use with speed control and speed controller.
6. Totally enclosed, air over (TEAO) condenser-fan motors shall be furnished for protection in harsh environments.
7. Final pass subcooling circuit shall be provided to allow additional cooling of refrigerant to compensate for long refrigerant line or applications with condenser below compressor.
8. Copper tube with copper fin or pre-coated ore-coated fins for corrosion protection.
9. Fused disconnect switch for 3-phase units.
10. Control transformer with 24 v output tooperate condenser and/or compressor and evaporator.
11. Defrost thermostat shall be available for field-installation on the evaporator coil for use with the winter start control. The thermostat will open the control switch if frost begins to form on the evaporator coil. The compressor will stop but the 09AZ unit will continue to run.
12. Solenoid valve shall be a field-supplied solenoid valve (located at indoor unit) wired in parallel with the compressor contactor coil will shut off the liquid line to prevent refrigerant migration back to the compressor during the off cycle.
13. Winter start shall be available for use in conjunction with the speed control option. The winter start control will bypass the low-pressure switch for 3 minutes on compressor start-up to allow system pressures to stabilize.
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