HVAC Guide Specifications
Air-Cooled Condensers
Size Range:
1 to 60 Tons
Carrier Model Number:
09AW
Part 1 — General
1.01 SYSTEM DESCRIPTION
Outdoor mounted, packaged air-cooled remote condenser.Unit shall discharge condenser air verticallyor horizontally as shown on contract drawings.
1.02 QUALITY ASSURANCE
A. Units shall be rated using refrigerant R-22, R-410Aor R-134a. Ratings shall be listed at 5 F subcoolingand 15 F subcooling refrigerant charge and in accordancewith AHRI Standard 460, latest edition.
B. Unit shall be designed to conform to the latest ANSI/ASHRAE 15 latest revision safety code, and ULStandard 1995, and shall be UL listed under bothAmerican and Canadian Standards.
C. Coils shall be leak tested up to 650 psig and unitoperation shall be tested at the factory.
1.03 DELIVERY, STORAGE AND HANDLING
Units shall be stored and handled according to manufacturer’srecommendations.
Part 2 — Products
2.01 EQUIPMENT
A. General:
Outdoor mounted, packaged, air-cooled remotecondenser. Factory-assembled unit shall consist ofcondenser coil, fan(s) and motor(s), mounting legs,factory wiring, piping and controls, and a shippingcharge of dry nitrogen.
B. Unit Cabinet:
1. Cabinet shall be constructed of minimum18 gage corrosion-resistant zinc-coated galvanizedsteel and are capable of withstanding Federaltest Method Standard No. 141 (Method6061) 500-hour salt spray test. Optional heavygage embossed aluminum shall be available.
2. Two-fan units shall be divided by full-width bafflesto separate individual fan sections, preventair bypass, and provide additional casing rigidity.
3. Units 12 ton and larger shall be furnished withlifting holes to aid in rigging.
4. Unit sizes 1 ton to 10 ton shall have minimum12 gage galvanized steel mounting legs 15 in.high and mounting rails. Legs shall be shippedwith the unit for field assembly. Headers shallbe arranged for horizontal or vertical airflow.
5. Unit sizes 12 ton to 60 ton shall have minimum10 gage galvanized steel legs 18 in. high and12 gage base rail.
6. Unit sizes 12 to 60 ton shall be factory arrangedfor vertical or horizontal airflow as required.Headers shall have proper arrangement andconnection locations for correct refrigerant andoil return for the required airflow.
C. Fans:
Fans shall be propeller type, direct driven by weatherproofmotors, and dynamically balanced. Dischargeside shall be protected by corrosion-resistantfan guards constructed of vinyl coated close-meshsteel wire. Fans shall have dual square head setscrews spaced 90 degrees apart that seat onto oneflat and one keyway on the motor shaft.
D.Coils:
Coils shall use 3/8-in. OD copper tube with staggeredaluminum fin (or optional copper tube withcopper fin, or be coated with polyester or e-coatflexible fin treatment as required) and galvanizedsteel tube sheets. Fins shall be bonded to tubes bymechanical expansion. Hot gas and liquid connectionsshall be made from the same end. Coil circuitingshall be single (100% capacity) or dual (50/50%capacity) circuit with or without a final pass subcoolingcircuit as required by the application. Fins shallnot exceed 14 fins per inch.
1. Copper-fin coils shall be constructed of copperfinsmechanically bonded to copper-tubes andcopper tube sheets. Galvanized steel tubesheets shall not be acceptable. A polymer stripshall prevent coil assembly from contactingsheet metal coil pan to minimize potential forgalvanic corrosion between the coil and pan. Allcopper construction shall provide protection inmoderate coastal environments.
2. E-coated aluminum-fin coils shall have a flexibleepoxy polymer coating uniformly applied to allcoil surface areas without material bridgingbetween fins. Coating process shall ensurecomplete coil encapsulation. Color shall be highgloss black with gloss requirements of 60° of 65to 90% per ASTM D523-89. Uniform dry filmthickness from 0.8 to 1.2 mil on all surfaceareas including fin edges. Superior hardnesscharacteristics of 2H per ASTM D3363-92Aand cross hatch adhesion of 4B-5B per ASTMD3359-93. Impact resistance shall be up to160 in./lb (ASTM D2794-93). Humidity andwater immersion resistance shall be up to aminimum of 1000 and 250 hours respectively(ASTM D2247-92 and ASTM D870-92). Corrosiondurability shall be confirmed throughtesting to no less than 1000 hours salt sprayper ASTM B117-90. Coil construction shall bealuminum-fins mechanically bonded to coppertubes.
3. E-coated copper-fin coils shall have a flexibleepoxy polymer coating uniformly applied to allcoil surface areas without material bridgingbetween fins. Coating process shall ensurecomplete coil encapsulation. Color shall be highgloss black with gloss requirements of 60° of 65to 90% per ASTM D523-89. Uniform dry filmthickness from 0.8 to 1.2 mil on all surfaceareas including fin edges. Superior hardnesscharacteristics of 2H per ASTM D3363-92Aand cross hatch adhesion of 4B-5B per ASTMD3359.93. Impact resistance shall be up to160 in./lb (ASTM D2794-93). Humidity andwater immersion resistance shall be up to aminimum of 1000 and 250 hours respectively(ASTM D2247-92 and ASTM D870-92). Corrosiondurability shall be confirmed throughtesting to no less than 1000 hours salt sprayper ASTM B117-90. Coil construction shall becopper-fins mechanically bonded to coppertubeswith copper tube sheets. Galvanized steeltube sheets shall not be acceptable. A polymerstrip shall prevent coil assembly from contactingsheet metal coil pan to maintain coating integrityand minimize corrosion potential betweenthe coil and pan.
E. Motors:
Motors shall be weatherproof and inherently protectedto operate at the specified electrical characteristics.Motor shall have permanently lubricatedball bearings. When required by environmental conditions,optional TEAO (totally enclosed, air over)motors shall be used. Motors shall be factory wiredto weatherproof NEMA 3R control box on oppositeheader end of unit. Fan motors have basket typemotor mounts. When required by specification, low-soundmotors shall be provided.
F. Operating Characteristics:
Unit shall be capable of rejecting the required heatat the required cfm and be capable of operating atmoderate entering-air temperatures as standard andat reduced entering-air temperatures with optionalfan cycling or fan motor speed control.
G. Electrical Characteristics:
All electrical power wiring shall enter the unit cabinetat a single location. Control circuit is 24 v andcontrol wiring shall enter the unit control box at oneconnection only.
H. Special Features:
Units shall be furnished with optional factory-mountedor field-installed special features (asrequired by application).
1. Embossed aluminum cabinet shall be providedfor enhanced appearance and corrosionprotection.
2. Extended length (30-in., 48-in., 72-in.) mountinglegs for unit sizes 12 ton and larger.
3. Low sound condenser-fan motors shall befurnished for lower condenser-fan soundapplications.
4. Fan contactor shall be factory wired to the condenserfan with 24 v coil for connection toindoor compressor unit.
5. Fan cycling (two-fan units only) shall includetemperature actuated fan cycling switch, fancontactors, and low voltage terminal strip.Factory-mounted control cycles one fan inresponse to entering air-temperature to maintainhead pressure.
6. Fan motor speed control shall be provided toallow operation up to –20 F. Factory mountedcontroller modulates the speed of the lead condenserfan in response to discharge head pressure.Fan cycling control and contactorsprovided wired with controls. Control shallinclude all components of fan cycling controland a single-phase motor qualified for use withspeed control and speed controller.
7. Totally Enclosed, Air Over (TEAO) condenser-fanmotors shall be furnished for protection inharsh environments.
8. Final pass subcooling circuit shall be provided toallow additional cooling of refrigerant to compensatefor long refrigerant line or applicationswith condenser below compressor.
9. Copper tube with copper fin or pre-coated ore-coated fins for corrosion protection.
10. Fused disconnect switch for 3-phase units.
11. Control transformer with 24 v output to operatecondenser and/or compressor and evaporator.
12. Defrost thermostat shall be available for field-installationon the evaporator coil for use withthe winter start control. The thermostat willopen the control switch if frost begins to formon the evaporator coil. The compressor willstop but the 09AW unit will continue to run.
13. Solenoid valve shall be a field-supplied solenoidvalve (located at indoor unit) wired in parallelwith the compressor contactor coil. The valvewill shut off the liquid line to prevent refrigerantmigration back to the compressor during the offcycle.
14. Winter start shall be available for use in conjunctionwith the speed control option. The winterstart control will bypass the low-pressure switchfor 3 minutes on compressor start-up to allowsystem pressures to stabilize.