AAON LF Series Owner's manual

LF Series
Air-Cooled Chillers
Installation, Operation,
& Maintenance
If the information in this manual is not
followed exactly, a fire or explosion
may result causing property damage,
personal injury or loss of life.
FOR YOUR SAFETY
Do not store or use gasoline or other
flammable vapors and liquids in the
vicinity of this or any other appliance.
WARNING
WARNING
QUALIFIED INSTALLER
Improper installation, adjustment,
alteration, service or maintenance can
cause property damage, personal
injury or loss of life. Installation and
service must be performed by a
Factory Trained Service Technician. A
copy of this IOM should be kept with
the unit.
WARNING

2
Table of Contents
AAON LF Series Features and Options Introduction..................................................................... 4
Safety .............................................................................................................................................. 5
LF Series Feature String Nomenclature.......................................................................................... 7
General Description...................................................................................................................... 12
Receiving Unit........................................................................................................................... 12
Chiller........................................................................................................................................ 13
Wiring Diagrams....................................................................................................................... 14
General Maintenance................................................................................................................. 14
Primary Pumping Package ........................................................................................................ 14
Glycol........................................................................................................................................ 15
Compression Tank..................................................................................................................... 15
Pressure Relief Valve................................................................................................................ 15
Manual and Automatic Air Vent............................................................................................... 15
Dual Pumps ............................................................................................................................... 15
Differential Pressure Gauge and Thermometers....................................................................... 16
Pipe Insulation........................................................................................................................... 16
Installation..................................................................................................................................... 16
Forklifting the Unit (4-17, 22 and 24 ton)................................................................................. 16
Lifting the Unit.......................................................................................................................... 17
Locating the Unit....................................................................................................................... 18
Water Connection...................................................................................................................... 18
Mounting Isolation.................................................................................................................... 19
Access Doors............................................................................................................................. 19
Low Ambient Operation............................................................................................................ 19
LAC Valve............................................................................................................................. 20
Condenser Flooding............................................................................................................... 21
Electrical.................................................................................................................................... 21
Startup........................................................................................................................................... 23
Maintenance.................................................................................................................................. 24
General ...................................................................................................................................... 24
Compressors.............................................................................................................................. 24
Refrigerant Filter Driers............................................................................................................ 24
Adjusting Refrigerant Charge ................................................................................................... 24
Lubrication ................................................................................................................................ 26
Service....................................................................................................................................... 27
Warranties ................................................................................................................................. 27
Condenser Tube Inspection....................................................................................................... 27
Pump Operation......................................................................................................................... 27
Access Doors............................................................................................................................. 27
Pump Bearings - Lubrication .................................................................................................... 27
Air Inlet ..................................................................................................................................... 27
Propeller Fans and Motors ........................................................................................................ 28

3
Recommended Annual Inspection ............................................................................................ 28
Air-Cooled Condenser............................................................................................................... 28
E-Coated Coil Cleaning ............................................................................................................ 28
Microchannel Coil Cleaning ..................................................................................................... 30
Replacement Parts..................................................................................................................... 32
AAON Technical Support......................................................................................................... 32
Appendix - Water Piping Component Information ...................................................................... 33
Water Pressure Relief Valve ..................................................................................................... 33
Automatic Air Vent Valves....................................................................................................... 33
Pumps: Installation and Operating Instructions ........................................................................ 34
Dual Pump Specific Information............................................................................................... 39
Valve Operation ........................................................................................................................ 39
Suction Guides .......................................................................................................................... 44
Flo-Trex Combination Valve .................................................................................................... 45
LF Series Startup Form................................................................................................................. 51
Maintenance Log .......................................................................................................................... 54
Literature Change History............................................................................................................. 55
Index of Tables and Figures
Tables:
Table 1 - 4-7 & 9 ton Service Clearances..................................................................................... 18
Table 2 - 8 & 10-13 ton Service Clearances................................................................................. 18
Table 3 - 14-17, 22 & 24 ton Service Clearances......................................................................... 18
Table 4 - 21 & 26-55 ton Service Clearances............................................................................... 18
Table 5 - Water Connection Sizes ................................................................................................ 19
Table 6 - Condenser Flooding....................................................................................................... 21
Table 7 - Nameplate Voltage Markings........................................................................................ 21
Table 8 - Max Filter Drier Pressure Drops ................................................................................... 24
Table 9 - Acceptable Refrigeration Circuit Values....................................................................... 25
Table 10 - R-410A Refrigerant Temperature-Pressure Chart....................................................... 26
Figures:
Figure 1 - Pressure Relief Valve................................................................................................... 15
Figure 2 - Forklifting an LF Series A, B and C Cabinet, 4-17, 22 and 24 tons............................ 16
Figure 3 - Lifting Details of a 4-17, 22 and 24 ton Standard Unit................................................ 17
Figure 4 - Lifting Details of a 21 and 26-55 ton Standard Unit.................................................... 17
Figure 5 - Piping Schematic of Example System using the LAC Valve ...................................... 20
V45070 · Rev. A · 190515
(ACP J00425)

4
AAON LF Series Features and Options Introduction
Energy Efficiency
•Staged or 10-100% Variable Capacity
R-410A Scroll Compressors
•High Efficiency Air-Cooled
Microchannel Condenser Coils
•VFD Controlled Pumping Packages
•VFD Controlled or ECM Condenser Fan
Head Pressure Control
•ECM Low Sound Condenser Fan Head
Pressure Control
•Waterside Economizers
•Factory Installed EXVs
Outdoor Mechanical Room
•Chilled Water Applications up to 55 tons
•Isolated Controls and Compressor
Compartment
•Isolated Evaporator and Pumping
Package Compartment
•Factory Engineered Primary Pumping
Packages
•Brazed Plate or Shell and Tube
Evaporators
Safety
•Phase and Brownout Protection
•Single Point Non-Fused Disconnect
Power Switch
•Waterside Thermometer and Pressure
Gauge
Installation and Maintenance
•Double Wall Rigid Polyurethane Foam
Injected Panel Construction
•Access Doors with Full Length Stainless
Steel Piano Hinges
•Molded Lockable Handles
•Factory Installed Convenience Outlet
•Service Vestibule Heating
•Controls Diagnostics
•Touchscreen Computer Controls
Interface
•Liquid Line Sight Glass
•Compressor Isolation Valves
•Color-Coded Wiring Diagrams
System Integration
•Complete System with AAON Chilled
Water Air Handling Units
•BMS Connectivity
•Grooved End Water Piping Connections
•Custom Order Paint Options
Environmentally Friendly
•R-410A Refrigerant
Extended Life
•5 Year Compressor Warranty
•Condenser Coil Guards
•2,500 Hour Salt Spray Tested Exterior
Corrosion Protection
•10,000 Hour Salt Spray Tested Polymer
E-Coated Condenser Coils

5
Safety
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.
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.

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.
WARNING
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.
WARNING
Electric shock hazard. Shut off all
electrical power to the unit to avoid
shock hazard or injury from rotating
parts.
WARNING

6
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. READ THE ENTIRE INSTALLATION,
OPERATION AND MAINTENANCE
MANUAL. OTHER IMPORTANT
SAFETY PRECAUTIONS ARE
PROVIDED THROUGHOUT THIS
MANUAL.
4. Keep this manual and all literature
safeguarded near or on the unit.
COMPRESSOR CYCLING
5 MINUTE MINIMUM OFF TIME
To prevent motor overheating
compressors must cycle off for a
minimum of 5 minutes.
2 MINUTE MINIMUM ON TIME
To maintain the proper oil level
compressors must cycle on for a
minimum of 2 minutes.
The cycle rate must not exceed 6
starts per hour.
WARNING
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.
WARNING
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

LF Series Feature String Nomenclature
Model Options
:
Unit Feature Options
GEN
MJREV
SIZE
SERIES
MNREV
VLT
A1
A2
A3
A4
A5
B1
B2
B3
B4
1
2
3A
3B
3C
3D
4A
4B
4C
4D
5A
5B
5C
5D
6
7
8A
8B
8C
LF
A
-
031
-
D
-
0
-
3
-
D
A
C
0
E
-
0
0
0
0
:
C
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
C
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
D
B
9
10A
10B
10C
10D
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26A
26B
26C
26D
26E
26F
27
28
29
30
31
32
33
34
35
7
LFSerie s Fea ture Stri ng Nom enclature
MODEL OPTIONS
SERIES AND GENERATION
LF
MAJOR REVISION
A
UNIT SIZE
004 = 4 ton Capacity
005 = 5 ton Capacity
007 = 7 ton Capacity
008 = 8 ton Capacity
009 = 9 ton Capacity
010 = 10 ton Capacity
011 = 11 ton Capacity
013 = 13 ton Capacity
014 = 14 ton Capacity
015 = 15 ton Capacity
017 = 17 ton Capacity
021 = 21 ton Capacity
022 = 22 ton Capacity
024 = 24 ton Capacity
026 = 26 ton Capacity
031 = 31 ton Capacity
042 = 42 ton Capacity
048 = 48 ton Capacity
055 = 55 ton Capacity
SERIES
A = 4-7 and 9 ton units
B = 8 and 10-13 ton unit
C = 14-17, 22 and 24 ton units
D = 21 and 26-55 ton units
MINOR REVISION
A
VOLTAGE
2 = 230V/3Φ/60Hz
3 = 460V/3Φ/60Hz
4 = 575V/3Φ/60Hz
8 = 208V/3Φ/60Hz
A1: COMPRESSOR STYLE
A = R-410A Scroll Compressors
D = R-410A Variable Capacity Scroll Compressors
E = R-410A Tandem Scroll Compressors
G = R-410A Tandem Variable Capacity Scroll
Compressors
A2: CONDENSER STYLE
A = Air-Cooled Microchannel Condenser
A3: EVAPORATOR CONFIGURATION
A = Brazed Plate
B = Oversized Brazed Plate
A4: Coating
0 = Standard
E = Polymer E-Coated Condenser Coil
A5: Staging
0 = Staged On/Off Compressors
E = All Variable Capacity Compressors
G = Half Variable Capacity Compressors
B1: Blank
0 = Standard
B2: Blank
0 = Standard
B3: Blank
0 = Standard
B4: Blank
0 = Standard

LF Series Feature String Nomenclature
Model Options
:
Unit Feature Options
GEN
MJREV
SIZE
SERIES
MNREV
VLT
A1
A2
A3
A4
A5
B1
B2
B3
B4
1
2
3A
3B
3C
3D
4A
4B
4C
4D
5A
5B
5C
5D
6
7
8A
8B
8C
LF
A
-
031
-
D
-
0
-
3
-
D
A
C
0
E
-
0
0
0
0
:
C
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
C
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
D
B
9
10A
10B
10C
10D
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26A
26B
26C
26D
26E
26F
27
28
29
30
31
32
33
34
35
8
UNIT FEATURE OPTIONS
1: Unit Orientation
0 = Standard Access End Water Connections
2: Pumping Style
B = Const. Primary Pumping System Large Pipe Size
D = Var. Primary Pumping System Large Pipe Size
J = No Pumping Package - Piping to Connections at
Wall Cutouts
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
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

LF Series Feature String Nomenclature
Model Options
:
Unit Feature Options
GEN
MJREV
SIZE
SERIES
MNREV
VLT
A1
A2
A3
A4
A5
B1
B2
B3
B4
1
2
3A
3B
3C
3D
4A
4B
4C
4D
5A
5B
5C
5D
6
7
8A
8B
8C
LF
A
-
031
-
D
-
0
-
3
-
D
A
C
0
E
-
0
0
0
0
:
C
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
C
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
D
B
9
10A
10B
10C
10D
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26A
26B
26C
26D
26E
26F
27
28
29
30
31
32
33
34
35
9
3D: Building Pump Motor Size
0 = No Building Pumps
A = 0.5 hp
B = 0.75 hp
C = 1 hp
D = 1.5 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
R = 60 hp
S = 75 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 = None
A = Hot Gas Bypass Non-Variable Capacity
Compressor Circuits
B = Hot Gas Bypass - All Circuits
7: Refrigeration Accessories
0 = Standard
A = Sight Glass
B = Compressor Isolation Valves
C = Option A + B
D = Single Circuit 0°F Low Ambient
E = Option A + D
F = Option B + D
G = Option A + B + D
H = Dual Circuits 0°F Low Ambient
J = Option A + H
K = Option B + H
L = Option A + B + H
8A: Unit Disconnect Type
0 = Standard Single Point Power Block
A = Single Point Power Non-fused Disconnect
8B: Disconnect 1 Size
0 = Power Block
N = 100 amps
R = 150 amps
V = 250 amps
Z = 400 amps
8C: Blank
0 = Standard
9: Accessories
0 = None
B = Phase & Brown Out Protection
E = Compressor Sound Blanket
M = Option B + E
10A: Unit Control Sequence
0 = Standard AAON Controls
10B: Unit Control Supplier
E = MCS Controls

LF Series Feature String Nomenclature
Model Options
:
Unit Feature Options
GEN
MJREV
SIZE
SERIES
MNREV
VLT
A1
A2
A3
A4
A5
B1
B2
B3
B4
1
2
3A
3B
3C
3D
4A
4B
4C
4D
5A
5B
5C
5D
6
7
8A
8B
8C
LF
A
-
031
-
D
-
0
-
3
-
D
A
C
0
E
-
0
0
0
0
:
C
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
C
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
D
B
9
10A
10B
10C
10D
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26A
26B
26C
26D
26E
26F
27
28
29
30
31
32
33
34
35
10
10C: Control Supplier Options
0 = None
C = Modem
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 = None
C = Vestibule Heating (Electric)
13: Maintenance Accessories
0 = None
A = 115VAC Convenience Outlet Factory Wired
B = 115VAC Convenience Outlet Field Wired
14: Blank
0 = Standard
15: Code Options
0 = Standard ETL U.S.A. Listing
16: Shipping Splits
0 = One Piece Unit
B = Crating
C = Export Crating
17: Air-Cooled Chiller Accessories
0 = Standard
A = Cond Coil Guards
C = ECM Condenser Fan Head Pressure Control
E = VFD Condenser Fan Head Pressure Control
G = Option A + C
J = Option A + E
N = Low Sound ECM Cond Fans –Head Pressure
Control
S = Option A + N
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 = None
A = Glycol chiller
C = Thermometers & Pressure Gauges
G = Option A + C
25: Blank
0 = Standard
26A: Blank
0 = Standard
26B: Blank
0 = Standard

LF Series Feature String Nomenclature
Model Options
:
Unit Feature Options
GEN
MJREV
SIZE
SERIES
MNREV
VLT
A1
A2
A3
A4
A5
B1
B2
B3
B4
1
2
3A
3B
3C
3D
4A
4B
4C
4D
5A
5B
5C
5D
6
7
8A
8B
8C
LF
A
-
031
-
D
-
0
-
3
-
D
A
C
0
E
-
0
0
0
0
:
C
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
C
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
D
B
9
10A
10B
10C
10D
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26A
26B
26C
26D
26E
26F
27
28
29
30
31
32
33
34
35
11
26C: Blank
0 = Standard
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 = Option B + Shrink Wrap
X = Special Pricing Authorization + Premium AAON
Gray Paint Exterior
1 = Option X + Shrink Wrap

12
General Description
LF Series air-cooled chillers are complete
self-contained liquid chilling units. They are
factory assembled, wired, charged and run-
tested. Primary pumping package is available
as an optional feature.
System should be sized in accordance with
the American Society of Heating,
Refrigeration and Air Conditioning
Engineers Handbook.
Installation of LF 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.
If repairs must be made to damaged goods,
then the factory should be notified before any
repair action is taken in order to protect the
warranty. Certain equipment alteration,
repair, and manipulation of equipment
without the manufacturer’s consent may void
the product warranty. Contact AAON
Technical Support for assistance with
Improper installation, adjustment,
alteration, service ormaintenance can
cause property damage, personal
injury or loss of life. Installation and
service must be performed by a
Factory Trained Service Technician.
WARNING
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.
CAUTION
Coils and sheet metal surfaces
present sharp edges and care must
be taken when working with
equipment.
WARNING
BURNING FOAM INSULATION IS
TOXIC! Do not cut holes into any
foam insulated panels with any flame
producing cutter such as a plasma
cutter or cutting torch.
WARNING
Failure to observe the following
instructions will result in premature
failure of your system and possible
voiding of the warranty.
WARNING

13
handling damaged goods, repairs, and freight
claims: [phone].
NOTE: Upon receipt check shipment for
items that ship loose. Consult order and
shipment documentation to identify potential
loose-shipped items. Loose-shipped items
may have been placed inside the unit cabinet
for security. Installers and owners should
secure all doors with locks or nuts and bolts
to prevent unauthorized access.
Chiller
Failure to observe the following instructions
will result in premature failure of your
system, and possible voiding of the warranty.
Never cut 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. Since the compressor is
designed to pump refrigerant gas, damage
may occur when power is restored.
Before unit operation, the main power switch
must be turned on for at least twenty four
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.
COMPRESSOR CYCLING
5 MINUTE MINIMUM OFF TIME
To prevent motor overheating
compressors must cycle off for a
minimum of 5 minutes.
2 MINUTE MINIMUM ON TIME
To maintain the proper oil level
compressors must cycle on for a
minimum of 2 minutes.
The cycle rate must not exceed 6
starts per hour.
WARNING
CRANKCASE HEATER
OPERATION
Units are 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.
CAUTION
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.
CAUTION
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.
CAUTION

14
Always control the system from the control
panel, never at the mainpower supply (except
for emergency or for complete shutdown of
the system).
The standard compressors must be on a
minimum of 2 minutes and off for a minimum
of 5 minutes. The cycle rate must be no more
than 6 starts per hour.
The variable capacity compressors must be
on a minimum of 3 minutes and off for a
minimum of 3 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.
The compressor life will be seriously
shortened by reduced lubrication, and the
pumping of excessive amounts of liquid oil
and refrigerant.
Wiring Diagrams
A complete set of unit specific wiring
diagram in point-to-point form is 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 sub-
cooling and superheat.
Primary Pumping Package
Primary pumping uses asingle pump to move
water (or glycol) through the evaporator and
back to the building. This pumping package
provides the necessary 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 the water flows through a
suction guide with strainer. Some units will
not include a suction guide if there is enough
straight piping before the pump. 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 strainer will be
included on all units.
FIELD WIRED CONNECTIONS
Some units may require field wired
connections. Refer to the wiring
diagrams contained within the unit to
identify any components or controls
requiring additional wiring in the field
before placing the unit into service. All
additional field wiring should be
performed by a Factory Trained
Service Technician.
CAUTION

15
The pump is installed after the strainer, and
before a combination valve (Flo-Trex). 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 set-
point, 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.
Glycol
Glycol units require a glycol feeder field
installed to replace fluid that is lost in the
system. Water should not be directly added to
glycol applications as this would dilute the
glycol concentration and thereby increase the
freezing temperature of the fluid.
Compression Tank
As the water temperature in the system
increases, the volume that water displaces
increases. In order to compensate for these
forces, AAON recommends a pre-
pressurized diaphragm compression tank that
is preset for 12 psig.
Pressure Relief Valve
Required pressure relief valve is installed in
the unit. This valve is set at 125 psig. Figure
1 shows inlet pressure versus capacity for this
pressure relief valve. See appendix for
additional information.
Figure 1 - Pressure Relief Valve
Manual and Automatic Air Vent
A manual air vent is supplied in chillers
without pumping packages. The air vent
valve must be in the proper position for
operation. Ensure that the small vent cap on
the automatic air vent is loosened one to 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, a
factory installed dualArm pump can be
ordered on units 15 tons and larger. A
dualArm pump is a pump with two
independent motors and pumps in a single
casing. This pump has a swing split-flapper
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.

16
Differential Pressure Gauge and
Thermometers
A differential pressure gauge and
thermometers are available as a factory
installed option when using a factory
installed pumping package. Thermometers
are installed around the evaporator of the
unit. A differential 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. Instead of two
pressure gauges, one pressure gauge is used
to minimize calibration and gauge errors.
Pipe Insulation
The evaporator in the LF Series chiller is
factory insulated. The water piping, pumps,
and other 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
Forklifting the Unit (4-17, 22 and 24 ton)
4-17, 22 and 24 ton units can be lifted using
a forklift. 8, 10-17, 22 and 24 ton units must
have forks 72” in length or the forks must
have 72” fork extensions. 4-7 and 9 ton units
must have forks at least 48” in length.
Standard units can be lifted from all sides
except the condenser side.
Forks must be perpendicular to the unit and
they must be in far enough that the back of
the forks are no more than 6” away from the
edge of the unit.
Figure 2 - Forklifting an LF Series A, B and C Cabinet, 4-17, 22 and 24 tons
FORKLIFTING
8, 10-17,22 AND 24 TON UNITS
Forks or Fork Extensions must be 72”
in length.
CAUTION
FORKLIFTING
4-7 AND 9 TON UNITS
Forks or Fork Extensions must be at
least 48” in length.
CAUTION
Forks

17
Lifting the Unit
If cables or chains are used to hoist the unit
they must be the same length. Minimum
cable length is 99” for 4-17, 22 and 24 ton
units and 180” for 21 and 26-55 ton units.
Care should be taken to prevent damage to
the cabinet, coils, and condenser fans.
Before lifting unit, be sure that all shipping
material has been removed from unit. Secure
hooks and cables at all lifting points / lugs
provided on the unit.
Hoist unit to a point directly above the curb
or concrete pad. Be sure that the gasket
material has been applied to curb.
Carefully lower and align the unit with utility
and duct openings. Lower the unit until the
unit skirt fits around the curb. Some units are
designed to overhang the curb. Take care that
any recessed base rails fit around the curb.
Make sure the unit is level and properly
seated on the curb or pad.
Figure 3 - Lifting Details of a 4-17, 22 and 24 ton Standard Unit
Figure 4 - Lifting Details of a 21 and 26-55 ton Standard Unit

18
Locating the Unit
The LF Series chiller 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. When installed at ground
level, a one-piece concrete slab should be
used with footings that extend below the frost
line. Also with ground level installation, care
must be taken to protect the coil from damage
due to vandalism or other causes. LF Series
chillers are available with factory installed
louvered sheet metal condenser coil guards.
The placement relative to the building air
intakes and other structures must be carefully
selected. Airflow to and from the chiller must
not be restricted to prevent a decrease in
performance and efficiency.
The installation position must provide at least
sufficient clearance for proper airflow to the
condenser coils. See Table 1 through Table 4
for individual unit clearances. When units
are mounted adjacent to each other, the
minimum clearance required between the
units is 6 feet
Table 1 - 4-7 & 9 ton Service Clearances
Location
Clearance
Left
42”
Right
36”
Compressor End
30”
Chiller HXC End
30”
Top
Open
Table 2 - 8 & 10-13 ton Service Clearances
Location
Clearance
Left
36”
Right
36”
Compressor End
30”
Chiller HXC End
30”
Top
Open
Table 3 - 14-17, 22 & 24 ton Service
Clearances
Location
Clearance
Left
42”
Right
36”
Compressor End
36”
Chiller HXC End
30”
Top
Open
Table 4 - 21 & 26-55 ton Service Clearances
Location
Clearance
Left
42”
Right
42”
Compressor End
36”
Chiller HXC End
36”
Top
Open
Units should not be installed in an enclosure
or pit that is deeper than the height of the unit.
When recessed installation is necessary, the
clearance to maintain proper airflow is at
least 6 feet.
LF Series chillers have a vertical air
discharge. There must be no obstruction
above the equipment. Do not place the unit
under an overhang.
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.
Water Connection
Connect the chiller supply and return water
lines. See Table 5 for the LF water
connection sizes. The water connections are
schedule 40 grooved black pipe. The
maximum operating pressure for the AAON
LF Series chiller is 125 psi.

19
Table 5 - Water Connection Sizes
Cabinet
Size
Model (LF-)
Supply and
Return
Connection Size
A
004, 005,
007, 009
1-1/2” SCH 40
grooved black
pipe
B & C
008, 010, 011,
013, 014, 015,
017, 022, 024
2” SCH 40
grooved black
pipe
D
021, 026, 031,
042, 048, 055
3” SCH 40
grooved black
pipe
Mounting Isolation
For roof mounted applications or anytime
vibration transmission is a factor, vibration
isolators may be used.
Access Doors
Access doors are provided to the compressor
and electrical compartment. A separate
access door is also provided to the
evaporator/heat exchanger compartment.
Low Ambient Operation
During low ambient temperatures, it is
difficult to start a system because the
refrigerant will migrate to the cold part of the
system (condenser) and make it difficult for
refrigerant to flow. All chiller compressors
are provided with factory installed crankcase
heaters. The LF Series chiller must have
continuous power 24 hours prior to startup.
This ensures the compressor will receive
sufficient refrigerant vapor at startup.
The AAON low ambient (condenser flood-
back) system is used to operate a refrigerant
system below 35°F outside air temperature.
As the ambient temperature drops, the
condenser becomes more effective therefore
lowering the head pressure.
The low ambient system maintains normal
head pressure during periods of low ambient
by restricting liquid flow from the condenser
to the receiver, and at the same time
bypassing hot gas around the condenser to the
inlet of the receiver. This reduces liquid
refrigerant flow from the condenser, reducing
its effective surface area, which in turn
increases the condensing pressure. At the
same time the bypassed hot gas raises liquid
pressure in the receiver, allowing the system
to operate properly. LF Series chillers use an
LAC valve for low ambient operation.
The chiller must be operated only with
liquid flowing through the evaporators.
WARNING
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. This will result in
complete piping system failure.
CAUTION
Installing Contractor is responsible for
proper sealing of the water piping and
electrical entries into the unit. Failure
to seal the entries may result in
damage to the unit and property.
CAUTION

20
LAC Valve
The LAC valve is a non-adjustable three way valve that modulates to maintain receiver pressure.
As the receiver pressure drops below the valve setting (295 psig for R-410A), the valve modulates
to bypass discharge gas around the condenser. The discharge gas warms the liquid in the receiver
and raises the pressure to the valve setting. The following schematic shows an example system
using the LAC valve.
Figure 5 - Piping Schematic of Example System using the LAC Valve