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Product Manual PM ALS-5

Air-Cooled Rotary Screw Chillers

Models ALS 141C to ALS 218C120 to 210 Tons, 420 to 735 kWHCFC-2260 Hz

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4 ALS 141C 218C Product Manual ALS-5

Customer Benefits

Unsurpassed Effic iency Zero clearance fit between the two gaterotors and main screw rotor virtually eliminates

leakage between the high and low-pressure sides during compression. Special gaterotor

material made from an advanced composite, temperature stable material makes a zeroclearance design possible. An internal economizer system enhances the unit's refrigeration effect providing more

BTUs per pound of refrigerant circulated. The result is higher efficiency and lower operating costs when compared to typical chillers without economizers.

The ALS air-cooled chiller is equipped with the most advanced means of refrigerantflow control available. An electronic expansion valve coupled with MicroTech fuzzylogic control provides excellent operating efficiencies both at full and part load operation.

Figure 1, StarGate Compressor Cutaway

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Product Manual ALS-5 ALS 141C 218C 5

Outstanding Reliability Features Full factory testing of the unit with water hookups provides a trouble-free start-up.

Extensive quality control checks during testing means that each equipment protectionand operating control is properly adjusted and operates correctly before it leaves thefactory. Factory installed options minimize field expenses and startup labor.

The rugged design of the single-screw compressor with its compliant gaterotors allowsit to tolerate liquid slugging. The ALS screw chiller will start and operate under conditions that would destroy a reciprocating compressor.

The elimination of many moving parts such as pistons, valves, and connecting rodsfound on reciprocating compressors results in the enhanced reliability of the single-screw compressor.

Due to symmetrical compression taking place on both sides of the main screw rotor, balanced forces result in the elimination of the large thrust loads inherent in twin-screwcompressors. Very low loading enhances the bearing and compressor reliability.

Integral to the basic design of the single-screw compressor, the main screw rotor shaftand the gaterotor shafts cross at right angles in the compressor. The result is amplespace to locate heavy duty bearings and increase compressor reliability since nolimitations are placed on bearing design as found in twin-screw compressors.

The compressor motor on the ALS screw chiller is liquid refrigerant cooled, allowingmotor operation at lower temperatures, enhancing system reliability and motor lifewhen compared to suction or discharge gas cooled designs.

Recent technological advancements have made available a composite material that prevents premature wear on the gaterotor. The composite material is made from amaterial designed for strength, temperature stability and durability.

Unmatched Serviceability Field serviceability has not been sacrificed to meet design performance objectives on

the ALS chiller. Inspection covers allow for an excellent visual inspection of the mainscrew and gaterotors. Compressors are equipped with suction and discharge service

valves. Compressors are located on the outside edges of the base allowing ready access.

Standard Solid State StartersThe addition of solid state starters as standard (a McQuay exclusive) on the "C" vintageunits takes a giant step forward in motor/compressor protection from failures from machineor electrical faults and includes self-diagnostics, metering and display. The starters providesmooth, slow stepless acceleration and controlled slow deceleration, reducing mechanicaland electrical stress for even greater compressor/motor life. Some of the informationavailable to the operator or service technician on each starter LED display follows:

Operating Messages Fault MessagesLine voltage not present System power not three phase

Voltage present, starter ready Phase sequence incorrectMotor accelerating Line frequency less than 25 HzMotor at full speed Line frequency more than 72 Hz

Motor at full speed, ramp time expired Excessive current unbalanceStop command received, motor decelerating Operating parameters lost Thermal overload has reached 90% to 99% No current after "Run" command Thermal overload at 100%, motor stopped Undercurrent trip occurred

Thermal overload reduced to 60%, motor can restart Overcurrent trip occurredPasscode enabled Control power too lowPasscode disabled Motor stalled during acceleration

Thermal overload content in percentage External fault

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Controls

MicroTech , The Ultimate Control System A fuzzy logic control system is employed in the ALS screw chiller that optimizes the

suction line superheat and the positioning of the electronic expansion valve at all

compressor capacities resulting in maximized unit operating efficiencies. Fuzzy logiccontrol is based on approximate reasoning that maintains tighter control of the system.

The MicroTech chiller controller, already proven superior to all other chiller controlsystems on reciprocating and centrifugal chillers, is employed in the ALS screw chiller.This advanced microprocessor-based control maintains a precise and stable leavingevaporator temperature set point. Utilization of fuzzy logic means compressor cyclingis minimized, reducing wear on both compressor and starting components.

Stand-alone unit controls designed with the system operator in mind provide access tothe unit temperatures, pressures, set points, operating states, schedules, and alarmmessages. The MicroTech controller includes password protection to guard againstunauthorized or accidental setpoint or parameter changes.

Complete instrumentation with state-of-the-art pressure transducers, temperaturesensors and optical oil level sensors for unparalleled operator information and diagnostics.

Superior head pressure control that maximizes unit efficiency by determining optimumcondenser fan operation. At least 5 and as many as 7 stages of heat rejection per circuitare provided.

An optional Remote Monitoring and Sequencing (RMS) panel provides monitoring and control of remote chillers via a single twisted pair of wires. The RMS panel allows theuser to access information such as unit status, temperatures and pressures, all controlset points, alarm conditions, time and date of alarm conditions, as well as the ability toclear alarms remotely. Up to three chillers can be sequenced and monitored from one

RMS panel. A personal computer equipped with optional MicroTech Monitor software can be used

to provide a high-level interface with the MicroTech controller. It can be connected tothe controller either directly or remotely via phone lines with an optional modem.

The optional MicroTech Network Master Panel (NMP) allows multiple screw chiller controllers to be incorporated into a building-wide network with other MicroTech unitand auxiliary controllers. In conjunction with a personal computer, it provides the

building operator with the capability to perform advanced equipment control and monitoring from a central or remote location.

Open Protocol is a commitment from McQuay International to provide a cost effectivemeans to building automation through a strategic and joint effort with major

temperature control companies. This optional feature provides an interface betweenMicroTech controllers and the building automation system. The result can be reduced installation costs, greater reliability and a seamless operator interface with allequipment in the building.

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MicroTech Controll er Utilizing Fuzzy LogicMcQuay International has combined microprocessor power and versatilityand our extensive experience in chiller design to create the MicroTech screwchiller controller utilizing a fuzzy logiccontrol system. The MicroTech control

provides low maintenance, high performance and energy efficientoperation that is so vital to profitable

building operation in today's economicclimate.

Fuzzy Logic Contro lTraditional control systems on today's chillers do not adequately provide precisiontemperature control of the system. McQuay International has implemented an advanced digital control method based upon fuzzy logic that maintains tighter and more stable controlof the chiller system.

Conventional control logic operates on the true/false, black and white theory. However, in practical applications everything is not black and white, but rather can be found somewherein between as shades of gray. Terms such as hot and cold in conventional controltechniques are replaced by ambiguous words like warm and cool . Fuzzy logic does notmaintain that a statement has to be true or false, but instead measures the degree of truthwithin the statement and begins to take action immediately. Unlike traditional controllersthat rely on a linear control theory, the fuzzy logic system is based upon approximatereasoning with a set of fuzzy rules. Fuzzy rules are "if-then" statements with varyingdegrees of precision.

A simple analogy of a "if-then" statement could be a car in traffic. If the distance betweentwo cars is adequate, then the car behind will continue at the same speed. If the distance

between the two cars increases, then the car in the rear can accelerate slowly. If thedistance between the two cars is reduced slightly, then the car behind brakes slowly. If thedistance between them is reduced quickly, then the car in the rear must brake much morequickly. Fuzzy logic operates on this same principle.

The MicroTech controller supplied on the ALS chillers utilizes fuzzy logic in the control of suction line superheat and the positioning of the electronic expansion valve in response tosystem load. Expansion valve hunting, not uncommon on traditional thermostaticexpansion valves, has been eliminated. Optimized superheat is maintained under allconditions providing excellent control.

Proactive Contro l

The MicroTech Control continuously monitors all important system parameters and willtake measures to avoid unit shutdown if a system imbalance or upset occurs. An alarmcircuit is energized under these circumstances.

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Stand-alone Unit ControlsThe MicroTech unit controller is a microprocessor-based direct digital control systemdesigned to provide sophisticated monitoring and control. Designed with the systemoperator in mind, the MicroTech controller features an easy to use 12-key keypad and 32-character display that provides access to temperatures, pressures, set points, operatingstates, schedules and alarm messages in either English or Metric units. The controller includes password protection to guard against unauthorized or accidental set point or

parameter changes.The MicroTech unit controller can be used as a stand-alone controller, or it can beintegrated into a MicroTech network by using the Network Master Panel or the RemoteMonitoring and Sequencing Panel. Regardless of whether the controller is stand-alone or included in a network, an IBM-compatible computer containing MicroTech Monitor software can be connected to give the operator full-screen unit monitoring and controlcapability.

Electronic Expansion ValveThe ALS air-cooled chiller is equipped with the mostadvanced means of refrigerant flow control available. Anelectronic expansion valve coupled with a MicroTech unitcontroller and fuzzy control logic provide excellentoperating efficiencies both at full and part load operation.

Unlike conventional thermal expansion valves whichrequire a large pressure drop across the valve and result inhigher condenser head pressure, the electronic valve doesnot need a large pressure drop across it to operateeffectively. During part load operation the electronicvalve allows the system to operate at lower condensing

pressure, minimizes suction line superheat and providesfor a more stable system operation. Unit efficiencies aredramatically improved. The electronic expansion valve is

an excellent choice of control for the ALS chiller line, providing precise control with a very fast response time.

Optional Remote Monitoring and Sequencing PanelThe MicroTech Remote Monitoring and Sequencing (RMS) panel provides monitoring of remote chillers via a single twisted pair of wires. The RMS panel allows the user to accessinformation such as unit status, temperatures and pressures, all control set points, alarmconditions, time and date of alarm conditions, as well as the ability to clear alarms remotely.The RMS panel is equipped with a keypad/display that is identical to the chiller controller'skeypad/display. With a special keystroke combination, the RMS keypad/display can beinterfaced with any Microtech chiller controller. It then operates identically to the chiller-mounted keypad/display. Thus the operator has full access to all networked chillers from a

single remote location. Panel-mounted LEDs clearly indicate with which controller theRMS Panel keypad/display is currently interfaced.

Any chiller alarm or loss of communication alarm that occurs will be indicated by a panel-mounted alarm LED. An alarm will also cause the panel-mounted annunciator to sound.The volume can be adjusted with a small potentiometer. Any alarm in the network can becleared at the RMS panel keypad.

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Optional Personal Computer Monitor ing(Part Number 063430513) A personal computer equipped with MicroTech Monitor software can be used to provide a high-level interface with the MicroTech controller. It can

be connected to the controller either directly or remotely via phone lines with an optionalmodem. If the controller is part of a MicroTech network personal computer, monitoring can

be done via network communications.

Optional Network Master Panel(Part Number 066003521) The MicroTech Network Master Panel (NMP) allows multiplescrew chiller controllers to be incorporated into a building-wide network with other MicroTech unit and auxiliary controllers. In conjunction with a personal computer, it

provides the building operator with the capability to perform advanced equipment controland monitoring from a central or remote location. This is strictly for use in a McQuayControls building automation system.

Optional Open ProtocolOpen Protocol is a commitment from McQuay International to provide a cost effectivemeans to building automation through a strategic and joint effort with major temperaturecontrol companies. Open Protocol provides an interface between one or multiple

MicroTech controllers and the building automation system. The result can be reduced installation costs, greater reliability and a seamless operator interface with all equipment inthe building. A nominal licensing fee per site is required (license Part Number 066532701).

Open Protocol Master (OPM)(Part Number 055104401) The MicroTech Open Protocol Master (OPM) panel is usuallyrequired to provide the temperature control company a single-point connection when two or more MicroTech controllers are being networked with the temperature control company'ssystem.

MicroTech BACdrop GatewayThe McQuay BACdrop Gateway panel allows any BACnet based building automationsystem (BAS) to communicate with MicroTech controllers. The panel translates betweenthe standard BACnet protocol (ANSI/ASHRAE 135-1995) and the MicroTech protocol. Nomodifications to the MicroTech hardware or software are necessary. Since BACnet is astandard, public protocol no license agreement is necessary.

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Design Advantages

Ultra-low Sound LevelsThe issue of objectionable sound or "noise" can no longer be treated lightly asmanufacturers may have done in the past. To an owner, sound levels can be as important as

unit efficiency and must be addressed prior to the start of any development program.Concentrated efforts to design the quietest air-cooled chiller in the market has paid off withthe ALS chiller line. Unique compressor and system design allow the ALS air-cooled chiller to produce sound levels considerably lower than competitive reciprocating and twin-screw compressor units in the market today.

The gaterotor material is manufactured from an advanced engineered composite, and thedifference in material density and coefficient of elasticity from the main screw rotor reduces noise levels through the compression chamber. The discharge housing is designed as a "tuned sound attenuator" to cancel out any noise pulsation. Also, the rotor injectionattenuates sound levels within the compressor.

Balanced Forces on Compressor The single-screw compressor has a well-balanced compression mechanism that cancels thescrew rotor load in both the radial and axial directions. Inherent to the basic single-screwcompressor design is the virtually load free operation that gives main bearings a design life3-4 times greater than twin-screws, and eliminates expensive and complicated thrust

balancing schemes. The two exactly opposed gaterotors create two exactly opposed compression cycles. Compression is made at the lower and upper parts of the screw rotor atthe same time, thus canceling the radial loads. Also, both ends of the screw rotor aresubjected to suction pressure only, which cancels the axial loads and eliminates the hugethrust loads inherent in twin-screw compressors.

Figure 2, Balanced Forces

Reliable Bearing DesignSince the main rotor shaft and gaterotor shafts cross at right angles in the single-screwcompressor, sufficient space to locate each bearing is obtained. Because of this uniquecharacteristic for the single-screw compressor, bearing life can be designed much higher compared to twin-screws.

Screw

Gaterotor Gaterotor

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Selection Procedures60 Hz - I-P UnitsThe Performance Data on the following pages are based on a 10 degree F (5.5 degree C)delta-T through the evaporator (2.4 gpm/ton). Adjustment factors for other delta-Ts can befound in Table 3. The minimum leaving chilled water temperature without glycol is 40.0 F(4.4C). For brine selections refer to Table 1 and Table 2 for ethylene or propylene glycol

adjustment factors. Ratings are based on a 0.0001 ft 2 x hr x F/BTU (0.0176 m 2 x C/kW)fouling factor in the evaporator and sea level operation. For other fouling factors or elevations refer to Table 3.

For applications outside the catalog ratings contact your local McQuay sales representative.

Selection ExampleGiven: 120 tons

95 F ambient air temperature, 4,000 feet elevation

288 gpm, 54 F to 44 F, 0.0001 evaporator fouling factor

1. Use the following formula (for water only) to calculate any missing elements:

(gpm x delta-T) /24 = tons

2. From Performance Data R-22, IP Units Table 4, an ALS 141C at the given conditionswill produce 124.5 tons with a compressor kW input of 140.8 and a unit EER of 9.6.Correct for elevation from Table 3:

Capacity: 124.5 tons x 0.973 = 121.1 tons

Power: 140.8 kW x 1.021 = 143.8 kW

EER = Output / Input = 9.6 x 0.973 / 1.021 = 9.1

3. Determine the evaporator pressure drop. Using Figure 3, enter at 288 gpm and followup to the ALS 141C line intersect. Read horizontally to obtain an evaporator pressure

drop of 8.9 ft.Selection example utilizing ethylene glycolGiven:

150 tons, 95 F ambient temperature

56F to 44F chilled fluid temperature

0.0001 evaporator fouling factor.

Protect against freezing to 0F

1. From Table 1 select an ethylene glycol concentration of 40% to protect to 0F.

2. Adjustment factors at 40% glycol:

Capacity = 0.961, Power = 0.976, Flow = 1.121, Pressure Drop = 1.263.

3. Adjustment Factor for 12 degree chilled water range from Table 3 is 1.005 Capacity,1.002 Power.

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4. Select an ALS 171C with a capacity of 155.8 tons and correct with 40% ethylene glycolfactors.

Correct capacity: 0.961 x 1.005 x 155.8 tons = 150.5 tons.

Correct compressor power: 0.976 x 1.002 x 176.9 kW = 173.0 kW

5. Correct chilled fluid flow:

Fluid flow (water) at 150 tons

gpm (water) = (tons x 24) / delta-T

gpm = (150 tons x 24) / 12 degrees = 300 gpm

Fluid flow (40% EG solution):

300 gpm (water) x 1.121 flow correction factor = 336 gpm (ethylene glycol)

6. Determine the evaporator pressure drop. Using Figure 3, enter at 300 gpm (water) and follow to the ALS 171C line intersect. Read horizontally to obtain an evaporator

pressure drop of 8.4 ft.

7. Correct the pressure drop for 40% EG solution:

8.4 ft x 1.263 pressure drop correction factor = 10.6 ft for ethylene glycol.

Performance Adjustment Factors

Ethylene and Propylene Glycol FactorsALS chiller units are designed to operate with leaving chilled fluid temperatures of 20.0Fto 60.0F (-6.7C to 15.5C). Leaving chilled fluid temperatures below 40 F (4.4C) resultin evaporating temperatures at or below the freezing point of water and a glycol solution isrequired. McQuay also recommends double insulation, and the system designer should determine its necessity. The use of glycol will reduce the performance of the unitdepending on its concentration. This should be taken into consideration during initialsystem design. On glycol applications the supplier normally recommends that a minimumof 25% solution by weight be used for protection against corrosion.

Alti tude Correction FactorsPerformance tables are based on sea level altitude. At elevations higher than sea level, the

performance of the unit will be decreased due to the lower air density. For performance atelevations other than sea level refer to Table 3.

Evaporator Temperature Drop FactorsPerformance tables are based on a 10 degree F (5.6 degree C) temperature drop through theevaporator. Other delta-Ts will require adjustment factors found in Table 3. Temperaturedrops outside a 6 to 16 degree F (3.3 to 8.9 degree C) range may adversely affect thesystem's capability to maintain acceptable control and are not recommended.

The maximum water temperature that can be circulated through the evaporator in a non-operating mode is 100F (37.8 C). High temperatures can result in poor performance and damage to the equipment.

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Fouling Factor Performance tables are based on water with a fouling factor of 0.0001 ft 2 x hr x F/BTU(0.0176 m 2 x C/kW) per ARI 550/590-98. As fouling is increased, performance decreases.For performance at other fouling factors refer to Table 3.

Foreign matter in the chilled water system will adversely affect the heat transfer capabilityof the evaporator and could increase the pressure drop and reduce the water flow. For optimum unit operation, proper water treatment and filtration must be maintained.

Table 1, Ethylene GlycolFreeze Poin t%

E.G. F CCapaci ty Power Flow PD

10 26 -3 0.991 0.996 1.013 1.07020 18 -8 0.982 0.992 1.040 1.12930 7 -14 0.972 0.986 1.074 1.18140 -7 -22 0.961 0.976 1.121 1.26350 -28 -33 0.946 0.966 1.178 1.308

Table 2, Propylene GlycolFreeze Poin t%

P.G. F CCapaci ty Power Fl ow PD

10 26 -3 0.987 0.992 1.010 1.06820 19 -7 0.975 0.985 1.028 1.14730 9 -13 0.962 0.978 1.050 1.24840 -5 -21 0.946 0.971 1.078 1.36650 -27 -33 0.929 0.965 1.116 1.481

Units operating with glycol are not included in the ARI Certification Program

Table 3, Correction FactorsChilled Water Fouling Factor

Delta-T 0.0001 (0.0176) 0.00025 (0.044) 0.00075 (0.132) 0.00175 (0.308) ALTITUDE

F C Cap. Power Cap. Power Cap. Power Cap. Power

6 3.3 0.992 0.995 0.985 0.993 0.962 0.986 0.919 0.972

8 4.4 0.995 0.997 0.988 0.995 0.965 0.988 0.922 0.974

10 5.6 1.000 1.000 0.993 0.998 0.970 0.991 0.927 0.977

12 6.7 1.005 1.002 0.998 1.000 0.975 0.993 0.932 0.97914 6.8 1.010 1.005 1.003 1.003 0.980 0.996 0.936 0.982

SEA

LEVEL

16 8.9 1.014 1.007 1.007 1.005 0.984 0.998 0.940 0.984

6 3.3 0.978 1.005 0.971 1.003 0.949 0.996 0.906 0.982

8 4.4 0.982 1.007 0.975 1.005 0.953 0.998 0.910 0.984

10 5.6 0.986 1.009 0.979 1.007 0.956 1.000 0.914 0.986

12 6.7 0.992 1.011 0.985 1.009 0.962 1.002 0.919 0.988

14 6.8 0.997 1.014 0.990 1.012 0.967 1.005 0.924 0.991

2000 feet(610 m)

16 8.9 1.000 1.016 0.993 1.014 0.970 1.007 0.927 0.993

6 3.3 0.966 1.016 0.959 1.014 0.937 1.007 0.895 0.993

8 4.4 0.969 1.018 0.962 1.016 0.940 1.009 0.898 0.995

10 5.6 0.973 1.021 0.966 1.019 0.944 1.012 0.902 0.998

12 6.7 0.978 1.025 0.971 1.023 0.949 1.016 0.906 1.002

14 6.8 0.982 1.027 0.975 1.025 0.953 1.018 0.910 1.004

4000 feet(1220 m)

16 8.9 0.986 1.028 0.979 1.026 0.956 1.019 0.914 1.005

6 3.3 0.953 1.025 0.946 1.023 0.924 1.016 0.883 1.002

8 4.4 0.955 1.028 0.948 1.026 0.926 1.019 0.885 1.005

10 5.6 0.959 1.031 0.952 1.029 0.930 1.022 0.889 1.008

12 6.7 0.963 1.034 0.956 1.032 0.934 1.024 0.893 1.011

14 6.8 0.968 1.036 0.961 1.034 0.939 1.026 0.897 1.013

6000 feet(1830 m)

16 8.9 0.972 1.037 0.965 1.035 0.943 1.027 0.901 1.014

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Performance Data

R-22, IP UnitsTable 4, ALS 141C ALS 218C

AMBIENT AIR TEMPERATUREALS LWT 75F 85F 95F 105F 115F

SIZE (F) Cap. PWR Cap. PWR Cap. PWR Cap. PWR Cap. PWR Tons kWi

EER Tons kWi

EER Tons kWi

EER Tons kWi

EER Tons kWi

EER

40.0 128.3 111.3 12.1 123.0 124.9 10.4 117.7 138.6 9.1 112.2 156.9 7.8 105.5 177.2 6.542.0 131.7 112.1 12.3 126.3 125.8 10.8 120.9 139.6 9.3 115.5 158.0 7.9 108.4 178.2 6.744.0 135.0 112.6 12.7 129.7 126.8 10.9 124.5 140.8 9.6 119.1 159.2 8.1 111.6 178.7 6.946.0 138.4 113.5 12.9 133.2 127.6 11.2 128.0 141.7 9.8 122.4 160.6 8.3 114.7 180.0 7.148.0 141.8 114.2 13.1 136.7 128.5 11.4 131.6 142.9 10.0 125.9 162.0 8.4 118.0 181.2 7.2

141C

50.0 144.7 115.1 13.3 140.0 129.8 11.6 135.2 144.6 10.2 129.4 163.6 8.6 121.6 182.3 7.440.0 143.9 126.1 12.1 137.9 141.5 10.5 132.1 156.9 9.1 126.0 177.8 7.8 118.4 200.8 6.542.0 147.7 126.9 12.3 141.8 142.4 10.8 135.7 158.1 9.3 129.5 179.0 7.9 121.6 201.7 6.744.0 151.5 127.6 12.7 145.5 143.5 11.0 139.7 159.4 9.6 133.7 180.3 8.1 125.3 202.4 6.946.0 155.3 128.5 12.9 149.5 144.5 11.2 143.7 160.6 9.8 137.3 181.8 8.3 128.7 203.8 7.148.0 159.1 129.3 13.3 153.3 145.6 11.4 147.5 161.9 10.0 141.3 183.5 8.4 132.4 205.1 7.2

150C

50.0 162.4 130.2 13.4 157.1 147.0 11.6 151.7 163.7 10.2 145.2 185.3 8.6 136.4 206.5 7.440.0 160.6 139.9 12.1 154.0 157.0 10.4 147.3 174.1 9.2 140.6 197.2 7.8 132.1 222.7 6.5

42.0 164.9 140.8 12.3 158.2 158.1 10.8 151.4 175.4 9.4 144.5 198.6 7.9 135.7 223.9 6.744.0 169.0 141.5 12.7 162.4 159.3 11.0 155.8 176.9 9.6 149.2 200.1 8.1 139.8 224.6 6.946.0 173.3 142.6 12.9 166.8 160.4 11.2 160.3 178.1 9.8 153.2 201.8 8.3 143.6 226.2 7.148.0 177.5 143.5 13.2 171.1 161.6 11.4 164.7 179.7 10.0 157.7 203.6 8.4 147.8 227.6 7.2

171C

50.0 181.2 144.6 13.3 175.3 163.1 11.6 169.2 181.7 10.2 162.1 205.6 8.6 152.3 229.0 7.340.0 175.2 154.3 12.1 168.0 173.1 10.4 160.7 191.9 9.1 153.3 217.4 7.8 144.1 245.5 6.542.0 179.8 155.2 12.3 172.5 174.3 10.8 165.2 193.4 9.3 157.7 218.9 7.9 148.1 246.8 6.744.0 184.4 156.0 12.7 177.2 175.6 10.9 170.0 195.0 9.6 162.7 220.6 8.1 152.5 247.5 6.946.0 189.0 157.2 12.9 182.0 176.8 11.2 174.9 196.4 9.8 167.1 222.4 8.3 156.7 249.3 7.148.0 193.7 158.2 13.1 186.7 178.1 11.4 179.6 198.0 10.0 171.9 224.5 8.4 161.2 250.9 7.2

186C

50.0 197.7 159.3 13.3 191.2 179.8 11.6 184.6 200.3 10.2 176.8 226.6 8.6 166.1 252.6 7.440.0 178.3 151.0 12.4 170.9 169.5 10.7 163.6 188.0 9.4 156.1 212.9 8.0 146.6 240.5 6.642.0 183.0 152.0 12.6 175.7 170.6 11.0 168.1 189.3 9.6 160.5 214.4 8.1 150.7 241.7 6.844.0 187.6 152.8 13.0 180.3 172.0 11.2 173.1 191.0 9.8 165.6 216.0 8.3 155.2 242.5 7.046.0 192.5 153.9 13.2 185.2 173.1 11.4 178.0 192.3 10.0 170.1 217.9 8.5 159.5 244.2 7.248.0 197.1 154.9 13.4 190.1 174.4 11.6 182.9 193.9 10.2 175.1 219.8 8.5 164.0 245.7 7.3

190C

50.0 201.3 156.0 13.5 194.6 176.1 11.8 187.9 196.1 10.4 179.9 221.9 8.7 169.1 247.4 7.540.0 189.9 163.8 12.3 182.0 183.8 10.6 174.2 203.8 9.3 166.2 230.8 7.9 156.1 260.7 6.642.0 194.8 164.8 12.5 186.9 185.0 10.9 178.9 205.3 9.5 170.8 232.4 8.0 160.4 262.0 6.844.0 199.8 165.7 12.8 191.9 186.5 11.1 184.2 207.1 9.7 176.3 234.2 8.2 165.3 262.9 6.946.0 204.8 166.9 13.0 197.0 187.7 11.3 189.4 208.6 9.9 181.0 236.2 8.4 169.7 264.7 7.148.0 209.8 168.0 13.3 202.2 189.1 11.5 194.6 210.2 10.1 186.3 238.3 8.5 174.6 266.4 7.2

200C

50.0 214.2 169.2 13.4 207.2 190.9 11.7 200.1 212.6 10.3 191.6 240.6 8.7 179.9 268.2 7.440.0 196.0 169.7 12.3 187.9 190.4 10.6 179.9 211.2 9.3 171.6 239.3 7.9 161.2 270.1 6.642.0 201.2 170.8 12.5 193.1 191.7 10.9 184.8 212.7 9.5 176.5 240.9 8.0 165.7 271.5 6.844.0 206.3 171.6 12.8 198.3 193.2 11.1 190.3 214.6 9.7 182.1 242.7 8.2 170.6 272.4 6.946.0 211.6 172.9 13.0 203.6 194.5 11.3 195.7 216.1 9.9 187.0 244.8 8.4 175.3 274.3 7.148.0 216.7 174.1 13.3 208.9 196.0 11.5 201.1 217.9 10.1 192.5 247.0 8.5 180.3 276.1 7.2

206C

50.0 221.2 175.3 13.4 213.9 197.9 11.7 206.7 220.4 10.3 197.8 249.3 8.7 185.9 277.9 7.440.0 210.7 176.0 12.4 202.0 197.5 10.7 193.3 219.1 9.4 184.4 248.2 8.0 173.3 280.2 6.642.0 216.2 177.2 12.6 207.5 198.9 11.0 198.6 220.7 9.6 189.6 249.8 8.1 178.0 281.7 6.8

44.0 221.7 178.1 13.0 213.0 200.4 11.2 204.4 222.6 9.8 195.6 251.7 8.3 183.4 282.6 7.046.0 227.3 179.4 13.2 218.7 201.8 11.4 210.3 224.2 10.0 201.0 253.9 8.5 188.3 284.6 7.248.0 232.9 180.6 13.4 224.5 203.3 11.6 216.1 226.1 10.2 206.8 256.2 8.5 193.8 286.4 7.3

218C

50.0 237.7 181.9 13.5 229.8 205.3 11.8 222.0 228.6 10.4 212.6 258.6 8.7 199.8 288.3 7.5NOTES:1. Rated in accordance with ARI Standard 550/590 . Shaded and bold ratings are certified in accordance with the ARI Water-Chilling P ackages Using the Vapor

Compression Cycle Certification Program, which is based on ARI Standard 550/590.2. Units with remote evaporators are not included in the ARI Certification Program.3. Ratings based on HCFC-22, evaporator fouling factor of 0.0001, 10 degree delta-T, evaporator flow of 2.4 gpm/ton and sea level altitude.4. For units with SpeedTrol option multiply capacity and EER by 0.99. For units operating at 208 volt, multiply capacity by 0.98.5. Interpolation is allowed, extrapolation is not permitted. Consult McQuay for performance outside the cataloged ratings.6. kW input is for compressors only. EE R is for the entire unit, including compressors, fan motors and control power. Total power to the unit can be calculated

by: kW =tons x 12 / EER7. Compressor loading and unloading is adaptively determined by system load, ambient air temperature, and other inputs to the MicroTech control algorithms.

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Part load Performance

Table 6, ALS 141C ALS 218C, R-22UnitSize % Load

Capacity Tons

PowerUnit kW EER IPLV

100.00 124.5 157.9 9.675.00 93.4 101.2 11.250.00 62.2 59.4 12.7141C25.00 31.2 25.8 14.6

12.3

100.00 139.7 176.7 9.675.00 104.7 113.3 11.250.00 69.8 66.5 12.7150C

25.00 34.9 28.9 14.7

12.3

100.00 155.8 195.6 9.675.00 116.9 125.4 11.250.00 77.9 73.5 12.7171C

25.00 39.0 31.9 14.6

12.4

100.00 170.0 215.7 9.675.00 127.5 138.3 11.250.00 85.0 81.1 12.7186C

25.00 42.5 35.2 14.6

12.3

100.00 173.1 212.7 9.875.00 129.8 136.3 11.450.00 86.5 80.0 13.0190C

25.00 43.3 34.7 14.9

12.5

100.00 184.2 228.8 9.775.00 138.1 146.7 11.350.00 92.1 86.0 12.8200C

25.00 46.0 37.4 14.7

12.4

100.00 190.3 236.3 9.775.00 142.7 151.4 11.350.00 95.1 88.9 12.8206C

25.00 47.6 38.6 14.7

12.4

100.00 204.4 251.2 9.875.00 153.3 161.1 11.450.00 102.2 94.4 13.0218C

25.00 51.1 41.1 14.9

12.5

NOTES:1. Certified in accordance with the ARI Water-Chilling Packages Using the Vapor Compression Cycle

Certification Program, which is based on ARI Standard 550/590.2. Units with remote evaporators are not included in the ARI Certification Program.3. Compressor unloading is adaptively determined by system load, ambient air temperature, and other

inputs to the MicroTech control algorithms.

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Pressure DropFigure 3, Evaporator Pressure Drop , ALS 141C - ALS 218C

ALS 141

ALS 206

ALS 150-200

ALS 218

Minimum/Maximum Flow Rates ALS

UnitSize

MinimumFlow gpm

PressureDrop ft.

NominalFlow gpm

PressureDrop ft.

MaximumFlow gpm

PressureDrop ft.

141 187 4.0 298.8 9.5 498 24.2150 209 4.2 335.3 10.5 559 28.5171 234 5.2 373.9 13.0 623 35.3186 255 6.1 408.0 15.4 680 41.9190 260 6.4 415.4 16.0 692 43.4200 276 7.2 442.1 18.0 737 49.0206 285 7.5 456.7 18.7 761 50.4218 307 5.0 490.6 13.1 818 36.8

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Sound DataSound levels can be as important as unit cost and efficiency, and must be addressed beforethe start of any project design. Efforts by McQuay design engineers to design chillers thatare sensitive to the sound requirements of the market, combined with McQuays inherentlyquiet rotary screw compressors, have paid off.

StandardsARI has established standards to provide uniform methods for the determination of thesound levels of equipment. For large air-cooled chillers it is ARI Standard 370, Sound

Ratings of Large Outdoor Refrigeration and Air-Conditioning Equipment.

Background InformationSound is a vibration in an elastic medium and is essentially a pressure and particledisplacement phenomena. A vibrating body produces compression waves and as the wavesare emitted from the vibrating body, molecules are ultimately compressed. These values aretransmitted through gases, liquids or solids-anything that is elastic or viscous.

The sound data provided in this section is presented with both sound pressure and sound power levels. Sound power is the total sound energy radiated by a source per unit of timeintegrated over the surface through which the sound is radiated. Sound power is acalculated quantity and cannot be measured directly like sound pressure. Sound power isnot dependent on the surrounding environment or distance from the source.

Sound pressure varies with the distance from the source and is dependent on itssurroundings. For example, a brick wall located 10 feet from a unit (two reflectingsurfaces, the roof and the wall) will affect the sound pressure measurements differently thana unit mounted on a roof with only one reflecting surface (the roof). Sound pressure ismeasured in decibels (dB), which is a dimensionless ratio (on a logarithmic scale) betweenmeasured sound pressure and a reference sound pressure level.

Sound Pressure Levels - Full LoadAll sound pressure tables give the overall "A" weighted sound pressure levels which are

considered typical of what may be measured in a hemispherical field with a hand held sound meter in the absence of any nearby reflective surfaces other than the ground itself.The sound pressure levels in Table 7 are measured at 30 feet from the side of the unit, at100% unit load, no reflecting walls (Q=2), and ARI conditions; 95F (35C) ambient air temperature and 54/44F (12/7C) chilled water temperatures.

Sound Power LevelsAcoustical consultants may require sound power octave band data to perform a detailed acoustical analysis. Sound measurements are taken over a prescribed area around the unitand the data is mathematically calculated to give the sound power in dB.

Table 7, Sound Pressure Octave Band Data, 60 HzUnit Octave Band & Center Frequency, Hz. Overall

Model 63 125 250 500 1000 2000 4000 8000 A-Weighted141 66 69 68 67 65 64 54 47 69150 66 69 68 68 65 64 54 47 70171 67 70 68 68 66 64 55 48 71186 68 71 69 67 67 64 56 49 72190 68 72 69 68 68 65 57 50 72200 70 73 70 69 69 66 58 51 73206 70 73 70 69 69 66 58 51 73218 71 74 71 70 70 67 59 52 74

Note: Data at:r=30 ft., .sound pressure at 30 feet (9.1 meters) from unitQ=2, unit on a flat roof or ground with no adjacent wall(s).

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Table 8, Sound Power Octave Band Data, 60 HzUnit Octave Band & Center Frequency, Hz. Overall

Model 63 125 250 500 1000 2000 4000 8000 A-Weighted141 93 96 95 94 92 91 81 74 96150 93 96 95 95 92 91 81 74 97171 94 97 95 95 93 91 82 75 98186 95 98 96 94 94 91 83 76 99190 95 99 96 95 95 92 84 77 99200 97 100 97 96 96 93 85 78 100206 97 100 97 96 96 93 85 78 100218 98 101 98 97 97 94 86 79 101

Note: Sound power octave band data, dB per ARI Standard 370.

Sound Reduction Due to Distance from a UnitThe distance between a source of sound and the location of the sound measurement

plays an important role in minimizing sound problems. The equation below can be used to calculate the sound pressure level at any distance if the sound power is known.Results for typical distances are tabulated in Table 9. Another way of determining theeffect of distance is to work from sound pressure only. Q, the directionality factor, isa dimensionless number that compensates for the type of sound reflection from thesource. For example, a unit sitting on a flat roof or ground with no other reflective

surfaces or attenuation due to grass, snow, etc., between source and receiver: Q=2.

Figure 4, "Q" Definition, Plan View, Unit Located in Center

Uniform Spherical RadiationQ=1 no reflecting surface

Uniform Hemispherical RadiationQ=2 single reflecting surface

Uniform Radiation over of sphereQ=4 two reflecting surfaces

Sound pressure can be calculated at any distance from the unit if the sound power isknown.

Lp=Lw-(20 log r) + (10 log Q) - .5

Lp = sound pressure r = distance from unit in feet

Lw = sound power Q = directionality factor

With Q=1, Unit suspended in space (theoretical condition), the equation simplifies to:

Lp = Lw (20)(log r) 0.5

With Q=2, for a unit sitting on a flat roof or ground with no adjacent vertical wall as areflective surface, the equation simplifies to:

Lp = Lw (20)(log r) + 2.5

With Q=4 for a unit sitting on a flat roof or ground with one adjacent vertical wall as areflective surface, the equation simplifies to:

Lp = Lw (20)(log r) + 5.5

The equations are reduced to table form in Table 9 for various distances and the twomost usual cases of Q type of location.

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Table 9, dB Conversion of Sound Power to Pressure for DistanceDB Reducti on from Sound Power at the Source to

Sound Pressure at Referenced DistanceDistance from Sound

Sourceft. (m) Q=2 Q=430 (9) 27.1 24.0

50 (15) 31.6 28.575 (23) 35.1 32.0

100 (30) 37.6 34.5150 (46) 41.1 38.0200 (61) 43.6 40.5300 (91) 47.6 44.0

Figure 5 gives the reduction in sound pressure due to distance.

Figure 5, Sound Pressure Attenuation Due to Distance from Unit

Air-Cooled Unit Orientation to Minimize SoundThe ALS chillers sound is directional in nature allowing the contractor/engineer to positionthe unit to minimize potential noise problems. Because the sound pressure levels are lower

at both ends of the unit than at the sides, the chiller should be oriented such that the control box end or end opposite the control box faces the direction where the lowest sound level isrequired.

The control box end provides an excellent acoustic barrier to the compressor sound as itcovers one full end of the unit. The sound pressure levels at the control box end will be 5dBA less than on the sides. On the end opposite the control box, the compressor sound is

blocked by the coil structure and evaporator and is naturally attenuated by distance as thecompressors are located approximately the length of the unit away from this end. Thesound pressure levels at the end opposite the control box will be 4 dBA less than on thesides.

Sound IsolationThe low sound level for the ALS screw chiller satisfies most customer requirements.However, there may be applications where even lower sound levels may be required. Themost effective isolation method is to locate the unit away from sound sensitive areas. Avoid locations beneath windows or between structures where normal operating sounds may beobjectionable. Isolating water lines, electrical conduit and the unit itself can reducestructurally transmitted sound. Wall sleeves and rubber isolated piping hangers can be used to reduce transmission of water or pump noise into occupied spaces, and flexible electricalconnections can be used to isolate sound through electrical conduit. Spring isolators are

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effective in reducing the low amplitude sound generated by screw compressors and can beused for unit isolation in sound sensitive areas.

Figure 6, Sound Directionality

Sound Pressure Levels, Low Ambient OperationUnit operation at a lower ambient temperature than 95F will also result in lower sound

pressure levels. The sound pressure level will decrease approximately 1 dBA for ambient

air temperatures between 85 F and 94 F, approximately 2 dBA for ambient air temperatures between 75 F and 84 F, and approximately 3 dBA for ambient air temperatures between65 F and 74 F.

Sound Pressure Levels, Multiple UnitsMultiple air-cooled unit installations will have a higher sound level than a single unit. Twounits will have approximately 3 dB higher sound level of one unit, 4 units will beapproximately 6 dB louder, and 8 units approximately 9 dB louder than one unit.

Sound Contro lWalls adjacent to a unit (20 feet {6.1meters} or less) will reflect sound outwards, increasing the sound

pressure on the side away from thewall. This sound increase could be ashigh as 3 dB for one wall and as highas 6 dB for a corner location. Unitorientation and/or distance as noted above will decrease sound levels.Sound levels can also be controlled by the installation of barrier walls. To be effective assound blockers, walls must be solid with no open penetrations. Sound tends to leak out of openings. Block walls with filler material and slots on the side facing the unit areespecially effective. The wall should be about 10 feet high (two feet higher than the unit)and located at least 10 feet away so as not to affect unit performance. A three-sided enclosure will be the most effective solution and will reduce sound levels by about 10 dB.Remember that the wall will increase the sound level on the side opposite it by 3 to 6 dB(one or three sided wall).

Note: The effect of adjacent walls on air recirculation and restriction must always beconsidered when employing sound barrier walls.

C

o

n

t

r

o

l

Compressor

Compressor

Sound pressure levels per Table 7

Sound pressure levels per Table 7

Sound pressure levelshere 4 dBA lower than Table 7

Sound pressure levelshere 5 dBA lower than Table 7 Evaporator

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Electr ical DataTable 10, ALS 141C ALS 218C, Electrical Data, Single-Point

POWER SUPPLY

FIELD WIRE HUB(Conduit Connection)

FIELD FUSE SIZE or HACR BREAKER SIZE

WIRE NOMINAL RECOM-

ALSUNITSIZE

VOLTS HZ

MINIMUMCIRCUIT

AMPACITY(MCA) QTY GAUGE QTY SIZE MENDED MAXIMUM

208 609 6 350 2 2.5 700 800230 558 6 300 2 2.5 700 700

141C 380 60 338 3 400 1 3.0 400 450460 278 3 300 1 2.5 350 350575 226 3 4/0 1 2.0 250 300208 686 6 500 2 3.0 800 800230 626 6 400 2 3.0 700 800

150C 380 60 379 3 500 1 3.0 450 500460 313 3 400 1 3.0 350 450575 252 3 250 1 2.5 300 350208 758 6 500 2 3.0 1000 1000230 693 6 500 2 3.0 800 800

171C 380 60 419 6 4/0 See Note 9 2 2.0 500 500460 346 3 500 1 3.0 400 450

575 277 3 300 1 2.5 350 350208 813 6 600 2 3.0 1000 1000230 742 6 500 2 3.0 1000 1000

186C 380 60 449 6 4/0 See Note 9 2 2.0 500 600460 370 3 500 1 3.0 450 500575 296 3 350 1 2.5 350 400208 825 6 600 2 3.0 1000 1000230 753 6 500 2 3.0 1000 1000

190C 380 60 456 6 4/0 See Note 9 2 2.0 600 600460 376 3 500 1 3.0 450 500575 301 3 350 1 2.5 350 400208* 869* 6 600* 2 3.0 1000 1200230 792 6 600 2 3.0 1000 1000

200C 380 60 480 6 250 2 2.5 600 600460 395 6 4/0 See Note 9 2 2.0 450 500

575 316 3 400 1 3.0 350 400208* 869* 6 600* 2 3.0 1000 1200230 792 6 600 2 3.0 1000 1000

206C 380 60 480 6 250 2 2.5 600 600460 395 6 4/0 See Note 9 2 2.0 450 500575 316 3 400 1 3.0 350 400208* 897* 6 600* 2 3.0 1000 1200230 812 6 600 2 3.0 1000 1000

218C 380 60 489 6 250 2 2.5 600 600460 406 6 4/0 See Note 9 2 2.0 450 500575 326 3 400 1 3.0 400 450

Notes1. (*) Table based on 75C field wire except (*) which require 90 C field wire.2. A HACR breaker is a circuit breaker designed for use on equipment with multiple motors. It stands for Heating, Air Conditioning, Refrigeration.3. Complete notes are on page 29.

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Table 11, ALS 141C ALS 218C, Electrical Data, Multiple-PointELECTRICAL CIRCUIT 1 (COMP 1) ELECTRICAL CIRCUIT 2 (COMP 2)

POWER SUPPLYFIELD

FUSINGPOWER SUPPLY FIELD FUSING

FIELD WIREHUB

ConduitConnection

FIELD WIREHUB

(ConduitConnection)

ALSUNITSIZE

VOLTS HZMINIMUMCIRCUIT AMPS(MCA)

QTYWIRE

GAUGEQTY

HUBSIZE

RECFUSESIZE

MAXFUSESIZE

MINIMUMCIRCUIT AMPS(MCA)

QTYWIRE

GAUGEQTY

HUBSIZE

RECFUSESIZE

MAXFUSESIZE

208 335 3 400 1 3.0 400 500 335 3 400 1 3.0 400 500

230 307 3 350 1 2.5 400 500 307 3 350 1 2.5 400 500

141C 380 60 186 3 3/0 1 2.0 225 300 186 3 3/0 1 2.0 225 300

460 153 3 2/0 1 1.5 200 250 153 3 2/0 1 1.5 200 250

575 124 3 1 1 1.5 150 200 124 3 1 1 1.5 150 200

208 335 6 4/0 2 2.0 400 500 412 6 4/0 2 2.0 500 700

230 307 3 350 1 2.5 400 500 375 3 500 1 3.0 450 600

150C 380 60 186 3 3/0 1 2.0 225 300 227 3 4/0 1 2.0 300 350

460 153 3 2/0 1 1.5 200 250 188 3 3/0 1 2.0 225 300

575 124 3 1 1 1.5 150 200 150 3 1/0 1 1.5 200 250

208 417 6 4/0 2 2.0 500 700 417 6 4/0 2 2.0 500 700

230 381 6 3/0 2 2.0 450 600 381 6 3/0 2 2.0 450 600171C 380 60 230 3 4/0 1 2.0 300 350 230 3 4/0 1 2.0 300 350

460 191 3 3/0 1 2.0 225 300 191 3 3/0 1 2.0 225 300

575 153 3 2/0 1 1.5 200 250 153 3 2/0 1 1.5 200 250

208 417 6 4/0 2 2.0 500 700 472 6 250 2 2.5 600 800

230 381 6 3/0 2 2.0 450 600 430 6 4/0 2 2.0 500 700

186C 380 60 230 3 4/0 1 2.0 300 350 260 3 300 1 2.5 350 450

460 191 3 3/0 1 2.0 225 300 214 3 4/0 1 2.0 300 350

575 153 3 2/0 1 1.5 200 250 171 3 2/0 1 1.5 225 250

208 423 6 4/0 2 2.0 500 700 478 6 250 2 2.5 600 800

230 387 6 3/0 2 2.0 500 600 436 6 4/0 SeeNote 9 2 2.0 600 700

190C 380 60 234 3 250 1 2.5 300 400 264 3 300 1 2.5 350 450

460 193 3 3/0 1 2.0 250 300 217 3 4/0 1 2.0 300 350

575 155 3 2/0 1 1.5 200 250 174 3 2/0 1 1.5 225 300

208 478 6 250 2 2.5 600 800 478 6 250 2 2.5 600 800

230 436 6 4/0 2 2.0 600 700 436 64/0 SeeNote 9 2 2.0 600 700

200C 380 60 264 3 300 1 2.5 350 450 264 3 300 1 2.5 350 450

460 217 3 4/0 1 2.0 300 350 217 3 4/0 1 2.0 300 350

575 174 3 2/0 1 1.5 225 300 174 3 2/0 1 1.5 225 300

208 478 6 250 2 2.5 600 800 478 6 250 2 2.5 600 800

230 436 6 4/0 SeeNote 9 2 2.0 600 700 436 64/0 SeeNote 9 2 2.0 600 700

206C 380 60 264 3 300 1 2.5 350 450 264 3 300 1 2.5 350 450

460 217 3 4/0 1 2.0 300 350 217 3 4/0 1 2.0 300 350

575 174 3 2/0 1 1.5 225 300 174 3 2/0 1 1.5 225 300

208 492 6 250 2 2.5 600 800 492 6 250 2 2.5 600 800

230 445 64/0 SeeNote 9 2 2.0 600 700 445 6

4/0 SeeNote 9 2 2.0 600 700

218C 380 60 269 3 300 1 2.5 350 450 269 3 300 1 2.5 350 450

460 223 3 4/0 1 2.0 300 350 223 3 4/0 1 2.0 300 350

575 179 3 3/0 1 2.0 225 300 179 3 3/0 1 2.0 225 300NOTE:1. Table based on 75C field wire2. Complete notes are on page 29

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Table 12, ALS141C ALS 218C, Compressor and Condenser Fan Motor Amp DrawRATED LOAD AMPS L R A SOLID-STATE STARTING INRUSH

AMPS PER COMPRESSOR ALSUNITSIZE

VOLTS HZCIRCUIT #1 CIRCUIT #2

FANMOTORS

FLA(EACH)

NO OFFAN

MOTORS

FANMOTORS(EACH) CIRCUIT #1 CIRCUIT #2

208 245 245 5.8 10 23.7 735 735230 222 222 5.8 10 21.4 666 666

141C 380 60 135 135 3.4 10 14.4 405 405460 111 111 2.8 10 10.7 333 333

575 90 90 2.3 10 11.5 270 270208 245 306 5.8 10 23.7 735 918230 222 277 5.8 10 21.4 666 831

150C 380 60 135 168 3.4 10 14.4 405 504460 111 139 2.8 10 10.7 333 417575 90 111 2.3 10 11.5 270 333208 306 306 5.8 12 23.7 918 918230 277 277 5.8 12 21.4 831 831

171C 380 60 168 168 3.4 12 14.4 504 504460 139 139 2.8 12 10.7 417 417575 111 111 2.3 12 11.5 333 333208 306 350 5.8 12 23.7 918 918230 277 316 5.8 12 21.4 831 831

186C 380 60 168 192 3.4 12 14.4 504 504460 139 158 2.8 12 10.7 417 417575 111 126 2.3 12 11.5 333 333208 306 350 5.8 14 23.7 918 1050230 277 316 5.8 14 21.4 831 948

190C 380 60 168 192 3.4 14 14.4 504 576460 139 158 2.8 14 10.7 417 474575 111 126 2.3 14 11.5 333 378208 350 350 5.8 14 23.7 1050 1050230 316 316 5.8 14 21.4 948 948

200C 380 60 192 192 3.4 14 14.4 576 576460 158 158 2.8 14 10.7 474 474575 126 126 2.3 14 11.5 378 378208 350 350 5.8 14 23.7 1050 1050230 316 316 5.8 14 21.4 948 948

206C 380 60 192 192 3.4 14 14.4 576 576460 158 158 2.8 14 10.7 474 474575 126 126 2.3 14 11.5 378 378

208 350 350 7.8 14 30.5 1050 1050230 316 316 7.2 14 27.6 948 948

218C 380 60 192 192 4.1 14 20.0 576 576460 158 158 3.6 14 13.8 474 474575 126 126 3.0 14 11.5 378 378

NOTE: Complete notes are on page 29

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Table 13, ALS 141C ALS 218C, Customer Wiring Information With Single-Point Power

WIRING TO STANDARD UNIT POWER BLOCK WIRING TO OPTIONAL NONFUSEDDISCONNECT SWITCH IN UNIT ALSUNITSIZE

VOLTS HZTERMINAL SIZE

AMPS

CONNECTOR WIRE RANGEPER PHASE

(COPPER WIRE ONLY)SIZE

CONNECTOR WIRE RANGEPER PHASE

(COPPER WIRE ONLY)

208 840 (2) 2 to 600 MCM 800 (3) 3/0 to 400 MCM230 840 (2) 2 to 600 MCM 600 (2) 250 to 350 MCM

141C 380 60 840 (2) 2 to 600 MCM 400 (1) 250 to 500 MCM460 840 (2) 2 to 600 MCM 400 (1) 250 to 500 MCM575 840 (2) 2 to 600 MCM 250 (1) 4 to 350 MCM208 840 (2) 2 to 600 MCM 800 (2) 500 to 700 MCM230 840 (2) 2 to 600 MCM 800 (3) 3/0 to 400 MCM

150C 380 60 840 (2) 2 to 600 MCM 400 (1) 250 to 500 MCM460 840 (2) 2 to 600 MCM 400 (1) 250 to 500 MCM575 840 (2) 2 to 600 MCM 400 (1) 250 to 500 MCM208 840 (2) 2 to 600 MCM 800 (2) 500 to 700 MCM230 840 (2) 2 to 600 MCM 800 (2) 500 to 700 MCM





206C 380 60 840 (2) 2 to 600 MCM 600 (2) 250 to 350 MCM

460 840 (2) 2 to 600 MCM 600 (2) 250 to 350 MCM575 840 (2) 2 to 600 MCM 400 (1) 250 to 500 MCM208 950 (2) 2 to 750 MCM 1200 (3) 500 to 750 MCM230 840 (2) 2 to 600 MCM 1200 (3) 500 to 750 MCM

218C 380 60 840 (2) 2 to 600 MCM 600 (2) 250 to 350 MCM460 840 (2) 2 to 600 MCM 600 (2) 250 to 350 MCM575 840 (2) 2 to 600 MCM 400 (1) 250 to 500 MCM

NOTE:1. Terminal size amps are the maximum amps that the power block is rated for.2. Complete notes are on page 29.

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Table 14, ALS 141CALS 218C, Wiring Information with Multiple-Point Power w/o DisconnectWIRING TO UNIT POWER BLOCK

TERMINAL SIZE (AMPS) CONNECTOR WIRE RANGE PER PHASE (COPPER WIRE ONLY) ALSUNITSIZE

VOLTS HZCKT 1 CKT 2 CKT 1 CKT 2

208 840 840 (2) #2 to 600 MCM (2) #2 to 600 MCM230 840 840 (2) #2 to 600 MCM (2) #2 to 600 MCM

141C 380 60 840 840 (2) #2 to 600 MCM (2) #2 to 600 MCM460 840 840 (2) #2 to 600 MCM (2) #2 to 600 MCM575 840 840 (2) #2 to 600 MCM (2) #2 to 600 MCM


150C 380 60 840 840 (2) #2 to 600 MCM (2) #2 to 600 MCM

460 840 840 (2) #2 to 600 MCM (2) #2 to 600 MCM

575 840 840 (2) #2 to 600 MCM (2) #2 to 600 MCM

208 840 840 (2) #2 to 600 MCM (2) #2 to 600 MCM

230 840 840 (2) #2 to 600 MCM (2) #2 to 600 MCM

171C 380 60 840 840 (2) #2 to 600 MCM (2) #2 to 600 MCM

460 840 840 (2) #2 to 600 MCM (2) #2 to 600 MCM

575 840 840 (2) #2 to 600 MCM (2) #2 to 600 MCM

208 840 840 (2) #2 to 600 MCM (2) #2 to 600 MCM

230 840 840 (2) #2 to 600 MCM (2) #2 to 600 MCM

186C 380 60 840 840 (2) #2 to 600 MCM (2) #2 to 600 MCM


208 840 840 (2) #2 to 600 MCM (2) #2 to 600 MCM

230 840 840 (2) #2 to 600 MCM (2) #2 to 600 MCM

190C 380 60 840 840 (2) #2 to 600 MCM (2) #2 to 600 MCM

460 840 840 (2) #2 to 600 MCM (2) #2 to 600 MCM

575 840 840 (2) #2 to 600 MCM (2) #2 to 600 MCM

208 840 840 (2) #2 to 600 MCM (2) #2 to 600 MCM

230 840 840 (2) #2 to 600 MCM (2) #2 to 600 MCM

200C 380 60 840 840 (2) #2 to 600 MCM (2) #2 to 600 MCM

460 840 840 (2) #2 to 600 MCM (2) #2 to 600 MCM

575 840 840 (2) #2 to 600 MCM (2) #2 to 600 MCM

208 840 840 (2) #2 to 600 MCM (2) #2 to 600 MCM

230 840 840 (2) #2 to 600 MCM (2) #2 to 600 MCM

206C 380 60 840 840 (2) #2 to 600 MCM (2) #2 to 600 MCM460 840 840 (2) #2 to 600 MCM (2) #2 to 600 MCM

575 840 840 (2) #2 to 600 MCM (2) #2 to 600 MCM

208 840 840 (2) #2 to 600 MCM (2) #2 to 600 MCM

230 840 840 (2) #2 to 600 MCM (2) #2 to 600 MCM

218C 380 60 840 840 (2) #2 to 600 MCM (2) #2 to 600 MCM460 840 840 (2) #2 to 600 MCM (2) #2 to 600 MCM575 840 840 (2) #2 to 600 MCM (2) #2 to 600 MCM

NOTES:1. Terminal size amps are the maximum amps that the power block is rated for.2. See Table 15 f or multiple point with Disconnect Switch connections.3. Complete notes are on page 29.

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Table 15, ALS 141C 218C, Wiring Data with Mul tip le-Point Power w / Disconnect SwitchWIRING TO UNIT DISCONNECT SWITCH

TERMINAL SIZE (AMPS) CONNECTOR WIRE RANGE PER PHASE (COPPER WIRE ONLY) ALSUNITSIZE

VOLTS HZCKT 1 CKT 2 CKT 1 CKT 2

208 400 400 (1) 250 to 500 MCM (1) 250 to 500 MCM230 400 400 (1) 250 to 500 MCM (1) 250 to 500 MCM

141C 380 60 225 225 (1) 4 to 4/0 (1) 4 to 4/0460 150 150 (1) 4 to 4/0 (1) 4 to 4/0575 150 150 (1) 4 to 4/0 (1) 4 to 4/0

208 400 400 (2) 3/0 to 250 MCM (2) 3/0 to 250 MCM230 400 400 (1) 250 to 500 MCM (1) 250 to 500 MCM

150C 380 60 225 225 (1) 4 to 4/0 (1) 4 to 4/0

460 150 225 (1) 4 to 4/0 (1) 4 to 4/0

575 150 150 (1) 4 to 4/0 (1) 4 to 4/0

208 400 400 (2) 3/0 to 250 MCM (2) 3/0 to 250 MCM

230 400 400 (2) 3/0 to 250 MCM (2) 3/0 to 250 MCM

171C 380 60 225 225 (1) 4 to 4/0 (1) 4 to 4/0

460 225 225 (1) 4 to 4/0 (1) 4 to 4/0

575 150 150 (1) 4 to 4/0 (1) 4 to 4/0

208 400 600 (2) 3/0 to 250 MCM (2) 250 to 350 MCM

230 400 600 (2) 3/0 to 250 MCM (2) 250 to 350 MCM

186C 380 60 225 250 (1) 4 to 4/0 (1) 4 to 350 MCM

460 225 225 (1) 4 to 4/0 (1) 4 to 4/0575 150 225 (1) 4 to 4/0 (1) 4 to 4/0

208 400 600 (2) 3/0 to 250 MCM (2) 250 to 350 MCM

230 400 600 (2) 3/0 to 250 MCM (2) 250 to 350 MCM

190C 380 60 225 250 (1) 4 to 4/0 (1) 4 to 350 MCM

460 225 225 (1) 4 to 4/0 (1) 4 to 4/0

575 150 225 (1) 4 to 4/0 (1) 4 to 4/0

208 600 600 (2) 250 to 350 MCM (2) 250 to 350 MCM

230 600 600 (2) 250 to 350 MCM (2) 250 to 350 MCM

200C 380 60 250 250 (1) 4 to 350 MCM (1) 4 to 350 MCM

460 225 225 (1) 4 to 4/0 (1) 4 to 4/0

575 225 225 (1) 4 to 4/0 (1) 4 to 4/0

208 600 600 (2) 250 to 350 MCM (2) 250 to 350 MCM

230 600 600 (2) 250 to 350 MCM (2) 250 to 350 MCM

206C 380 60 250 250 (1) 4 to 350 MCM (1) 4 to 350 MCM460 225 225 (1) 4 to 4/0 (1) 4 to 4/0

575 225 225 (1) 4 to 4/0 (1) 4 to 4/0

208 600 600 (2) 250 to 350 MCM (2) 250 to 350 MCM

230 600 600 (2) 250 to 350 MCM (2) 250 to 350 MCM

218C 380 60 250 250 (1) 4 to 350 MCM (1) 4 to 350 MCM460 225 225 (1) 4 to 4/0 (1) 4 to 4/0575 225 225 (1) 4 to 4/0 (1) 4 to 4/0

NOTE:1. Terminal size amps are the maximum amps that the disconnect switch is rated for.2. Complete notes are on page 29.

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Physical Data

Table 16, Phys ical Data, ALS 141C ALS 186C ALS MODEL NUMBER

DATA 141C 150C 171C 186CCkt 1 Ckt 2 Ckt 1 Ckt 2 Ckt 1 Ckt 2 Ckt 1 Ckt 2

BASIC DATA

Unit Cap. @ ARI Conditions, tons (kW) 124.5 (436) 139.7 (489) 155.8 (545) 170 (595)Unit Operating Charge R-22, lbs (kg) 140 (63.5) 140 (63.5) 140 (63.5) 150 (68.1) 150 (68.1) 150 (68.1) 150 (68.1) 160 (72.6)

Cabinet DimensionsL x W x H, in. (mm)

228.7 x 83.4 x 92.5(5809 x 2118 x 2350)

228.7 x 83.4 x 92.5(5809 x 2118 x 2350)

228.7 x 83.4 x 92.5(5809 x 2118 x 2350)

228.7 x 83.4 x 92.5(5809 x 2118 x 2350)

Unit Operating Weight, lbs. (kg) 9700 (4395) 9880 (4475) 9890 (4480) 9900 (4485)Unit Shipping Weight, lbs (kg) 9420 (4270) 9550 (4325) 9560 (4330) 9570 (4335)

COMPRESSORS, SCREW, SEMI-HERMETICNominal Capacity, tons (kW) 65 (230) 65 (230) 65 (230) 80 (280) 80 (280) 80 (280) 80 (280) 95 (335)

CONDENSERS, HIGH EFFICIENCY FIN AND TUBE TYPE WITH INTEGRAL SUBCOOLERCoil Face Area, ft. (m 2) 115.6 (10.7) 115.6 (10.7) 115.6 (10.7) 115.6 (10.7) 115.6 (10.7) 115.6 (10.7) 115.6 (10.7) 115.6 (10.7)

Finned Height x Finned Lengthft. (mm)

80 x 208(2032 x 5283)

80 x 208(2032 x 5283)

80 x 208(2032 x 5283)

80 x 208(2032 x 5283)

80 x 208(2032 x 5283)

80 x 208(2032 x 5283)

80 x 208(2032 x 5283)

80 x 208(2032 x 5283)

Fins Per Inch x Rows Deep 16 x 3 16 x 3 16 x 3 16 x 3 16 x 3 16 x 3 16 x 3 16 x 3CONDENSER FANS, DIRECT DRIVE PROPELLER TYPENo. of Fans -- Fan Diameter, in. (mm) 10 - 28 (711) 10 - 28 (711) 12 - 28 (711) 12 - 28 (711)

No. of Motors -- hp (kW) 10 - 1.5 (1.1) 10 - 1.5 (1.1) 12 - 1.5 (1.1) 12 - 1.5 (1.1)Fan & Motor RPM, 60Hz 1140 1140 1140 1140

60 Hz Fan Tip Speed, fpm 8357 8357 8357 835760 Hz Total Unit Airflow, cfm 90200 90200 108240 108240

EVAPORATOR, DIRECT EXPANSIONShell Dia.-Tube Length

in.(mm) - in. (mm)12.75 94.6(324 - 2403)

14.0 95.5(356 - 2425)

14.0 95.5(356 - 2425)

14.0 95.5(356 - 2425)

Evaporator R-22 Charge lbs (kg) 34 (15.4) 34 (15.4) 45 (20.4) 45 (20.4) 45 (20.4) 45 (20.4) 45 (20.4) 45 (20.4)Water Volume, gallons (liters) 34 (129) 40 (151) 40 (151) 40 (151)

Max. Water Pressure, psi (kPa) 152 (1048) 152 (1048) 152 (1048) 152 (1048)Max. Refrigerant Pressure, psi (kPa) 300 (2068) 300 (2068) 300 (2068) 300 (2068)

Table 17, Phys ical Data, ALS 190C ALS 218C ALS MODEL NUMBER

DATA 190C 200C 206C 218CCkt 1 Ckt 2 Ckt 1 Ckt 2 Ckt 1 Ckt 2 Ckt 1 Ckt 2

BASIC DATAUnit Cap. @ ARI Conditions, tons (kW) 173.1 (606) 184.2 (645) 190.3 (666) 204.4 (715)

Unit Operating Charge R-22, lbs (kg) 170 (77.0) 180 (81.5) 180 (81.5) 180 (81.5) 185 (83.8) 185 (83.8) 210 (95.1) 210 (95.1)Cabinet Dimensions,L x W x H, in. (mm)

263.4 x 83.4 x 92.5(6690 x 2118 x 2350)

263.4 x 83.4 x 92.5(6690 x 2118 x 2350)

263.4 x 83.4 x 92.5(6690 x 2118 x 2350)

263.4 x 83.4 x 92.5(6690 x 2118 x 2350)

Unit Operating Weight, lbs. (kg) 10620 (4810) 10630 (4815) 10960 (4965) 11550 (5230)Unit Shipping Weight, lbs (kg) 10290 (4660) 10300 (4665) 10500 (4755) 10730 (4860)

COMPRESSORS, SCREW, SEMI-HERMETICNominal Capacity, tons (kW) 80 (280) 95 (335) 95 (335) 95 (335) 95 (335) 95 (335) 95 (335) 95 (335)

CONDENSERS, HIGH EFFICIENCY FIN AND TUBE TYPE WITH INTEGRAL SUBCOOLERCoil Face Area, ft. (m 2) 135.0 (12.5) 135.0 (12.5) 135.0 (12.5) 135.0 (12.5) 135.0 (12.5) 135.0 (12.5) 135.0 (12.5) 135.0 (12.5)

Finned Height x Finned Lengthft. (mm)

80 x 243(2032 x 6172)

80 x 243(2032 x 6172)

80 x 243(2032 x 6172)

80 x 243(2032 x 6172)

80 x 243(2032 x 6172)

80 x 243(2032 x 6172)

80 x 243(2032 x 6172)

80 x 243(2032 x 6172)

Fins Per Inch x Rows Deep 16 x 3 16 x 3 16 x 3 16 x 3 16 x 3 16 x 3 16 x 3 16 x 3CONDENSER FANS, DIRECT DRIVE PROPELLER TYPENo. of Fans -- Fan Diameter, in. (mm) 14 - 28 (711) 14 - 28 (711) 14 - 28 (711) 14 - 28 (711)

No. of Motors -- hp (kW) 14 - 1.5 (1.1) 14 - 1.5 (1.1) 14 - 1.5 (1.1) 14 - 2.0 (1.5)

Fan & Motor RPM, 60Hz 1140 1140 1140 114060 Hz Fan Tip Speed, fpm 8357 8357 8357 835760 Hz Total Unit Airflow, cfm 126280 126280 126280 138908

EVAPORATOR, DIRECT EXPANSIONShell Dia. -- Tube Length

in.(mm) - in. (mm)14.0 95.5(356 - 2425)

14.0 95.5(356 - 2425)

16.0 96.8(406 - 2459)

20.0 99.7(508 -2532)

Evaporator R-22 Charge lbs (kg) 45 (20.4) 45 (20.4) 45 (20.4) 45 (20.4) 57 (25.8) 57 (25.8) 68 (30.8) 68 (30.8)Water Volume, gallons (liters) 40 (151) 40 (151) 55 (208) 98 (371)

Max. Water Pressure, psi (kPa) 152 (1048) 152 (1048) 152 (1048) 152 (1048)Max. Refrigerant Pressure, psi (kPa) 300 (2068) 300 (2068) 300 (2068) 300 (2068)

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Figure 9, ALS141C ALS186C Lifting and Mounting Locations

M1

M2

M3

M4

M5

M6

L1

L2

L3

L4

C O N

T R O L

B O X

36 (914)102 (2591)

192 (4877)

46 (1168)161 (4089)

2 (51) Typical Spacingfor IsolatorMounting (6)

83.4(2118)

Lifting Weight for Each Pointlb (kg)

Mounting Loads for Each Pointlb. (kg)ALS

Model L1 & L2 L3 & L4 M1 & M2 M3 & M4 M5 & M6

Operating Wtlb. (kg)

Shipping Wt.lb. (kg)

Copper FinAdd

141 2585 (1171) 2125 (963) 1835 (831) 1785 (809) 1230 (557) 9700 (4394) 9420 (4267) 1370 (620)

150 2570 (1164) 2205 (999) 1830 (829) 1805 (818) 1305 (591) 9880 (4476) 9550 (4326) 1370 (620)171 2570 (1164) 2210 (1001) 1830 (829) 1810 (820) 1305 (591) 9890 (4472) 9560 (4331) 1370 (620)

186 2575 (1166) 2210 (1001) 1830 (829) 1810 (820) 1310 (593) 9900 (4485) 9570 (4335) 1370 (620)

NOTES:

1. 2 in. (63.5 mm) lifting holes at location "L" on side of base rail.

2. 1 in. (25.4 mm) mounting holes at location "M" on bottom of base rail.

Figure 10, ALS190C - ALS218C Lifting and Mounting Locations

L1 L3

L2 L4

M1

M2

M3

M4

M5

M6

C O N T R O L

B O X

36 (914)123 (3124)

224 (5690)

46 (1168)195 (4953)

2 (51) Typical Spacingfor Isolator

Mounting (6)

83.4(2118)

Lifting Weight for Each Pointlb (kg)

Mounting Loads for Each Pointlb. (kg)ALS

Model L1 & L2 L3 & L4 M1 & M2 M3 & M4 M5 & M6

Operating Wtlb. (kg)

Shipping Wt.lb. (kg)

Copper FinAdd

190 2915 (1320) 2230 (1010) 2010 (910) 2135 (967) 1165 (527) 10620 (4811) 10290 (4661) 1610 (730)

200 2920 (1323) 2230 (1010) 2015 (913) 2135 (967) 1165 (527) 10630 (4815) 10300 (4666) 1610 (730)

206 2940 (1332) 2310 (1046) 2000 (906) 2240 (1015) 1240 (562) 10960 (4965) 10500 (4756) 1610 (730)

218 2960 (1341) 2405 (1089) 1985 (899) 2425 (1098) 1365 (618) 11550 (5232) 10730 (4861) 1610 (730)

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Installation and Application

RiggingCare must be taken to avoid dropping the unit during unloading or moving as this can resultin serious property damage and personal injury. Do not push or pull the unit from anything

other than the base, and block the forklift away from the unit to prevent damage to the sheetmetal cabinet and end frame. Do not lift the unit with a fork lift truck. To lift the unit, two(or three or four depending on unit size) 2 1/2 inch (65mm) diameter lifting holes are

provided on each side in the base of the unit. Lengthwise and crosswise spreader bars must be used between rigging lines to prevent damage to the condenser coils or unit cabinet and to keep the lines coming up from the rigging holes to the spreaders vertical.

Unit PlacementFor roof mounted applications, the unit must be installed on a steel channel or I-beam frameto support the unit above the roof. For ground level applications, the unit must be installed on a substantial base that will not settle. McQuay recommends a one piece concrete slabwith footings extended below the frost line, and the installation engineer should determineits necessity. The foundation must be level within 1/2 inch (13mm) over its length and width and strong enough to support the unit's operating weight as listed in the Physical Datatables.

On ground level applications fin protection against vandalism is recommended, either bythe optional factory installed condenser coil guard or a field installed screen fence. Notethat the fence must allow free flow of air to the condenser coil for proper unit operation.

ClearancesAir-cooled units require free air flow to and from the condenser coils. Units should beinstalled per the listed installation clearances. There must be no obstructions above thefan discharge that may cause air recirculation. Air restriction and recirculation can cause

high pressure trips and will reduce capacity, efficiency, and compressor life. Do not installductwork on condenser fans. Structures, other equipment, fencing, plants, and trees must be considered for air flow interference. Ventilators and any sources of contaminated or heated discharges gases and air will affect system performance. Pit type installation mustmeet McQuays requirements.

Service AccessEach end of the unit must be accessible after installation for periodic service work.Compressors, filter-driers, and manual liquid line shutoff valves must be accessible on eachside of the unit adjacent to the control box. High pressure and low pressure transducers aremounted on the compressor. The cooler barrel heater thermostat is located on the cooler.Compressor overloads, microprocessor, and most other operational, safety and startingcontrols are located in the unit control box.

The electric disconnect switch should be mounted adjacent to the unit but not directly onunit sheet metal components.

On all ALS units the condenser fans and motors can be removed from the top of the unit.The complete fan/motor assembly can be removed for service. The fan blade and fan motor rain shield must be removed for access to wiring terminals at the top of the motor.

Consult minimum clearance requirement drawings on the following pages for equipmentspace layout.

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Restr icted Air Flow

GeneralThe clearances required for design-life operation of ALS air-cooled condensers aredescribed in the previous section. Occasionally, these clearances cannot be maintained dueto site restrictions such as units being too close together or a fence or wall restricting

airflow, or both.Fortunately the McQuay ALS chillers have several features that can mitigate the penaltiesattributable to restricted airflow.

The condenser section is U shaped, as shown below. This allows inlet air for thesecoils to come in from either side. A vertical coil and its adjacent horizontal coil aremanifolded together to serve one compressor circuit. Every compressor always has itsown independent refrigerant circuit.

The MicroTech control is proactive in response to off-design conditions. In the caseof single or compounded influences restricting airflow to the unit, the microprocessor will act to keep the compressor(s) running (at reduced capacity) rather than allowing a

shut-off on high discharge pressure. The MicroTech control can be programmed to sequence the compressors in the most

advantageous way. For example, in the diagram shown below, it might be desirable to program circuit #1 to be the lag circuit (last circuit to reach full load) during periods of high ambient temperatures.

Figure 12, Coil and Fan Arrangement

The following sections discuss the most common situations of condenser air restriction and give capacity and power adjustment factors for each. Note that in unusually severeconditions, the MicroTech controller would adjust the unit operation to remain online untila less severe condition is reached.

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Case 1, Building or Wall on One Side of One UnitThe existence of a screening wall or the wall of a building in close proximity to an air-cooled chiller is common in both rooftop and ground level applications. Hot air recirculation on the coils adjoining the wall will increase compressor discharge pressure,decreasing capacity and increasing power consumption. Only the compressor(s) connected to these coils will be affected. Circuits opposite the wall are unaffected.

When close to a wall, it is desirable to place chillers on the North or East side of them. It isalso desirable to have prevailing winds blowing parallel to the units long axis. The worstcase is to have wind blowing hot discharge air into the wall.

Figure 13, Unit Adjacent to Wall

Figure 14, Adjus tment Factors

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Case 2, Two Units Side By SideTwo or more units sited side by side are common. If spaced closer than 12 feet (3.7 meters)it is necessary to adjust the performance of each unit; circuits adjoining each other areaffected. NOTE: This case applies only to two units side by side. See Case 3 for three or more parallel units. If one of the two units also has a wall adjoining it, see Case 1. Add thetwo adjustment factors together and apply to the unit located between the wall and the other unit.

Mounting units end to end will not necessitate adjusting performance. Depending on theactual arrangement, sufficient space must be left between the units for access to the control

panel door opening and/or evaporator tube removal. See Clearance section of this guidefor requirements for specific units.

Pit or solid wall surrounds should not be used where the ambient air temperature exceeds105 F (40 C).

Figure 15, Two Units Side by Side

Figure 16, Adjustment Factor

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Case 3, Three or More Units Side By SideWhen three or more units are side by side, the outside chillers (1 and 3 in this case) areinfluenced by the middle unit only on their inside circuits. Their adjustment factors will bethe same as Case 2. All inside units (only number 2 in this case) are influenced on bothsides and must be adjusted by the factors shown below.

Figure 17, Three or More Units

Figure 18, Adjus tment Factor

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Case 4, Open Screening WallsDecorative screening walls are often used to help conceal a unit either on grade or on arooftop. These walls should be designed such that the combination of their open area and distance from the unit do not require performance adjustment. It is assumed that the wallheight is equal to or less than the unit height when mounted on its base support. This isusually satisfactory for concealment. If the wall height is greater than the unit height, seeCase 5, Pit Installation.

The distance from the ends of the unit to the end walls should be sufficient for service,opening control panel doors, and pulling evaporator tubes, as applicable.

If each side wall is a different distance from the unit, the distances can be averaged providing either wall is not less than 8 feet (2.4 meters) from the unit. For example, do notaverage 4 feet and 20 feet to equal 12 feet.

Figure 19, Open Screening Walls

Figure 20, Wall Free Area vs Distance

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Case 5, Pit/Solid Wall Ins tallationPit installations can cause operating problems and great care should be exercised if they areto be used on an installation. Recirculation and restriction can both occur. A solid wallsurrounding a unit is substantially the same as a pit and the data presented here should beused.

Steel grating is sometimes used to cover a pit to prevent accidental falls or trips into the pit..

The grating material and installation design must be strong enough to prevent suchaccidents, yet provide abundant open area or serious recirculation problems will occur.Have any pit installation reviewed by McQuay application engineers prior to installation tomake sure it has sufficient air-flow characteristics. The installation design engineer mustapprove the work to avoid an unreasonable risk of accident.

Figure 21, Pit Installation

Figure 22, Adjus tment Factor

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Chilled Water Systems

McQuay requires that chilled water piping for its chillers be designed and installed inconformance with the system recommendations described in (American Society of HeatingRefrigeration and Air-Conditioning Engineers, Inc.) ASHRAE Handbooks. Specificallythe 1996 Edition, HVAC Systems & Equipment, Chapter 12.

Multiple UnitsChillers are frequently installed in multiple. Doing so provides standby reliability and improved performance, and is recommended. Multiplicity of machines however can resultin unexpected problems where chiller controls or capacity reduction are overlooked in thedesign. Single chiller installations are equally susceptible to application oversight. Thefollowing offers supplemental information to that discussed in ASHRAE for the purpose of minimizing installation problems.

Water FlowChilled water systems are normally designed with leaving chilled water temperatures of 40F to 46F (5 C to 8 C), a 10 degree F (6 degree C) water temperature difference and 0.0001 fouling factor. Catalog performance tables display data for the chillers at theseconditions. Actual design may be different, and Product Manuals include adjustmentfactors or special rating tables to account for other conditions.

1. Addition of secondary coolants such as ethylene glycol

2. Variances from 10 degree F (6 degree C) water temperature differences

3. More than standard water fouling

4. Elevation and ambient air temperatures

Specifications and start-up procedures should:

1. Confirm that the chilled water piping system had been properly flushed out before being connected to the chiller vessel.

2. Confirm that the piping contains

a) A cleanable strainer at the evaporator inlet to remove impurities before they reachthe chiller vessel

b) An expansion tank in the piping, and

c) An air vent located at the system high point to purge trapped air in the pipingsystem. An air vent is also located at the top of the direct expansion chiller vesseland in the water head of a flooded vessel evaporator or condenser. Note: Theevaporator will not provide venting and must not be the high point in the system.

All water systems include air in solution with the water. The percentage of air that can beretained in solution is a function of the water temperature and water pressure. Since thesetwo values change in both chilled and hot water systems, the presence of both b and ccomponents listed above are vital to the successful operation of the system.

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The presence of a cleanable filter or strainer (2a above) in a chilled water piping system isfrequently taken for granted. The fact is that the filter or strainer may be inadequate for theinstallation or may be installed in the wrong location.

1. If the chilled water pump is located in the chilled water piping exiting the chiller vessel(down stream of the chiller), and the strainer is in its normal position ahead of thechilled water pump, then system impurities will be drawn, unfiltered through the chiller vessel. Severe reduction in chiller performance or damage to the evaporator tubes is

the probable result.2. Many chiller installations today are replacements for older less efficient machines or

chillers with CFC refrigerants. Existing piping is drained down, opened to atmosphere,and reconnected to the new chiller vessel. Rust formed over the years and during thereplacement process can break loose, pass through a conventional strainer, and settle inthe chiller vessel that is frequently the lowest point in the piping system. Not only is ahigher capacity filter required for these installations, but chemical treatment of thewater is recommended immediately and should be maintained throughout theequipment life.

Figure 23, Typical Chilled Water Piping

Protect all f ield pipingagainst freezing

VibrationEliminator

VibrationEliminator

FlowSwitch

Balancingvalve

Gate valveValved

pressuregauge

Waterstrainer

Gate valve

Vent

Outlet

Drain

Note: The cross piping for the pressure gauge can be as small as inch. The purpose of this arrangement is to provide an easymethod to use one gauge to accurately measure both pressures

Checking Water FlowThe simplest method of checking water flow in a clean system (the chiller vessel has not

been fouled nor is air bound), is to read the entering and leaving pressures and compare theactual pressure drop to the value published in the product catalog.

Pressure drops at the job are read in psi or feet of water (kPa). Published values aredisplayed in feet of water. Use the following formula to convert from one to another.

2.31 x PSI = Feet of water

or

Feet of water x 0.433 = PSI

System Water VolumeIt is important to have adequate water volume in the system to provide an opportunity for the chiller to sense a load change, adjust to the change and stabilize. As the expected load change becomes more rapid, a greater water volume is needed. The system water volume isthe total amount of water in the evaporator, air handling products and associated piping. If the water volume is too low, operational problems can occur including rapid compressor

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cycling, rapid loading and unloading of compressors, erratic refrigerant flow in the chiller,improper motor cooling, shortened equipment life and other undesirable occurrences.

For normal comfort cooling applications where the cooling load changes relatively slowly,we recommend a minimum system volume of seven minutes times the flow rate (GPM).For example, if the design chiller flow rate is 400 GPM, we recommend a minimum systemvolume of 2800 gallons (400 GPM x 7 minutes).

For process applications where the cooling load can change rapidly, additional system water volume is needed. A process example would be the cooling of hot metal objects. The load would be very stable until the hot metal is dipped into the water tank. Then, the load would increase drastically. For this type of application, we recommend the normal comfortcooling recommendation addressed above plus three minutes of ballast for every 10% quick change in load. For example, if the hot metal example load changes from a stable 50% load to an immediate 100% load for metal cooling, the recommended system volume would increase to 8800 gallons.

System volume = {400 GPM x 7 Minutes} + {(5 increment of 10% increase) x (3 Minutes)x 400 GPM} = 8800 Gallons

Since there are many other factors that can influence performance, systems maysuccessfully operate below these suggestions. However, as the water volume decreases

below these suggestions, the possibility of problems increases. We believe that theseguidelines should be an industry standard and not just recommendations from McQuay.

Freeze ProtectionMcQuay air-cooled chillers are equipped with thermostatically controlled heat tape under the insulation of the evaporator barrels. The heater comes from the factory connected to thecontrol power circuit but can be rewired to a separate 120V (110V, 50 Hz) supply. If this isdone, the disconnect switch should be clearly marked to avoid accidental deactivation of theheater during freezing temperatures. The heater will provide freeze protection to -20F(-29 C). However, this does not provide protection to the exposed chilled water piping.

Unless the evaporator is flushed and drained as described in note 4 two or more of thefollowing recommendations should be part of the system design and be implemented.

1. Continuous circulation of water through the piping and heat exchanger.

2. Addition of the required concentration of a glycol anti-freeze to the circuit. This willresult in decreased capacity and increased pressure drop. Note: Do not use automotivegrade antifreezes that contain inhibitors harmful to chilled water systems. Only useglycols specifically designated for use in building cooling systems.

3. Addition of insulation and heat to any exposed piping and equipment.

4. Draining and flushing the chiller with glycol.

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Electrical Connections

All wiring must be done in accordance with applicable local and national codes.

ALS units may be ordered with internal power wiring for either single or multiple point power connections. If single point power connection is ordered, a single power terminal block is provided and wiring within the unit is sized in accordance with the U.S.A. National

Electrical Code. A single field supplied disconnect is required or can be furnished as afactory option. If multiple point power wiring is ordered, two power connections arerequired for ALS 141C through ALS 218C. Wiring within the unit is sized in accordancewith the U.S.A. National Electrical Code. Separate field supplied or factory supplied disconnects are required for each circuit.

Disconnecting means are addressed by Article 440 of the U.S.A. National Electrical Code(NEC) which requires "disconnecting means capable of disconnecting air conditioning and refrigerating equipment including motor-compressors, and controllers from the circuitfeeder." The disconnect switch should be selected and located within the NEC guidelines.Maximum recommended fuse sizes are given in the electrical data tables of this catalog for help in sizing the disconnect.

Terminals are provided in the unit control center for optional field hookup of the controlcircuit to a separate fused 115 volt power supply. A control circuit transformer is factoryinstalled to eliminate the requirement for a separate power supply to the control circuit.

Terminals are provided in the unit control center for field hookup of the evaporator heater to either a separate 115 volt power supply or to control circuit power.

Remote Evaporator

GeneralThe multiple compressor ALS air-cooled chillers are available with remote evaporator.This allows the main unit to be installed outdoors to save interior room and eliminates theneed for anti-freeze solutions and heat tracing of chilled water lines since the chilled water system is indoors. There are some general guidelines to review before proceeding:

1. R-22 only.

2. Maximum line length of 50 ft (15 m) and Total Equivalent Length (TEL) of 120 ft(37 m).

3. Evaporator not more than 6 ft (1.8 m) above the compressor or 16 ft (5 m) belowcompressor.

4. No underground piping.

5. No hot gas bypass.

6. Units with remote evaporator are not included in the ARI Certification Program.

The remote evaporator is shipped separately, ready for quick and easy installation at the jobsite. All refrigerant accessories such as liquid-vapor line shut-off valves, replaceable corefilter-driers, liquid line solenoid valves, electronic expansion valves, and sightglasses arealready included on the ALS condensing unit. The evaporator is equipped with entering

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and leaving chilled water temperature sensor wells. The sensors are pre-wired to the ALSunit with 75 feet long sensor leads that m

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