SECTION 15785

COMPUTER ROOM AIR CONDITIONING UNITS

PART 1 GENERAL

SECTION INCLUDES

Air conditioning units.

Controls and control panels.

PRODUCTS FURNISHED BUT NOT INSTALLED UNDER THIS SECTION

Section 15952 - Controls and Instrumentation: Installation and wiring of thermostats and control components.

Section 16180 - Equipment Wiring System: Installation and wiring of thermostats and control components.

RELATED SECTIONS

Section 10270 - Access Flooring.

Section 15170 - Motors: Evaporator [and condenser] fan motors.

Section 15290 - Ductwork Insulation: Duct liner.

Section [_____ - __________:] Interlock with halon system.

Section 15570 - HVAC Pumps: Glycol system pumps.

Section 15742 - Air Cooled Refrigerant Condensers.

Section 15790 - Air Coils: Chilled water, hot water, steam, glycol coils.

Section 15952 - Controls and Instrumentation.

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

REFERENCES

ANSI/ASME - Boilers and Pressure Vessels Code.

ANSI/NEMA 250 - Enclosures for Electrical Equipment (1000 Volts Maximum).

ANSI/NFPA 90A - Installation of Air Conditioning and Ventilation Systems.

ASHRAE 52 - Air-Cleaning Devices Used in General Ventilation for Removing Particulate Matter.

FS TT-C-490 - Cleaning Method and Pretreatment of Ferrous Surfaces for Organic Coatings.

UL - Underwriters Laboratories.

REGULATORY REQUIREMENTS

Conform to ANSI/NFPA 90A for the installation of computer room air conditioning units.

SUBMITTALS

Submit [shop drawings and] product data under provisions of Section [01300.] [01340.]

Submit [shop drawings and] product data for manufactured products and assemblies required for this project.

Indicate water, drain, electrical[,] [and] [refrigeration] rough-in connections on [shop drawings or] product data.

Submit manufacturer's installation instructions under provisions of section [01300.] [01340.]

OPERATION AND MAINTENANCE DATA

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

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

WARRANTY

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

Warranty: Include coverage of [refrigeration compressors.] [entire unit.] [____________________.]

EXTRA MATERIALS

Provide [one] [_____] sets of filters under provisions of Section [01700.] [01750.]

PART 2 PRODUCTS

MANUFACTURERS

[____________________________________________.]

[____________________________________________.]

[____________________________________________.]

Substitutions: Under provisions of Section [01600.] [01630.]

MANUFACTURED UNITS

Provide packaged, [water] [air] cooled, factory assembled, pre-wired and pre-piped unit, consisting of cabinet, fans filters, humidifier, controls.

Assemble unit for [up-flow] [down-flow] air delivery, in [draw-through] [or] [blow-through] configuration.

CABINET AND FRAME

Structural Frame: [10] [14] [_____] gage ([3.3] [1.8] [_____] mm) welded steel suitably braced for rigidity, capable of supporting compressors and other mechanical equipment and fittings[;][.] [welded tubular steel floor stand with adjustable legs and vibration isolation pads.]

Doors and Access Panels: [18] [20] [_____] gage ([1.2] [0.9] [_____] mm) [galvanized] steel with polyurethane gaskets, hinges to allow removal of panels, and concealed fastening devices.

Insulation: Thermally and acoustically line cabinet interior with one inch (25 mm) thick acoustic duct liner.

Finish of Exterior Surfaces: FS TT-C-490 prepared, baked-on textured vinyl enamel; [_____] color[.] [to match computer equipment.] [as selected.]

EVAPORATOR FANS AND MOTORS

Fans: Double inlet, forward curved centrifugal fans, statically and dynamically balanced[,] [on steel shaft with self-aligning [grease] [permanently] lubricated ball bearings, and V-belt drive.] [directly driven.]

Motor: [Refer to Section 15170 - Motors.] [Drip proof, permanently lubricated ball bearing motor with built-in current and overload protection.]

V-Belt Drive: Cast iron or steel sheaves, dynamically balanced, keyed, variable and adjustable pitch motor sheave, minimum of two matched belts, drive rated minimum 2.0 times nameplate rating of motor.

COMPRESSORS

[Semi-hermetic with suction gas cooled motors, vibration isolators, thermal overloads, oil sight glass, manual reset high pressure switch, pump down low pressure switch, suction line strainer, reversible oil pumps, 1750 rpm][.] [or,] [Hermetic with resilient suspension system, oil strainer, crankcase sight glass, internal motor protection, low pressure switch, manual reset high pressure switch.]

Compressors shall be individually servicable without dismantling other components[.] [or removing unit from service.]

EVAPORATOR COILS

[Alternate row] [Split face] circuits, direct expansion cooling coils of seamless copper tubes expanded into aluminum fins[,][.] [in A-frame configuration.] [in vertical flat face configuration.]

Two refrigeration circuits, each with hot gas mufflers, thermal expansion valve with external equalizer, liquid line solenoid valve, liquid line filter-drier, refrigerant sight glass with moisture indicator, service shut-off valves and charging valves[,][.] [accumulator sized for liquid seal under light load.]

Mount coil assembly in stainless steel drain pan.

CONDENSERS

Water Cooled: [Shell and tube type to Section 8D of ANSI/ASME code] [or] [Coaxial tube in tube type] with liquid line stop valve and head pressure actuated water regulating valve. Terminate cabinet for easy external connections.

Air Cooled: Air cooled refrigerant condenser[,] [refer to Section 15742,] consisting of corrosion resistant cabinet, copper tube aluminum fin coils arranged for two circuits, multiple direct drive propeller fans with [permanently lubricated ball bearing] single phase motors with internal overload protection. [Refer to Section 15170.]

[CHILLED WATER] [HOT WATER REHEAT] [STEAM REHEAT] [GLYCOL COOLING] COIL

Seamless copper tubes expanded into aluminum fins with [three way modulated valve.] [two way modulating control valve and strainer.] [two way modulating control valve, strainer, and float and thermostatic trap.] [head pressure actuated three way glycol regulating valve.]

REHEAT COIL

Hot gas refrigerant coil of seamless copper tubes expanded into aluminum fins with three way solenoid valve on first stage refrigerant circuit.

FILTERS

Media: Pleated, lofted, non-woven, reinforced cotton fabric; supported and bonded to welded wire grid; enclosed in cardboard frame; [2 inch (50 mm)] [4 inch (100 mm)] nominal thickness.

Rating: ASHRAE 52; 25-30 percent dust spot efficiency, 90-92 percent weight arrestance; 500 ft/min (2.54 m/sec) face velocity, 0.30 inch WG (75 Pa) initial resistance, 1.0 inch WG (250 Pa) recommended final resistance.

Model: [_______________] manufactured by [____________________.]

HEATING COILS

Heating Coils: Enclosed fin electrical elements arranged for minimum of [two] [three] stages.

Circuit Protection: Primary and secondary thermal cutouts, differential air pressure switch, and manual reset overload protection, branch circuit overcurrent protection.

HUMIDIFIER

Infrared Type: High intensity quartz lamps mounted above stainless steel evaporator pan, servicable without disconnecting water, drain, or electrical connections; pre-piped and utilizing condensate water from cooling coils with stainless steel or brass float valve mechanism; located in bypass air stream[;][.] [with flush cycle timer and solenoid drain valve.]

Evaporative Pan Type: Stainless steel pan and cover, servicable without disconnecting water, drain, or electrical connections; pre-piped with stainless steel or brass float valve mechanism; electric heating coil and low water cut-off switch; with flush cycle timer and solenoid drain valve.

REMOTE GLYCOL COOLER

Corrosion resistant [aluminum] [_____] cabinet with copper tube aluminum fin coil, multiple direct drive propeller fans with fan guard and [permanently lubricated ball bearing] single phase motors with internal overload protection. [Refer to Section 15170.]

GLYCOL PUMP PACKAGE

Cabinet: Weatherproof and vented enclosure of enamelled, galvanized steel on structural base frame.

Pumps: [One] [Two] centrifugal pumps with mechanical seal. [Refer to Section 15540.]

Controls: Electrical control cabinet with starters, disconnect, lead/lag switch, and automatic switch-over and alarm light.

Piping: Interconnecting piping, from suction to discharge with shut-off valves, flow switches, check valves in pump discharge, unions, and pressurized expansion tank with air purge vent and system charging connection.

ELECTRICAL PANEL

Service Connections, Wiring, and Disconnect Requirements: Conform to Section 16180.

Control Cabinet: NEMA 250; Type [2] [_____] enclosure, UL listed, with piano hinged door, grounding lug, combination magnetic starters with overload relays, circuit breakers and cover interlock, and fusible control circuit transformer.

Disconnect Switch: Non-automatic molded case circuit breaker with handle accessible with panel closed[.] [and capable of preventing access until switched to "off" position.]

ELECTRONIC CONTROL SYSTEM

Solid state with start button, stop button, temporary loss of power indicator, manual reset circuit breakers, temperature control humidity control, and monitor panel.

Monitor Panel: Backlighted with no visible indicator lights until operating function is activated; indicators include cooling, humidification, loss of air flow, change filters, high temperature, low temperature, high humidity, low humidity, high head pressure (each compressor), and low suction pressure (each compressor).

Temperature and Humidity Control Modules: Solid state plug-in with adjustable set point, "push-to-test" calibration check button, and built-in visual indicators to indicate mode of operation.

Location: Through hinged door in front of unit; isolated from conditioned air stream to allow service while system is operating.

MICROPROCESSOR CONTROL SYSTEM

Logic Circuitry: Microprocessor shall continuously monitor operation of process cooling system; continuously digitally display room temperature and room relative humidity; sound alarm on system malfunction and simultaneously display problem. When more than one malfunction occurs, flash fault in sequence with room temperature, remember alarm even when malfunction cleared, and continue to flash fault until reset.

Malfunctions: Power Loss, Loss of Air Flow, Clogged Air Filter, High Room Temperature, Low Room Temperature, High Humidity, Low Humidity, [Smoke/Fire,] Compressor No. 1 -Overload, Compressor No. 1 - Low Pressure, Compressor No. 1 - High Pressure, Compressor No. 2 - Overload, Compressor No. 2 - Low Pressure, Compressor No. 2 - High Pressure, [Water-Under-Floor,] and Supply Fan Overload.

Light Emitting Diodes Display: Control Power On, System On, Humidification, De-humidification taking place, Compressor No. 1 operating, Compressor No. 2 operating, Heat or Reheat operating, Economy Cooling.

Provide push buttons to STOP process cooling system, START process cooling system, SILENCE audible alarm, push-to-test LED indicators, and display room relative humidity.

PERFORMANCE

Cooling Capacity: [_____] Btu/hr ([_____] W) with [_____] cfm ([_____] L/sec) of air entering evaporator at [_____] degrees F ([_____] degrees C) DB and [_____] degrees F ([_____] degrees C) WB, leaving evaporator at [_____] degrees F) [_____] degrees C) DB and [_____] degrees F ([_____] degrees C) WB, with [one] [two] evaporator fan motors at [_____] hp ([_____] W).

[Water] [Glycol] Cooled: [_____] gpm ([_____] L/sec) condenser water entering at [_____] degrees F ([_____] degrees C), [one] [two] [_____] condenser fan motors at [_____] hp ([_____] W).

Air Cooled: Air entering air cooled condensing unit at [_____] degrees F ([_____] degrees C), [one] [two] [_____] condenser fan motors at [_____] hp ([_____] W).

Reheat Capacity: [_____] Btu/hr ([_____] W) when supplied with [_____] gpm ([_____] L/sec) water entering at [_____] degrees F ([_____] degrees C) and leaving at [_____] degrees F ([_____] degrees C).

Reheat Capacity: [_____] Btu/hr ([_____] W) when supplied with [_____] lb/hr ([_____] kg/hr) steam at [_____] psig ([_____] kPa).

Reheat Capacity: [_____] Btu/hr ([_____] W).

Glycol Cooling: Coil capacity of [_____] Btu/hr ([_____] with air entering at [_____] degrees F ([_____] degrees DB and [_____] degrees F ([_____] degrees C) WB,leaving at [_____] degrees F ([_____] degrees C) DB and [_____] degrees F ([_____] degrees C) WB, when supplied with [_____] gpm ([_____] L/sec) glycol entering at [_____] degrees F ([_____] degrees C), [one] [two] pumps at [_____] hp ([_____] W).

Humidifier: Total capacity of [_____] lb/hr ([_____] kg/hr) with [_____] W input.

PART 3 EXECUTION

EXAMINATION

Verify that flooring system is ready to receive work and opening dimensions are as [indicated on shop drawings.] [instructed by the manufacturer.]

Verify that proper power supply is available.

INSTALLATION

Install units in accordance with manufacturer's instructions.

Coordinate installation of computer room air conditioning units with computer room raised floor installer.

Provide adequate drainage connections for [water cooled units] [condensate] and humidifier flushing system.

Provide shut-off valves in condenser water inlet and outlet piping on water cooled units.

SCHEDULE

Drawing_Code CAC-1 CAC-2 CAC-3 Location

Manufacturer

Model Number

Cooling Capacity

Total

Sensible

Evaporator

Air Flow

Entering Air DB Temp

Entering Air WB Temp

Leaving Air DB Temp

Leaving Air WB Temp

Evaporator Fan Motors

Condenser

Water Flow

Water Temp

Ambient Air Temp

Fan Motors

Glycol Flow

Glycol Temp

Reheat

Capacity

Water Flow

Entering Water Temp

Leaving Water Temp

Steam Flow

Steam Pressure

Glycol Cooling

Total Capacity

Entering Air DB Temp

Entering Air WB Temp

Leaving Air DB Temp

Leaving Air WB Temp

Glycol Flow

Entering Glycol Temp

Glycol Pump Motors

Humidifier

Capacity

Power Input

END OF SECTION