SECTION 15624

DIRECT FIRED AIR UNITS

PART 1 GENERAL

SECTION INCLUDES

Direct fired make-up air heater.

Cooling coil section and compressor-condenser unit.

Service platform.

Controls.

RELATED SECTIONS

Section 15860 - Centrifugal Fans: Supply Fans.

Section 15885 - Air Cleaning: Filters.

Section 15952 - Controls and Instrumentation: Control components, time clocks.

Section 16180 - Equipment Wiring Systems: Electrical supply to units.

REFERENCES

ANSI/ASHRAE - 90A - Energy Conservation in New Building Design.

ANSI/UL 207 - Refrigerant - Containing Components and Accessories, Non-Electrical.

ANSI/UL 303 - Refrigeration and Air-Conditioning Condensing, and Air-Source Heat Pump Equipment.

ANSI/Z223.1 (NFPA 54) - National Fuel Gas Code.

ARI 210/240 - Unitary Air-Conditioning and Air-Source Heat Pump Equipment.

ARI 270 - Sound Rating of Outdoor Unitary Equipment.

ARI 520 - Positive Displacement Refrigerant Compressors, Compressor Units and Condensing Units.

ASHRAE 14 - Methods of Testing for Rating Positive Displacement Condensing Units.

FS F-F 300A - Filter, Air Conditioning: Viscous Impingement and Dry Types, Cleanable.

FS F-F 310A - Filter, Air Conditioning: Viscous Impingement and Dry Types, Replaceable.

NFPA 90A - Installation of Air Conditioning and Ventilating Systems.

SUBMITTALS

Submit shop drawings under provisions of Section [01300.] [_____.]

Submit shop drawings: Indicate dimensions, duct and service connections, accessories, controls, electrical nameplate data, and wiring diagrams.

Product Data: Indicate dimensions, duct and service connections, accessories, controls, electrical nameplate data, and wiring diagrams.

Manufacturer's Installation Instructions: Indicate rigging, assembly, and installation instructions.

OPERATION AND MAINTENANCE DATA

Submit operation data under provisions of Section [01700.] [01730.]

Include manufacturer's descriptive literature, operating instructions, installation instructions, maintenance and repair data, and parts listing.

WARRANTY

Provide [five] [_____] year warranty under provisions of Section [01700.] [01740.]

Warranty: Include coverage for [compressor/condenser unit.] [_______________.]

MAINTENANCE SERVICE

Furnish service and maintenance of units for [one] [_____] year from Date of Substantial Completion.

EXTRA MATERIALS

Provide [two] [_____] set of filters under provisions of Section [01700.] [_____.]

PART 2 PRODUCTS

MANUFACTURERS

[___________________________________] Model [__________.]

[___________________________________] Model [__________.]

[___________________________________] Model [__________.]

Substitutions: Under provisions of Section [01600.] [_____.]

MANUFACTURED :UNITS

Unit: [Dual volume] [outdoor] [indoor] unit[.] [with refrigeration package.]

Construction and Ratings: In accordance with ARI 210/240 [, and ANSI/UL 207 and ANSI/UL 303]. Testing: ASHRAE 14.

Performance Ratings: Energy Efficiency Rating (EER) not less than requirements of ANSI/ASHRAE 90A.

Heating Capacity: [_____] degrees F [_____] (degrees C) delivery temperature based on [_____] degrees F [_____] (degrees C) temperature rise of [_____] cu ft/min ([_____] cu m/sec) at [_____] inches wg ([_____] Pa) external static pressure with [_____] hp ([____] W) motor.

Cooling Capacity: [_____] Btu/hr ([_____] W) rated cooling output with [_____] degrees F ([_____] degrees C) DB and [_____] degrees F ([_____] degrees C) WB air entering the evaporator, [_____] degrees F ([_____] degrees C) DB condenser ambient air, minimum energy efficiency ratio [_____.] [Unit sound rating number based on ARI 270: [_____].]

Scheduled Performance: [ARI 210/240 Test Conditions.] [Air entering evaporator at [_____] degrees F ([_____] degrees DB and [_____] degrees F ([_____] degrees C) WB [_____] degrees F ([_____] degrees C) condenser ambient air.] [Sound rating numbers are in accordance with ARI 270.]

FABRICATION

Casing and Components: Steel Panels, 18 gage (1.2 mm) reinforced with structural angles and channels to ensure rigidity; access panels to burner and blower motor assemblies from either side of unit.

Observation Port: On burner section for observing main and pilot flames.

Insulation: Neoprene faced glass fiber insulation one inch (25 mm) thick on [inlet components to burner profile plate.] [complete unit.]

Finish: Heat resistant baked enamel.

Suspended Installations: Service platforms complete with handrails and access ladder.

Outdoor Installation: Weatherproofed casing, with intake louver or hood.

FILTERS

Filter: [FS F-F-300A] [FS F-F-310A] removable [one inch (25 mm)] [2 inch (50 mm)] thick [high velocity permanent] [glass fiber disposable] filters in metal frames.

BURNERS

Assembly: For [natural] [propane] gas, capable of modulating turn down ratio of 25:1, including electric modulating main gas valve, motorized shut down valve, main and pilot gas regulators, pilot electric gas valve, manual shut-off valve and pilot adjustment valve.

Pilot: Electrically ignited by spark rod through high voltage ignition transformer and supervised.

Damper: Motorized with end switch to prove position before burner will fire.

FAN

Fan: Statically and dynamically balanced centrifugal fan mounted on solid steel shaft with heavy duty self-aligning pre-lubricated ball bearings and V-belt drive with matching motor sheaves and belts.

CONTROLS

Controls: Pre-wire unit for connection of power supply. Field wiring from unit to remote control panel makes unit operative.

Remote Control Panel: On-off-[auto] switch, [summer-winter switch,] indicating lights for supply fan, [exhaust fan,] pilot operation, burner operation, clogged filter indication and [lockout indication].

Interlocks: Unit to start when exhaust fan is running. Burner to operate when flow switch located in exhaust duct proves flow. [Exhaust fan speed control with inlet damper and burner profile damper to provide dual volume air capacity.] [Exhaust fans operate with inlet damper and burner profile damper to provide dual volume operation.]

Fan Discharge Thermostat: Controls modulating gas valve to maintain supply air temperature. [Provide remote discharge thermostat adjustment [within 20 ft (6.096 m) of unit.] [in excess of 20 ft (6.096 m) of unit.]] [Provide room thermostat to reset discharge thermostat minimum of three temperature levels.]

Timer: Operates fan system [off at night.] [on low volume at night.]

Carbon Monoxide Monitoring System: Operates fan on high volume when pre-determined carbon monoxide concentration is detected.

Safety Controls: Sense correct air flow before energizing pilot and sense pilot ignition before activating main gas valve.

Manual Reset Low and High Limit Controls: Maintain supply air temperature between set points and shut fan down if temperatures are exceeded.

Purge Period Timer: Automatically delays burner ignition and bypass low limit control.

REFRIGERATION PACKAGE

Evaporator Coil: Copper tube aluminum fin coil assembly with galvanized drain pan and expansion valve.

Compressor: [ARI 520] hermetic, 3600 rpm maximum resiliently with positive lubrication, crankcase heater, high pressure control, motor overload protection, service valves and drier.

Condenser: [ARI 520] aluminum fin and copper tube coil, direct drive axial fan resiliently mounted, galvanized fan guard.

Operating Controls: Low voltage, adjustable room thermostat controls compressor and condenser fan to maintain room temperature setting.

PART 3 EXECUTION

INSTALLATION

Install in accordance with manufacturer's instructions.

Install to NFPA 90A.

Install to ANSI Z223.1 (NFPA 54).

SCHEDULES

Drawing_Code	MAU-1	MAU-2

Location

Manufacturer

Model

Supply Fan

Air Flow

External Static Pressure

Fan Motor

Heat

Input

Air Delivery Temp

Air Temp Rise

Cooling

Sensible

Total

Evap Coil entering DB temp

Evap Coil entering WB temp

Evap Coil leaving DB temp

Evap Coil Leaving WB Temp

Condenser ambient air temp

Energy Efficiency Ratio

Compressor Power Input

Nominal Capacity (Tons)

Sound Rating Number

END OF SECTION