AEC ACOA Series Air-Cooled Central Chillers User Manual

Operation and Installation Manual

ACOA Series Air-Cooled

Central Chillers

Important! Read Carefully before Attempting to Install or Operate Equipment

$30.00

Part No. A0537576 Bulletin No. AE3-620

Performance figures stated in this manual are based on a standard atmosphere of 59°F
(15°C) at 29.92” Hg (1,014 millibars) at sea level, using 60 hz power. Ambient air
temperature is an important consideration when specifying an air-cooled central chiller.
AEC/Application Engineering can advise you on proper selection and sizing of systems
for your operating environment.

AEC/Application Engineering is committed

to a continuing program of product improvement.

Specifications, appearance, and dimensions described in this manual

are subject to change without notice.

© Copyright AEC/Application Engineering and AEC, Inc. 2004
All rights reserved. Effective 7/23/2004
Part No. A0537576 Bulletin No. AE3-620.2

Page 2

ACOA Series Air-Cooled Central Chillers

Safety Considerations

AEC, Inc. ACOA air-cooled central chillers are designed to provide safe and reliable operation
when installed and operated within design specifications, following national and local safety
codes.

To avoid possible personnel injury or equipment damage when installing, operating or
maintaining this equipment, use good judgment and follow these safe practices:

Follow all SAFETY CODES.
Wear SAFETY GLASSES and WORK GLOVES.
Use care when LOADING, UNLOADING, RIGGING or MOVING this equipment.
Operate this equipment within design specifications.
OPEN, TAG AND LOCK ALL DISCONNECTS before working on equipment. It is a

good idea to remove the fuses and carry them with you.

Make sure the chiller is properly GROUNDED before switching power on.
When welding or brazing in or around this equipment be sure VENTILATION is

ADEQUATE. PROTECT adjacent materials from flame or sparks by shielding with sheet
metal. An approved FIRE EXTINGUISHER should be close at hand and ready for use if
needed.

The refrigeration system can develop refrigerant pressures in excess of 500 PSI. DO NOT

CUT into the system without first relieving pressure.

Do not jump or bypass any electrical safety control.
Do not restore power until all tools, test equipment etc. have been removed and the panels

replaced.

Only PROPERLY TRAINED personnel familiar with the information within this manual

should work on this equipment.

ACOA Series Air-Cooled Central Chillers Page 3

Table of Contents

1 General Information ................................................. 7

1-1 Introduction
1-2 Necessary Documents
1-3 Models Covered
1-4 ACOA Physical Specifications

2 Shipping Information.............................................. 19

2-1 Unpacking and Inspection
2-2 In the Event of Shipping Damages
2-3 If the Shipment is Not Complete
2-4 If the Shipment is Not Correct
2-5 Returns
2-6 Uncrating Your Chiller

3 Installation...............................................................21

3-1 Installation Location Considerations
3-2 Process Water Piping Considerations
3-3 Galvanic Corrosion Considerations
3-4 Water Treatment Considerations
3-5 Making Process Water Connections
3-6 Refrigerant Charge Considerations
3-7 Making Electrical Connections
3-8 Checking Motor Rotation Direction

4 Sequence of Operation ..........................................25

4-1 General Information
4-2 Circuit Operation

5 Startup and Operation............................................ 33

5-1 Introduction
5-2 Pre-Startup Checklist
5-3 Starting the Chiller
5-4 Lubricating the Compressor
5-5 System Flow Rate
5-6 Capacity Control

Page 4

ACOA Series Air-Cooled Central Chillers

Table of Contents

6 Electrical Devices ...................................................41

6-1 Control Circuit Power Switch - S1
6-2 Compressor Switch - S2, S3, S4, S5
6-3 Flow Switch - FLS
6-4 Chilled Water Pump Interlock - CWP
6-5 High Pressure Safety Switch - 1PS
6-6 Pumpdown Switch - 4PS
6-7 Compressor Oil Failure Switch - 3PS
6-8 Low Pressure Switch - 9PS, 5TR, 3TAS
6-9 Fan Pressure Switch - 10PS, 11PS
6-10 Compressor Cycle Timer - 1TR
6-11 Timer - 4TR
6-12 Contactors - M
6-13 Relays - CR
6-14 Crankcase Heater - HTR
6-15 Operating Thermostat - 4TAS
6-16 Liquid Line Solenoid Valve - SOL
6-17 Unloading Solenoid Valve
6-18 Motor Overload Protection - 1TAS
6-19 Undervoltage Relay - UVR
6-20 Fan Speed Control - SCR

7 Maintenance............................................................45

7-1 Making Periodic Inspections
7-2 Making Monthly Inspections
7-3 Maintaining the Evaporator and Condenser
7-4 Cleaning the Evaporator
7-5 Cleaning Air Cooled Condensers
7-6 Protections Against Electrical Malfunctions
7-7 Maintaining Compressors
7-8 The Refrigerant Charge
7-9 Preventive Maintenance Service

8 Troubleshooting.....................................................49

ACOA Series Air-Cooled Central Chillers Page 5

Charts and Figures

1

ACOA Specifications 9

2

ACOA15, ACOA20, and ACOA25 Outline Drawing 10

3

ACOA30 and ACOA35 Outline Drawing 11

4

ACOA45 Outline Drawings 12

5

ACOA55 Outline Drawing 13

6

ACOA70 Outline Drawing 14

7

ACOA80 Outline Drawing 15

8

ACOA90 and ACOA100 Outline Drawing 16

9

ACOA110 Outline Drawing 17

10
11
12
13
14
15
16
17
18
19
20
21

ACOA125 and ACOA135 Outline Drawing 18

ACOA Control Settings and Set Points (Unit is Off) 28

Typical ACOA Wiring Diagram 29

Typical ACOA Option Wiring Details 30

One Circuit ACOA Refrigerant Piping Schematic 31

Two Circuit ACOA Refrigerant Piping Schematic 31

Three Circuit ACOA Refrigerant Piping Schematic 32

Four Circuit ACOA Refrigerant Piping Schematic 32

ACOA Evaporator Pressure Drop Curves 36

ACOA Capacity Control 38

ACOA Fan Cycling Control Chart 39

ACOA Load Points 50

22
23

Page 6

ACOA Isolator Specifications 51

R-22 Refrigerant Pressure/Temperature Properties 53

ACOA Series Air-Cooled Central Chillers

1 General Information

1-1 Introduction

This manual provides all necessary information for installation, operation and maintenance of
AEC/Application Engineering ACOA Series air-cooled water chillers.

To use this manual effectively, you must first determine your unit model number from the unit
nameplate. Since this manual is comprehensive for a wide variety of units, you should be careful
to use only those sections which apply to your model. Note that each section is clearly marked as
to the applicable models.

Your AEC/Application Engineering chiller has been manufactured under a careful quality
control system. If the package is installed, operated, and maintained with care and attention to
these instructions, your chiller should give many years of satisfactory service.

You should have a basic understanding of the principles of air conditioning, refrigeration, and
electrical controls for installing, operating, and maintaining this equipment.

1-2 Necessary Documents

These documents are necessary for the operation, installation, and maintenance of AEC/
Application Engineering ACOA chillers. Additional copies are available from AEC, Inc. Make
sure that the appropriate personnel are familiar with these documents:

• This manual.

• The schematic and connection diagram in the control enclosure.

• The operation and installation manuals for accessories and options selected by the

customer.

• The Customer Parts List included in the information packet.

1-3 Models Covered

The chiller serial tag lists model numbers. A -Q following the model number indicates a
specially constructed unit; not all information in this manual may apply. You should know the
model number, serial number, and operating voltage of your chiller if you need to contact AEC.

ACOA chiller models are designated by the total compressor horsepower of all circuits (15 to

135). For example, an ACOA chiller with two 45 hp compressors has a model designation of

ACOA90.

ACOA Series Air-Cooled Central Chillers Page 7

1-4 ACOA Physical Specifications

These air cooled units include semi-hermetic compressor(s), direct expansion internal finned
evaporator, copper tube/aluminum fin condenser coil with integral subcooling coil, and heavy
duty fan motors.

ACOA units are designed for operation down to -20ºF (-29ºC) ambient air temperature by
cycling condenser fans in response to refrigerant condensing pressure. Cylinder unloading, a fan
cycling switch, and heaters on the evaporator are standard.

All systems have pre-piped refrigeration circuits(s) and are pre-wired with a 115-volt control
transformer. Outside installation is possible with controls mounted in a weatherproof, galvanized
steel enclosure.

Page 8

ACOA Series Air-Cooled Central Chillers

Figure 1

ACOA Specifications

Model

number Circuits Lbs. Qty cfm qts. % watts in. in. in. qty. kW

ACOA15 1 30 1 35.3 4.5 0, 50, 100 65 5 60 1 5/8 2 2.0
ACOA20 1 50 1 60.1 4.1 0, 50, 100 100 6 60 3 2 2.7
ACOA25 1 50 1 60.1 4.4 0, HGP, 50, 100 100 7 60 3 2 2.7

ACOA30 1 60 1 75.5 5

ACOA35 1 60 1 90.1 7.5

ACOA45 2 90 2 100.6 8.5

ACOA55 2 110 1 135.5 9.8

ACOA70 2 140 2 180.2 15

ACOA80 2 150 2 214.3 16.2

ACOA90 3 180 3 226.5 15

ACOA100 3 180 3 270.2 22.5

ACOA110 4 210 4 271 19.5

ACOA125 4 225 4 360 30

ACOA135 4 225 4 360 30

refrig-

Total

erant

charge

Displace-

ment

Compressor(s)

Steps of

Oil

chg

capacity

reduction

0, HGB, 30,

67, 100

0, HGB, 30,

67, 100

0, HGB, 25,

50,75, 100

0, HGB, 21,

42, 78, 100

0, HGB, 34,

50, 84, 100

0, HGB, 25,

50, 75, 100

0, HGB, 22, 33,

56, 67, 89, 100

0, HGB, 22, 33,

56, 67, 89, 100

0, HGB, 21,

42, 71, 100

0, HGB, 25,

50, 75, 100

0, HGB, 25,

50, 75, 100

Evaporator

Crankcase

heater

200 7 60 3 3 4.4

200 8 60 3 3 4.4

200 10 60 4 4 5.4

300 11 60 4 5 7.1

400 12 60 4 6 10.2

400 13 60 4 8 13.6

600 12 102 4 9 15.3

600 14 92 4 9 15.3

600 14 102 5 10 17

800 14 102 5 12 20.4

800 16 122 6 12 20.4

Shell

dia.

Tube

length

Conn.

size

Air-cooled
condenser

Fans

Total

Cooling Capacity, Unit Weights

Cooling capacity  Weights

Model 100% water 50% H2O, 50% glycol Shipping weight Operating weight

no. tons Kcal/hr. tons Kcal/hr. lbs. kg lbs. kg

ACOA15 14.7 44,453 14.1 42,683 1,835 834 1,865 847
ACOA20 19.0 57,456 18.1 54,734 1,967 894 2,017 916
ACOA25 24.9 75,298 23.9 72,274 2,158 980 2,208 1,003
ACOA30 32.7 98,885 31.0 93,744 2,687 1,220 2,747 1,248
ACOA35 36.4 110,074 34.8 105,235 2,835 1,288 2,895 1,315
ACOA45 43.1 130,334 41.5 125,496 3,939 1,789 4,029 1,830
ACOA55 57.4 173,578 54.9 166,018 4,631 2,106 4,741 2,153
ACOA70 71.9 217,426 69.1 208,958 5,252 2,385 5,392 2,444
ACOA80 87.0 263,088 83.3 251,899 6,998 3,173 7,138 3,241
ACOA90 98.0 296,352 95.3 288,187 8,220 3,732 8,437 3,831
ACOA100 107.6 325,382 102.1 308,750 8,582 3,897 8,807 3,999
ACOA110 115.0 347,760 107.9 326,290 9,397 4,267 9,647 4,380
ACOA125 131.0 396,144 120.9 365,602 10,160 4,613 10,410 4,727
ACOA135 147.1 444,830 142.1 429,710 11,087 5,034 11,472 5,209

 Based on 60ºF (16ºC) return from process, 50ºF (10ºC) chilled water supply temperature, and 95ºF (35ºC)

ambient. Consult factory for requirements below 40ºF (4ºC).

fan

ACOA Series Air-Cooled Central Chillers Page 9

Figure 2

ACOA15, ACOA20, and ACOA25 Outline Drawing

ALLOW 60" FOR
SERVICE ACCESS

DOOR SWING

WATER

OUT

MOUNTING LOCATIONS

LIFTING

HOLE

90-3/16"

101"

50-3/16"

B

84"

AIR FLOW

CONTROL

BOX

AIR FLOW

`D'

`C'

MOUNTING
LOCATION

37-5/16

43"

MODEL

MODEL

ACOA

EVAP.

15

CHS00560
CHS00660
CHS00760

23-3/16" 80-13/16"

23-15/16"

20
25

NOTES:

1 - ALL DIMENSIONS IN INCHES.
2 - VENT AND DRAIN CONNECTIONS PROVIDED ON COOLER.
3 - ALLOW 60" CLEARANCE AT CONTROL PANEL END OF UNIT FOR SERVICE
4 - USE MINIMUM 36" FLEXIBLE CONDUIT TO CONTROL BOX TO ISOLATE UNIT.
5 - WATER PIPING TO BE SUPPORTED TO MINIMIZE LOAD ON UNIT.
6 - ALL DIMENSIONS AND SPECIFICATIONS ARE SUBJECT TO CHANGE WITHOUT

NOTICE.

DIMENSIONS

'A'

80"

24"

80-1/16"

AIR

FLOW

POWER
ENTRY

'B'

'C'

5-1/16"

9-3/4"

5-7/16"

10-3/16"

2-3/4"

10-15/16"

73"

'D'

WATER

20"

A

79"

WATER

CONNECTION

1-1/2" N.P.T.

3" N.P.T.
3" N.P.T.

POWER ENTRY

IN

(SEE NOTE 4)

13-13/16"

Page 10

ACOA Series Air-Cooled Central Chillers

Figure 3

ACOA30 and ACOA35 Outline Drawing

ALLOW 60" FOR
SERVICE ACCESS

DOOR SWING

LIFTING

HOLE

WATER

OUT

MOUNTING LOCATIONS

120"

130-3/16"

141"

90-3/16"

WATER

IN

20"

A

50-3/16"

70"

B

13-13/16"

POWER ENTRY
(SEE NOTE 4)

AIR FLOW

CONTROL

BOX

AIR FLOW

`D'

`C'

MOUNTING

LOCATION

37-5/16"

43"

AIR

FLOW

POWER
ENTRY

79"

73"

MODEL

MODEL

ACOA

EVAP

30 CHS00760

ACOA Series Air-Cooled Central Chillers Page 11

23-15/16" 80-1/16"

25-1/4" 78-3/4" 11-1/2"

CHS0086035

NOTES:

1 - ALL DIMENSIONS IN INCHES.
2 - VENT AND DRAIN CONNECTIONS PROVIDED ON COOLER.
3 - ALLOW 60" CLEARANCE AT CONTROL PANEL END OF UNIT FOR SERVICE
4 - USE MINIMUM 36" FLEXIBLE CONDUIT TO CONTROL BOX TO ISOLATE UNIT.
5 - WATER PIPING TO BE SUPPORTED TO MINIMIZE LOAD ON UNIT.
6 - ALL DIMENSIONS AND SPECIFICATIONS ARE SUBJECT TO CHANGE WITHOUT NOTICE

DIMENSIONS

'C'

B'

`A'

10-15/16"

2-3/4"

1-5/8"

'D'

WATER

CONNECTION

3" N.P.T.
3" N.P.T.

Figure 4

ACOA45 Outline Drawing

ALLOW 60" FOR

SERVICE ACCESS

DOOR SWING

WATER

OUT IN

MOUNTING LOCATIONS

LIFTING
HOLES

50-3/16"

78-3/4"

84"

90-3/16"

101"

AIR

FLOW

12-1/16"

4-11/16"

NOTES:

1 - ALL DIMENSIONS IN INCHES.
2 - VENT AND DRAIN CONNECTIONS PROVIDED ON COOLER.
3 - ALLOW 60" CLEARANCE AT CONTROL PANEL END OF UNIT FOR SERVICE
4 - USE MINIMUM 36" FLEXIBLE CONDUIT TO CONTROL BOX TO ISOLATE UNIT.
5 - WATER PIPING TO BE SUPPORTED TO MINIMIZE LOAD ON UNIT.
6 - ALL DIMENSIONS AND SPECIFICATIONS ARE SUBJECT TO CHANGE WITHOUT NOTICE

CONTROL

BOX

AIR FLOW

MOUNTING LOCATIONS

80-5/16"

86"

25-1/4"

AIR FLOWAIR FLOW

CONTROL

BOX

20"

WATER

MODEL

ACOA

45

13-13/16"

AIR

FLOW

POWER
ENTRY

CHD01060

POWER ENTRY
(SEE NOTE 4)

MODEL

EVAP.

79"

73"

WATER

CONNECTION

4" N.P.T.

Page 12

ACOA Series Air-Cooled Central Chillers

Figure 5

ACOA55 Outline Drawing

ALLOW 60" FOR

SERVICE ACCESS

DOOR SWING

FLOW

3-9/16"

12-5/8"

AIR

WATER

OUT

LIFTING
HOLES

CONTROL

BOX

130-3/16"

141"

AIR FLOW

120"

AIR FLOWAIR FLOW

CONTROL

MOUNTING

LOCATIONS

78-3/4"

90-3/16"

BOX

13-13/16"

POWER ENTRY
(SEE NOTE 4)

WATER

IN

20"

25-1/4"

50-3/16"

70"

AIR

FLOW

POWER
ENTRY

79"

73"

MOUNTING LOCATION

80-5/16"

86"

NOTES:

1 - ALL DIMENSIONS IN INCHES.
2 - VENT AND DRAIN CONNECTIONS PROVIDED ON COOLER.
3 - ALLOW 60" CLEARANCE AT CONTROL PANEL END OF UNIT FOR SERVICE
4 - USE MINIMUM 36" FLEXIBLE CONDUIT TO CONTROL BOX TO ISOLATE UNIT.
5 - WATER PIPING TO BE SUPPORTED TO MINIMIZE LOAD ON UNIT.
6 - ALL DIMENSIONS AND SPECIFICATIONS ARE SUBJECT TO CHANGE WITHOUT NOTICE

ACOA Series Air-Cooled Central Chillers Page 13

MODEL

MODEL

EVAP.

ACOA

55 CHD01160 4" N.P.T.

WATER

CONNECTION

Figure 6

ACOA70 Outline Drawing

AIR FLOW

AIR FLOW

ALLOW 60" FOR
SERVICE ACCESS

DOOR SWING

2-5/16"

13-3/16"

WATER

LIFTING

HOLES

OUT

CONTROL

BOX

POWER ENTRY

MOUNTING LOCATIONS

120"

130-3/16"

141"

AIR FLOW

CONTROL

BOX

AIR FLOW

MOUNTING LOCATION

80-5/16"

86"

90-3/16"

78-3/4"

13-13/16"

WATER

CONNECTION

4" N.P.T.

POWER ENTRY
(SEE NOTE 4)

WATER

IN

20"

25-1/4"

50-3/16"

70"

79"

73"

MODEL

MODEL

EVAP.

ACOA

CHD01260

70

Page 14

NOTES:

1 - ALL DIMENSIONS IN INCHES.
2 - VENT AND DRAIN CONNECTIONS PROVIDED ON COOLER.
3 - ALLOW 60" CLEARANCE AT CONTROL PANEL END OF UNIT FOR SERVICE.

4 - USE MINIMUM 36" FLEXIBLE CONDUIT TO CONTROL BOX TO ISOLATE UNIT.
5 - WATER PIPING TO BE SUPPORTED TO MINIMIZE LOAD ON UNIT.
6 - ALL DIMENSIONS AND SPECIFICATIONS ARE SUBJECT TO CHANGE WITHOUT NOTICE

ACOA Series Air-Cooled Central Chillers

Figure 7

ACOA80 Outline Drawing

AIR FLOW

SIDE & BOTTOM

AIR FLOW

SIDE & BOTTOM

ALLOW 60" FOR

SERVICE ACCESS

MOUNTING
LOCATION

12-3/8"

WATER WATER IN

OUT

AIR FLOW

CONTROL BOX

POWER ENTRY (SEE NOTE #4)

132-3/4"

175"

191"

83-3/8"

77-3/8"

CONTROL BOX

LIFTING HOLE

79-1/4"

98"

4-1/2"

52-5/8"

59-5/8"

16"

16-1/8"

MOUNTING LOCATION

NOTE:
1 - ALL DIMENSIONS IN INCHES.

2 - VENT AND DRAIN CONNECTIONS PROVIDED ON COOLER.
3 - ALLOW 60" CLEARANCE AT CONTROL PANEL END OF UNIT FOR SERVICE.
4 - USE MINIMUM 36" FLEXIBLE CONDUIT TO CONTROL BOX TO ISOLATE UNIT.
5 - WATER PIPING TO BE SUPPORTED TO MINIMIZE LOAD ON UNIT.
6 - ALL DIMENSIONS AND SPECIFICATIONS ARE SUBJECT TO CHANGE WITHOUT NOTICE

ACOA Series Air-Cooled Central Chillers Page 15

83"

86"

MODEL

ACOA

80

MODEL

EVAP.

CHD01360 4" NPT

WATER

CONNECTION

Figure 8

ACOA90 and ACOA100 Outline Drawing

AIR FLOW

SIDE & BOTTOM

AIR FLOW

SIDE & BOTTOM

ALLOW 60" FOR

SERVICE ACCESS

WATER OUT WATER IN

MOUNTING
LOCATION

AIR FLOW

CONTROL BOX

271"

255"

77-3/8"

229-3/16"

83-3/8"

POWER ENTRY (SEE NOTE #4)

148-3/16"

175"

CONTROL BOX

LIFTING HOLE

98"

4-1/2"

52-5/8"

59-5/8"

16"

Page 16

16-3/8"

MODEL

MOUNTING

86"

LOCATION

83"

45-7/16"

NOTES:

1 - ALL DIMENSIONS IN INCHES.
2 - VENT AND DRAIN CONNECTIONS PROVIDED ON COOLER.
3 - ALLOW 60" CLEARANCE AT CONTROL PANEL END OF UNIT FOR SERVICE.
4 - USE MINIMUM 36" FLEXIBLE CONDUIT TO CONTROL BOX TO ISOLATE UNIT.
5 - WATER PIPING TO BE SUPPORTED TO MINIMIZE LOAD ON UNIT.
6 - ALL DIMENSIONS AND SPECIFICATIONS ARE SUBJECT TO CHANGE WITHOUT NOTICE

ACO

090 & 100

ACOA Series Air-Cooled Central Chillers

EXT14092

MODEL

EVAP.

WATER

CONNECTION

5" VICTAULIC