SECTION 15623
FORCED AIR FURNACES AND EVAPORATOR COILS
PART 1 - GENERAL
1.1 SUMMARY
A. Forced air furnaces.
B. Refrigerant cooling coil.
1.2 RELATED SECTIONS
A. Section 15671 – Air Cooled Condensing Units
B. Section 15971 – HVAC Electric Control Systems
1.3 REFERENCES
A. Air Conditioning and Refrigeration Institute (ARI)
1. ARI 210/240 -Unitary Air Conditioning and Air-Source Heat Pump Equipment
2. ARI 520 -Positive Displacement Refrigerant Compressors, Compressor Units and Condensing Units
3. ARI 630 -Selection, Installation and Servicing of Humidifiers
B. American Society of Heating, Refrigerating and Air Conditioning Engineers (ASHRAE)
1. ASHRAE 14 -Methods of Testing for Rating Positive Displacement Condensing Units
C. National Fire Protection Association (NFPA)
1. NFPA 90A - Installation of Air Conditioning and Ventilating Systems
D. American National Standards Institute (ANSI)
1. ANSI Z223.1- National Fuel Gas Code
2. ANSI/ASHRAE 90A - Energy Conservation in New Building Design
3. ANSI/ASHRAE 103 - Heating Seasonal Efficiency of Central Furnaces and Boilers, Methods of Testing
4. ANSI/NEMA MG1 - Motors and Generators
5. ANSI/NFPA 90B - Installation of Warm Air Heating and Air Conditioning Systems
6. ANSI/NFPA 211 - Chimneys, Fireplaces, Vents and Solid Fuel Burning Appliances
1.4 SUBMITTALS
A. Submit shop drawings in accordance with the General Conditions and Division 1.
1.5 MINIMUM WARRANTY REQUIREMENTS
A. Furnace Heat Exchanger
Twenty year heat exchanger limited warranty and five year limited warranty on entire unit.
B. Cased Cooling Coil
Standard limited five year warranty on parts.
PART 2 - PRODUCTS
2.1 MANUFACTURERS
A. Provide units with capacities as scheduled on drawings.
B. Acceptable Manufacturers: Carrier, or Trane.
2.2 MANUFACTURED UNITS
A. Configuration
Upflow, type as shown on drawings with gas burner and direct expansion refrigeration. Single or two-stage as scheduled on drawings.
B. Units
Self-contained, packaged, factory assembled, pre-wired unit consisting of cabinet, supply fan, heat exchanger, burner or heater, controls, air filter, refrigerant cooling coil and outdoor package containing compressor, condenser coil and condenser fan
C. Refrigerant: Puron (R-410A).
D. Construction and Ratings: In accordance with ARI 210/240. Testing: ASHRAE 14.
E. Performance Ratings
Energy Efficiency Rating (EER) not less than requirements of ANSI/ASHRAE 90A; seasonal efficiency to ANSI/ASHRAE 103. Provide units with meet or exceed the requirement of those scheduled on the drawings.
F. Heating Capacity and Staging: As scheduled on plans.
G. Air Handling: As scheduled on plans.
H. Cooling Capacity and Staging: As scheduled on plans.
2.3 FABRICATION
A. Cabinet
Galvanized steel with baked enamel finish, easily removed and secured access doors, glass fiber insulation and reflective liner.
B. Heat Exchanger
1. Primary: 3-pass 20 gauge corrosion resistant aluminized steel of fold and crimp sectional design which operates under negative pressure
2. Secondary: Flow-through design having an interior laminate coating of polypropylene for corrosion resistance with fold and crip design which operates under negative pressure
3. Power vent fan, single or 2 speed as applicable.
C. Supply Fan
Centrifugal type rubber mounted with direct drive.
D. Motor
ANSI/NEMA MG 1; 1750 rpm rubber isolated hinge mounted, 4 speed.
E. Air Filters
Two-inch thick glass fiber, disposable type arranged for easy replacement.
2.4 BURNER
A. Gas Burner
Sealed combustion type with power vent fan, slow-opening dual rate gas valve, electric switch gas shut-off; flame proving sensor, hot surface igniter, pressure switch assembly; flame rollout switch, drain tubing and condensate trap, blower and inducer assembly, 40va transformer for thermostat power. Suitable for use with LP gas.
B. Burner Operating Controls
1. High Limit Control: Fixed stop at maximum permissible setting, de energizes burner on excessive bonnet temperature and re-energizes when temperature drops to lower safe value.
2. Control Supply Fan: Bonnet temperatures and independent of burner controls, manual switch for continuous fan operation.
3. Single or two stage control as Scheduled
C. Evaporator Coil
1. Coil and Coil Casing: Copper tube aluminum fin assembly, galvanized drain pan, drain connection, refrigerant piping connections and factory installed thermostatic expansion valve, fully insulated cabinet.
D. Thermostat Controls: Specified in Section 15971 – HVAC Electric Control Systems.
PART 3 - EXECUTION
3.1 GENERAL
A. Coordinate furnace, cased cooling coil with air cooled condensing unit furnished under spec section 15671 – Air Cooled Condensing Units. All equipment shall be matched to work together and be of the same manufacturer.
B. Verify pressure of natural gas to furnace. Install stepdown regulator if required.
3.2 EXAMINATION
A. Verify that floors are ready for installation of units and openings are as indicated on shop drawings. Verify that supports for air cooled condensers are completed.
B. Verify that proper power supply is available for furnace and condenser package.
C. Verify that proper fuel supply is available for connection.
3.3 INSTALLATION
A. Install in accordance with manufacturer's instructions.
B. Install refrigerant lines from indoor equipment to outdoor condensing units. Insulate as required and recommended by manufacturer. Refrigerant lines are to be insulated.
C. Install condensate drains to Hub drains as shown on plans. Pipe condensate utilizing schedule 40 PVC drain piping.
D. Install interconnecting control wiring between thermostat, furnace and air cooled condensing unit.
E. Install to NFPA 90A and ANSI/NFPA 90B.
F. Install gas fired furnaces to ANSI Z223.1 (NFPA 54).
G. Provide vent connections to ANSI/NFPA 211.
END OF SECTION
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