Air-Cooled Screw Compressor Chiller Installation, Operation and Maintenance Manual 60 Hertz

Air-Cooled Screw Compressor Chiller Installation, Operation and Maintenance Manual 60 Hertz

Installation, Operation and Maintenance Manual

IOMM ALS-4

Group: Chiller

Part Number: 330145709

Date: August 2001

Supersedes: IOMM ALS-3

Air-Cooled Screw Compressor Chiller

ALS 141C through 218C

60 Hertz

2

Table Of Contents

Introduction .............................. 3

General Description................................... 3

Nomenclature ............................................ 3

Inspection .................................................. 3

Installation and Start-up ........... 3

Handling .................................................... 4

Location..................................................... 5

Service Access ........................................... 5

Clearance Requirements ............................ 6

Vibration Isolators ..................................... 7

Lifting and Mounting Weights ................... 8

Water Piping .............................................. 9

System Water Volume .............................. 10

Variable Water Flow ................................ 10

Evaporator Freeze Protection .................. 11

Flow Switch ............................................. 11

Water Connections................................... 12

Refrigerant Charge................................... 12

Glycol Solutions ...................................... 12

Remote Evaporator ................. 13

General .................................................... 13

Performance Derate Factors .................... 13

Refrigerant Piping.................................... 14

Startup Procedures................................... 17

Dimensions, Remote Evaporator ............. 18

Water Flow and Pressure Drop19

Physical Data .......................... 21

Compressor Staging................ 22

Dimensional Data ................... 23

Wind Baffles and Hail Guards 24

Electrical Data ........................ 26

Field Wiring............................................. 26

Wire Sizing Ampacities ........................... 27

Field Wiring Diagram............. 35

Solid State Starters ................. 36

Unit Layout and Principles of

Operation ................................43

Major Component Location..................... 43

Control Center ......................................... 43

Sequence of Operation ............................ 44

Start-up and Shutdown ...........47

Seasonal Start-up ..................................... 47

Temporary Shutdown............................... 47

Start-up After Temporary Shutdown........ 48

Extended (Seasonal) Shutdown ............... 48

Start-up After Extended (Seasonal)

Shutdown................................................. 49

System Maintenance ...............50

General .................................................... 50

Compressor Maintenance ........................ 50

Lubrication .............................................. 50

Electrical Terminals................................. 50

Condensers .............................................. 50

Refrigerant Sightglass.............................. 51

Lead-Lag ................................................. 51

Preventative Maintenance Schedule ........ 52

Service ....................................53

Compressor Solenoids ............................. 53

Filter-Driers ............................................. 53

Liquid Line Solenoid Valve ..................... 55

Electronic Expansion Valve..................... 55

Electronic Expansion Valve Operation .... 56

Evaporator ............................................... 57

Charging Refrigerant ............................... 57

Charging Oil ............................................ 58

In-Warranty Return Material

Procedure ................................59

Standard Controls ...................60

Optional Controls .................................... 64

Controls, Settings and Functions ............. 65

Troubleshooting Chart ............................. 66

Periodic Maintenance Log....................... 67

Our facility is

ISO Certified

Initial Issue January 1998

"McQuay" is a registered trademarks of McQuay International

2001 McQuay International

"Information covers the McQuay International products at the time of publication and we reserve the right to make changes in design and construction at anytime without notice"

IOMM ALS-4

Introduction

General Description

McQuay air-cooled water chillers are complete, self-contained automatic refrigerating units that include the latest in engineering components arranged to provide a compact and efficient unit. Each unit is completely assembled, factory wired, evacuated, charged, tested and comes complete and ready for installation, except for remote evaporator models. Each unit consists of multiple air-cooled condensers with integral subcooler sections, multiple accessible semi-hermetic single-screw compressors, solid-state starters, multiple circuit shell-and-tube evaporator, and complete refrigerant piping. Liquid line components included are manual liquid line shutoff valves, charging valves, filterdriers, liquid line solenoid valves, sightglass/moisture indicators, and electronic expansion valves.

Compressor suction and discharge shutoff valves are included. Other features include compressor heaters, an evaporator heater for low ambient water freeze protection, automatic one time pumpdown of refrigerant circuit upon circuit shutdown, and an advanced fully integrated microprocessor control system.

Nomenclature

A L S - XXX C

Air-Cooled

Liquid Oil Injected

Rotary Screw Compressor

Design Vintage

Nominal Tons

Inspection

When the equipment is received, all items should be carefully checked against the bill of lading to ensure a complete shipment. All units should be carefully inspected for damage upon arrival. All shipping damage must be reported to the carrier and a claim must be filed with the carrier. The unit’s serial plate should be checked before unloading the unit to be sure that it agrees with the power supply available. Physical damage to unit after acceptance is not the responsibility of McQuay

International.

Note: Unit shipping and operating weights are available in the Physical Data Tables.

Installation and Start-up

Note: Installation and maintenance are to be performed only by qualified personnel who are familiar

with local codes and regulations, and experienced with this type of equipment.

CAUTION

Sharp edges and coil surfaces are a potential injury hazard. Avoid contact with them.

Start-up by McQuayService is included on all units sold for installation within the USA and Canada and must be performed by them. Two week prior notification of start-up is required. The contractor should obtain a copy of the Start-up Scheduled Request Form from the sales representative or from the nearest office of McQuayService.

IOMM ALS-4

3

Handling

Care should be taken to avoid rough handling or shock due to impact or dropping the unit. Do not push or pull the unit from anything other than the base, and block the pushing vehicle away from the

unit to prevent damage to the sheet metal cabinet and end frame (see Figure 1).

Never allow any part of the unit to fall during unloading or moving as this may result in serious damage.

To lift the unit, 2½ “ (64 mm) diameter lifting holes are provided in the base of the unit. Spreader bars

and cables should be arranged to prevent damage to the condenser coils or unit cabinet (see Figure 2).

Figure 1, Suggested Pushing Method

Figure 2, Required Lifting Method

4

NOTES:

1. All 4 rigging points on a unit must be used. See Figure 5 through

Figure 6

for location, and weight at lifting points for a specific size unit.

2. Crosswise and lengthwise spreader bars must be used to avoid damage to unit. Lifting cables from the unit mounting holes up must be vertical.

3. The number of condenser sections, and fans can vary from this diagram.

IOMM ALS-4

IOMM ALS-4

Location

Care should be taken in the location of the unit to provide proper airflow to the condenser. (See

Figure 3 for required clearances).

Due to the vertical condenser coil design of the ALS chillers, it is recommended that the unit be oriented so that prevailing winds blow parallel to the unit length, thus minimizing the wind effect on condensing pressure and performance. It is recommended that wind baffles be installed if the unit is installed with no protection against prevailing winds.

Using less clearances than shown in Figure 3, will cause discharge air recirculation to the condenser

and could have a significant and detrimental effect on unit performance. See the current version of

McQuay Product Manual PM ALS for more detailed information on the subject of air recirculation.

Service Access

Each end of the unit must be accessible after installation for periodic service work. Compressors, filter-driers, and manual liquid line shutoff valves are accessible on each side of the unit adjacent to the control box. High pressure and low pressure transducers are mounted on the compressor. The cooler barrel heater thermostat is located on the cooler. Compressor microprocessor and most other operational and equipment protection controls are located in the unit control box. The solid-state starters with their internal electrical protection features are mounted on the base side rails adjacent to the compressor they serve.

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.

WARNING

Disconnect all power to the unit while servicing condenser fan motors.

Failure to do so may cause bodily injury or death.

Do not block access to the sides or ends of the unit with piping or conduit. These areas must be open for service access. Do not block any access to the control panel with a field mounted disconnect switch.

5

Clearance Requirements

Figure 3, Clearance Requirements, ALS 141-218

6

Notes:

1. Minimum side clearance between two units is 12 feet.

2. Unit must not be installed in a pit or enclosure that is deeper or taller than the height of the unit unless extra clearance is provided per note 4.

3. Minimum clearance on each side is 8 feet when installed in a pit no deeper than the unit height.

4. Minimum side clearance to a side wall or building taller than the unit height is 8 feet provided no solid wall above 6 feet is closer than 12 feet to the opposite side of the unit.

5. The evaporator can be removed from the side of the unit.

6. Do not mount electrical conduits, etc, above the side rail on either side if the unit.

7. There must be no obstruction of the fan discharge.

8. It is recommended that field supplied disconnect switches not be mounted on the unit.

IOMM ALS-4

Vibration Isolators

Vibration isolators are recommended for all roof mounted installations or wherever vibration transmission is a consideration. The following section "Lifting and Mounting Weights" contains the location of unit lifting holes and the load at each location. Mounting holes are also dimensioned and the bearing weight at each hole given.

The unit should be initially installed on shims or blocks at the illustrated "free height" of the isolator.

Six inches for the McQuay isolators shown. When all piping, wiring, flushing, charging, etc is complete, the springs should be adjusted upward to load them and free the blocks which are then removed.

Installation of spring isolators requires flexible pipe connections and at least three fett of conduit flex tie-ins. Piping and conduit should be supported independently from the unit.

Figure 4, Spring Flex Isolators

Table 1, Spring Vibration Isolators, Part Numbers

Model R1

Mounting Location (See Footprint Drawings Figure 5 or Figure 6

R2 R3

ALS 141-ALS 186 Isolator kit part number 350014880

Max Load 2200 2200

Spring P/N

Color

Housing P/N

022611901

Gray

022610300

022611901

Gray

022610300

2600

022612000

White

022610300

R4

2600

02261200

White

022610300

R5

1800

022611800

Green

022610300

R6

1800

022611800

Green

022610300

ALS 190-ALS 218 Isolator kit part number 350014881

Max Load 2600 2600

Spring P/N

Color

Housing P/N

022612000

White

022610300

022612000

White

022610300

3000

330202101

Gold

022610300

3000

330202101

Gold

022610300

2200

022611901

Gray

022610300

2200

022611901

Gray

022610300

Notes:

1. The same isolators are used when the chiller is supplied with the optional copper finned condenser coils.

2. The spring is fully compressed at approximately 3900 lb. (1769 kg).

IOMM ALS-4

7

Lifting and Mounting Weights

Figure 5, ALS 141C – ALS 186C Lifting and Mounting Locations

NOTES:

1. 2 ½ in. (63.5 mm) lifting holes at location "L" on side of base rail.

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

L2

L4

36 (914)

R2 R4 R6

102 (2591)

192 (4877)

83.4

(2118)

46 (1168)

R1

161 (4089)

R3 R5

L1

L3

2 (51)

Typical Spacing for Isolator

Mounting (6)

ALS

Model

141

150

171

186

Lifting Weight for Each Point lb (kg)

L1 & L2 L3 & L4

2585 (1171)

2570 (1164)

2125 (963)

2205 (999)

2570 (1164) 2210 (1001)

2575 (1166) 2210 (1001)

Mounting Loads for Each Point

lb. (kg)

R1 & R2 R3 & R4 R5 & R6

1835 (831)

1830 (829)

1785 (809)

1805 (818)

1230 (557)

1305 (591)

1830 (829)

1830 (829)

1810 (820)

1810 (820)

1305 (591)

1310 (593)

Operating Wt lb. (kg)

9700 (4394)

9880 (4476)

9890 (4472)

9900 (4485)

Shipping Wt.

lb. (kg)

Copper Fin

Add

9420 (4267)

9550 (4326)

9560 (4331)

9570 (4335)

1370 (620)

1370 (620)

1370 (620)

1370 (620)

Figure 6, ALS 190C – ALS 218C Lifting and Mounting Locations

L2 L4

36 (914)

R2

R4 R6

123 (3124)

224 (5690)

83.4

(2118)

46 (1168)

R1

L1

195 (4953)

R3

L3

R5

2 (51)

Typical Spacing for Isolator

Mounting (6)

8

ALS

Model

190

200

206

218

Lifting Weight for Each Point lb (kg)

L1 & L2 L3 & L4

2915 (1320) 2230 (1010)

2920 (1323) 2230 (1010)

2940 (1332) 2310 (1046)

2960 (1341) 2405 (1089)

Mounting Loads for Each Point

lb. (kg)

R1 & R2 R3 & R4 R5 & R6

2010 (910)

2015 (913)

2000 (906)

1985 (899)

2135 (967)

2135 (967)

2240 (1015)

2425 (1098)

1165 (527)

1165 (527)

1240 (562)

1365 (618)

Operating Wt lb. (kg)

10620 (4811)

10630 (4815)

10960 (4965)

11550 (5232)

Shipping Wt.

lb. (kg)

Copper Fin

Add

10290 (4661)

10300 (4666)

10500 (4756)

10730 (4861)

1610 (730)

1610 (730)

1610 (730)

1610 (730)

IOMM ALS-4

IOMM ALS-4

Water Piping

Due to the variety of piping practices, it is advisable to follow the recommendations of local authorities. They can supply the installer with the proper building and safety codes required for a safe and proper installation.

Basically, the piping should be designed with a minimum number of bends and changes in elevation to keep system cost down and performance up. It should contain:

1. Vibration eliminators to reduce vibration and noise transmission to the building.

2. Shutoff valves to isolate the unit from the piping system during unit servicing.

3. Manual or automatic air vent valves at the high points of the system. Drains at the low parts in the system. The evaporator should not be the highest point in the piping system.

4. Some means of maintaining adequate system water pressure (e.g., expansion tank or regulating valve).

5. Water temperature and pressure indicators located at the unit to aid in unit servicing.

6. A strainer or some means of removing foreign matter from the water before it enters the pump.

The strainer should be placed far enough upstream to prevent cavitation at the pump inlet

(consult pump manufacturer for recommendations). The use of a strainer will prolong pump life and help maintain high system performance levels.

WARNING

7. A strainer must also be placed in the supply water line just prior to the inlet of the evaporator.

This will aid in preventing foreign material from entering the evaporator and causing damage or decreasing its performance. Care must also be exercised if welding pipe to the evaporator connections to prevent any weld slag from entering the vessel.

8. The shell-and-tube evaporator has a thermostat and heating cable to prevent freeze-up down to -

20

°

F (-28.8

°

C). It is suggested that the heating cable be wired to a separate 110V supply circuit.

As shipped from the factory, it is factory wired to the control circuit. Any water piping to the unit must also be protected to prevent freezing.

9. If the unit is used as a replacement chiller on a previously existing piping system, the system should be thoroughly flushed prior to unit installation and then regular chilled water analysis and chemical water treatment is recommended immediately at equipment start-up.

10. The total water quantity in the system should be sufficient to prevent frequent "on-off" cycling.

For air-conditioning systems, system gallons equal to 7 time the flow rate is recommended.

11. In the event glycol is added to the water system, as an afterthought for freeze protection, recognize that the refrigerant suction pressure will be lower, cooling performance less, and water side pressure drop greater. If the percentage of glycol is large, or if propylene is employed in lieu of ethylene glycol, the added pressure drop and loss of performance could be substantial.

12. For operations requiring the ice mode feature, logic in MicroTech will adjust the freezestat to a pressure equivalent to 13.5

°

F (7.5

°

C) below the leaving evaporator water temperature. However, if a different freezestat pressure value is desired, the freezestat can be manually changed through

MicroTech. Refer to the current OM ALSMICRO for additional information.

CAUTION

If a separate disconnect is used for the 110V supply to the cooler heating cable, it should be clearly marked so that it is not accidentally shut off during cold seasons.

A preliminary leak check should be made prior to insulating the piping and filling the system,.

Piping insulation should include a vapor barrier to prevent moisture condensation and possible damage to the building structure. It is important to have the vapor barrier on the outside of the insulation to prevent condensation within the insulation on the cold surface of the pipe.

9

10

System Water Volume

It 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 is the 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 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 five minutes times the flow rate (gpm). For example, if the design chiller flow rate is 400 gpm, we recommend a minimum system volume of 2000 gallons (400 gpm x 5 minutes).

For process applications where the cooling load can change rapidly, additional system water volume is needed. A process example would be a quenching tank. The load would be very stable until the hot material is immersed in the water tank. Then, the load would increase drastically. For this type of application, system volume may need to be increased drastically.

Since there are many other factors that can influence performance, systems may successfully operate below these suggestions. However, as the water volume decreases below these suggestions, the possibility of problems increases.

Variable Water Flow

Variable water flow involves changing the water flow through the evaporator as the load changes.

McQuay chillers are designed for this duty provided that the rate of change in water flow is slow and the minimum and maximum flow rates for the vessel are not exceeded.

The recommended change in water flow is listed in the table below. As the number of stages of control increase, the slower the permissible rate of change in flow rate becomes. The ALS control logic has timers that limit the rate of unloading or loading allowed. Slow changes allow the chiller the opportunity to sense a change, react to the change and stabilize preventing operational problems.

ALS Size

141 to 218

Number of

Compressors

2

Unloading

Steps

8

Maximum allowable % per minute of flow change

10.0

For example, assume that an ALS with two compressors has a design flow of 500 gpm and the minimum vessel flow rate of 300 gpm. The allowable amount of flow change is 200 gpm. An ALS with two compressors has an allowable change rate of 10% of change per minute. Therefore, the maximum rate of change recommended would be 20 gpm/minute (200 X .10).

The water flow through the vessel must remain between the minimum and maximum values listed on

Figure 13. If flow drops below the minimum allowable, large reductions in heat transfer can occur. If

the flow exceeds the maximum rate, excessive pressure drop and tube erosion can occur.

IOMM ALS-4

IOMM ALS-4

Evaporator Freeze Protection

All evaporators come equipped with thermostatically controlled resistive element heater. When power is applied to terminals 13 and 16, the heat element will provide freeze protection down to -

20

°

F (-28.8

°

C). However, this should not be the only method of freeze protection. Unless the evaporator is flushed and drained as is described below in note 4, two or more of the remaining three recommendations must be followed as part of the system design:

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

2. The inclusion of glycol solution in the chilled water circuit.

3. The addition of insulation and heat to the exposed piping.

4. Draining and flushing the chiller vessel with glycol during subfreezing weather. NOTE: The

heater element must be disconnected and made inoperative any time there is no fluid in the evaporator. Failure to do so can cause the element to create excessive heat and to burn out.

It is the responsibility of the installing contractor and/or on-site maintenance personnel to insure that this additional protection is provided. Routine checks should be made to insure adequate freeze protection is maintained.

Failure to do so may result in damage to unit components. Freeze damage is not considered a warranty failure.

Freeze protection should also be extended to any water piping exposed to freezing temperatures.

Figure 7, Typical Field Water Piping

Vent

Outlet

Valved pressure gauge

Vibration

Eliminator

Flow

Switch

Balancing valve

Gate valve

Protect all field piping against freezing

Vibration

Eliminator

Water strainer

Gate valve

Drain

Flow Switch

A water flow switch must be mounted in the leaving water line to insure that there will be adequate water flow to the evaporator before the unit can start. This will safeguard against slugging the compressors on start-up. It also serves to shut down the unit in the event that water flow is interrupted to guard against evaporator freeze-up.

A flow switch is available from McQuay under ordering number 017503300. It is a "paddle" type switch and adaptable to any pipe size from 1" (25mm) to 8" (203mm) nominal.

Certain minimum flow rates are required to close the switch and are listed in Table 2. Installation should be as shown in Figure 8.

Electrical connections in the unit control center should be made at terminals 62 and 63. The normally open contacts of the flow switch should be wired between these two terminals. Flow switch contact quality must be suitable for 24 VAC, low current (16ma). Flow switch wire must be in separate conduit from any high voltage conductors (115 VAC and higher).

11

12

Figure 8, Flow Switch

Flow direction marked on switch

1" (25mm) NPT flow switch connection

Tee

Table 2, Switch Minimum Flow Rates

NOMINAL PIPE SIZE

INCHES (MM)

MINIMUM REQUIRED FLOW TO

ACTIVATE SWITCH - GPM (LPS)

5 (127)

6 (152)

58.7 (3.7)

79.2 (5.0)

8 (203) 140 (8.8)

Note: Water pressure differential switches are not recommended for outdoor applications.

1 1/4" (32mm) pipe dia. min. after switch

1 1/4" (32mm) pipe dia. min. before switch

Water Connections

Water piping to the cooler can be brought up through the bottom of the unit or through the side

between the vertical supports. The dimensional drawings in Figure 14 give the necessary dimensions

and locations for all piping connections. Evaporator piping connections face toward the left side of the unit when looking at the control panel.

Refrigerant Charge

All units are designed for use with HCFC-22 (and are compatible with some HCFC alternatives) and are shipped with a full operating charge. The operating charge for each unit is shown in the Physical

Data Tables. Units ordered with a remote evaporator are shipped with a unit operating charge of refrigerant pumped down in the unit condensers. The McQuay authorized startup technician will top off the system charge at startup.

Glycol Solutions

When using glycol anti-freeze solutions the chiller's capacity, glycol solution flow rate, and pressure drop through the cooler may be calculated using the following formulas and tables.

Note: The procedure below does not specify the type of glycol. Use the derate factors found in Table

3 for corrections when using propylene glycol and those in Table 4 for ethylene glycol.

1. Capacity - Cooling capacity is reduced from that with plain water. To find the reduced value, multiply the chiller’s water system tonnage by the capacity correction factor to find the chiller’s capacity when using glycol.

2. Flow - To determine flow (or delta-T) knowing delta-T (or flow) and capacity:

factor

)

GPM

=

flow

Delta

T

3. Pressure drop - To determine pressure drop through the cooler, when using glycol, enter the water pressure drop curve at the water flow rate. Multiply the water pressure drop found there by the "PD" factor to obtain corrected glycol pressure drop.

4. To determine glycol system kW, multiply the water system kW by the factor designated "Power".

Test coolant with a clean, accurate glycol solution hydrometer (similar to that found in service stations) to determine the freezing point. Obtain percent glycol from the freezing point table below.

On glycol applications the supplier normally recommends that a minimum of 25% solution by weight be used for protection against corrosion.

IOMM ALS-4

CAUTION

Do not use automotive grade antifreeze. Industrial grade glycols must be used. Automotive antifreeze contains inhibitors that will cause plating on the copper tubes within the chiller evaporator. The type and handling of glycol used must be consistent with local codes.

Table 3, Propylene Glycol

%

P.G.

10

20

30

40

50

FREEZE

POINT.

o

F o

C

26

19

-3

-7

9

-5

-13

-21

-27 -33

CAP

0.987

0.975

0.962

0.946

0.965

POWER

0.992

0.985

0.978

0.971

0.965

FLOW

1.010

1.028

1.050

1.078

1.116

PD

1.068

1.147

1.248

1.366

1.481

Table 4, Ethylene Glycol

%

E.G.

10

20

30

40

50

FREEZE

POINT.

o

F o

C

26

18

7

-7

-28

-3

-8

-14

-22

-33

CAP

0.991

0.982

0.972

0.961

0.946

POWER

0.996

0.992

0.986

0.976

0.966

FLOW

1.013

1.040

1.074

1.121

1.178

PD

1.070

1.129

1.181

1.263

1.308

Remote Evaporator

General

The multiple compressor ALS air-cooled chillers are available with the evaporator shipped loose for remote mounting. This allows the main unit to be installed outdoors to save interior room and eliminates the need 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) below compressor.

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 job site. All refrigerant accessories such as liquid-vapor line shut-off valves, replaceable core filter-driers, liquid line solenoid valves, electronic expansion valves, and sightglasses are already included on the ALS condensing unit. The evaporator is equipped with entering and leaving chilled water temperature sensor wells. The sensors are pre-wired to the ALS unit with 75 feet long sensor leads and must be field connected to the evaporator thermowells. Suction pressure transducers and temperature sensors must also be relocated to the evaporator. ALS units are factory charged with a full unit charge pumped down into the condensers. Field piping must be leak tested, evacuated and charged during installation. Do not exceed 150 psig test pressure unless the unit is blanked off from the piping.

Performance Derate Factors

All performance tables and adjustment factors found in the current version of the Air-Cooled Screw

Chiller catalog (PM ALS-x) are applicable for remote evaporator installations. However, a performance derate must be applied to the R-22 performance data due to additional pressure drops in the suction and liquid lines which cause a loss of compressor performance. These derates are based on a suction line pressure drop equivalent of approximately 2°F (1°C) change in saturation temperature.

For R-22 applications:

Capacity = Tons (kW) x 0.97

Power = Compressor kW x 0.99

IOMM ALS-4

13

14

Refrigerant Piping

General

Careful design of the refrigerant piping is necessary for efficient system operation. The refrigerant piping should be designed for a low refrigerant pressure drop to obtain maximum capacity and efficiency while maintaining adequate velocity. Lines should slope in the direction of flow to assure good oil return to the compressors. Cost considerations favor keeping line sizes as small as possible while not exceeding acceptable pressure drops in order to maintain unit performance.

NOTE

All refrigerant piping must be reviewed and approved by McQuay Application

Engineers prior to order entry and will be verified by McQuay startup technicians.

Equivalent Line Lengths

Recommended refrigerant line sizes are based on equivalent line lengths of straight pipe, that is, a combination of straight pipe, fittings and valves. The pressure drop through valves and fittings is determined by establishing the equivalent straight length of pipe of the same size with the same friction loss. The "Total Equivalent Length" is the sum of the "Lineal Line Length" and the appropriate "Valve and Fitting Losses in Equivalent Feet of Pipe for Field Supplied Piping" given in

Table 5

Table 5, Fitting Equivalent Feet of Pipe

Line Size (in.)

1 1/8

1 3/8

1 5/8

2 1/8

2 5/8

3 1/8

Angle Valve

12

15

18

24

29

35

Globe Valve

29

38

43

55

69

84

90° Std. Radius Elbow 90° Long Radius Elbow

2.6

3.3

4.0

5.0

6.0

7.5

1.7

2.3

2.6

3.3

4.1

5.0

Location and Arrangement

Refrigerant lines should be as short and direct as possible to minimize tubing and fittings. Long radius elbows must be used (except for traps) to minimize the pressure drops. Traps should be as short as possible to minimize oil accumulation. Refrigerant piping should be arranged so that normal inspection of the equipment is not hindered. Adequate clearance should be provided between refrigerant piping and adjacent walls for insulation. Piping should be run so that it does not interfere with compressor service access, passages or obstruct headroom, windows and doors. Suction line hangers must be sized and located to support the weight of the piping in accordance with good piping practice.

Horizontal portions of the suction lines must be downward sloping toward the compressors. Slope all piping in the direction of flow. Vertical portions of the suction lines must be sized for oil return at minimum compressor load.

Note:

Double section risers must not be utilized on any circuit. Traps must be provided as shown on

Figure 9 and Figure 10.

Suction Line Sizing

Pressure drop in the suction line reduces system capacity and efficiency because it forces the compressor to operate at lower suction pressure. The suction line should be sized for a pressure drop approximately equivalent of 2°F (1

°

C) change in saturation temperature. For suction line sizing see

Table 7 and Table 8. For applications with the evaporator below the ALS unit, the vertical section of

the suction lines must be sized to return oil to the compressors at the minimum compressor capacity step.

IOMM ALS-4

IOMM ALS-4

Example of Suction Line Size Calculation

ALS150C condensing unit with refrigerant R-22

Evaporator located 5 feet below the ALS compressor

Lineal length of horizontal suction line is 25 feet

Suction line requires 7 long radius (90°) elbows; 3 in the horizontal, 4 in the riser

From Table 6, the nominal circuit capacities for circuit 1 and 2 are 65 and 80 tons respectively

Total lineal suction line length = 30 feet each circuit (25 feet horizontal plus 5 feet vertical riser).

For the first try, assume that the total equivalent suction line length is twice the lineal suction line length.

Therefore the estimated total equivalent suction line length = 60 feet

From Table 7 and Table 8, For nominal circuit capacities of 65 & 80 tons and total equivalent line

length of 60 ft, the suction line size = 2 5/8" for horizontal lines and 2 1/8" for vertical lines.

From Table 5, Fitting loss for 2 5/8" long radius (90°) elbow = 4.1 ft, and 3.3 ft for the 2 1/8 elbows.

Therefore fitting loss in equivalent feet of pipe for (3) 2 5/8" long radius (90°) elbow = 12.3 ft, and 13.2 ft for (4) 2 1/8" elbows.

Therefore the actual equivalent suction line length = 30 + 12.3 + 13.2 = 55.5 feet

From and Table 8, For nominal circuit capacities of 65 & 80 tons and equivalent line length of 55.5 ft

the suction line size is correct.

Table 6, ALS 141C-420C Nominal Circuit Capacities

ALS Model

141

150

171

186

190

200

206

218

Circuit 1

Tons (kW)

65 (229)

65 (229)

80 (262)

80 (262)

80 (262)

95 (334)

95 (334)

95 (334)

Circuit 2

Tons (kW)

65 (229)

80 (262)

80 (262)

95 (334)

95 (334)

95 (334)

95 (334)

95 (334)

Table 7, Vertical Upflow Suction Line Sizes

Nominal Circuit

Capacity

Tons (kW)

65 (229)

80 (262)

95 (334)

Vertical Upflow Suction Lines

Equivalent Line Length Ft (m) Suction Line Size (in.)

40 (12)

75 (23)

40 (12)

75 (23)

40 (12)

75 (23)

2 1/8

2 1/8

2 1/8

2 1/8

2 5/8

2 5/8

Table 8, Horizontal and Vertical Downflow Suction Line Sizes

Vertical Downflow and Horizontal Suction Lines Nominal Circuit

Capacity

Tons (kW)

65 (229)

80 (262)

95 (334)

Equivalent Line Length Ft (m)

40 (12)

75 (23)

115 (35)

40 (12)

75 (23)

115 (35)

40 (12)

75 (23)

115 (35)

Suction Line Size, in.

2 5/8

2 5/8

2 5/8

2 5/8

2 5/8

3 1/8

2 5/8

3 1/8

3 1/8

15

16

Liquid-Vapor Lines

The liquid-vapor line from the ALS condensing unit to the evaporator liquid connection is not a conventional liquid line since it carries both liquid and vapor. The compressors on the ALS units utilize a liquid cooled motor and an economizer. Therefore the expansion valve which feeds the full flow of liquid refrigerant into the compressor for motor cooling is mounted in the liquid line between the condenser sub-cooling coil and the compressor inlet, not at the evaporator inlet. The liquid-vapor line to the evaporator is a low-pressure line downstream of the expansion valve and the size is slightly

larger than a normal liquid line. For liquid line sizing see Table 9 and Table 10.

Table 9, Vertical Upflow Liquid-Vapor Line Sizes

Nominal Circuit

Capacity

Tons (kW)

65 (229)

80 (262)

95 (334)

Vertical Upflow Liquid-Vapor Lines

Equivalent Line Length

Ft (m)

Liquid-Vapor Line Size o.d (in.)

40 (12)

75 (23)

1 3/8

1 3/8

40 (12)

75 (23)

40 (12)

75 (23)

1 3/8

1 3/8

1 5/8

1 5/8

Table 10, Horizontal and Vertical Downflow Liquid-Vapor Line Sizes

Nominal Circuit

Capacity

Tons (kW)

65 (229)

80 (262)

95 (334)

Vertical Downflow and Horizontal Liquid-Vapor Lines

Equivalent Line Length

Ft (m)

Liquid-Vapor Line Size

o.d (in.)

40 (12)

75 (23)

115 (35)

1 3/8

1 3/8

1 3/8

40 (12)

75 (23)

115 (35)

40 (12)

75 (23)

115 (35)

1 3/8

1 5/8

1 5/8

1 5/8

1 5/8

1 5/8

Figure 9, Evaporator Above ALS Unit

Evaporator

Trap

ALS Unit

Suction Line

Figure 10, Evaporator Below ALS Unit

ALS Unit

Suction Line

Evaporator

Trap

NOTE: Keep the trap width at a minimum to avoid trapping excessive oil.

IOMM ALS-4

IOMM ALS-4

Insulation

All piping joints and fittings must be thoroughly leak tested before insulation is applied. Suction lines must be insulated and should not be installed underground. Suction line insulation must be selected to prevent condensation under local ambient conditions with the lines at 40°F to 50°F (4.4

°

C to 10

°

C) operating temperatures. The liquid-vapor lines will operate at 40°F to 60°F (4.4

°

C to 15.6

°

C) and

must

also be insulated to prevent sweating and heat gain.

Startup Procedures

NOTE

: McQuayService or a factory authorized McQuay service agent must do initial start-up and commissioning.

Filter Driers

Following an initial 24 hour operation the pressure drop across the replaceable core filter-drier should

be checked. If this pressure drop exceeds the values given in Table 11 at the various load conditions

the filter drier cores must be replaced. Also if the moisture indicating sight glass shows a wet system condition after 24 hours of operation the filter cores must be changed. This should remove any contaminants introduced during field piping. The filter drier cores must also be changed anytime the system is opened for servicing.

Table 11, Filter Drier Pressure Drop

Percent Circuit

Loading (%)

100

75

50

25

Maximum Recommended Pressure Drop Across Filter Drier

psig (kPa)

7 (48.3)

5 (34.5)

3 (20.7)

3 (20.7)

Refrigerant and Oil Charge

The relative position of the ALS unit and the evaporator and the distance between them plays a critical role in determining suction and liquid line sizes and the field refrigerant and oil charges. ALS units with the remote evaporator option are shipped with a unit operating charge of refrigerant and oil.

It will be necessary to evacuate the evaporator and field installed line and top off the charge See

Table 12 for refrigerant charge for suction and liquid-vapor lines. McQuay Service will supply and

add additional oil as required. The correct oil is Planetelf

ACD68AW, McQuay Part No.

735030439 (5 gal.), 735030438 (1 gal.).

Charging Procedure

The calculated refrigerant charge must be added through the factory supplied charging valve located on the liquid-vapor line coming out of the compressor. Sufficient charge must be added to clear the liquid line sight glass located at the outlet of the condenser. Add an extra 10 lb. of refrigerant after the sight glass is clear.

Table 12, Refrigerant Charge for Suction and Liquid-Vapor Lines

Lineal Tubing

Length ft (m)

10 (3)

20 (6)

30 (9)

40 (12)

Notes: See next page

Suction Line Refrigerant Charge

lb (kg)

Line (in.)

2 1/8

2 5/8

3 1/8

R-22

0.33 (0.15)

0.51 (0.23)

0.71 (0.32)

2 1/8

2 5/8

3 1/8

2 1/8

2 5/8

3 1/8

2 1/8

2 5/8

3 1/8

0.66 (0.30)

1.02 (0.46)

1.42 (0.64)

0.99 (0.45)

1.53 (0.69)

2.13 (0.96)

1.32 (0.60)

2.04 (0.92)

2.84 (1.29)

Liquid-Vapor Line Refrigerant Charge lb (kg)

Line (in.)

1 3/8

1 5/8

R-22

3.6 (1.6)

5.0 (2.3)

1 3/8

1 5/8

1 3/8

1 5/8

1 3/8

1 5/8

7.2 (3.3)

10.0 (4.5)

10.8 (4.9)

15.0 (6.8)

14.4 (6.5)

20.0 (9.0)

17

1. The only approved oil is that identified on the label attached to the compressors. All POE oils are hygroscopic and care should be exercised in handling the oil to avoid absorption and retention of moisture.

2. Do not leave the oil container open for more than a minute while charging oil. Do not use oil that has not been properly sealed and stored.

3. Charge must never be added through the compressor suction line

Dimensions

Use the ALS dimension drawings Figure 14 for the ALS with remote evaporator. The refrigerant

connections are located approximately where the refrigerant connections to the unit mounted

evaporator are on a packaged chiller. The remote evaporator dimensions are Figure 11 Figure 12.

Dimensions, Remote Evaporator

Figure 11, Evaporator for ALS 141 - ALS 200

18

ALS

Model

Evaporator

Model

Water

Volume gal. (l)

141 CDE350332801 34 (128)

150-200 CDE350332901 40 (150)

Refrigerant

Volume cu. ft. (L)

1.4 (40.0)

1.8 (52.4)

Unit Weights lb. (kg)

Operating Shipping

934 (424)

1127 (512)

635 (288)

758 (343)

R-22 Operating Charge lb. (kg)

Circuit 1 Circuit 2

34 (15.4)

45 (20.4)

34 (15.4)

45 (20.4)

ALS

Model

141

150-200

Overall Dimensions in. (mm)

Length "K" Height "A"

94.6 (2403)

95.5 (2426)

17.8 (452)

18.4 (467)

"B" "C" "D" "H" "J"

Conn.

"G"

11.0 (279) 10.2 (259) 12.8 (325) 6.4 (163) 85.2 (2164) 5 (152)

12.0 (305) 10.2 (259) 14.0 (356) 6.8 (173) 84.0 (2134) 8 (203)

IOMM ALS-4

Figure 12, Evaporator for ALS 206 - ALS 218

ALS

Model

206

218

Evaporator

Model

CDE350281651

CDE350282101

Water Volume gal. (l)

55 (208)

98 (373)

Refrig Volume cu. ft. (l)

2.4 (67.9)

2.8 (79.2)

Weights lb. (kg)

Operating Shipping

1464 (665) 943 (428)

2028 (921) 1121 (509)

R-22 Opn Charge lb. (kg)

Circuit 1 Circuit 2

57 (25.8)

68 (30.9)

57 (25.8)

68 (30.9)

ALS

Model

206

218

A

21.3 (542)

23.6 (601)

C

12.1 (307)

12.4 (315)

D

Dimensional Data

H

16.0 (406)

20.0 (508)

6.9 (176)

9.2 (235)

J

84.5 (2149)

86.6 (2202)

K

96.7 (2459)

99.7 (2533)

Water Flow and Pressure Drop

The chilled water flow through the evaporator should be adjusted to meet specified conditions. The flow rates must fall between the minimum and maximum values shown in. Flow rates below the minimum values shown will result in laminar flow that will reduce efficiency, cause erratic operation of the electronic expansion valve and could cause low temperature cutouts. On the other hand flow rates exceeding the maximum values shown can cause erosion on the evaporator water connections and tubes.

Measure the chilled water pressure drop through the evaporator at field installed pressure taps. It is important not to include valve or strainer pressure drop in these readings.

IOMM ALS-4

19

Figure 13, Evaporator Pressure Drops

ALS 141

ALS 150-200

ALS 218

ALS 206

20

Table 13, Minimum/Nominal/Maximum Flow Rates

ALS

Unit

Size

141

150

171

186

190

200

206

218

Minimum

Flow gpm

187

209

234

255

260

276

285

307

Pressure

Drop ft.

4.0

4.2

5.2

6.1

6.4

7.2

7.5

5.0

Nominal

Flow gpm

298.8

335.3

373.9

408.0

415.4

442.1

456.7

490.6

Pressure

Drop ft.

9.5

10.5

13.0

15.4

16.0

18.0

18.7

13.1

Maximum

Flow gpm

498

559

623

680

692

737

761

818

Pressure

Drop ft.

24.2

28.5

35.3

41.9

43.4

49.0

50.4

36.8

IOMM ALS-4

Physical Data

Table 14, Physical Data, ALS 141C – ALS 186C

DATA

Ckt 1

141C

Ckt 2 Ckt 1

10 - 28 (711)

10 - 1.5 (1.1)

1140

14.0 – 95.5

(356 - 2425)

45 (20.4)

150C

ALS MODEL NUMBER

171C

Ckt 2 Ckt 1

8357

90200

45 (20.4)

40 (151)

152 (1048)

300 (2068)

12 - 28 (711)

12 - 1.5 (1.1)

1140

45 (20.4)

8357

108240

40 (151)

Ckt 2

14.0 – 95.5

(356 - 2425)

45 (20.4)

152 (1048)

300 (2068)

Ckt 1

186C

12 - 28 (711)

12 - 1.5 (1.1)

1140

8357

108240

14.0 – 95.5

(356 - 2425)

45 (20.4)

40 (151)

45 (20.4)

152 (1048)

300 (2068)

Ckt 2

BASIC DATA

Unit Cap. @ ARI Conditions, tons (kW)

Unit Operating Charge R-22, lbs (kg)

Cabinet Dimensions

L x W x H, in. (mm)

Unit Operating Weight, lbs. (kg)

Unit Shipping Weight, lbs (kg)

124.5 (436)

140 (63.5) 140 (63.5)

228.7 x 83.4 x 92.5

(5809 x 2118 x 2350)

9700 (4395)

9420 (4270)

139.7 (489)

140 (63.5) 150 (68.1)

228.7 x 83.4 x 92.5

(5809 x 2118 x 2350)

9880 (4475)

9550 (4325)

155.8 (545)

150 (68.1) 150 (68.1)

228.7 x 83.4 x 92.5

(5809 x 2118 x 2350)

9890 (4480)

9560 (4330)

170 (595)

150 (68.1) 160 (72.6)

228.7 x 83.4 x 92.5

(5809 x 2118 x 2350)

9900 (4485)

9570 (4335)

COMPRESSORS, SCREW, SEMI-HERMETIC

Nominal 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 SUBCOOLER

Coil Face Area, ft

2

. (m

2

)

Finned Height x Finned Length

ft. (mm)

Fins Per Inch x Rows Deep

115.6 (10.7)

80 x 208

(2032 x 5283)

16 x 3

115.6 (10.7)

80 x 208

(2032 x 5283)

16 x 3

115.6 (10.7)

80 x 208

(2032 x 5283)

16 x 3

115.6 (10.7)

80 x 208

(2032 x 5283)

16 x 3

115.6 (10.7)

80 x 208

(2032 x 5283)

16 x 3

115.6 (10.7)

80 x 208

(2032 x 5283)

16 x 3

115.6 (10.7)

80 x 208

(2032 x 5283)

16 x 3

115.6 (10.7)

80 x 208

(2032 x 5283)

16 x 3

CONDENSER FANS, DIRECT DRIVE PROPELLER TYPE

No. of Fans -- Fan Diameter, in. (mm) 10 - 28 (711)

No. of Motors -- hp (kW)

Fan & Motor RPM, 60Hz

60 Hz Fan Tip Speed, fpm

60 Hz Total Unit Airflow, cfm

EVAPORATOR, DIRECT EXPANSION

10 - 1.5 (1.1)

1140

8357

90200

Shell Dia.- Length

in.(mm) - in. (mm)

Evaporator R-22 Charge lbs (kg)

Water Volume, gallons (liters)

Max. Water Pressure, psi (kPa)

Max. Refrigerant Pressure, psi (kPa)

12.75 – 94.6

(324 - 2403)

34 (15.4) 34 (15.4)

34 (129)

152 (1048)

300 (2068)

Table 15, Physical Data, ALS 190C – ALS 218C

DATA

No. of Fans -- Fan Diameter, in. (mm)

No. of Motors -- hp (kW)

Fan & Motor RPM, 60Hz

60 Hz Fan Tip Speed, fpm

60 Hz Total Unit Airflow, cfm

EVAPORATOR, DIRECT EXPANSION

Ckt 1

190C

Ckt 2 Ckt 1

200C

ALS MODEL NUMBER

206C

Ckt 2 Ckt 1 Ckt 2 Ckt 1

218C

Ckt 2

BASIC DATA

Unit Cap. @ ARI Conditions, tons (kW)

Unit Operating Charge R-22, lbs (kg)

Cabinet Dimensions,

L x W x H, in. (mm)

Unit Operating Weight, lbs. (kg)

Unit Shipping Weight, lbs (kg)

173.1 (606)

170 (77.0) 180 (81.5)

263.4 x 83.4 x 92.5

(6690 x 2118 x 2350)

10620 (4810)

10290 (4660)

COMPRESSORS, SCREW, SEMI-HERMETIC

Nominal Capacity, tons (kW) 80 (280) 95 (335)

184.2 (645)

180 (81.5) 180 (81.5)

263.4 x 83.4 x 92.5

(6690 x 2118 x 2350)

10630 (4815)

10300 (4665)

190.3 (666)

185 (83.8) 185 (83.8)

263.4 x 83.4 x 92.5

(6690 x 2118 x 2350)

10960 (4965)

10500 (4755)

204.4 (715)

210 (95.1) 210 (95.1)

263.4 x 83.4 x 92.5

(6690 x 2118 x 2350)

11550 (5230)

10730 (4860)

95 (335) 95 (335) 95 (335) 95 (335) 95 (335) 95 (335)

CONDENSERS, HIGH EFFICIENCY FIN AND TUBE TYPE WITH INTEGRAL SUBCOOLER

Coil Face Area, ft

2

. (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 Length ft. (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

CONDENSER FANS, DIRECT DRIVE PROPELLER TYPE

16 x 3 16 x 3 16 x 3 16 x 3 16 x 3 16 x 3 16 x 3

14 - 28 (711)

14 - 1.5 (1.1)

1140

8357

126280

14 - 28 (711)

14 - 1.5 (1.1)

1140

8357

126280

14 - 28 (711)

14 - 1.5 (1.1)

1140

8357

126280

14 - 28 (711)

14 - 2.0 (1.5)

1140

8357

138908

Shell Dia. -- Length in.(mm) - in. (mm)

Evaporator R-22 Charge lbs (kg)

Water Volume, gallons (liters)

Max. Water Pressure, psi (kPa)

Max. Refrigerant Pressure, psi (kPa)

14.0 – 95.5

(356 - 2425)

45 (20.4) 45 (20.4)

40 (151)

152 (1048)

300 (2068)

14.0 – 95.5

(356 - 2425)

45 (20.4) 45 (20.4)

40 (151)

152 (1048)

300 (2068)

16.0 – 96.8

(406 - 2459)

57 (25.8) 57 (25.8)

55 (208)

152 (1048)

300 (2068)

20.0 – 99.7

(508 - 2532)

68 (30.8) 68 (30.8)

98 (371)

152 (1048)

300 (2068)

IOMM ALS-4

21

Compressor Staging

ALS 141-218

Table 16, Two Compressors Available

STAGE UP

3

4

5

1

2

6

7

8

LEAD

COMPRESSOR

-

50%

75%

50%

75%

75%

100%

100%

LAG 1

COMPRESSOR

-

0%

0%

50%

50%

75%

75%

100%

Table 17, One Compressor Available

STAGE UP

1

2

3

4

LEAD

COMPRESSOR

-

50%

75%

50%

LAG 1

COMPRESSOR

-

0%

0%

0%

UNIT

CAPACITY

0%

25.0%

37.5%

50.0%

62.5%

75.0%

87.5%

100.0%

UNIT

CAPACITY

0%

25.0%

37.5%

50.0%

STAGE DOWN

3

4

5

1

2

6

7

8

LEAD

COMPRESSOR

25%

50%

75%

50%

75%

75%

100%

100%

LAG 1

COMPRESSOR

0%

0%

0%

50%

50%

75%

75%

100%

UNIT

CAPACITY

12.5%

25.0%

37.5%

50.0%

62.5%

75.0%

87.5%

100.0%

STAGE Down

1

2

3

4

LEAD

COMPRESSOR

25%

50%

75%

100%

LAG 1

COMPRESSOR

0%

0%

0%

0%

UNIT

CAPACITY

12.5%

25.0%

37.5%

50.0%

22

IOMM ALS-4

Note: Remote evaporator connections in this location.

Victaulic Connections

Couplings by Others.

Control

Center

Power

Center

Control wiring entry knockouts for ½ (13) conduit both sides of unit.

6.0

(152)

Compressor

#1

Compressor

#2

“B”

Inlet Outlet

“C”

“D”

83.4

(2118)

Notes:

1. All dimensions in inches (mm).

2. Only water connections as shown are available.

Power entry location this side only.

2 additional knockouts 6.0 (152) above and below this opening for multiple power supply.

Standard Coil Guards

Air

Discharge

92.5

(2350)

48.6

(1234)

8.1

(206)

“X”

“A”

28.5 (724)

6.50 (165)

“Y”

“E”

A B

Evaporator

C

D

E X

Center of Gravity

Y

Conn. Size

In.

ALS

Size

141C

150C

171C

186C

190C

200C

206C

218C

Wind Baffles and Hail Guards

Wind Baffles/Hail Guards are a field installed option that is used to stabilize unit operation in high wind

areas and to assist in operation at low ambient temperatures. Figure 15 is a sketch of a typical panel

assembly on an ALS unit. The actual number of panels and parts will vary by model size. The parts are shown in the table below and referenced by balloon numbers.

Figure 15, Installation Sequence

Rib Attachment

RIB FLANGES ON THE END

MUST POINT TO CENTER

OF COIL TO HAVE A FINISHED

LOOK. INTERIOR RIB FLANGES

CAN POINT IN ANY DIRECTION.

UNIT VERTICAL COIL

ATTACH ALL RIBS TO

COIL VERTICAL CHANNELS.

Top Attachment

E

ATTACH TOP "A" AT HORIZONTAL

COIL CHANNEL FIRST. THIS WILL

SQUARE THE PANEL.

UNIT VERTICAL COIL

B

A

C

D

ATTACH LEFT SIDE SECOND.

LAP PANEL "B" OVER PANEL "A"

AND REPEAT ATTACHMENT PROCEDURE.

24

IOMM ALS-4

IOMM ALS-4

Front Attachment

HANG FRONT "A" BY TOP FLANGE

AND FASTEN AT TOP AND LEFT SIDE.

UNIT VERTICAL COIL

E

D

C

2

A

3

B

HANG FRONT "B" BY LAPPING

OVER "A" AND REPEAT

ATTACHMENT PROCEDURE.

1

Table 18, Packing List

Description

Part

Number

Vertical Support Rib

34" Top Cover

34" Front Panel

330228101

330228201

330228301

41" Top Cover

41" Front Panel

330228401

330228501

¼ - 20 x ½” Screw (Place in Poly Bag) 046093807

Packing List and Hail Guard Assembly Sht. 1 & 2 R330228601

Erection Sequence R330229301

Applies to Unit Models

171-186, 190-218

141-150

Bubble

Number

1

2

3

2

3

Figure 16, Rib, Cover and Panel

VERTICAL SUPPORT RIB TOP COVER FRONT PANEL

25

Electrical Data

Field Wiring

General

Wiring must comply with all applicable codes and ordinances. Warranty is voided if wiring is not in accordance with specifications. An open fuse indicates a short, ground, or overload. Before replacing a fuse or restarting a compressor or fan motor, the trouble must be found and corrected.

Copper wire is required for all power lead terminations at the unit and copper must be used for all other wiring to the unit.

ALS units may be ordered with main power wiring for either single or multiple point power connection. If single point power connection is ordered, a single large power terminal block is provided and wiring within the unit is sized in accordance with the National Electrical code. A disconnect is required and can be furnished as a factory option. The 115-volt control transformer is factory mounted and wired.

If multiple point power wiring is ordered, two power connections are required and wiring within the unit is sized in accordance with the National Electrical Code. A separate circuit is required for the

115-volt control circuit. Separate field supplied disconnects are required for each electrical circuit.

It may be desirable to have the unit evaporator heater on a separate disconnect switch from the main unit power supply so that the unit may be shut down without defeating the freeze protection provided by the cooler heater.

CAUTION

ALS unit compressors are single direction rotation compressors. For this reason proper phasing of electrical power is important. Electrical phasing must be A, B, C for electrical phases 1, 2 and 3

(A=L1, B=L2, C=L3) for single or multiple point wiring arrangements. The solid-state starters contain the phase reversal protection. Do not alter the wiring to the starters.

CAUTION

Internal power wiring to the compressors for the single point versus the multiple point option is different. It is imperative that the proper field wiring be installed according to the way the unit is built.

26

IOMM ALS-4

Wire Sizing Ampacities

Table 19, ALS 141C – ALS 218C, Electrical Data, Single-Point

ALS

UNIT

SIZE

141C

150C

171C

186C

VOLTS

380

460

575

208

230

380

460

575

208

230

380

460

575

208

230

208

230

380

460

575

HZ

60

60

60

60

MINIMUM

CIRCUIT

AMPACITY

(MCA)

419

346

277

813

742

449

370

296

686

626

379

313

252

758

693

609

558

338

278

226

6

3

6

6

3

6

3

3

3

3

6

6

3

6

6

3

3

6

6

3

QTY

POWER SUPPLY

FIELD WIRE

WIRE

HUB

(Conduit Connection)

NOMINAL

QTY

GAUGE SIZE

350

300

400

300

4/0

2

2

1

1

1

2.5

2.5

3.0

2.5

2.0

500

400

500

400

250

500

500

4/0 See Note 9

500

300

600

500

4/0 See Note 9

500

350

2

2

1

1

1

2

2

2

1

1

2

2

2

1

1

3.0

3.0

2.0

3.0

2.5

2.0

3.0

2.5

3.0

3.0

3.0

3.0

2.5

3.0

3.0

FIELD FUSE SIZE or

HACR BREAKER SIZE

500

400

350

1000

1000

500

450

350

800

700

450

350

300

1000

800

RECOM-

MENDED

700

700

400

350

250

MAXIMUM

190C

200C

206C

380

460

575

208*

230

380

460

575

208

230

380

460

575

208*

230

60

60

60

825

753

456

376

301

869*

792

480

395

316

869*

792

480

395

316

6

6

6

3

3

6

6

6

6

3

6

6

6

6

3

600

500

4/0 See Note 9

500

350

600*

600

250

4/0 See Note 9

400

600*

600

250

4/0 See Note 9

400

2

2

2

1

1

2

2

2

2

1

2

2

2

2

1

3.0

3.0

2.0

3.0

2.5

3.0

3.0

2.5

2.0

3.0

3.0

3.0

2.5

2.0

3.0

1000

1000

600

450

350

1000

1000

600

450

350

1000

1000

600

450

350

218C

208*

230

380

460

60

897*

812

489

406

6

6

6

6

600*

600

250

4/0 See Note 9

2

2

2

2

3.0

3.0

2.5

2.0

1000

1000

600

450

1200

1000

600

500

575 326 3 400 1 3.0

400 450

Notes

1.

2.

3.

Table based on 75°C field wire except (*) which require 90

°

C field wire.

A “HACR” breaker is a circuit breaker designed for use on equipment with multiple motors. It stands for Heating, Air Conditioning, Refrigeration.

Complete notes are on page 33.

600

500

400

1200

1000

600

500

400

1000

1000

600

500

400

1200

1000

500

450

350

1000

1000

600

500

400

800

800

500

450

350

1000

800

800

700

450

350

300

IOMM ALS-4

27

Table 20, ALS 141C – ALS 218C, Electrical Data, Multiple-Point

ALS

UNIT

SIZE

141C

150C

171C

186C

190C

VOLTS

208

230

380

460

208

230

380

460

575

575

208

230

380

460

575

208

230

380

460

575

208

230

380

460

575

208

HZ

60

60

60

60

60

MINIMUM

CIRCUIT

AMPS

(MCA)

ELECTRICAL CIRCUIT 1 (COMP 1)

POWER SUPPLY

FIELD WIRE

QTY

WIRE

GAUGE

HUB

(Conduit

Connection)

QTY

HUB

SIZE

FIELD FUSING

REC

FUSE

SIZE

MAX

FUSE

SIZE

MINIMUM

CIRCUIT

AMPS

(MCA)

ELECTRICAL CIRCUIT 2 (COMP 2)

POWER SUPPLY

FIELD WIRE

HUB

(Conduit

Connection)

QTY

WIRE

GAUGE

QTY

HUB

SIZE

FIELD FUSING

REC

FUSE

SIZE

MAX

FUSE

SIZE

387

234

193

155

478

230

436

200C

380

460

575

208

60

264

217

174

478

230

436

206C

380

460

575

208

60

264

217

174

492

230

445

218C

380

460

60 269

223

575 179

NOTE:

1. Table based on 75°C field wire

2.

Complete notes are on page 33.

417

381

230

191

335

307

186

153

124

153

417

381

230

191

153

335

307

186

153

124

423

3

3

6

6

3

3

6

3

3

3

3

3

6

6

3

3

3

3

3

3

6

6

3

3

3

6

6

3

3

3

6

6

3

3

3

6

6

3

3

3

4/0

3/0

4/0

3/0

4/0

350

3/0

2/0

1

2/0

4/0

3/0

4/0

3/0

2/0

400

350

3/0

2/0

1

4/0

3/0

250

3/0

2/0

250

4/0

300

4/0

2/0

250

4/0 See

Note 9

300

4/0

2/0

250

4/0 See

Note 9

300

4/0

3/0

1

1

2

2

1

1

2

1

1

1

1

1

2

2

1

1

1

1

1

1

2

2

1

1

1

2

2

1

1

1

2

2

1

1

1

2

2

1

1

1

2.0

2.0

2.0

2.0

2.0

2.5

2.0

1.5

1.5

1.5

2.0

2.0

2.0

2.0

1.5

3.0

2.5

2.0

1.5

1.5

2.0

2.0

2.5

2.0

1.5

2.5

2.0

2.5

2.0

1.5

2.5

2.0

2.5

2.0

1.5

2.5

2.0

2.5

2.0

2.0

500

450

300

225

400

400

225

200

150

200

500

450

300

225

200

400

400

225

200

150

500

500

300

250

200

600

600

350

300

225

600

600

350

300

225

600

600

350

300

225

700

600

350

300

500

500

300

250

200

250

700

600

350

300

250

500

500

300

250

200

700

600

400

300

250

800

700

450

350

300

800

700

450

350

300

800

700

450

350

300

417

381

230

191

412

375

227

188

150

153

472

430

260

214

171

335

307

186

153

124

478

436

264

217

174

478

436

264

217

174

478

436

264

217

174

492

445

269

223

179

3

3

6

6

3

3

6

3

3

3

3

3

6

6

3

3

3

3

3

3

6

6

3

3

3

6

6

3

3

3

6

6

3

3

3

6

6

3

3

3

1

1

2

2

1

1

2

1

1

1

1

1

2

2

1

1

1

1

1

1

2 250

4/0 See

Note 9

300

4/0

2/0

250

4/0 See

Note 9

300

4/0

2/0

250

4/0 See

Note 9

300

4/0

2/0

250

4/0 See

Note 9

300

4/0

3/0

4/0

3/0

4/0

3/0

4/0

500

4/0

3/0

1/0

2/0

250

4/0

300

4/0

2/0

400

350

3/0

2/0

1

2

1

1

1

2

2

1

1

1

2

2

1

1

1

2

2

1

1

1

2.0

2.0

2.0

2.0

2.0

3.0

2.0

2.0

1.5

1.5

2.5

2.0

2.5

2.0

1.5

3.0

2.5

2.0

1.5

1.5

2.5

2.0

2.5

2.0

1.5

2.5

2.0

2.5

2.0

1.5

2.5

2.0

2.5

2.0

1.5

2.5

2.0

2.5

2.0

2.0

500

450

300

225

500

450

300

225

200

200

600

500

350

300

225

400

400

225

200

150

600

600

350

300

225

600

600

350

300

225

600

600

350

300

225

600

600

350

300

225

700

450

350

300

800

700

700

600

350

300

700

600

350

300

250

250

800

700

450

350

250

500

500

300

250

200

800

450

350

300

800

450

350

300

700

450

350

300

800

700

28

IOMM ALS-4

Table 21, ALS141C – ALS 218C, Compressor and Condenser Fan Motor Amp Draw

ALS

UNIT

SIZE

VOLTS HZ

RATED LOAD AMPS

CIRCUIT #1

141C

150C

171C

186C

190C

200C

208

230

380

460

575

230

380

460

575

208

230

380

460

575

208

208

230

380

460

575

230

380

460

575

208

230

380

460

575

208

60

60

60

60

60

60

206C

208

230

380

460

575

208

60

218C

230

380 60

316

192

460 158

575 126

NOTE: Complete notes are on page 33.

350

316

192

158

126

350

350

316

192

158

126

277

168

139

111

306

277

168

139

111

306

306

277

168

139

111

222

135

111

90

245

222

135

111

90

245

CIRCUIT #2

5.8

5.8

3.4

2.8

2.3

7.8

7.2

4.1

3.6

3.0

5.8

5.8

3.4

2.8

2.3

5.8

3.4

2.8

2.3

5.8

5.8

3.4

2.8

2.3

5.8

FAN

MOTORS

FLA

(EACH)

NO OF

FAN

MOTORS

5.8

5.8

3.4

2.8

2.3

5.8

3.4

2.8

2.3

5.8

5.8

3.4

2.8

2.3

5.8

12

12

12

12

12

10

10

10

10

10

10

10

10

10

10

14

14

14

14

14

14

14

14

14

14

14

14

14

14

14

14

14

14

14

12

12

12

12

12

14

23.7

21.4

14.4

10.7

11.5

21.4

14.4

10.7

11.5

23.7

21.4

14.4

10.7

11.5

23.7

L R A

FAN

MOTORS

(EACH)

23.7

21.4

14.4

10.7

11.5

23.7

21.4

14.4

10.7

11.5

23.7

21.4

14.4

10.7

11.5

23.7

21.4

14.4

10.7

11.5

30.5

27.6

20.0

13.8

11.5

350

316

192

158

126

316

192

158

126

350

316

192

158

126

350

306

277

168

139

111

277

168

139

111

245

222

135

111

90

306

350

316

192

158

126

350

316

192

158

126

1050

948

576

474

378

1050

948

576

474

378

1050

948

576

474

378

831

504

417

333

918

831

504

417

333

918

SOLID-STATE STARTING INRUSH

AMPS PER COMPRESSOR

CIRCUIT #1 CIRCUIT #2

918

831

504

417

333

666

405

333

270

735

666

405

333

270

735

918

831

504

417

333

831

504

417

333

735

666

405

333

270

918

1050

948

576

474

378

1050

948

576

474

378

1050

948

576

474

378

948

576

474

378

1050

948

576

474

378

1050

IOMM ALS-4

29

Table 22, ALS 141C – ALS 218C, Customer Wiring Information With Single-Point Power

ALS

UNIT

SIZE

VOLTS

208

HZ

WIRING TO STANDARD UNIT POWER BLOCK

TERMINAL SIZE

AMPS

840

CONNECTOR WIRE RANGE

PER PHASE

(COPPER WIRE ONLY)

(2) 2 to 600 MCM

WIRING TO OPTIONAL NONFUSED

DISCONNECT SWITCH IN UNIT

SIZE

CONNECTOR WIRE RANGE

PER PHASE

(COPPER WIRE ONLY)

800 (3) 3/0 to 400 MCM

141C

150C

208

230

380

460

575

230

380

460

575

60

60

840

840

840

840

840

840

840

840

840

(2) 2 to 600 MCM

(2) 2 to 600 MCM

(2) 2 to 600 MCM

(2) 2 to 600 MCM

(2) 2 to 600 MCM

(2) 2 to 600 MCM

(2) 2 to 600 MCM

(2) 2 to 600 MCM

(2) 2 to 600 MCM

800

800

400

400

400

600

400

400

250

(2) 250 to 350 MCM

(1) 250 to 500 MCM

(1) 250 to 500 MCM

(1) 4 to 350 MCM

(2) 500 to 700 MCM

(3) 3/0 to 400 MCM

(1) 250 to 500 MCM

(1) 250 to 500 MCM

(1) 250 to 500 MCM

171C

186C

190C

208

230

380

460

575

230

380

460

575

208

230

380

460

575

208

60

60

60

840

840

840

840

840

840

840

840

840

840

840

840

840

840

840

(2) 2 to 600 MCM

(2) 2 to 600 MCM

(2) 2 to 600 MCM

(2) 2 to 600 MCM

(2) 2 to 600 MCM

(2) 2 to 600 MCM

(2) 2 to 600 MCM

(2) 2 to 600 MCM

(2) 2 to 600 MCM

(2) 2 to 600 MCM

(2) 2 to 600 MCM

(2) 2 to 600 MCM

(2) 2 to 600 MCM

(2) 2 to 600 MCM

(2) 2 to 600 MCM

200C

206C

208

230

380

460

575

208

230

380

460

575

60

60

950

840

840

840

840

950

840

840

840

840

(2) 2 to 750 MCM

(2) 2 to 600 MCM

(2) 2 to 600 MCM

(2) 2 to 600 MCM

(2) 2 to 600 MCM

(2) 2 to 750 MCM

(2) 2 to 600 MCM

(2) 2 to 600 MCM

(2) 2 to 600 MCM

(2) 2 to 600 MCM

218C

208

230

380

460

60

950

840

840

840

(2) 2 to 750 MCM

(2) 2 to 600 MCM

(2) 2 to 600 MCM

(2) 2 to 600 MCM

575 840 (2) 2 to 600 MCM

NOTE:

1. Terminal size amps are the maximum amps that the power block is rated for.

2.

Complete notes are on page 33.

1200

600

600

400

1200

1200

600

600

400

1200

1200

600

600

400

1200

800

600

400

400

1200

800

600

400

400

800

800

600

400

400

1200

(2) 500 to 700 MCM

(2) 500 to 700 MCM

(2) 250 to 350 MCM

(1) 250 to 500 MCM

(1) 250 to 500 MCM

(3) 500 to 750 MCM

(2) 500 to 700 MCM

(2) 250 to 350 MCM

(1) 250 to 500 MCM

(1) 250 to 500 MCM

(3) 500 to 750 MCM

(2) 500 to 700 MCM

(2) 250 to 350 MCM

(1) 250 to 500 MCM

(1) 250 to 500 MCM

(3) 500 to 750 MCM

(3) 500 to 750 MCM

(2) 250 to 350 MCM

(2) 250 to 350 MCM

(1) 250 to 500 MCM

(3) 500 to 750 MCM

(3) 500 to 750 MCM

(2) 250 to 350 MCM

(2) 250 to 350 MCM

(1) 250 to 500 MCM

(3) 500 to 750 MCM

(3) 500 to 750 MCM

(2) 250 to 350 MCM

(2) 250 to 350 MCM

(1) 250 to 500 MCM

30

IOMM ALS-4

Table 23, ALS 141C – ALS 218C, Wiring Information with Multiple-Point Power w/o Disconnect

ALS

UNIT

SIZE

141C

150C

171C

186C

190C

200C

206C

218C

VOLTS

208

230

380

460

575

208

230

380

460

575

208

230

380

460

575

208

230

380

460

575

208

230

380

460

575

208

230

380

460

575

208

230

380

460

208

230

380

460

575

HZ

60

60

60

60

60

60

60

60

840

840

840

840

840

840

840

840

840

840

840

840

840

840

840

840

840

840

840

840

840

840

840

840

TERMINAL SIZE (AMPS)

CKT 1 CKT 2

840

840

840

840

840

840

840

840

840

840

840

840

840

840

840

840

840

840

840

840

840

840

840

840

840

840

840

840

840

840

840

840

840

840

840

840

840

840

840

840

840

840

840

840

840

840

840

840

840

840

840

840

840

840

WIRING TO UNIT POWER BLOCK

CONNECTOR WIRE RANGE PER PHASE (COPPER WIRE ONLY)

CKT 1 CKT 2

(2) #2 to 600 MCM

(2) #2 to 600 MCM

(2) #2 to 600 MCM

(2) #2 to 600 MCM

(2) #2 to 600 MCM

(2) #2 to 600 MCM

(2) #2 to 600 MCM

(2) #2 to 600 MCM

(2) #2 to 600 MCM

(2) #2 to 600 MCM

(2) #2 to 600 MCM

(2) #2 to 600 MCM

(2) #2 to 600 MCM

(2) #2 to 600 MCM

(2) #2 to 600 MCM

(2) #2 to 600 MCM

(2) #2 to 600 MCM

(2) #2 to 600 MCM

(2) #2 to 600 MCM

(2) #2 to 600 MCM

(2) #2 to 600 MCM

(2) #2 to 600 MCM

(2) #2 to 600 MCM

(2) #2 to 600 MCM

(2) #2 to 600 MCM

(2) #2 to 600 MCM

(2) #2 to 600 MCM

(2) #2 to 600 MCM

(2) #2 to 600 MCM

(2) #2 to 600 MCM

(2) #2 to 600 MCM

(2) #2 to 600 MCM

(2) #2 to 600 MCM

(2) #2 to 600 MCM

(2) #2 to 600 MCM

(2) #2 to 600 MCM

(2) #2 to 600 MCM

(2) #2 to 600 MCM

(2) #2 to 600 MCM

(2) #2 to 600 MCM

(2) #2 to 600 MCM

(2) #2 to 600 MCM

(2) #2 to 600 MCM

(2) #2 to 600 MCM

(2) #2 to 600 MCM

(2) #2 to 600 MCM

(2) #2 to 600 MCM

(2) #2 to 600 MCM

(2) #2 to 600 MCM

(2) #2 to 600 MCM

(2) #2 to 600 MCM

(2) #2 to 600 MCM

(2) #2 to 600 MCM

(2) #2 to 600 MCM

575 840 840 (2) #2 to 600 MCM

NOTES:

1. Terminal size amps are the maximum amps that the power block is rated for.

2. See Table 24 for multiple point with Disconnect Switch connections

3. Complete notes are on page 33.

(2) #2 to 600 MCM

(2) #2 to 600 MCM

(2) #2 to 600 MCM

(2) #2 to 600 MCM

(2) #2 to 600 MCM

(2) #2 to 600 MCM

(2) #2 to 600 MCM

(2) #2 to 600 MCM

(2) #2 to 600 MCM

(2) #2 to 600 MCM

(2) #2 to 600 MCM

(2) #2 to 600 MCM

(2) #2 to 600 MCM

(2) #2 to 600 MCM

(2) #2 to 600 MCM

(2) #2 to 600 MCM

(2) #2 to 600 MCM

(2) #2 to 600 MCM

(2) #2 to 600 MCM

(2) #2 to 600 MCM

(2) #2 to 600 MCM

(2) #2 to 600 MCM

(2) #2 to 600 MCM

(2) #2 to 600 MCM

(2) #2 to 600 MCM

IOMM ALS-4

31

32

Table 24, ALS 141C –218C, Wiring Data with Multiple-Point Power w/ Disconnect Switch

ALS

UNIT

SIZE

141C

150C

171C

186C

190C

200C

VOLTS

208

230

380

460

575

208

230

380

460

575

208

230

380

460

575

208

230

380

460

575

208

230

380

460

575

208

230

380

460

575

HZ

60

60

60

60

60

60

TERMINAL SIZE (AMPS)

CKT 1 CKT 2

400

400

225

150

150

400

400

225

150

150

400

400

225

225

150

400

400

225

225

150

400

400

225

225

150

600

600

250

225

225

400

400

225

150

150

400

400

225

225

150

400

400

225

225

150

600

600

250

225

225

600

600

250

225

225

600

600

250

225

225

WIRING TO UNIT DISCONNECT SWITCH

CONNECTOR WIRE RANGE PER PHASE (COPPER WIRE ONLY)

CKT 1

(1) 250 to 500 MCM

(1) 250 to 500 MCM

(1) 4 to 4/0

(1) 4 to 4/0

(1) 4 to 4/0

(2) 3/0 to 250 MCM

(1) 250 to 500 MCM

(1) 4 to 4/0

(1) 4 to 4/0

(1) 4 to 4/0

(2) 3/0 to 250 MCM

(2) 3/0 to 250 MCM

(1) 4 to 4/0

(1) 4 to 4/0

(1) 4 to 4/0

(2) 3/0 to 250 MCM

(2) 3/0 to 250 MCM

(1) 4 to 4/0

(1) 4 to 4/0

(1) 4 to 4/0

(2) 3/0 to 250 MCM

(2) 3/0 to 250 MCM

(1) 4 to 4/0

(1) 4 to 4/0

(1) 4 to 4/0

(2) 250 to 350 MCM

(2) 250 to 350 MCM

(1) 4 to 350 MCM

(1) 4 to 4/0

(1) 4 to 4/0

206C

218C

208

230

380

460

208

230

380

460

575

60

60

600

600

250

225

225

600

600

250

225

600

600

250

225

225

600

600

250

225

(2) 250 to 350 MCM

(2) 250 to 350 MCM

(1) 4 to 350 MCM

(1) 4 to 4/0

(1) 4 to 4/0

(2) 250 to 350 MCM

(2) 250 to 350 MCM

(1) 4 to 350 MCM

(1) 4 to 4/0

575 225 225 (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 33.

CKT 2

(1) 250 to 500 MCM

(1) 250 to 500 MCM

(1) 4 to 4/0

(1) 4 to 4/0

(1) 4 to 4/0

(2) 3/0 to 250 MCM

(1) 250 to 500 MCM

(1) 4 to 4/0

(1) 4 to 4/0

(1) 4 to 4/0

(2) 3/0 to 250 MCM

(2) 3/0 to 250 MCM

(1) 4 to 4/0

(1) 4 to 4/0

(1) 4 to 4/0

(2) 250 to 350 MCM

(2) 250 to 350 MCM

(1) 4 to 350 MCM

(1) 4 to 4/0

(1) 4 to 4/0

(2) 250 to 350 MCM

(2) 250 to 350 MCM

(1) 4 to 350 MCM

(1) 4 to 4/0

(1) 4 to 4/0

(2) 250 to 350 MCM

(2) 250 to 350 MCM

(1) 4 to 350 MCM

(1) 4 to 4/0

(1) 4 to 4/0

(2) 250 to 350 MCM

(2) 250 to 350 MCM

(1) 4 to 350 MCM

(1) 4 to 4/0

(1) 4 to 4/0

(2) 250 to 350 MCM

(2) 250 to 350 MCM

(1) 4 to 350 MCM

(1) 4 to 4/0

(1) 4 to 4/0

IOMM ALS-4

Electrical Data Notes

1. Allowable voltage limits

Unit nameplate 208V/60Hz/3PH: 187V to 229V

Unit nameplate 230V/60Hz/3Ph: 207V to 253V

Unit nameplate 380V/60Hz/3Ph: 342V to 418V

Unit nameplate 460V/60Hz/3Ph: 414V to 506V

Unit nameplate 575V/60Hz/3Ph: 517V to 633V

2. Unit wire size ampacity (MCA) is equal to 125% of the largest compressor-motor RLA plus 100% of RLA of all other loads in the circuit including control transformer. Wire size ampacity for separate 115V control circuit power is 15 amps for ALS 141C through ALS 295C.

3. Compressor RLA values are for wire sizing purposes only but do reflect normal operating current draw at unit rated capacity. If unit is equipped with SpeedTrol condenser fan motors, the first motor on each refrigerant circuit is a single phase, 1 hp motor, with a FLA of 2.8 amps at 460 volts (5.6 amps at 208/230 volts). If the unit is not equipped with SpeedTrol, the standard fan motor will be 1 1/2 hp, 3-phase ODP (except ALS 218C which will be 2 hp, 3-phase TEFC ) with FLA as shown in the electrical tables

4. Single point power supply requires a single disconnect to supply electrical power to the unit. The disconnect device may be in the unit as an option or supplied and installed in the field within sight of the unit. The power supply must be fused or have a HACR Type breaker.

5. Multiple point power supply requires two independent power circuits on ALS 141C-ALS 218C. The disconnect devices may be in the unit as an option or supplied and installed in the field within sight of the unit. The power supplies must be fused or have a HACR Type breaker.

6. All field wiring to unit power block or optional nonfused disconnect switch must be copper.

7. Field wire size values given in tables apply to 75°C rated wire per NEC except for ALS 200C-ALS 218C for

208V single point which require 90°C rated wire or as noted.

8. If unit is to be factory supplied with the optional non-fused disconnect switch, the recommended field wire size needs to be (6) 250MCM wire in place of the standard (6) 4/0 wire to match the disconnect switch terminal lug size which is approved for 250MCM minimum.

9. External disconnect switch(s) or HACR breakers must be field supplied. Note: On single point power units a non-fused disconnect switch in the cabinet is available as an option.

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

11. Recommended time delay fuse size or HACR circuit breakers is equal to 150% of the largest compressor motor RLA plus 100% of remaining compressor RLAs and the sum of condenser fan FLAs.

12. Maximum time delay fuse size or HACR circuit breakers is equal to 225% of the largest compressor-motor

RLA plus 100% of remaining compressor RLAs and the sum of condenser fan FLAs.

13. MCA may vary slightly due to fan motor options such as Speedtrol, TEFC.

IOMM ALS-4

33

Table 25, Electrical Legend

34

IOMM ALS-4

Field Wiring Diagram

Figure 17, Typical Field Wiring Diagram

IOMM ALS-4

35

Solid State Starters

Solid state starters are standard on all "C" Vintage ALS units. A solid state starter uses a silicon controlled rectifier (SCR) power section to allow a motor to be brought to full speed by way of a reduced initial voltage that increases to full line voltage over a given time. The McQuay motor starter, custom designed for this specific application, is microprocessor controlled. Along with this starting technique, the motor starter also provides protection for the motor and monitors its load conditions.

The starter offers:

Solid state design.

Closed-loop motor current control.

Programmable motor protection.

Programmable operating parameters.

Programmable metering options.

The three-phase starter contains a six SCR power section with two SCRs per phase connected in inverse parallel. This power section is capable of providing maximum torque per amp throughout the motor’s speed-torque curve with minimal motor and starter heating. At the same time, the starter continually monitors the amount of current being delivered to the motor, thus protecting the motor from overheating or drawing excessive current. The starter will automatically stop the motor if the line-to-line current is not within acceptable ranges or if the current is lost in a line. The motor current scaling is set according to the motor size and the specific application. The starter circuitry is contained on a single printed circuit board, which contains all the logic and SCR gate drive circuitry.

Operating messages are displayed on the three-character LED display on the control card. The LED display on the control card displays:

Operating messages that indicate the status of the motor and/or starter.

Operating parameters that are programmed into the starter.

Fault codes that indicate a problem with the motor application or starter.

Operating Messages

Possible operating messages are as follows:

Meaning

Line voltage is not present.

Message

noL rdy acc uts run dCL

Line voltage is present and starter is ready.

Motor is accelerating after a start command has been received.

The motor has achieved full speed.

Motor is operating at full speed, and ramp time has expired.

OL

A Stop command was received and the motor is decelerating with the set deceleration profile.

OL will alternately blink with the normal display on the LED display when motor thermal overload content has reached 90% to 99% of its capacity.

36

IOMM ALS-4

IOMM ALS-4

F29

F30

F31

F52

F53

F16

F17

F23

F24

F4

F5

F6

F11

CODE

F1

F2

F3

OLL

OLt

The motor thermal overload content has reached 100%, and the motor has stopped. The motor cannot be restarted until the overloaded motor has cooled and

OLt is displayed.

The motor thermal overload content has been reduced to 60% or less, and the motor may be restarted.

Passcode protection is enabled.

ena dis oxx

Passcode is disabled.

xx = overload thermal content in percentage. Press the Down button to toggle to this display.

xx = pending fault.

cxx no

Attempted to change a passcode protected parameter.

… Three decimal places blink when remote display is active.

Fault Codes

Fault codes will be displayed on the red, three-character LED display. Fault codes indicate a problem with the starter or motor application.

FAULT

Power line phase sensitivity parameter set to ABC for CBA line sequence.

Power line phase sensitivity parameter set to CBA for ABC line sequence.

System power is not three phase.

System power is not single phase.

Line frequency is less than 25 Hz.

Line frequency is greater than 72 Hz.

Line sequence has changed since last start.

Excessive line noise.

Extreme line noise.

Line current imbalance is greater than set current imbalance level.

Line current became very unbalanced while the motor was running.

Operating parameters have been lost.

Three phase default parameters have been loaded.

Single-phase default parameters have been loaded.

A motor current greater than 12.5% was detected while the motor was stopped.

No current detected after “Run” command was given.

37

38

F73

F74

F75

F77

F54

F55

F70

F71

F78

F90

F92

F97

F98

An undercurrent trip has occurred.

An overcurrent trip has occurred.

Control power is too low.

Motor current transformer scaling switches were changed while the motor was running.

Bypass failed to operate when unit came up to speed.

The motor stalled while accelerating.

External fault.

Control card fault.

Control card fault.

Incorrect set-up.

A shorted SCR was detected during acceleration.

Control card fault.

Line power was missing when Start command was given or while starter was operating the motor.

Load current very high.

F99

Preventative Maintenance

During Commissioning;

Torque all power connections during commissioning. This includes factory wired components.

Check all of the control wiring in the package for loose connections.

During the first month after the starter has been put in operation;

Re-torque all power connections every two weeks. This includes factory-wired components.

Inspect cooling fans (if applicable) after two weeks to ensure proper operation.

After the first month of operation;

Re-torque all power connections every year.

Clean any accumulated dust from the starter using a clean source of compressed air.

Inspect the cooling fans (if applicable) every three months to ensure proper operation.

Clean or replace any air vent filters on the starter every three months.

NOTE:

If mechanical vibrations are present at the installation site, inspect the connections more frequently.

IOMM ALS-4

IOMM ALS-4

Figure 18, Trouble Shooting Guide

Start

Replace

Fuses

Replace

Circuit

Breaker

Correct

Inline Fault

No

No

F uses OK?

1

Yes

Circuit

Breaker OK?

2

Yes

No

In-Line OK?

Yes

Correct Power

S ource

Problem

Correct

Interlock

State

Correct

Wiring

Yes

3

Low or Missing

L ine?

No

Phase Order

Fault

4

No

Yes

Yes

No

Thermal Trip?

5

Yes

No

Interlock

Open?

6

No

Wiring OK?

7

Yes

No

Replace

Control Card

Does Problem

Still Exist

Yes

Goto Page 2

S wap Any

2 Power

Leads

No

High

Ambient?

8

Yes

No

Correct and

Wait to Cool

Return To

Service

Yes

No

Bad Air

Circulation?

9

No

Motor

Overloaded?

10

Yes

Wiring OK?

7

Yes

Lower Motor

Load

Correct

Wiring

Correct and

Wait to Cool

Return To

Service

39

40

From Page 1

Correct Wiring

Replace

Defective SCRs

11

Cu rrent

Imbalance Fault?

No

Yes

No

7

Wiring Good?

Yes

14

All Gate

Pulses Present?

Yes

No

Fuses Blown or

Breaker Tripped?

Yes

No

No

12

Motor

Winding Short?

Yes

No

Replace Fuse

or Reset Breaker

SCRs OK?

13

Yes

12

Motor P roblem?

No

Yes

Repair or

Replace Motor

Replace

Control Card

Contact

Benshaw

For Assistance

CT Burden

Switches Set

Correctly?

Yes

Replace

Control Card

15

No

Check Jumpers

Parameters and CTs

Return to

Normal

Op eration

No

Does Problem

Still Exist?

Yes

Con tact

Benshaw

For Assistance

IOMM ALS-4

IOMM ALS-4

1.

2.

3.

Fuses

Circuit Breaker

Power Line Voltage

FLOWCHART DETAILS:

Determine if power line fuses have been installed, and if they are operating properly.

Determine if the circuit breaker is off, or has tripped and disconnected the line from the starter.

Verify that line voltage is present, and is the correct voltage.

4.

5.

6.

7.

8.

9.

Phase Order Fault

Heat Sink Switch

Safety Device

Wiring Connections

Air Temperature

Air Circulation

10. Motor Overload

11. Current Imbalance Fault

12. Motor Winding Problem

If Fault Codes F1 or F2 are displayed on the control card LED display exchange any two incoming power line cable connections.

Investigate whether heat sink thermal switch is open.

Determine if an equipment protection device attached to the starter is disabling the start command.

Verify that the wiring connections are correct and the terminations are tightened.

Investigate whether the air temperature surrounding the heat sink is hot.

Determine if the airflow around the heat sink fins is being restricted, or if a fan has failed.

Determine if the motor’s load is too large for the motor size.

If Fault Codes F23 or F24 are displayed on the control card

LED display, diagnose and correct the cause of the current imbalance parameter P16.

Conducting a megger test of the motor may identify an internal motor winding problem. NOTE: To avoid damaging the starter isolate the motor before conducting the megger test.

CAUTION:

Hazardous voltages exist at the starter terminals. LOCK OUT ALL OF THE POWER SOURCES before making resistance measurements to avoid personal injury

13. SCRs

14. Gate Pulses

15. Motor Current

This step may help determine if a problem exists with the SCRs.

Using a multi-meter or similar device, measure the resistance between:

L1 terminal and T1 terminal

L2 terminal and T2 terminal

L3 terminal and T3 terminal

The resistance should be more than 50k ohms. Measure the gate resistance between the white and red of each twisted pair (6 total). The gate resistance should be between 8 and 50 ohms

.

This step may help to determine if the control card is functioning properly. Check for gate firing voltage between 0.3 and 1.5

volts when the card is operating.

Determine if motor current signal scaling is correct

.

41

42

Solid State Starter Settings

Operating Parameters

Parameter Description Default Programmed

P1...................Motor Full Load Amps .................................. 1 Amp .............

P2...................Motor Service Factor.......................................1.25 ...............

P3...................Motor Thermal Overload .............................Class 10 ............

P4...................Initial Motor Starting Current.........................225% ..............

P6...................Motor Ramp Time .......................................7 seconds ...........

P7...................Motor Stall Time ........................................10 seconds ..........

P8...................Deceleration Level 1 ......................................100% ..............

P9...................Deceleration Level 2 ........................................0% ................

P10.................Deceleration Time .......................................2 seconds ...........

P11.................Overcurrent Trip Level...................................140% ..............

P12.................Overcurrent Trip Time.................................2 seconds ...........

P13.................Undercurrent Trip Level..................................25% ...............

P14.................Undercurrent Trip Time....................................Off ................

P15.................Line Phasing Sensitivity ................................. ABC...............

P16.................Motor Current Imbalance ................................10% ...............

P17.................Current Transformer Ratio .......(460Volt) ....... 864................

(208Volt) .....2.64

P18.................Meter Mode...................................................... 10.................

P19.................Meter Dwell Time ............................................Off ................

P20.................Passcode ...........................................................Off ................

P21.................Auto Reset Capability ......................................Off ................

IOMM ALS-4

Unit Layout and Principles of Operation

Major Component Location

Figure 19, ALS 141-218

14 Fans ALS 190-218C

12 Fans ALS 171-186C

10 Fans ALS 141-150C

Cond

Fan

11

Cond

Fan

21

Cond

Fan

12

Cond

Fan

22

Cond

Fan

13

Cond

Fan

23

Cond

Fan

14

Cond

Fan

24

Cond

Fan

15

Cond

Fan

25

Cond

Fan

16

Cond

Fan

26

Cond

Fan

17

Cond

Fan

27

Compressor

#1

Compressor

#2

Inlet Outlet

Control Center

All electrical controls are enclosed in a weather resistant control center with keylocked, hinged access doors. The control center is composed of two separate compartments, high voltage and low voltage.

All of the high voltage components are located in the compartment on the right side of the unit.

The low voltage components are located on the left side with the 115 VAC terminals located behind the deadfront panel. This protects service personnel from 115 VAC terminals when accessing the adjustable and resettable controls.

IOMM ALS-4

43

44

Figure 20, Control Center Layout, ALS 141C-218C

AOX EXV

KEYPAD

MECH. RELAYS

F1 C0 F2

NB

LOW VOLTAGE WIREWAY

MCB1 A01

LOW VOLTAGE WIREWAY

TB4

TB5

LOW VOLTAGE WIREWAY

T4

T8

T2

T7

SC

Sequence of Operation

The following sequence of operation is typical for McQuay models ALS chillers. The sequence may vary depending on the software revision or various options that may be installed on the chiller.

Off conditions

With power supplied to the unit, 115 VAC power is applied through the control fuse F1 to the compressor heaters (HTR1, HTR2, HTR3, HTR4 and evaporator heater) and the primary of the 24V control circuit transformer. Note: Compressor heaters must be on for at least 12 hours prior to

start-up.

The 24V transformer provides power to the MicroTech controller and related components.

With 24V power applied, the controller will check the position of the front panel system switch. If the switch is in the "stop" position the chiller will remain off and the display will indicate the operating mode to be OFF: System Sw. The controller will then check the pumpdown switches. If any of the switches are in the "stop" position, that circuit’s operating mode will be displayed as OFF:

PumpDwnSw.

If the switches for both circuits are in the "Stop" position the unit status will display

OFF: PumpdownSw’s

. If the remote start/stop switch is open the chiller will be OFF: RemoteSw.

The chiller may also be commanded off via communications from a separate communicating panel such as the Remote Monitoring and Sequencing Panel or an Open Protocol interface. The display will show OFF: RemoteComm if this operating mode is in effect. If an alarm condition exists which prevents normal operation of both refrigerant circuits, the chiller will be disabled and the display will indicate OFF: Alarm. If the control mode on the keypad is set to "Manual Unit Off," the chiller will be disabled and the unit status will display OFF: ManualMode. Assuming none of the above stop conditions are true, the controller will examine the internal time schedule to determine whether the chiller should be permitted to start. The operating mode will be OFF: TimeClock if the time schedule indicates time remaining in an "off" time period.

IOMM ALS-4

IOMM ALS-4

Alarm

The alarm light on the front panel will be illuminated when one or more of the cooling circuits has an active alarm condition which results in the circuit being locked out. Unless the alarm condition affects all circuits the remaining circuits will operate as required. Please refer to current version of

IM ALSMICRO for details.

Start-up

If none of the above "off" conditions are true, the MicroTech controller will initiate a start sequence and energize the chiller water pump output relay. The chiller will remain in the WaitForFlow mode until the field installed flow switch indicates the presence of chilled water flow. If flow is not proven within 30 seconds, the alarm output will be turned on, the keypad display will be WaitForFlow and the chiller will continue to wait for proof of chilled water flow. Once flow is established, the controller will sample the chilled water temperature and compare it against the Leaving Chilled Water

Set Point, the Control Band, and the Start-up Delta Temperature, which have been programmed into the controller’s memory. If the leaving chilled water temperature is above the Leaving Chilled Water

Set Point plus ½ the Control Band plus the adjustable Start-up Delta Temperature, the controller will select the refrigerant circuit with the lowest number of starts as the lead circuit and energize the first stage of the Cool Staging mode. The controller will start the compressor and energize the compressor liquid injection solenoid along with the main liquid line solenoid. The controller will delay the opening of the electronic expansion valve until the evaporator pressure decreases to a preset value.

This is the evaporator prepurge mode and the display will show Pre-Purge. The valve will then open allowing refrigerant to flow through the expansion valve and into the evaporator and the display will show Opened EXV. If additional cooling capacity is required, the controller will energize the additional cooling capacity by activating the first compressor’s capacity control solenoids. As the system load increases, the controller will start the lag refrigerant circuit in the same manner after interstage timers are satisfied. The compressors and capacity control solenoids will automatically be controlled as required to meet the cooling needs of the system. The electronic expansion valves are operated by the MicroTech controller to maintain precise refrigerant control to the evaporator at all conditions.

Condenser Control

The first condenser fan stage will be started along with the first compressor to provide initial condenser head pressure control. The MicroTech controller will activate the remaining condenser fans as needed to maintain proper condenser pressure. The MicroTech controller continuously monitors the condenser minus evaporator lift pressure and will adjust the number of operating condenser fans as required. The number of condenser fans operating will vary with outdoor temperature and system load. The condenser fans are matched to the operating compressors so that when a compressor is off all fans for that circuit will also be off. On units with the fan speed control option (SpeedTrol) the lead fan on each circuit will vary in speed to maintain condenser pressure at lower outdoor temperatures.

Pumpdown

As the system chilled water requirements diminish. The compressors will be unloaded. As the system load continues to drop, the electronic expansion valves will be stepped closed and the refrigerant circuits will go through a pumpdown sequence. As the evaporator pressure falls below the pumpdown pressure set point while pumping down, the compressor(s) and condenser fans will stop. The unit has a one time pumpdown control logic; therefore, if the evaporator pressure rises while the refrigerant circuit is in a pumpdown mode, the controller will not initiate another pumpdown sequence. The controller will keep the unit off until a call for cooling occurs. Refer to the pumpdown control section in the current version of OM ALSMICRO for additional details. The chilled water pump output relay will remain energized until the time schedule’s "on" time expires, the remote stop switch is opened, the system switch is moved to the stop position, or a separate communications panel such as the

Remote Monitoring and Sequencing Panel or an Open Protocol interface deactivates the chilled water pump output.

45

WARNING

The screw compressor must not be used as a pump out compressor for service work involving removal of refrigerant from the compressor or evaporator. That is, the compressor must not be run with the liquid line valve (king valve) closed. Portable recovery equipment must be used to remove the refrigerant.

Figure 21, ALS Piping Schematic

46

IOMM ALS-4

Start-up and Shutdown

NOTICE

McQuayService personnel or factory authorized service agency must perform initial start-up.

CAUTION

Most relays and terminals in the unit control center are powered when S1 is closed and the control circuit disconnect is on. Therefore do not close S1 until ready for start-up.

Seasonal Start-up

1. Double check that the compressor suction and discharge shutoff valves are backseated. Always replace valve seal caps.

2. Insure that the ball valves are open on the lines entering the evaporator.

3. Insure that the manual liquid-line shutoff valve at the outlet of the subcooler is open.

4. Adjust the leaving chilled water temperature set point on the MicroTech controller to the desired chilled water temperature. The control band is preset for 10 degrees Delta-T between the entering and leaving evaporator water temperature at full load. If the Delta-T is outside an 8

°

-

12

°

F range, at full load, reset the control band as per the instructions found in the MicroTech

Manual IM ALSMICRO.

5. Start the auxiliary equipment for the installation by turning on the time clock, and/or remote on/off switch, and chilled water pump.

6. Check to see that pumpdown switches PS1 and PS2 are in the "Pumpdown and Stop" (open) position. Throw the S1 switch to the "auto" position.

7. Under the "Control Mode" menu of the keypad place the unit into the automatic cool mode.

8. Start the system by moving pumpdown switch PS1 to the "auto" position.

9. After running circuit #1 for a short time, check for flashing in the refrigerant sightglass under stable conditions.

10. Repeat steps 8 and 9 for PS2.

11. Superheat is factory adjusted to maintain between 6

°

and 12

°

F.

CAUTION

The superheat should be between 6

°

F and 12

°

F, with the liquid line sightglass full, once the system temperatures have stabilized at the MicroTech set point temperatures.

Temporary Shutdown

Move pumpdown switches PS1 and PS2 to the "Pumpdown and Stop" position. After the compressors have pumped down, turn off the chilled water pump. Caution: Do not turn the unit off using the "S1" switch, without first moving PS1 and PS2 to the "Stop" position, unless it is an emergency as this will prevent the unit from going through a pumpdown.

IOMM ALS-4

47

48

IMPORTANT

The unit has one time pumpdown operation. When PS1 and PS2 are in the "Pumpdown and Stop" position the unit will pumpdown once and not run again until the PS1 and PS2 switches are moved to the auto position. If PS1 and PS2 are in the auto position and the load has been satisfied the unit will go into one time pumpdown and will remain off until MicroTech senses a call for cooling and starts the unit. Under no circumstance use the compressors for pumpdown with the liquid line valves closed.

CAUTION

The unit must not be cycled off by using the evaporator pump or the disconnect switch.

It is important that the water flow to the unit is not interrupted before the compressors pumpdown to avoid freeze-up in the evaporator.

If all power is turned off to the unit the compressor heaters will become inoperable. Once power is resumed to the unit it is important that the compressor heaters are energized a minimum of 12 hours before attempting to start the unit. Failure to do so could damage the compressors due to excessive accumulation of liquid in the compressor.

Start-up After Temporary Shutdown

1. Insure that the compressor heaters have been energized for at least 12 hours prior to starting the unit.

2. Start the chilled water pump.

3. With System switch S1 in the "on" position, move pumpdown switches PS1 and PS2 to the

"auto" position.

4. Observe the unit operation until the system has stabilized.

WARNING

If shutdown occurs or will continue through periods below freezing ambient temperatures, protect the chiller vessel from freezing.

Extended (Seasonal) Shutdown

1. Move the PS1 and PS2 switches to the manual pumpdown position.

2. After the compressors have pumped down, turn off the chilled water pump.

3. Turn off all power to the unit and to the chilled water pump.

4. Move the emergency stop switch S1 to the "off" position.

5. Close the compressor suction and discharge valves as well as the liquid line shutoff valves.

6. Tag all opened disconnect switches to warn against start-up before opening the compressor suction and discharge valves and liquid line shutoff valves.

7. If glycol is not used in the system, drain all water from the unit evaporator and chilled water piping if the unit is to be shutdown during winter. Do not leave the vessels or piping open to the atmosphere over the shutdown period.

8. Leave power applied to the evaporator heating cable if a separate disconnect is used.

IOMM ALS-4

Start-up After Extended (Seasonal) Shutdown

1. With all electrical disconnects open, check all screw or lug type electrical connections to be sure they are tight for good electrical contact.

2. Check the voltage of the unit power supply and see that it is within the

±

10% tolerance that is allowed. Voltage unbalance between phases must be within

±

3%.

3. See that all auxiliary control equipment is operative and that an adequate cooling load is available for start-up.

4. Check all compressor valve connections for tightness to avoid refrigerant loss. Always replace valve seal caps.

5. Make sure system switch S1 is in the "Stop" position and pumpdown switches PS1 and PS2 are set to "Pumpdown and Stop," throw the main power and control disconnect switches to "on."

This will energize crankcase heaters. Wait a minimum of 12 hours before starting up unit. Turn compressor circuit breakers to "off" position until ready to start unit.

6. Open the compressor suction and discharge valves as well as the liquid line shutoff valves.

7. Vent the air from the evaporator water side as well as from the system piping. Open all water flow valves and start the chilled water pump. Check all piping for leaks.

IOMM ALS-4

49

System Maintenance

General

On initial start-up and periodically during operation, it will be necessary to perform certain routine service checks. Among these are checking the liquid line sightglasses and taking condensing and section pressure readings. Through the MicroTech keypad, check to see that the unit has normal superheat and subcooling readings. A recommended maintenance schedule is located at the end of this section.

A Periodic Maintenance Log is located at the end of this manual. It is suggested that the report be completed on a weekly basis. The log will serve as a useful tool for a service technician in the event service is required.

Compressor Maintenance

Since the compressor is semi-hermetic no yearly compressor maintenance is normally required.

However, vibration is an excellent check for proper mechanical operation. Compressor vibration is an indicator of the requirement for maintenance and contributes to a decrease in unit performance and efficiency. It is recommended that the compressor be checked with a vibration analyzer at or shortly after start-up and again on an annual basis. When performing the test the load should be maintained as closely as possible to the load of the original test. The initial vibration analyzer test provides a benchmark of the compressor and when performed routinely can give a warning of impending problems.

Lubrication

No routine lubrication is required on ALS units. The fan motor bearings are permanently lubricated.

No further lubrication is required. Excessive fan motor bearing noise is an indication of a potential bearing failure.

Compressor oil must be Planetelf

ACD68AW. McQuay Part Number 735030439 in a 5 gallon container, 735030438 in 1 gallon size. This is synthetic polyolester oil with anti-wear additives and is highly hygroscopic. Care must be taken to minimize exposure of the oil to air when charging oil into the system.

An oil filter is located in the oil return line from the oil separator to the compressor. This filter should be replaced if the pressure drop exceeds 25 psi as measured at Schrader fittings up and down stream from the filter.

Electrical Terminals

WARNING

Electric shock hazard. Turn off all power before continuing with following service.

Periodically check electrical terminals for tightness and tighten as required.

Condensers

The condensers are air-cooled and constructed of 3/8" (9.5mm) OD internally finned copper tubes bonded in a staggered pattern into louvered aluminum fins. No maintenance is ordinarily required except the routine removal of dirt and debris from the outside surface of the fins. McQuay recommends the use of foaming coil cleaners available at most air conditioning supply outlets. Use caution when applying such cleaners as they may contain potentially harmful chemicals. Care should be taken not to damage the fins during cleaning.

50

IOMM ALS-4

IOMM ALS-4

If the service technician has reason to believe that the refrigerant circuit contains noncondensables, purging may be required strictly following Clean Air Act regulations governing refrigerant discharge to the atmosphere. The purge Schrader valve is located on the vertical coil header on both sides of the unit at the control box end of the coil. Access panels are located at the end of the condenser coil directly behind the control panel. Purge with the unit off, after shutdown of 15 minutes or longer, to allow air to collect at the top of the coil. Restart and run the unit for a brief period. If necessary, shut unit off and repeat the procedure. Follow accepted environmentally sound practices when removing refrigerant from the unit.

Refrigerant Sightglass

The refrigerant sightglasses should be observed periodically. (A weekly observation should be adequate.) A clear glass of liquid indicates that there is adequate refrigerant charge in the system to provide proper feed through the expansion valve. Bubbling refrigerant in the liquid line sightglass, during stable run conditions, indicates that the system may be short of refrigerant charge. Refrigerant gas flashing in the sightglass could also indicate an excessive pressure drop in the liquid line, possibly

due to a clogged filter-drier or a restriction elsewhere in the liquid line (see Table 27 for maximum

allowable pressure drops). If subcooling is low add charge to clear the sightglass. If subcooling is normal (10

°

-15

°

F) and flashing is visible in the sightglass check the pressure drop across the filterdrier. Subcooling should be checked at full load with 70

°

F (21.1

°

C) outdoor air temperature and all fans running.

An element inside the sightglass indicates the moisture condition corresponding to a given element color. If the sightglass does not indicate a dry condition after about 12 hours of operation, the circuit should be pumped down and the filter-drier changed.

Lead-Lag

A feature on all McQuay ALS air-cooled chillers is a system for alternating the sequence in which the compressors start to balance the number of starts and run hours. Lead-Lag of the refrigerant circuits is accomplished automatically through the MicroTech Controller. When in the auto mode the circuit with the fewest number of starts will be started first. If all circuits are operating and a stage down in the number of operating compressors is required, the circuit with the most operating hours will cycle off first. The operator may override the MicroTech controller, and manually select the lead circuit as circuit #1, #2, #3 or circuit #4.

51

52

Preventative Maintenance Schedule

PREVENTATIVE MAINTENANCE SCHEDULE

OPERATION WEEKLY

MONTHLY

(Note 1)

General

Complete unit log and review (Note 3)

Visually inspect unit for loose or damaged components

Inspect thermal insulation for integrity

Clean and paint as required

X

X

Electrical

Check terminals for tightness, tighten as necessary

Clean control panel interior

Visually inspect components for signs of overheating

Verify compressor heater operation

Megger compressor motor every five years

Refrigeration

Leak test

Check sight glasses for clear flow

Check filter-drier pressure drop (see manual for spec)

Perform compressor vibration test

X

X

X

X

X

Condenser (air-cooled)

Clean condenser coils (Note 4)

Check fan blades for tightness on shaft (Note 5)

Check fans for loose rivets and cracks

Check coil fins for damage

Notes:

1. Monthly operations include all weekly operations.

2. Annual (or spring start-up) operations includes all weekly and monthly operations.

3. Log readings may be taken daily for a higher level of unit observation.

4. Coil cleaning may be required more frequently in areas with a high level of airborne particles.

5. Be sure fan motors are electrically locked out.

ANNUAL

(Note 2)

X

X

X

X

X

X

X

X

X

IOMM ALS-4

Service

IOMM ALS-4

CAUTION

1. Service on this equipment is to be performed by qualified refrigeration personnel familiar with equipment operation, maintenance, correct servicing procedures, and the safety hazards inherent in this work. Causes for repeated tripping of equipment protection controls must be investigated and corrected.

2. Disconnect all power before doing any service inside the unit.

3. Anyone servicing this equipment shall comply with the requirements set forth by the EPA in regards to refrigerant reclamation and venting.

Compressor Solenoids

The ALS unit screw compressors are equipped with 3 solenoids to control compressor unloading.

The solenoids are controlled by MicroTech outputs. See unit wiring diagrams. The solenoids are energized at various compressor load conditions as indicated in the table below.

Table 26, Compressor Unloading

COMPRESSOR

LOADING %

100%

75%

50%

25%

COMPRESSOR UNLOADING SOLENOID STATUS

TOP

SOLENOID

BOTTOM FRONT

SOLENOID

BOTTOM REAR

SOLENOID

Energized

Energized

Off

Off

Off

Energized

Off

Energized

Energized

Off

Energized

Off

Location of the solenoids is as follows:

The top solenoid is on top of the compressor near the discharge end.

The bottom solenoids are on the lower side of the compressor on the opposite side from the terminal box. The bottom front solenoid is the one closest to the discharge end of the compressor. The bottom rear solenoid is the one closest to the motor end of the compressor.

If the compressor is not loading properly check the solenoids to see if they are energized per the above chart. A complete check will include a check of the MicroTech output, the wiring to the solenoid and the solenoid coil itself.

Filter-Driers

A replacement of the filter-drier is recommended any time excessive pressure drop is read across the filter-drier and/or when bubbles occur in the sightglass with normal subcooling. The maximum recommended pressure drop across the filter-drier is as follows:

Table 27, Filter-Drier Pressure Drop

PERCENT CIRCUIT

LOADING (%)

100%

75%

50%

25%

MAXIMUM RECOMMENDED PRESSURE

DROP ACROSS FILTER DRIER PSIG (KPA)

7 (48.3)

5 (34.5)

3 (20.7)

3 (20.7)

53

54

The filter-drier should also be changed if the moisture indicating liquid line sightglass indicates excess moisture in the system.

During the first few months of operation the filter-drier replacement may be necessary if the pressure drop across the filter-drier exceeds the values listed in the paragraph above. Any residual particles from the condenser tubing, compressor and miscellaneous components are swept by the refrigerant into the liquid line and are caught by the filter-drier.

The following is the procedure for changing the filter-drier core:

This procedure is slightly different from a typical reciprocating compressor unit due to the use of a liquid injection feature on the ALS screw compressor unit. Anytime the compressor contactor is closed, liquid from the liquid line is injected into the screw for cooling and sealing the rotor. This liquid injection also occurs during normal pumpdown and limits how low a pumpdown pressure can be achieved.

The standard unit pumpdown is set to stop pumpdown when 34 psig (235 kPa) suction pressure is reached. To fully pump down a circuit beyond 34 psig (235kPa) for service purposes a "Full

Pumpdown" service mode can be activated using the keypad. Go to the "Alarm Spts" Menu on the

MicroTech keypad, step through the menu items until "FullPumpDwn" is displayed. Change the setting from "No" to "Yes".

The next time either circuit is pumped down, the pumpdown will continue until the evaporator pressure reaches 2 psig (14 kPa) or 60 seconds have elapsed, whichever occurs first. Upon completing the pumpdown, the "FullPumpDwn" set point is automatically changed back to "No".

The procedure to perform a full service pumpdown for changing the filter-drier core is as follows:

1. Perform a normal pumpdown to 34 psig (235 kPa) by moving the pumpdown switch to the

"Pumpdown" position. This step will pump down the evaporator with compressor liquid injection still active.

2. Under the "Alarm Spts", change the "FullPumpDwn" set point from "No" to "Yes".

3. The circuit status should be "Off:PumpDwnSw". Move the circuit pumpdown switch from

"Pumpdown and Stop" to "Auto". Also clear the anticycle timers through the MicroTech keypad.

4. The compressor should pump down the circuit until the evaporator pressure reaches 2 psig (14 kPa) or 60 seconds has elapsed, whichever occurs first.

5. Upon completing the full pumpdown per step 4, the "FullPumpDwn" set point is automatically changed back to "No" which reverts back to standard 34 psig (235 kPa) stop pumpdown pressure.

6. If the pumpdown does not go to 2 psig (14 kPa) on the first attempt, one more attempt can be made by repeating steps 3, 4 and 5 above. Do not repeat "FullPumpDwn" more than once to avoid excessive screw temperature rise under this abnormal condition.

7. The circuit is now in the deepest pumpdown which can equipment protection be achieved by the use of the compressor. Close the liquid line shutoff valve upstream of the filter-drier, on the circuit to be serviced plus the suction shutoff valve and the liquid/vapor shutoff valve. Any remaining refrigerant must be removed from the circuit by the use of a refrigerant recovery unit.

8. Loosen the cover bolts, remove the cap and remove the filter.

9. Evacuate and open valves.

Remove and replace the filter-drier(s). If the refrigerant circuit is opened for more than 10 minutes evacuate the lines through the liquid line manual shutoff valve(s) to remove noncondensables that may have entered during filter replacement. A leak check is recommended before returning the unit to operation.

IOMM ALS-4

IOMM ALS-4

Liquid Line Solenoid Valve

The liquid line solenoid valves that shut off refrigerant flow in the event of a power failure does not normally require any maintenance. (On a sudden power failure the electronic expansion valve

remains open at the position it was at when the power failure occurred. During normal operation the

EEV closes for automatic pumpdown and the liquid line solenoid valve closes only when the compressor stops

.) The solenoids may, however, require replacement of the solenoid coil or of the entire valve assembly.

The solenoid coil can be checked to see that the stem is magnetized when energized by touching a screwdriver to the top of the stem. If there is no magnetization either the coil is bad or there is no power to the coil.

The solenoid coil may be removed from the valve body without opening the refrigerant piping after first moving pumpdown switches PS1, PS2, and PS3 to the "manual pumpdown" position and opening the S1 switch. For personal safety shut off and lock out the unit power.

The coil can then be removed from the valve body by simply removing a nut or snap-ring located at the top of the coil. The coil can then be slipped off its mounting stud for replacement. Be sure to replace the coil on its mounting stud before returning pumpdown switches PS1, PS2 and PS3 to the

"auto pumpdown" position. Failure to do so will lead to solenoid coil failure.

To replace the entire solenoid valve follow the steps involved when changing a filter-drier.

Electronic Expansion Valve

The electronic expansion valve is located adjacent to the compressor. The refrigerant is piped to first pass through the electronic expansion valve, then through the motor housing cooling the motor before

going into the evaporator. Refer to the Figure 21, ALS Piping Schematic.

The expansion valve meters the amount of refrigerant entering the evaporator to match the cooling load. It does this by maintaining a constant superheat. (Superheat is the difference between the actual refrigerant temperature of the vapor as it leaves the evaporator and the saturation temperature corresponding to the evaporator pressure.) All ALS chillers are factory set between 8

°

F (4.5

°

C) and

12

°

F (6.6

°

C) superheat at 75% to 100% load and between 6

°

F (3.3

°

C) and 10

°

F (5.6

°

C) below 75% load. The superheat is controlled by the microprocessor and is not adjustable.

The expansion valve, like the solenoid valve, should not normally require maintenance, but if it requires replacement, the unit must be pumped down by following the steps involved when changing a filter-drier.

If the problem can be traced to the electric motor only, it can be unscrewed from the valve body without removing the valve but only after pumping the unit down. Disassemble valve at the brass hex nut. Do not disassemble valve at the aluminum housing.

55

Figure 22, Electronic Expansion Valve

56

Electronic Expansion Valve Operation

There are three colored indicator LEDs (green, red, yellow) located in the control panel on the electronic expansion valve (EXV) board. When the control panel is first powered the microprocessor will automatically step the valve to the fully closed (shut) position and the indicator lights on the EXV will blink in sequence. The valve can also be heard closing as it goes through the steps. The valve will take approximately 14 seconds to go from a full open position to a full closed position.

The position of the valve can be viewed at any time by using the MicroTech keypad through the circuit pressure menus. There are a total of 760 steps between closed and full open.

A feature of the electronic expansion valve is a maximum operating pressure setting (MOP). This setting limits the load on the compressor during start-up periods where high return evaporator water temperatures may be present. The valve will limit the maximum suction pressure at start-up to approximately 85 psig (586 kPa). The valve will close to a point necessary to maintain the 85 psig

(586 kPa). During this time the superheat will rise above 12

°

F (6.6

°

C) and not drop below 12

°

F

(6.6

°

C) until the suction pressure drops below 85 psig (586 kPa). The valve will maintain evaporator pressure close to 85 psig (586 kPa) until the evaporator water temperature decreases to approximately

55

°

F to 60

°

F (12.7

°

C to 15.6

°

C).

When the circuit starts the valve opens as soon as the evaporator pressure decreases to 40 psig (275 kPa). At the end of the cooling cycle the valve closes causing the system to pump down. The valve closes at the rate of approximately 55 steps per second, or from full open to full closed in approximately 14 seconds. The valve closing during pumpdown will occur in approximately 20-30 seconds after the pumpdown switch is moved to the "Pumpdown and Stop" position.

IOMM ALS-4

IOMM ALS-4

Evaporator

The evaporator is the direct expansion, shell-and-tube type with refrigerant flowing through the tubes and water flowing through the shell over the tubes. The tubes are internally finned to provide extended surface as well as turbulent flow of refrigeration through the tubes. Normally no service work is required on the evaporator.

Charging Refrigerant

ALS air-cooled screw chillers are shipped factory charged with a full operating charge of refrigerant but there may be times that a unit must be recharged at the job site. Follow these recommendations

when field charging. Refer to the unit operating charge found in the Physical Data Tables, Table 14 and Table 15.

Unit charging can be done at any steady load condition (preferably at 75 to 100% load) and at any outdoor temperature (preferably higher than 70

°

F (21.1

°

C). Unit must be allowed to run 5 minutes or longer so that the condenser fan staging is stabilized at normal operating discharge pressure. For best results charge with two or more condenser fans operating on each refrigerant circuit.

The ALS units have a condenser coil design with approximately 15% of the coil tubes located in a subcooler section of the coil to achieve liquid cooling to within 5

°

F (3

°

C) of the outdoor air temperature when all condenser fans are operating. This is equal to about 15

°

F-20

°

F (8.3

°

C-11.1

°

C) subcooling below the saturated condensing temperature when the pressure is read at the liquid valve between the condenser coil and the liquid line filter drier. Once the subcooler is filled, extra charge will not lower the liquid temperature and does not help system capacity or efficiency. However, a little extra (10-15 lbs) will make the system less sensitive.

Note:

As the unit changes load or fans cycle on and off, the subcooling will vary but should recover within several minutes and should never be below 6

°

F (3.3

°

C) subcooling at any steady state condition. Subcooling will vary somewhat with evaporator leaving water temperature and suction superheat. As the evaporator superheat decreases the subcooling will drop slightly.

One of the following two scenarios will be experienced with an undercharged unit:

1. If the unit is slightly undercharged the unit will show bubbles in the liquid line sightglass.

Recharge the unit as described in the charging procedure below.

2. If the unit is moderately undercharged it will normally trip on freeze protection. Recharge the unit as described in the charging procedure below.

Procedure to charge a moderately undercharged ALS unit:

1. If a unit is low on refrigerant you must first determine the cause before attempting to recharge the unit. Locate and repair any refrigerant leak. Evidence of oil is a good indicator of leakage, however oil may not be visible at all leaks. Liquid leak detector fluids work well to show bubbles at medium size leaks but electronic leak detectors may be needed to locate small leaks.

2. Add the charge to the system through the suction shutoff valve or through the Schrader fitting on the tube entering the evaporator between the compressor and the evaporator head.

3. The charge can be added at any load condition between 25-100% load per circuit but at least two fans should be operating per refrigerant circuit if possible. The suction superheat should be in the 6

°

F-12

°

F (3.3

°

C-6.6

°

C) range.

4. Add sufficient charge to clear the liquid line sightglass and until all flashing stops in the sightglass. Add an extra 15-20 lbs. of reserve to fill the subcooler if the compressor is operating at 50-100% load.

5. Check the unit subcooling value by reading the liquid line pressure and temperature at the liquid line near the king valve. The subcooling values should be between 6

°

F-20

°

F (6.6

°

C-11.1

°

C).

The subcooling values will be lowest at 75-100% load, approximately 10

°

F-15

°

F (5.5

°

C-8.2

°

C) and highest at 50% load, approximately 28

°

F-32

°

F (15.4

°

C-17.6

°

C at 25% load).

57

58

6. With outdoor temperatures above 60

°

F (15.6

°

C) all condenser fans should be operating and the liquid line temperature should be within 5

°

F-10

°

F (2.8

°

C-5.6

°

C) of the outdoor air temperature.

At 25-50% load the liquid line temperature should be within 5

°

F (2.8

°

C) of outdoor air temperature with all fans on. At 75-100% load the liquid line temperature should be within 10

°

F

(5.6

°

C) of outdoor air temperature with all fans on.

7. Overcharging of refrigerant will raise the compressor discharge pressure due to excessive covering of the condenser tubes with refrigerant.

Charging Oil

The oil separator is equipped with two sight glasses that are used to determine the oil level.

Each sight glass has a ball float retained in it that floats on the oil. A ball located in the top of the glass signifies that the oil level is somewhere above the top of the glass. A ball located at the bottom signifies that the oil level is somewhere below the bottom of the glass.

Ball

Float

Upper

Sight Glass

Oil

Separator

1. If the bottom sight glass ball is not at the top, oil should be added. This condition can also cause NoOil NoRun alarms.

2. Pump oil into the system per instruction #2 above. It is preferable to add oil at 100% circuit operation.

3. Add oil during operation until the top sight glass ball begins to float.

Ball

Float

Lower

Sight Glass

Notes:

At part load operation oil will not be visible in the top sight glass, i.e. the ball will be at the bottom of the glass.

Under any operating condition, the bottom glass should be full of oil, i.e. the ball should be at the top of the glass.

The only acceptable oil is Planetelf

ACD68AW.

IOMM ALS-4

In-Warranty Return Material Procedure

In the U.S. and Canada

Compressor

: In the event of a failure contact the nearest McQuayService office for assistance.

Components Other Than Compressors

: Material may be returned only with permission from authorized factory service personnel of McQuay International in Staunton, Virginia. A "return goods" tag will be sent and is to be shipped with the returned material. Enter the required information on the tag in order to expedite handling at our factories.

The return of the part does not constitute an order for replacement. Therefore, a purchase order must be entered through your nearest McQuay representative. The order should include part name, part number, model number and serial number of the unit involved.

Following McQuay's inspection of the returned part, and if it is determined that the failure is due to faulty material or workmanship, and it is within the warranty period, credit will be issued against the customer’s purchase order.

All parts shall be returned to the designated McQuay factory with transportation charges prepaid.

IOMM ALS-4

59

Standard Controls

Thermistor sensors

Note:

Refer to the current version of OM ALSMICRO-x for a more complete description of the controls application, settings, adjustments, and checkout procedures.

All sensors are premounted and connected to the MicroTech field wiring strip with shielded cable. A description of each sensor is listed here.

Evaporator leaving water temperature

- This sensor is located on the evaporator water outlet connection and is used for capacity control of the chiller and low water temperature freeze protection.

Evaporator entering water temperature

- This sensor is located on the evaporator water inlet connection and is used for monitoring purposes and return water temperature control.

Evaporator pressure transducer circuit #1

- This sensor is located on the suction side of compressor #1 and is used to determine saturated suction refrigerant pressure and temperature. It also provides low pressure freeze protection for circuit #1.

Evaporator pressure transducer circuit #2

- This sensor is located on the section side of compressor #2 and is used to determine saturated suction refrigerant pressure and temperature. It also provides low pressure freeze protection for circuit #2.

Condenser pressure transducer circuit

#1 - the sensor is located on the discharge of compressor #1 and is used to read saturated refrigerant pressure and temperature. The transducer will unload the compressor should a rise in head pressure occur which is outside the MicroTech set point limits. The signal is also used in the calculation of circuit #1 subcooling.

Condenser pressure transducer circuit #2

- The sensor is located on the discharge of compressor

#2 and is used to read saturated refrigerant pressure and temperature. The transducer will unload the compressor should a rise in head pressure occur which is outside the MicroTech set point limits. The signal is also used in the calculation of circuit #2 subcooling.

Outside air

- This sensor is located on the back of the control box on compressor #1 side. It measures the outside air temperature, is used to determine if low ambient start logic is necessary and can be the reference for low ambient temperature lockout.

Suction temperature circuit #1

- The sensor is located in a well brazed to circuit #1 suction line.

The purpose of the sensor is to measure refrigerant temperature to control and maintain proper superheat.

Suction temperature circuit #2

- The sensor is located in a well brazed to circuit #2 suction line.

The purpose of the sensor is to measure refrigerant temperature to control and maintain proper superheat.

Discharge line temperature circuit #1

- The sensor is located in a well brazed to circuit #1 discharge line. It measures the refrigerant temperature and is used to calculate discharge superheat.

Discharge line temperature circuit #2

- The sensor is located in a well brazed to circuit #2 discharge line. It measures the refrigerant temperature and is used to calculate discharge superheat.

Demand limit

- This requires a field connection of a 4-20 milliamp DC signal from a building automation system. It will determine the maximum number of cooling stages which may be energized.

Evaporator water temperature reset

- This requires a 4-20 milliamp DC signal from a building automation system or temperature transmitter to reset the leaving chilled water set point.

Percent total unit amps

- (optional) this is located in the power side of the control panel. An adjustable voltage resistor and a signal converter board sends a DC signal proportional to the total compressor motor current to the microprocessor.

60

IOMM ALS-4

IOMM ALS-4

High condenser pressure control

MicroTech is also supplied with high pressure transducers on each refrigerant circuit. The main purpose of the high pressure transducer is to maintain proper head pressure control. Another purpose is to convey a signal to the MicroTech control to unload the compressor in the event of an excessive rise in discharge pressure to within 20 psi (138 kPa) of the condenser pressure control setpoint of 380 psig (2620 kPa). Also, a MicroTech control setting will not allow additional circuit loading at approximately 40 psi (276 kPa) below the high pressure switch trip setting. The high pressure alarm is in response to the signal sent by the pressure transducer. The high pressure transducer can be checked by elevating discharge pressure (see Mechanical High Pressure Equipment Protection

Control) and observing the MicroTech display (or a pressure gage), and unit operation as the pressures pass the rising high pressure values noted. After the test reset the High Condenser Pressure alarm set point to 380 psig (2620 kPa).

Mechanical high pressure equipment protection control

The high pressure equipment protection control is a single pole pressure activated switch that opens on a pressure rise. When the switch opens, the control circuit is de-energized dropping power to the compressor and fan motor contactors. The switch is factory made to open at 400 psig (2760 kPa)

(+10 psig) and reclose at 300 psig (2070 kPa). Although the high pressure switch will close again at

300 psig (2070 kPa), the control circuit will remain locked out and it must be reset through

MicroTech.

The control is mounted on the compressor attached to a fitting ahead of the discharge shut off valve.

Remove wire 133 from terminal 20 of the MicroTech controller. This will disable all but one fan.

Observe the cut out point of the control through the MicroTech keypad display, or by means of a service gauge on the back seat port on the discharge service valve. Important: Closely monitor the

High Pressure Control and stay within reach of the emergency stop switch. Do not let the pressure exceed 420 psig (2900 kPa) during the test. If the condenser pressure reaches 420 psig

(2900 kPa) open the emergency stop switch.

The MicroTech keypad display may read slightly lower than a service gauge. Upon completion of the test reset the High Pressure Control back to

380 psig (2620 kPa).

To check the control on circuit #2 repeat the same procedure after removing wire 233 from terminal

30.

Compressor motor protection

The compressors are supplied with two types of motor protection. Solid state electronic overloads mounted in the control box sense motor current to within 2% of the operating amps. The MUST

TRIP amps are equal to 140% of unit nameplate compressor RLA. The MUST HOLD amps are equal to 125% of unit nameplate RLA. A trip of these overloads can result from the unit operating outside of normal conditions. Repeat overload trips under normal operation may indicate wiring or compressor motor problems. The overloads are manual reset and must be reset at the overload as well as through MicroTech.

The compressors also have a solid state Guardister

 circuit that provides motor over temperature protection. The Guardister

 circuit has automatic reset but must also be reset through MicroTech.

FanTrol head pressure control

FanTrol is a method of head pressure control that automatically cycles the condenser fans in response to condenser pressure. This maintains head pressure and allows the unit to run at all ambient air temperatures within the control design parameters.

All ALS units have independent circuits with the fans being controlled independently by the condensing pressure of each circuit. If one circuit is off all fans on that circuit will also be off. The use of multiple fans enables the unit to have excellent head pressure control at low outside ambient temperatures by cycling the fans to maintain the compressor discharge pressure within the desired operating band.

61

62

At outdoor temperatures above approximately 65

°

F (18.3

°

C) all of the fans for a circuit will be operating to achieve the most efficient unit operation. At any compressor load condition of 50% or above the unit has the highest overall efficiency with all fans operating. When the compressor unloads below 50% the last fan stage is cut off because the fan energy saved is more than the increase of compressor power at this light loading. Below approximately 65

°

F (18.3

°

C) outdoor temperature the fans are cycled off as needed on each refrigerant circuit by the MicroTech control to maintain the compressor discharge pressure in the optimum range for best unit operation and highest overall efficiency.

MicroTech controls fans in response to the system discharge pressure. The use of MicroTech to stage on the fans as needed allows more precise control and prevents undesirable cycling of fans.

One fan always operates with the compressor and other fans are activated one at a time as needed.

The control uses 6 stages of fan control with four outputs to activate up to six additional fans per circuit. MicroTech logic sequences fan contactors to stage one fan at a time. On units with six or seven fans per circuit, a single fan is cut off when two fans are started to achieve adding one operating

fan. See Table 28.

Table 28, Fan Staging

ALS 141C THRU ALS 150C (FANS PER CKT=5)

MicroTech fan stage

Fan output relay on

Total fans operating

0

-

1

1

1

2

2

1,2

3

3

1,2,3

4

4

1,2,3,4

5

ALS 171C THRU ALS 186C (FANS PER CKT=6) (Note 1)

MicroTech fan stage

Fan output relay on

Total fans operating

0

-

1

1

1

2

2

1,2

3

3

1,2,3

4

4

1,2,4

5

ALS 190C THRU 218C (FANS PER CKT=7) (Note 2)

MicroTech fan stage

Fan output relay on

Total fans operating

0

-

1

1

1

2

2

1,2

3

3

1,3

4

4

1,2,3

5

Notes

:

1. On ALS 171C thru 186C, two fans are controlled by fan output #4.

2. On ALS 190C thru 218C, two fans each are controlled by fan outputs #3 and #4.

5

1,2,3,4

6

5

1,3,4

6

6

1,2,3,4

7

MicroTech evaluates several factors to determine the number of fans to be operated. These include:

1. The compressor loading as percent of full load.

2. The minimum lift pressure required at this load (The lift pressure equals the discharge pressure minus the suction pressure.)

3. The addition of a control pressure band to the minimum lift pressure to prevent fan cycling.

4. A target discharge pressure is determined by adding the minimum lift pressure to the suction pressure.

At any operating condition the MicroTech controller will determine the minimum lift pressure and a target discharge pressure, and will add or remove operating fans in sequence until the discharge pressure reaches the target value or falls within the control band of pressure set just above the target pressure value.

Each fan added has a decreasing percentage effect so the control pressure band is smaller when more fans are on and largest with only one or two fans on.

Unit operation, with FanTrol, is satisfactory down to outdoor temperatures of 30

°

F (-1.1

°

C). Below this temperature the SpeedTrol option is required to regulate the speed of the first fan on the system to adequately control the discharge pressure. SpeedTrol option allows unit operation to 0

°

F (-17.8

°

C) outdoor temperature assuming that no greater than 5 mph wind. If SpeedTrol is used in conjunction with wind baffles and hail guards, the unit can operate down to -10

°

F (-23

°

C).

IOMM ALS-4

IOMM ALS-4

For windy locations operating below 40

°

F (-1.1

°

C) outdoor air temperature, wind gusts must be prevented from blowing into the unit coils by either locating the unit in a protected area or by the addition of field supplied wind barriers or by mounting optional factory supplied wind barriers.

FanTrol operation example:

Unit operating at 100% load on both circuits

Suction Pressure = 65 psig (448 kPa)

Minimum lift pressure at 100% load = 12- psig (828 kPa)

Minimum discharge pressure = 65 + 120 psig = 185 psig (1276 kPa)

Discharge pressure control band = 35 psig (241 kPa)

Maximum discharge pressure = 185 + 35 = 220 psig (1517 kPa)

If the discharge pressure is between the minimum of 185 psig (1276 kPa) and maximum of 220 psig

(1517 kPa) the fan stages in operation are correct and if the pressure falls outside this range the

MicroTech controller will stage fans on or off to bring it within range.

CAUTION

SpeedTrol and FanTrol will provide reasonable operating refrigerant discharge pressures at the ambient temperatures listed for them provided the coil is not affected by the existence of wind. Wind baffles must be utilized for low ambient operation below 40

°

F if the unit is subjected to winds greater than 5 mph.

Low ambient start

Low ambient start is incorporated into the MicroTech logic. The MicroTech will measure the difference between freezestat and evaporator pressure and determine the length of time the compressor will be allowed to run (to build up evaporator pressure) before taking the compressor off line. The danger of allowing the compressor to run for to long before building up evaporator pressure is that the evaporator could freeze. The low ambient timer setting is determined by the pressure

shown in Table 29. If the low ambient timer is greater than the maximum time allowed the MicroTech

will shut off the compressor and display an alarm.

Table 29, Pressure Difference vs. Time to Alarm

PRESSURE DIFFERENCE BETWEEN

FREEZESTAT AND EVAPORATOR

12 psig (84 kPa)

8 psig (56 kPa)

4 psig (28 kPa)

0 psig (0 kPa)

TIME

(SECONDS)

180

240

300

360

Phase/voltage monitor

The phase/voltage monitor is a device that provides protection against three-phase electrical motor loss due to power failure conditions, phase loss, and phase reversal. Whenever any of these conditions occur, a contact opens to the MicroTech controller (PVR Input) which then de-energizes all inputs.

When proper power is restored, contacts close and MicroTech enables compressors for operation.

When three-phase power has been applied, the output relay should close and the "run light" should come on. If the output relay does not close, perform the following tests.

1. Check the voltages between L1-L2, L1-L3 and L2-L3. These voltages should be approximately equal and within +10% of the rated three-phase line-to-line voltage.

63

64

2. If these voltages are extremely low or widely unbalanced check the power system to determine the cause of the problem.

3. If the voltages are within range, use a phase tester to verify that phases are in A, B, C sequence for L1, L2 and L3. Correct rotation is required for compressor operation. If incorrect phase sequence is indicated, turn off the power and interchange any two of the supply power leads at the disconnect switch.

This may be necessary as the phase/voltage monitor is sensitive to phase reversal. Turn on the power.

The output relay should now close after the appropriate delay.

Compressor short cycling protection

MicroTech contains logic to prevent rapid compressor restarting. Excessive compressor starts can be hard on starting components and create excessive motor winding temperatures. The anti-cycle timers are set for a five-minute stop-to-start cycle and a 15-minute start-to-start cycle. Both are adjustable through MicroTech.

Optional Controls

SpeedTrol head pressure control (optional)

The SpeedTrol system of head pressure control operates in conjunction with MicroTech’s standard head pressure control by modulating the motor speed on fans 11, 21, 31, and 41 in response to condensing temperature. By reducing the speed of the last fan as the condensing pressure falls, the unit can operate at lower ambient temperatures. Start-up with low ambient temperature is improved because the SpeedTrol fans 11, 21,31, and 41 do not start until the condenser pressure builds up.

The SpeedTrol fan motor is a single phase, 208-230/460 volt, thermally protected motor specially designed for variable speed application. The solid-state speed controls SC11, SC21, SC31, and SC41 are accessible through the panel directly above the control box. Units with 575 volt power have a transformer mounted inside the condenser fan compartment to step the voltage down to 230 volts for the SpeedTrol motor.

The SpeedTrol control starts to modulate the motor speed at less than 65

°

F (18.3

°

C) and maintains a minimum condensing pressure of 170 to 180 psig (1172 to 1241 kPa) at full circuit load. For part load operation the condensing pressure is allowed to fall below this level.

IOMM ALS-4

Controls, Settings and Functions

Table 30, Controls

DESCRIPTION

Compressor Heaters

Compressor

Solenoid - Top

Compressor

Solenoid - Bottom

Compressor

Solenoid - Bottom

Evaporator Heater

Electronic Expansion

Valve Board

Electronic Expansion

Valve

FUNCTION

To provide heat to drive off liquid refrigerant when compressor is off.

In circuit 1, 2 energizes to load 50% of compressor capacity.

In circuit 1, 2 energizes to unload 25% of compressor capacity.

In circuit 1, 2 energizes to load 25% of compressor capacity.

Coiled around the evaporator to prevent freezing the water inside.

To provide power and step control to the EXV stepper motors commanded by the MCB250.

To provide efficient unit refrigerant flow and control superheat.

SYMBOL

HTR1,2

CS11,21

CS12,22

CS13,23

HTR5

EXV (Bd)

EXV

Solid State Starter

Thermister Card

Mechanical High

High Pressure Switch

MicroTech Unit

Controller

Solid State Starter K2

Phase Voltage Monitor

To provide motor temperature protection at about 220 o

F (104 o

C).

For UL, ETL, etc…safety code to prevent high pressure above the relief valve.

To control unit and all safeties. Refer to OM

ALSMICRO.

Protects the compressor motor from over heating due to high amps.

to prevent reverse rotation of the motor and protect it from under/over voltage.

To provide 1 sec delay for reduced inrush.

K2 Fault

MHPR1,2

MCB250

K2 Fault

PVM1,2

TD5,6

SETTING

On, when compressor is off.

N/A

RESET

N/A

N/A

N/A

N/A

38 o

F (3.3

o

C)

N/A

N/A

N/A

N/A

N/A

In Controller Code N/A On the

Compressor main liquid line

Starter Box None,

Inherent in design

Refer to

OM ALSMICRO

N/A

Auto

Auto Control Box

Refer to OM

ALSMICRO

Manual

Control Box

Starter Box Solid State Starter

Parameter #1

N/A Auto Control Box

N/A

LOCATION

On the

Compressor

On the

Compressor

On the

Compressor

On the

Compressor

On the Cooler

Control Box

Control Box Reduced Inrush

Time Delay

Signal Converter

Set 4Vdc for full load amps

0-75 psig

(0-517 kPa)

N/A

N/A

N/A

Control Box

Liquid Line Solenoid Valve

Liquid Line

Solenoid Valve

Interstage Injection

SpeedTrol Head

Pressure Control

Surge Capacitor

Oil Separator Heaters

To convert AC current signal volts to DC volts.

SIG.Con

V (SC)

To provide a positive shut off of liquid refrigerant when power is lost.

SVLIQ

SVINT To allow liquid injection into the screw for cooling

To provide more uniform head pressure control.

SC11,21

To protect from high voltage spikes and surges.

Provide heat to maintain viscosity at low temperatures

C1,2

HTR 6-13

N/A

N/A

N/A

On when compressor is off

N/A

N/A

N/A

N/A

On compressor oil Injection

Above Control

Box

Control Box

Power Side

Oil Separator

IOMM ALS-4

65

Troubleshooting Chart

Table 31, Troubleshooting

PROBLEM

Compressor will not run.

POSSIBLE CAUSES

1. Main power switch open.

2. Unit S1 system switch open.

3. Circuit switch PS1, PS2 in pumpdown position.

4. Chilled water flow switch not closed.

5. Circuit breakers open.

6. Fuse blown or circuit breakers tripped.

7. Unit phase voltage monitor not satisfied.

8. Compressor overload tripped.

9. Defective compressor contactor or contactor coil.

10. System shut down by protection devices.

11. No cooling required.

12. Motor electrical trouble.

13. Loose wiring.

Compressor Noisy or Vibrating

Compressor

Overload Relay

Tripped or Circuit

Breaker Trip or

Fuses Blown

Compressor Will

Not Load or Unload

Compressor Liquid

Injection Protection

Trip

1. Compressor Internal problem.

2. Liquid injection not adequate.

1. Low voltage during high load condition.

2. Loose power wiring.

3. Power line fault causing unbalanced voltage.

4. Defective or grounded wiring in the motor.

5. High discharge pressure.

1. Defective capacity control solenoids.

2. Unloader mechanism defective.

1. Liquid injection solenoid did not open at start.

2. Inadequate liquid to liquid injection at start due to a clogged filter drier or low charge.

3. Inadequate liquid to liquid injection during run.

High Discharge

Pressure

Low Discharge

Pressure

Low Suction

Pressure

High Suction

Pressure

1.

5.

Discharge shutoff valve partially closed.

2. Noncondensables in the system.

3. Fans not running.

4. Fan control out of adjustment.

System overcharged with refrigerant.

6. Dirty condenser coil.

7. Air recirculation from outlet into unit coils.

8. Air restriction into unit.

1. Wind effect a low ambient temperature.

2. Condenser fan control not correct.

3. Low section pressure.

4. Compressor operating unloaded.

1. Inadequate refrigerant charge quantity.

2. Inadequate liquid to liquid injection at start. Clogged liquid line filter-drier.

3. Expansion valve malfunctioning.

4. Insufficient water flow to evaporator.

5. Water temperature leaving evaporator is too low.

6. Evaporator tubes fouled.

7. Evaporator head ring gasket slippage.

8. Glycol in chilled water system

1. Excessive load - high water temperature.

2. Compressor unloaders not loading compressor.

3. Superheat is too low.

POSSIBLE CORRECTIVE STEPS

2. Check unit status on MicroTech display. Close switch.

3. Check circuit status on MicroTech display. Close switch.

4. Check unit status on MicroTech display. Close switch.

5. Close circuit breakers.

6. Check electrical circuits and motor windings for shorts or grounds.

Investigate for possible overloading. Check for loose or corroded connections. Reset breakers or replace fuses after fault is corrected.

7. Check unit power wiring to unit for correct phasing. Check voltage.

8. Overloads are manual reset. Reset overload at button on overload.

Clear alarm on MicroTech.

9. Check wiring. Repair or replace contactor.

10. Determine type and cause of shutdown and correct problem before attempting to restart.

11. Check control settings. Wait until unit calls for cooling.

12. See 6,7,8 above.

13. Check circuits for voltage at required points. Tighten all power wiring terminals

2. Check to assure liquid line sightglass is full during steady operation.

1. Check supply voltage for excessive voltage drop.

2. Check and tighten all connections.

3. Check supply voltage.

4. Check motor and replace if defective.

5. See corrective steps for high discharge pressure.

1. Check solenoids for proper operation. See capacity control section.

2. Replace.

1. Check and replace liquid injection solenoid.

2. Check liquid injection line sight glass. If flashing check filter drier and unit charge.

3. Check liquid injection line sightglass. If flashing check filter-drier and unit charge. Discharge pressure too low. Protect condenser coil from wind.

1. Open shutoff valve.

2. Purge the noncondensables from the condenser coil after shutdown.

3. Check fan fuses and electrical circuits.

4. Check that unit setup in MicroTech matches the unit model number.

Check MicroTech condenser pressure sensor for proper operation.

5. Check for excessive subcooling above 30

°

F (-1.1

°

C). Remove the excess charge.

6. Clean the condenser coil.

7. Remove the cause of recirculation.

8. Remove obstructions near unit.

1. Protect unit against excessive wind into vertical coils.

2. Check that unit setup in MicroTech matches the unit model number.

Check SpeedTrol fan on units with SpeedTrol option.

3. See corrective steps for low suction pressure.

4. See corrective steps for failure to load.

1. Check liquid line sightglass. Check unit for leaks. Repair and recharge to clear sightglass.

2. Check pressure drop across filter-drier. Replace cores.

3. Check expansion valve superheat and valve opening position.

Replace valve only if certain valve is not working.

4. Check water pressure drop across the evaporator and adjust gpm.

5. Adjust water temperature to higher value.

6. Inspect by removing water piping. Clean chemically.

7. Low suction pressure and low superheat both present may indicate an internal problem. Consult factory.

8. Check glycol concentration

1. Reduce load or add additional equipment.

2. See corrective steps below for failure of compressor to load.

3. Check superheat on MicroTech display. Check suction line sensor installation and sensor.

66

IOMM ALS-4

Periodic Maintenance Log

IOMM ALS-4

67

68

IOMM ALS-4

Post Office Box 2510, Staunton, Virginia 24402 USA

(800) 432-1342

www.mcquay.com

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