Aaon LN-075 Installation Manual

LN Series

Chillers and Outdoor Mechanical Rooms

FIRE OR EXPLOSION HAZARD

Failure to follow safety warnings exactly could result in serious injury, death or property damage.

Be sure to read and understand the installation, operation and service instructions in this manual.

Improper installation, adjustment, alteration, service or maintenance can cause serious injury, death or property damage.

A copy of this IOM should be kept with the unit.

Do not store gasoline or other flammable vapors and liquids in the vicinity of this or any other appliance.

WHAT TO DO IF YOU SMELL GAS

 Do not try to light any appliance.  Do not touch any electrical switch;

do not use any phone in your building.

 Leave the building immediately.  Immediately call you gas supplier

from a phone remote from the building. Follow the gas supplier’s instructions.

 If you cannot reach your gas

supplier call the fire department.

Startup and service must be performed by a Factory Trained Service Technician.

Installation, Operation,

& Maintenance

Table of Contents

Safety .............................................................................................................................................. 6

LN Series Feature String Nomenclature ....................................................................................... 11

General Information ...................................................................................................................... 16

Codes and Ordinances ............................................................................................................... 16

Receiving Unit ........................................................................................................................... 16

Storage ....................................................................................................................................... 16

Chiller ........................................................................................................................................ 17

Wiring Diagrams ....................................................................................................................... 18

General Maintenance ................................................................................................................. 18

Chiller Primary Pumping .......................................................................................................... 18

Automatic Air Vent ................................................................................................................... 18

Dual Pumps ............................................................................................................................... 19

Pressure Gauges and Thermometers ......................................................................................... 19

Pipe Insulation ........................................................................................................................... 19

Installation..................................................................................................................................... 20

Chiller Placement ...................................................................................................................... 20

Curb and Steel Mount Installation ............................................................................................ 20

Lifting and Handling ................................................................................................................. 21

Water Connection ...................................................................................................................... 23

Mounting Isolation .................................................................................................................... 23

Access Doors ............................................................................................................................. 23

End Flashing Installation ........................................................................................................... 23

Low Ambient Operation ............................................................................................................ 24

Electrical .................................................................................................................................... 24

Startup ........................................................................................................................................... 26

Axial Flow Condenser Fans ...................................................................................................... 27

Maintenance .................................................................................................................................. 30

General ...................................................................................................................................... 30

Compressors .............................................................................................................................. 30

Adjusting Refrigerant Charge ................................................................................................... 30

Lubrication ................................................................................................................................ 34

Air-Cooled Condenser ............................................................................................................... 34

Brazed Plate Heat Exchanger Cleaning..................................................................................... 34

E-Coated Coil Cleaning ............................................................................................................ 34

Recommended Coil Cleaner .................................................................................................. 35

Recommended Chloride Remover ......................................................................................... 35

Microchannel Coil Cleaning ..................................................................................................... 36

Service ....................................................................................................................................... 36

Replacement Parts ..................................................................................................................... 38

AAON Warranty, Service and Parts Department ...................................................................... 38

Appendix - Water Piping Component Information ...................................................................... 39

Automatic Air Vent Valves ....................................................................................................... 39

Pumps - Installation and Operating Instructions ....................................................................... 41

Pump Piping - General .............................................................................................................. 42

Pump Operation ......................................................................................................................... 43

General Care .............................................................................................................................. 44

Dual Pump Specific Information ............................................................................................... 46

Suction Guides .......................................................................................................................... 51

Flo-Trex Combination Valve .................................................................................................... 52

LN Series Startup Form ................................................................................................................ 58

Maintenance Log .......................................................................................................................... 61

Literature Change History............................................................................................................. 62

V28980 · Rev. A · 150724

Index of Tables and Figures

Tables:

Table 1 - Service Clearances ......................................................................................................... 20

Table 2 - Mounting Dimensions ................................................................................................... 21

Table 3 - Return/Exhaust Fan Pin Location .................................................................................. 28

Table 4 - Return/Exhaust Fan Pin Location .................................................................................. 28

Table 5 - Fan Assembly Bushing Torque Specifications.............................................................. 29

Table 6 - Acceptable Refrigeration Circuit Values ....................................................................... 31

Table 7 - R-410A Refrigerant Temperature-Pressure Chart ......................................................... 33

Figures:

Figure 1 - Curb Mounting with Dimensions ................................................................................. 20

Figure 2 - Steel Mounting Rail with Dimensions ......................................................................... 21

Figure 3 - Lifting Points ................................................................................................................ 21

Figure 4 - Lifting Detail of a 45-60 ton Unit ................................................................................ 22

Figure 5 - Lifting Detail of a 75-140 ton Unit .............................................................................. 22

Figure 6 - Factory Supplied End Flashings ................................................................................... 23

Figure 7 - Front View of Utility Entry and Power Switch from Control Compartment ............... 24

Figure 8 - Fan with the HUB on the top and RET on the bottom. ................................................ 27

Figure 9 - Bushing Mount Location .............................................................................................. 27

Figure 10 - RET with Pin in Groove 4 .......................................................................................... 27

Figure 11 - Fan HUB and RET Castings ...................................................................................... 28

Figure 12 - Pitch Insert ................................................................................................................. 29

AAON® LN Series Features and Options Introduction

Energy Efficiency

 High Efficiency Air-Cooled

Microchannel Condenser

 Staged or VFD Controlled Variable

Speed R-410A Scroll Compressors

 Two Inch Double Wall Rigid

Polyurethane Foam Panel Construction

 VFD Controlled Pumping Package  Glycol Chillers  Constant or Variable Flow Factory

Installed Pumping System

 VFD Controlled Condenser Fan Head

Pressure Control

 Factory Installed EXVs

Outdoor Mechanical Room

 Lighted Service Compartment  Shell and Tube or Brazed Plate Heat

Evaporators

 Factory Engineered Primary Pumping

Package

Safety

 Phase and Brownout Protection  Compressor Isolation Valves

Installation and Maintenance

 Run Test Report and Installation Manuals

Included in Controls Compartment

 Color Coded Wiring Diagrams  Sight Glass  Compressors include Rubber Isolation

Mounts

 Auxiliary Electric Heating in Service

Compartment

System Integration

 Complete System with AAON Chilled

Water Air Handling Units

 Single Point Power  Glycol Chillers  Compressor Isolation Valves  Grooved End Water Piping Connections  Constant or Variable Flow Factory

Installed Pumping System

 BMS Connectivity

Environmentally Friendly

 R-410A Refrigerant

Extended Life

 2,500 Hour Salt Spray Tested Exterior

Corrosion Paint

 Optional 5 Year Non-Prorated

Compressor Warranty

 Polymer E-Coated Condenser Coils  Exterior Cabinet Paint Exceeds 2,500

Salt Spray Test

 Condenser Coil Guards

Safety

ELECTRIC SHOCK, FIRE OR EXPLOSION HAZARD

Failure to follow safety warnings exactly could result in dangerous operation, serious injury, death or property damage.

Improper servicing could result in dangerous operation, serious injury, death, or property damage.

 Before servicing, disconnect all

electrical power to the furnace. More than one disconnect may be provided.

 When servicing controls, label all

wires prior to disconnecting. Reconnect wires correctly.

 Verify proper operation after

servicing. Secure all doors with key-lock or nut and bolt.

Attention should be paid to the following statements:

NOTE - Notes are intended to clarify the unit installation, operation and maintenance.

CAUTION - Caution statements are given to prevent actions that may result in

equipment damage, property damage, or personal injury.

WARNING - Warning statements are given to prevent actions that could result in

equipment damage, property damage, personal injury or death.

DANGER - Danger statements are given to prevent actions that will result in equipment

damage, property damage, severe personal injury or death.

QUALIFIED INSTALLER

Improper installation, adjustment, alteration, service or maintenance can cause property damage, personal injury or loss of life. Startup and service must be performed by a Factory Trained Service Technician. A copy of this IOM should be kept with the unit.

WHAT TO DO IF YOU SMELL GAS

 Do not try to turn on unit.  Shut off main gas supply.  Do not touch any electric switch.  Do not use any phone in the

building.

 Never test for gas leaks with an

open flame.

 Use a gas detection soap solution

and check all gas connections and shut off valves.

FIRE, EXPLOSION OR CARBON MONOXIDE POISONING HAZARD

Failure to replace proper controls could result in fire, explosion or carbon monoxide poisoning. Failure to follow safety warnings exactly could result in serious injury, death or property damage. Do not store or use gasoline or other flammable vapors and liquids in the vicinity of this appliance.

Electric shock hazard. Before servicing, shut off all electrical power to the unit, including remote disconnects, to avoid shock hazard or injury from rotating parts. Follow proper Lockout-Tagout procedures.

VARIABLE FREQUENCY DRIVES

Do not leave VFDs unattended in hand mode or manual bypass. Damage to personnel or equipment can occur if left unattended. When in hand mode or manual bypass mode VFDs will not respond to controls or alarms.

During installation, testing, servicing, and troubleshooting of the equipment it may be necessary to work with live electrical components. Only a qualified licensed electrician or individual properly trained in handling live electrical components shall perform these tasks.

Standard NFPA-70E, an OSHA regulation requiring an Arc Flash Boundary to be field established and marked for identification of where appropriate Personal Protective Equipment (PPE) be worn, should be followed.

GROUNDING REQUIRED

All field installed wiring must be completed by qualified personnel. Field installed wiring must comply with NEC/CEC, local and state electrical code requirements. Failure to follow code requirements could result in serious injury or death. Provide proper unit ground in accordance with these code requirements.

Electric motor over-current protection and overload protection may be a function of the Variable Frequency Drive to which the motors are wired. Never defeat the VFD motor overload feature. The overload ampere setting must not exceed 115% of the electric motors FLA rating as shown on the motor nameplate.

PVC (Polyvinyl Chloride) and CPVC (Chlorinated Polyvinyl Chloride) are vulnerable to attack by certain chemicals. Polyolester (POE) oils used with R-410A and other refrigerants, even in trace amounts, in a PVC or CPVC piping system will result in stress cracking of the piping and fittings and complete piping system failure.

CAUTION

UNIT HANDLING

To prevent injury or death lifting equipment capacity shall exceed unit weight by an adequate safety factor. Always test-lift unit not more than 24 inches high to verify proper center of gravity lift point to avoid unit damage, injury or death.

Door compartments containing hazardous voltage or rotating parts are equipped with door latches to allow locks. Door latch are shipped with nut and bolts requiring tooled access. If you do not replace the shipping hardware with a pad lock always re-install the nut & bolt after closing the door.

Rotation must be checked on all MOTORS AND COMPRESSORS of 3 phase units at startup by a qualified service technician. Scroll compressors are directional and can be damaged if rotated in the wrong direction. Compressor rotation must be checked using suction and discharge gauges. Fan motor rotation should be checked for proper operation. Alterations should only be made at the unit power connection

CAUTION

Do not use oxygen, acetylene or air in place of refrigerant and dry nitrogen for leak testing. A violent explosion may result causing injury or death.

WARNING

To prevent damage to the unit, do not use acidic chemical coil cleaners. Use alkaline chemical coil cleaners with a pH value of 5-9, after mixing, without first using an aluminum corrosion inhibitor in the cleaning solution.

CAUTION

Some chemical coil cleaning compounds are caustic or toxic. Use these substances only in accordance with the manufacturer’s usage instructions. Failure to follow instructions may result in equipment damage, injury or death.

WARNING

Do not clean DX refrigerant coils with hot water or steam. The use of hot water or steam on refrigerant coils will cause high pressure inside the coil tubing and damage to the coil.

CAUTION

Polyolester (POE) and Polyvinylether (PVE) oils are two types of lubricants used in hydrofluorocarbon (HFC) refrigeration systems. Refer to the compressor label for the proper compressor lubricant type.

CAUTION

COMPRESSOR CYCLING

5 MINUTE MINIMUM OFF TIME To prevent motor overheating compressors must cycle off for a minimum of 5 minutes.

5 MINUTE MINIMUM ON TIME To maintain the proper oil level compressors must cycle on for a minimum of 5 minutes.

The cycle rate must not exceed 6 starts per hour.

WARNING

1. Startup and service must be performed

by a Factory Trained Service Technician

2. The unit is for outdoor use only. See

General Information section for more information.

3. Every unit has a unique equipment

nameplate with electrical, operational, and unit clearance specifications. Always refer to the unit nameplate for specific ratings unique to the model you have purchased.

4. READ THE ENTIRE INSTALLATION,

OPERATION AND MAINTENANCE MANUAL. OTHER IMPORTANT SAFETY PRECAUTIONS ARE

PROVIDED THROUGHOUT THIS MANUAL.

5. Keep this manual and all literature

safeguarded near or on the unit.

LN Series Feature String Nomenclature

Model Options

Unit Feature Options

GEN

MJREV

SIZE SERIES MNREV

VLT A1

5D 6

7 8A

8C 9 10A

10B

10C

10D

LN A – 140 – C – 0 – 3 – F A C 0 E – 0 0 0 0 : A 0 – 0 0 0 0 – 0 0 0 0 – 0 0 0 0 – 0 0 – 0 0 0 – 0 – 0 E 0 0 –

0 0 0 0 0 – 0 A 0 0 0 – 0 0 0 0 0 – 0 0 0 0 0 0 – 0 0 0 0 0 – 0 0 0 B

26A

26B

26C

26D

26E

26F

MODEL OPTIONS

SERIES AND GENERATION

MAJOR REVISION

UNIT SIZE

045 = 45 ton Capacity 055 = 55 ton Capacity 060 = 60 ton Capacity 075 = 75 ton Capacity 095 = 95 ton Capacity 105 = 105 ton Capacity 120 = 120 ton Capacity 140 = 140 ton Capacity

SERIES

A = 45-60 ton units B = 75 ton unit C = 95-140 ton units

MINOR REVISION

VOLTAGE

2 = 230V/3Φ/60Hz 3 = 460V/3Φ/60Hz 4 = 575V/3Φ/60Hz 8 = 208V/3Φ/60Hz

A1: COMPRESSOR STYLE

F = R-410A Tandem VFD Compatible Scroll Compressor

A2: CONDENSER STYLE

A = Air-Cooled Microchannel Condenser

A3: EVAPORATOR CONFIGURATION

A = Standard Brazed Plate Constant Flow B = Oversized Brazed Plate Constant Flow C = Standard Shell & Tube Constant Flow D = Oversized Shell & Tube Constant Flow

A4: COATING

0 = Standard E = Polymer E-Coated Condenser Coil

A5: STAGING

0 = Staged Compressors E = All Circuits with Variable Capacity Compressors

- 2 Circuits G = Half Circuits with Variable Capacity Compressors - 2 Circuits

B1: BLANK

0 = Standard

B2: BLANK

0 = Standard

B3: BLANK

0 = Standard

B4: BLANK

0 = Standard

UNIT FEATURE OPTIONS

1: UNIT ORIENTATION

A = Standard Access Left Water Connections B = Standard Access Right Water Connections C = Standard Access Bottom Water Connections

2: PUMPING STYLE

0 = No Pumps B = Constant Flow Primary Pumping System - Large Pipe Size D = Variable Flow Primary Pumping System - Large Pipe Size

LN Series Feature String Nomenclature

Model Options

Unit Feature Options

GEN

MJREV

SIZE SERIES

MNREV VLT

B4 1 2

5D 6 7 8A

8C 9

10A

10B

10C

10D

LN A – 140 – C – 0 – 3 – F A C 0 E – 0 0 0 0 : A 0 – 0 0 0 0 – 0 0 0 0 – 0 0 0 0 – 0 0 – 0 0 0 – 0 – 0 E 0 0 –

0 0 0 0 0 – 0 A 0 0 0 – 0 0 0 0 0 – 0 0 0 0 0 0 – 0 0 0 0 0 – 0 0 0 B

26A

26B

26C

26D

26E

26F

3A: BUILDING PUMP CONFIGURATION

0 = No Building Pumps A = 1 Pump + High Eff Motor B = 1 Dual Pump + High Eff Motors D = 1 Pump + VFD + High Eff Motor E = 1 Dual Pump + 2 VFD's + High Eff Motors K = 1 Pump + Field Installed VFD + High Eff Motor L = 1 Dual Pump + 2 Field Installed VFD's + High Eff Motors

3B: BUILDING PUMP SERIES AND RPM

0 = No Building Pumps A = 4360 (1,170 nominal rpm) B = 4360 (1,760 nominal rpm) C = 4360 (3,520 nominal rpm) D = 4380 (1,170 nominal rpm) E = 4380 (1,760 nominal rpm) F = 4380 (3,520 nominal rpm) K = 4382 (1,170 nominal rpm) L = 4382 (1,760 nominal rpm) M = 4382 (3,520 nominal rpm)

3C: PUMP SIZE

0 = No Building Pumps A = 1.5B B = 2B C = 2D D = 3D E = 1.5x1.5x6 F = 2x2x6 G = 3x3x6 H = 4x4x6 J = 6x6x6 K = 1.5x1.5x8 L = 2x2x8 M = 3x3x8 N = 4x4x8 P= 5x5x8 Q = 6x6x8 R = 8x8x8 S = 2x2x10 T = 3x3x10 U = 4x4x10 V = 6x6x10 W = 8x8x10 Y = 4x4x11.5 Z = 5x5x11.5 1 = 6x6x11.5 2 = 8x8x11.5 3 = 4x4x13 4 = 6x6x13 5 = 8x8x13

LN Series Feature String Nomenclature

GEN

MJREV

SIZE SERIES

MNREV VLT

B4 1 2 3A

6 7 8A

9 10A

10B

10C

10D

LN A – 140 – C – 0 – 3 – F A C 0 E – 0 0 0 0 : A 0 – 0 0 0 0 – 0 0 0 0 – 0 0 0 0 – 0 0 – 0 0 0 – 0 – 0 E 0 0 -

0 0 0 0 0 – 0 A 0 0 0 – 0 0 0 0 0 – 0 0 0 0 0 0 – 0 0 0 0 0 – 0 0 0 B

26A

26B

26C

26D

26E

26F

Model Options

Unit Feature Options

3D: BUILDING PUMP MOTOR SIZE

0 = No Building Pumps C = 1 hp E = 2 hp F = 3 hp G = 5 hp H = 7.5 hp J = 10 hp K = 15 hp L = 20 hp M = 25 hp N = 30 hp P = 40 hp Q = 50 hp

4A: BLANK

0 = Standard

4B: BLANK

0 = Standard

4C: BLANK

0 = Standard

4D: BLANK

0 = Standard

5A: BLANK

0 = Standard

5B: BLANK

0 = Standard

5C: BLANK

0 = Standard

5D: BLANK 0 = Standard

6: REFRIGERATION OPTIONS

0 = Standard A = Hot Gas Bypass on Non-Variable Capacity Circuits B = Hot Gas Bypass - All Circuits

7: REFRIGERATION ACCESSORIES

0 = Standard A = Sight Glass B = Compressor Isolation Valves C = Option A + B

8A: UNIT DISCONNECT TYPE

0 = Standard Single Point Power Block A = Single Point Power Non-fused Disconnect

8B: DISCONNECT SIZE

0 = Power Block N = 100 amps R = 150 amps U = 225 amps Z = 400 amps 3 = 600 amps 5 = 800 amps 7 = 1200 amps

8C: BLANK

0 = Standard

9: ACCESSORIES

0 = Standard B = Phase & Brown Out Protection

10A: UNIT CONTROL SEQUENCE

0 = Standard Controls

10B: UNIT CONTROL SUPPLIER

E = MCS Controls

10C: CONTROL SUPPLIER OPTIONS

0 = Standard A = Touchscreen Interface C = Modem G = Option A + C

LN Series Feature String Nomenclature

Model Options

Unit Feature Options

GEN

MJREV

SIZE SERIES

MNREV VLT

B4 1 2

5D 6 7 8A

8C 9

10A

10B

10C

10D

LN A – 140 – C – 0 – 3 – F A C 0 E – 0 0 0 0 : A 0 – 0 0 0 0 – 0 0 0 0 – 0 0 0 0 – 0 0 – 0 0 0 – 0 – 0 E 0 0 –

0 0 0 0 0 – 0 A 0 0 0 – 0 0 0 0 0 – 0 0 0 0 0 0 – 0 0 0 0 0 – 0 0 0 B

26A

26B

26C

26D

26E

26F

10D: BMS CONNECTION & DIAGNOSTICS

0 = None A = BACnet IP B = BACnet MSTP C = Modbus IP D = Modbus RTU E = Lontalk H = No BMS Connection with Diagnostics J = BACnet IP with Diagnostics K = BACnet MSTP with Diagnostics L = Modbus IP with Diagnostics M = Modbus RTU with Diagnostics N = Lontalk with Diagnostics

11: BLANK

0 = Standard

12: VESTIBULE ACCESSORIES

0 = Standard C = Vestibule Heating (Electric)

13: MAINTENANCE ACCESSORIES

0 = Standard A = 115VAC Convenience Outlet Factory Wired B = 115VAC Convenience Outlet Field Wired C = Service Lights F = Options A + C J = Options B + C

14: BLANK

0 = Standard

15: CODE OPTIONS

0 = Standard ETL U.S.A. Listing A = Chicago Code B = ETL U.S.A. + Canada Listing

16: SHIPPING SPLITS

0 = One Piece Unit

17: AIR-COOLED CONDENSER ACCESSORIES

H = Cond Coil Guards + Three Phase Cond Fan Motor + Fan Cycling- 25°F Low Ambient J = Cond Coil Guards + VFD Cond Fan Head Pressure Control - 0°F Low Ambient

18: BLANK

0 = Standard

19: BLANK

0 = Standard

20: BLANK

0 = Standard

21: BLANK

0 = Standard

22: BLANK

0 = Standard

23: BLANK

0 = Standard

24: CHILLER ACCESSORIES 1

0 = Standard A = Glycol Chiller C = Thermometers & Pressure Gauges G = Option A + C

25: BLANK

0 = Standard

26A: BLANK

0 = Standard

26B: BLANK

0 = Standard

26C: BLANK

0 = Standard

LN Series Feature String Nomenclature

Model Options

Unit Feature Options

GEN

MJREV

SIZE SERIES

MNREV VLT

B4 1 2

5D 6 7 8A

8C 9

10A

10B

10C

10D

LN A – 140 – C – 0 – 3 – F A C 0 E – 0 0 0 0 : A 0 – 0 0 0 0 – 0 0 0 0 – 0 0 0 0 – 0 0 – 0 0 0 – 0 – 0 E 0 0 –

0 0 0 0 0 – 0 A 0 0 0 – 0 0 0 0 0 – 0 0 0 0 0 0 – 0 0 0 0 0 – 0 0 0 B

26A

26B

26C

26D

26E

26F

26D: BLANK

0 = Standard

26E: BLANK

0 = Standard

26F: BLANK

0 = Standard

27: BLANK

0 = Standard

28: BLANK

0 = Standard

29: BLANK

0 = Standard

30: BLANK

0 = Standard

31: BLANK

0 = Standard

32: BLANK

0 = Standard

33: WARRANTY

0 = Standard Warranty D = Compressor Warranty Years 2-5

34: CABINET MATERIAL

0 = Standard - Double Wall + R-13 Foam Insulation

35: PAINT & SPECIAL PRICING AUTHORIZATIONS

B = Premium AAON Gray Paint Exterior E = Premium AAON Gray Paint Exterior + Shrink Wrap X = Special Pricing Authorization + Premium AAON Gray Paint Exterior 1 = SPA + Premium AAON Gray Paint Exterior + Shrink Wrap 4 = Special Pricing Authorization + Special Exterior Paint Color 7 = SPA + Special Exterior Paint Color + Shrink Wrap

General Information

The Clean Air Act of 1990 bans the intentional venting of refrigerant as of July 1, 1992. Approved methods of recovery, recycling, or reclaiming must be followed.

Coils and sheet metal surfaces present sharp edges and care must be taken when working with equipment.

Failure to observe the following instructions will result in premature failure of your system and possible voiding of the warranty.

AAON LN Series chillers are complete selfcontained liquid chilling units. They are assembled, wired, charged and run-tested. Models are available for air-cooled applications. Chiller primary pumping packages are available as optional features.

Codes and Ordinances

LN Series units have been tested and certified, by ETL, in accordance with UL Safety Standard 1995/CSA C22.2 No. 236.

System should be sized in accordance with the American Society of Heating, Refrigeration and Air Conditioning Engineers Handbook.

Installation of LN Series units must conform to the ICC standards of the International Mechanical Code, the International Building Code, and local building, plumbing and waste water codes. All appliances must be electrically grounded in accordance with local codes, or in the absence of local codes, the current National Electric Code, ANSI/NFPA 70 or the current Canadian Electrical Code CSA C22.1.

Receiving Unit

When received, the unit should be checked for damage that might have occurred in transit. If damage is found it should be noted

on the carrier’s Freight Bill. A request for

inspection by carrier’s agent should be made

in writing at once. Nameplate should be checked to ensure the correct model sizes and voltages have been received to match the job requirements.

Storage

If installation will not occur immediately following delivery, store equipment in a dry protected area away from construction traffic and in the proper orientation as marked on the packaging with all internal packaging in place. Secure all loose-shipped items.

Chiller

Rotation must be checked on all MOTORS AND COMPRESSORS of three phase units. All motors, to include and not be limited to pump motors and condenser fan motors, should all be checked by a qualified service technician at startup and any wiring alteration should only be made at the unit power connection.

Scroll compressors are directional and will be damaged by operation in the wrong direction. Low pressure switches on compressors have been disconnected after factory testing. Rotation should be checked by a qualified service technician at startup using suction and discharge pressure gauges and any wiring alteration should only be made at the unit power connection.

CRANKCASE HEATER

OPERATION Units may be equipped with compressor crankcase heaters, which should be energized at least 24 hours prior to cooling operation, to clear any liquid refrigerant from the compressors.

COMPRESSOR CYCLING

5 MINUTE MINIMUM OFF TIME To prevent motor overheating compressors must cycle off for a minimum of 5 minutes.

5 MINUTE MINIMUM ON TIME To maintain the proper oil level compressors must cycle on for a minimum of 5 minutes.

The cycle rate must not exceed 6 starts per hour.

WARNING

Failure to observe the following instructions will result in premature failure of your system, and possible voiding of the warranty.

Never turn off the main power supply to the unit, except for complete shutdown. When power is cut off from the unit, any compressors using crankcase heaters cannot prevent refrigerant migration. This means the compressor will cool down, and liquid refrigerant may accumulate in the compressor. The compressor is designed to pump refrigerant gas and damage may occur

when power is restored if liquid enters the compressor.

Before unit operation, the main power switch must be turned on for at least 24 hours for units with compressor crankcase heaters. This will give the crankcase heater time to clear any liquid accumulation out of the compressor before it is required to run.

Never cut off the main power supply to the unit, except for complete shutdown. Always control the system from the building management system, or control panel, never at the main power supply (except for emergency or for complete shutdown of the system).

Scroll compressors must be on a minimum of 5 minutes and off for a minimum of 5 minutes. The cycle rate must be no more than 6 starts per hour.

The chiller is furnished with a pressure differential switch that is factory installed between the chilled water supply and return connections. This sensor must not be bypassed since it provides a signal to the unit controller that water flow is present in the heat exchanger and the unit can operate without the danger of freezing the liquid.

Compressor life will be seriously shortened by reduced lubrication, and the pumping of excessive amounts of liquid oil and liquid refrigerant.

Wiring Diagrams

A complete set of unit specific wiring diagrams in both ladder and point-to-point form are laminated in plastic and located inside the control compartment door.

General Maintenance

When the initial startup is made and on a periodic schedule during operation, it is necessary to perform routine service checks on the performance of the chiller. This includes reading and recording suction pressures and checking for normal subcooling and superheat. See the air-cooled condenser sections in this manual for specific details.

Chiller Primary Pumping

Primary pumping uses a single pump to move water (or glycol) through the chiller barrel and back to the building. This pumping package provides a constant flow of water to the system. The pump is activated whenever the chiller is given a run signal.

Water enters the unit through the return water piping, and then travels through an air separator to remove any air that is entrapped in the water. Following this, the water flows through a suction guide with strainer. The end of the suction guide is removable for strainer access. The strainer assembly is composed of two parts, the operational strainer and the startup strainer, (located inside the operational strainer) which is to be removed 24 hours after startup.

The pump is installed after the suction guide, and before a combination valve (FloTrex). This combination valve acts as isolation valve, check valve, and flow balancing valve. The shell and tube or brazed plate evaporator, is placed after the combination valve in the water circuit, with a differential pressure switch installed across its inlet and outlet. This pressure switch closes when the differential pressure increases above the setpoint, which should be set 1-2 psig below the pressure drop across the heat exchanger at design flow rate. The closing differential pressure switch signals the control system to indicate flow through the heat exchanger and allow cooling to activate as required to maintain the setpoint. The water exiting the shell and tube or brazed plate evaporator, leaves the unit through the water out connection.

Automatic Air Vent

There is an automatic air vent installed at the high point of the system inside the pumping package compartment. The air vent valve must be in the proper position for operation. Ensure that the small vent cap is loosened two turns from the closed position, allowing air to be vented from the system. It is advisable to leave the cap on to prevent impurities from entering the valve. See appendix for additional information.

Dual Pumps

When redundant pumping is required, factory installed dual pumps can be ordered. A dual pump is a pump with two independent motors and pumps in a single casing. This dual pump has a swing splitflapper valve in the discharge port to prevent liquid recirculation when only one pump is operating. Isolation valves in the casing allow one pump to be isolated and removed for service while the other pump is still operating.

The controls package will activate the pump when the unit is given a run command. If the controls do not recognize flow in 60 seconds, the second pump will be activated and an alarm signal will be generated. If the second pump does not activate, the cooling will be locked out. See appendix for additional information.

Pressure Gauges and Thermometers

Pressure gauges and thermometers are available as a factory installed option. Thermometers are installed on the inlet and outlet of the unit. One pressure gauge is installed at each pump. This pressure gauge is connected in three places to the water piping before the suction guide/strainer, after the suction guide and before the pump, and after the pump. There is also a needle valve at each of these points to isolate the pressure. To measure the pressure at any given point, open the needle valve at that point and close the other two needle valves. One gauge is used so that the calibration of the pressure gauge is irrelevant in the calculation of the differential pressure.

Pipe Insulation

The water piping and components on units with pumping packages are not insulated at the factory. Insulation should be installed on the water piping after the system has been checked for leaks.

Installation

Location

Unit Size

45-140 tons

Front -

(Controls Side)

72”

Back

72”

Ends

96”

Top

Unobstructed

All roofing work should be performed by competent roofing contractors to avoid any possible leakage.

CAUTION

Chiller Placement

The AAON LN Series is designed for outdoor applications and mounting at ground level or on a rooftop. It must be placed on a level and solid foundation that has been prepared to support its weight.

The placement relative to the building air intakes and other structures must be carefully selected. Be sure to observe the dimensions that are on the rating plate of the chiller for operational and service clearances.

Table 1 - Service Clearances

Condenser coils and fans must be free of any obstructions in order to start and operate properly with a correct amount of airflow. For proper unit operation, the immediate area around condenser must remain free of debris that may be drawn in and obstruct airflow in the condensing section.

Consideration must be given to obstruction caused by snow accumulation when placing the unit.

Curb and Steel Mount Installation

Make openings in the roof decking large enough to allow for water piping, electrical penetrations, and workspace only. Do not make openings larger than necessary. Set the curb to coincide with the openings. Make sure curb is level.

Unit specific curb drawing is included with job submittal. See SMACNA Architectural Sheet Metal Manual for curb installation details.

Units require rail support along all four sides of the unit base.

When installed at ground level, a one-piece concrete slab should be used with footings that extend below the frost line. Care must also be taken to protect the coil and fins from damage due to vandalism or other causes.

If unit is elevated a field supplied catwalk is recommended to allow access to unit service doors.

This unit ships with a curb gasket that is

1¼” wide and 1½” tall. It is recommended

that this or another similar gasket be used between the curb and the unit to reduce vibration from the unit to the building.

Figure 1 - Curb Mounting with Dimensions

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