SECTION 15671

AIR COOLED CONDENSING UNITS

PART 1 GENERAL

SECTION INCLUDES

Condensing unit package.

Charge of refrigerant and oil.

Controls and control connections.

Refrigerant piping connections.

Motor starters.

Electrical power connections.

RELATED SECTIONS

Section 03300 - Cast-in-Place Concrete: Equipment bases.

Section 15170 - Motors.

Section 15242 - Vibration Isolation: Placement of vibration isolators.

Section 15260 - Piping Insulation.

Section 15280 - Equipment Insulation.

Section 15535 - Refrigeration Piping and Specialties.

Section 15623 - Forced Air Furnaces.

Section 15790 - Air Coils.

Section 15835 - Terminal Heat Transfer Units: Fan-coil units.

Section 15855 - Air Handling Units with Coils.

Section 15952 - Controls and Instrumentation.

Section 16180 - Equipment Wiring Systems.

REFERENCES

ANSI/ASHRAE 15 - Safety Code for Mechanical Refrigeration.

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

ANSI/NEMA MG 1 - Motors and Generators.

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/UL 465 - Central Cooling Air Conditioners.

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

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

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

ARI 270 - Sound Rating of Outdoor Unitary Equipment.

SUBMITTALS

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

Submit shop drawings indicating components, assembly, dimensions, weights and loadings, required clearances, and location and size of field connections. Include schematic layouts showing condensing units, cooling coils, refrigerant piping, and accessories required for complete system.

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

Submit product data indicating rated capacities, weights specialties and accessories, electrical nameplate data, and wiring diagrams.

Submit design data under provisions of Section [01300.] [01340.]

Submit design data indicating pipe and equipment sizing.

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 start-up instructions, maintenance instructions, parts lists, controls, and accessories.

DELIVERY, STORAGE, AND HANDLING

Deliver products to site under provisions of Section

[01600.] [01610.]

Store and protect products under provisions of Section [01600.] [01620.]

Comply with manufacturer's installation instructions for rigging, unloading, and transporting units.

Protect units on site from physical damage. Protect coils.

WARRANTY

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

Warranty: Include coverage for refrigerant compressors.

EXTRA MATERIALS

Provide [one] [_____] complete change of lubricating oil under provisions of Section [01700.] [01750.]

PART 2 PRODUCTS

MANUFACTURERS

[______________________________] Model [__________.]

[______________________________] Model [__________.]

[______________________________] Model [__________.]

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

MANUFACTURED UNITS

Units: Self-contained, packaged, factory assembled and pre-wired units suitable for outdoor use consisting of cabinet, compressors, condensing coil and fans, integral sub-cooling coil, controls, liquid receiver, [wind deflector,] and screens.

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

Performance Ratings: Energy Efficiency Rating (EER) [and Coefficient of Performance (COP)] not less than prescribed by ANSI/ASHRAE 90A.

Heat Rejection Capacity: [_____] Btu/hr, ([_____] W) with a saturated suction temperature of [_____] degrees F ([_____] degrees C) and air entering condenser at [_____] degrees F ([_____] degrees C), EER of [_____.]

Heat Pump Capacity: [_____] Btu/hr, ([_____] W) with saturated suction temperature of [_____] degrees F ([_____] degrees C) and air entering outdoor coil at [47 degrees F (8 degrees C) dry bulb and 43 degrees F (6 degrees C) wet bulb,] [17 degrees F (-8 degrees C) dry bulb and 15 degrees F (-9 degrees C) wet bulb,] COP of [_____.]

[Condenser] [Outdoor Coil] Air Flow: [_____] cfm ([_____] L/sec) with [_____] condenser fan motors at [_____] hp ([_____] kW).

Compressor input [_____] kW, with [_____] steps unloading.

CASING

House components in [welded steel frame with] [galvanized] steel panels with weather resistant, baked enamel finish.

Mount starters, disconnects, and controls in weatherproof panel provided with full opening access doors. Provide mechanical interlock to disconnect power when door is opened.

Provide removable access doors or panels with [piano hinges and] quick fasteners.

CONDENSER COILS

Coils: Aluminum fins mechanically bonded to seamless copper tubing. Provide sub-cooling circuits. Air test under water to 425 psig (2900 kPa), and [vacuum] dehydrate. Seal[.] [with holding charge of [nitrogen.] [refrigerant.]]

Coil Guard: [Expanded metal][.] [Louvered][.] [PVC coat steel wire][.] [with lint screens.]

FANS AND MOTORS

Vertical discharge [direct] [belt] driven propeller type condenser fans with fan guard on discharge. [Equip with roller or ball bearings with grease fittings extended to outside of casing.]

Weatherproof motors suitable for outdoor use, single phase permanent split capacitor or 3 phase, with permanent lubricated ball bearings and built in [current and] thermal overload protection[.] [Refer to Section 15170.]

Horizontal discharge, double width, double inlet [forward curved] [backward inclined] centrifugal type condenser fans, equipped with roller or ball bearings with grease fittings extended to outside of casing, V-belt drive with belt guard.

Motors as indicated, in compliance with Section 15170.

COMPRESSORS

Construction: Semi-hermetic [or hermetic] reciprocating type with heat treated forged steel or cast iron shafts, aluminum alloy connecting rods, automotive type pistons, rings to prevent gas leakage, suction and discharge valves, and sealing surface immersed in oil.

Mounting: Statically and dynamically balance rotating parts and mount on [spring] [rubber-in-shear] vibration isolators. [Internally isolate hermetic units on springs.] [Refer to Section 15252.]

Lubrication System: Reversible, positive displacement oil pump with oil charging valve, oil level sight glass, oil filter, and magnetic plug or strainer.

Capacity Reduction Equipment: Suction valve unloaders, with lifting mechanism operated by electrically actuated solenoid valve. Provide for unloaded compressor start. Control unloading from [suction pressure.] [room thermostat.] [______________.]

Motor: Constant speed [1800] [3600] rpm suction gas cooled with electronic sensor and winding over temperature protection, designed for across-the-line starting. [Refer to Section 15170.] Furnish with starter.

Crankcase Heater: Evaporates refrigerant returning to crankcase during shut down. Energize heater [continuously][,][.] [thermostatically][,][.] [and] [when compressor is not operating.]

REFRIGERANT CIRCUIT

Provide each unit with [one refrigerant circuit,] [two independent refrigerant circuits,] factory supplied and piped. Refer to Section 15535.

Provide the following for each refrigerant circuit:

Filter dryer[.] [replaceable core type.]

Liquid line sight glass and moisture indicator.

Thermal expansion valve for maximum operating pressure.

Insulated suction line.

Suction and liquid line service valves[,][.] [and gage ports.]

Liquid line solenoid valve.

Charging valve.

Discharge line check valve.

Compressor discharge service valve.

Condenser pressure relief valve.

For heat pump units, provide reversing valve, suction line accumulator, [discharge muffler,] flow control check valve, and solid-state defrost control utilizing thermisters.

CONTROLS

On unit, mount weatherproof steel control panel, NEMA 250, containing power and control wiring, [molded case disconnect switch,] factory wired with single point power connection.

For each compressor, provide [across-the-line] [part winding] starter, non-recycling compressor overload, starter relay, and control power transformer or terminal for controls power. Provide manual reset current overload protection. For each condenser fan, provide across-the-line starter with starter relay.

Provide the following safety controls arranged so that operating any one will shut down machine and require manual reset:

High discharge pressure switch (manual reset)[.] [for each compressor.]

Low suction pressure switch (automatic reset)[.] [for each compressor.]

Oil Pressure switch (manual reset).

Provide the following operating controls:

Thermostat located in [room] [supply air with outdoor reset] [return air] cycles compressors[,][.] [activates cylinder unloaders][,][.] [and] [activates solenoid valves in refrigerant circuit.]

[One] [Five] minute off timer prevents compressor from short cycling.

Periodic pump-out timer to pump down on high evaporator refrigerant pressure.

Low ambient temperature controls.

Hot gas bypass sized for minimum compressor loading[,] [on one compressor only,] bypasses hot refrigerant gas to evaporator.

Lead-lag switch to alternate compressor operation.

Low ambient thermostat to lock out compressor at low ambient temperatures.

Provide controls to permit operation down to [0] [_____] degrees F ([-18] [_____] degrees C) ambient temperature.

Thermostat to cycle fan motors in response to outdoor ambient temperature.

Head pressure switch to cycle fan motors in response to refrigerant condensing pressure.

Solid state control to vary speed of one condenser fan motor in response to refrigerant condensing pressure.

Electronic control consisting of mixing damper assembly, controlled to maintain constant refrigerant condensing pressure.

Provide pre-piped gage board with pressure gages for suction and discharge refrigerant pressures, and oil pressures[.] [for each compressor.]

For multiple units, provide remote mounted sequence panel to allow operation with lead-lag switching and time delay timer.

Refer to Section 15952.

Provide low voltage, adjustable thermostat to control [heating stages in sequence with delay between stages,] [compressor stages] and supply fan to maintain temperature setting, Model [_____] manufactured by [_______________.]

Include system selector switch [(heat-off-cool)][,][.] [(auto-on)][,][.] [(off-heat-auto-cool)][,][.] [and fan control switch (auto-on).]

Provide double acting thermostat with minimum [_____] stage heating and [_____] stage cooling.

Provide single acting thermostat with minimum [_____] stage cooling.

Locate thermostat in [room as shown.] [supply air.] [return air.]

Provide electric solid state microcomputer based room thermostat, located as indicated[.] [in service area with remote sensor located as indicated.] Model [__________] manufactured by [_______________.]

Room thermostat shall incorporate:

Automatic switching from heating to cooling.

Preferential rate control to minimize overshoot and deviation from set point.

Set-up for four separate temperatures per day.

Instant override of setpoint for continuous or timed period from one hour to 31 days.

Short cycle protection.

Programming based on weekdays, Saturday and Sunday.

Switch selection features including imperial or metric display, 12 or 24 hour clock, keyboard disable, remote sensor, fan on-auto.

Room thermostat display shall include:

Time of Day.

Actual room temperature.

Programmed temperature.

Programmed time.

Duration of timed override.

Day of week.

System mode indication: Heating, cooling, auto, off, fan auto, fan on.

Stage (heating or cooling) operation.

PART 3 EXECUTION

INSTALLATION

Install in accordance with manufacturer's instructions.

Provide for connection to electrical service. Refer to Section 16180.

Install units on vibration isolation. Refer to Section 15252.

Install units on concrete base as indicated.	Refer to Section 03300.

Provide connection to refrigeration piping system and evaporators. Refer to Section 15535. Comply with ANSI/ASHRAE 15.

MANUFACTURER'S FIELD SERVICES

Prepare start systems under provisions of Section [01600.] [01650.]

Provide initial and cooling season start-up, and winter season shut down during first year of operation, including routine servicing and check out.

Supply initial charge of refrigerant and oil for each refrigerant circuit. Replace losses of refrigerant and oil.

Inspect and test for refrigerant leaks every [_____] during first year of operation.

SCHEDULES

Drawing_Code ACC-1 ACC-2 ACC-3

Location

Manufacturer

Model Number

Cooling

Capacity

Saturated Suction Temp

Condenser Ent. Air Temp

Condensing Temp

Air Flow

No. of Fans

Power

Heating

Capacity

Saturated Suction Temp

Ent. Air DB Temp

Ent. Air WB Temp

Compressor

Number

Steps Unloading

RPM

Starter Type

Power Input

EER

COP

END OF SECTION