Guide specications, Hvac Guide Specications

Guide speci®cations

Packaged Heating/Cooling Units

Constant Volume Application

HVAC Guide Speci®cations

Size Range: 11¤2 to 5 Tons, Nominal Cooling 40,000 to 140,000 Btuh, Nominal Input Heating

Carrier Model Number: 48SS

Part 1 Ð General

1.01SYSTEM DESCRIPTION

Outdoor rooftop mounted, gas heating/electric cool- ing unit utilizing a rotary, reciprocating, or scroll her- metic compressor for cooling duty. Unit shall discharge supply air downward or horizontally as shown on con- tract drawings. Outdoor fan/coil section shall have a blow-thru design for minimum sound levels.

1.02 QUALITY ASSURANCE

A.Unit shall be rated in accordance with ARI Standards 210/240 and 270.

B.Unit shall be designed in accordance with UL Stand- ard 564.

C.Unit shall be UL listed and CSA certi®ed as a total package for safety requirements.

D.Roof curb shall be designed to conform to NRCA Standards.

E.Insulation and adhesive shall meet NFPA 90A re- quirements for ¯ame spread and smoke generation.

F.Cabinet insulation shall meet ASHRAE standard no. 62.

1.03DELIVERY, STORAGE, AND HANDLING

Unit shall be stored and handled per manufacturer's recommendations.

Part 2 Ð Products

2.01EQUIPMENT A. General:

Factory-assembled, single-piece heating and cooling unit. Contained within the enclosure shall be all fac- tory wiring, piping, controls, refrigerant charge (R-22), and special features required prior to ®eld start-up.

B.Unit Cabinet:

1.Unit cabinet shall be constructed of phosphated, zinc-coated prepainted steel, capable of withstand- ing 500 hours in salt spray.

2.Cabinet panels shall be easily removed for servicing.

3.Indoor blower compartment interior cabinet sur- faces shall be insulated with a minimum 1¤2-in. thick, ¯exible cleanable insulation, coated on the air side. Aluminum foil-faced cleanable insulation shall be used in the entire section.

4.Unit shall utilize a sloped condensate drain pan. External trap required.

C.Fans:

1.The indoor (evaporator) fan shall be 2- or 3-speed direct-drive, as shown on equipment drawings.

2.Fan wheel shall be made from steel, be double- inlet type with forward curved blades with corro- sion resistant ®nish and be dynamically balanced.

3.Outdoor (condenser) fan shall be of the direct driven, propeller type with aluminum blades riv- eted to corrosion resistant steel spiders, be dy- namically balanced, and discharge air vertically upwards and horizontally.

D.Compressor:

1.Fully hermetic compressor with factory-installed vi- bration isolation.

2.Rotary compressors shall be standard on unit size 018. Reciprocating compressors shall be stand- ard on unit sizes 024-042. Scroll compressors shall be standard on unit sizes 048 and 060.

E.Coils:

Evaporator and condenser coils shall have aluminum plate ®ns mechanically bonded to seamless copper tubes with all joints brazed. Tube sheet openings shall be belled to prevent tube wear.

F.Heating Section:

1.Induced-draft combustion type with energy saving direct spark ignition system and redundant main gas valve.

2.Induced-draft motors shall be provided with solid- state hall effects sensor to ensure adequate airflow for combustion.

3.The heat exchangers shall be constructed of alu- minized steel for corrosion resistance.

4.Burners shall be of the in-shot type constructed of aluminum coated steel.

5.Integrated gas control board shall provide control of heating and simplify troubleshooting through its built-in diagnostic function. The IGC shall pro- vide timed control of indoor-fan functioning and burner ignition. A light-emitting diode (LED) shall provide diagnostic information. The IGC board shall also contain anti-short cycle protection for gas heat operation.

6.All gas piping and electric power shall enter the unit cabinet at a single location.

G.Refrigerant Components:

Refrigerant components shall be of the Acutrol™ feed system type.

H.Controls:

Unit shall be complete with self-contained low-voltage control circuit.