AAON CB-024 Owner's manual

CB SERIES
Condensing Units
Installation, Operation
& Maintenance
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
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.
WARNING
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.
WARNING

2
Table of Contents
AAON®CB Series Features and Options Introduction.................................................................. 5
Safety .............................................................................................................................................. 6
CB Base Model and Features Description.................................................................................... 10
General Description...................................................................................................................... 11
Codes and Ordinances .............................................................................................................. 11
Receiving Unit.......................................................................................................................... 11
Storage ...................................................................................................................................... 12
Direct Expansion (DX) Condensing Units ............................................................................... 12
Wiring Diagrams....................................................................................................................... 13
General Maintenance................................................................................................................ 13
Installation..................................................................................................................................... 14
Lifting the Unit ......................................................................................................................... 14
Locating Unit............................................................................................................................ 14
Mounting Isolation.................................................................................................................... 15
Access Panel ............................................................................................................................. 15
Electrical................................................................................................................................... 16
Thermostat................................................................................................................................ 17
Refrigerant Piping..................................................................................................................... 18
General.................................................................................................................................. 18
Determining Refrigerant Line Size....................................................................................... 18
Liquid Line Sizing ................................................................................................................ 19
Suction Line Sizing............................................................................................................... 20
Hot Gas Bypass Line ............................................................................................................ 22
Hot Gas Reheat..................................................................................................................... 22
Predetermined Line Sizes ..................................................................................................... 23
Startup........................................................................................................................................... 26
Compressors.............................................................................................................................. 26
Charging Refrigerant & Adjusting Refrigerant Charge............................................................ 27
Before Charging.................................................................................................................... 27
Checking Liquid Sub-cooling............................................................................................... 27
Checking Evaporator Superheat ........................................................................................... 28
Adjusting Sub-cooling and Superheat Temperatures ........................................................... 28
Air Flow.................................................................................................................................... 29
Operation....................................................................................................................................... 31
Thermostat Operation............................................................................................................... 31
Compressor............................................................................................................................... 31
Variable Capacity Compressor Controller................................................................................ 31
Low Ambient Operation........................................................................................................... 34
LAC Valve................................................................................................................................ 35
Condenser Flooding.................................................................................................................. 36

3
Compressor Lockouts ............................................................................................................... 36
Maintenance.................................................................................................................................. 37
Coils.......................................................................................................................................... 37
E-Coated Coil Cleaning............................................................................................................ 37
DX Cooling............................................................................................................................... 39
Condenser Fan Motor ............................................................................................................... 39
Replacement Parts..................................................................................................................... 39
Warranty, Service, and Parts Department................................................................................. 39
Refrigerant Piping Diagrams ........................................................................................................ 40
CB Series Startup Form................................................................................................................ 52
Literature Change History............................................................................................................. 55

4
Index of Tables and Figures
Tables:
Table 1 - Recommended Elevation Minimums............................................................................ 15
Table 2 - Predetermined Line sizes for CB units with two step compressors and R-410A.......... 25
Table 3 - Acceptable Refrigeration Circuit Values....................................................................... 28
Table 4 - Performance Testing Air Flow Setpoints...................................................................... 29
Table 5 - R-410A Refrigerant Temperature-Pressure Chart......................................................... 30
Table 6 - Demand Signal vs. Compressor Capacity Modulation.................................................. 32
Table 7 - Thermistor Temperature vs. Resistance Values............................................................ 33
Table 8 - Condenser Flooding....................................................................................................... 36
Figures:
Figure 1 –Forklift Channels & Access Panel............................................................................... 14
Figure 2 –Condensing Unit Clearances ....................................................................................... 15
Figure 3 –Utility Entry................................................................................................................. 16
Figure 4 –Heat Pump Piping Schematic of Suction Vapor Flow Down in Double Riser ........... 21
Figure 5 –Heat Pump Piping Schematic of Discharge Vapor Flow Up in Double Riser............ 21
Figure 6 - Riser height versus total equivalent line length ........................................................... 25
Figure 7 - Variable Capacity Compressor Controller................................................................... 32
Figure 8 - Compressor Controller Flash Code Details.................................................................. 33
Figure 9 - Adjustable Fan Cycling Switch.................................................................................... 34
Figure 10 - Piping Schematic of Example System using the LAC Valve .................................... 35
Figure 11 - Adjustable compressor lockout.................................................................................. 36
Figure 12–A/C only piping, AHU above CU .............................................................................. 40
Figure 13 –A/C only piping, AHU below CU............................................................................. 41
Figure 14 –Modulating hot gas reheat piping, AHU above CU .................................................. 42
Figure 15 –Modulating hot gas reheat piping, AHU below CU.................................................. 43
Figure 16 –Hot gas bypass piping, AHU above CU.................................................................... 44
Figure 17 –Hot gas bypass piping, AHU below CU.................................................................... 45
Figure 18 –Modulating hot gas reheat with hot gas bypass piping, AHU above CU.................. 46
Figure 19 –Modulating hot gas reheat with hot gas bypass piping, AHU below CU.................. 47
Figure 20 –Heat pump piping, AHU above CU .......................................................................... 48
Figure 21 –Heat pump piping, AHU below CU .......................................................................... 49
Figure 22 –Heat pump with modulating hot gas reheat piping, AHU above CU........................ 50
Figure 23 –Heat pump with modulating hot gas reheat, AHU below CU................................... 51
R57611 · Rev. A · 161221
(ACP J00187)

5
AAON®CB Series Features and Options Introduction
Energy Efficiency
Two Step or Variable Capacity Scroll
Compressor
Air-Source Heat Pump
Variable Speed Condenser Fans for Head
Pressure Control
Humidity Control
Modulating Hot Gas Reheat
Safety
Suction Pressure Transducer
Heavy Duty Wire Guards or Louvered
Panels for Condenser Coils
Automatic Low Pressure and Manual
reset High Pressure Safety Cut-outs
Suction and Liquid Line Schrader Valves
Installation and Maintenance
Easily Removable Panel Access to
Service Compartment
Run Test Report and Installation Manuals
Included in Controls Compartment
Color Coded Wiring and Wiring
Diagrams
24V Control Circuit Transformer Option
System Integration
Split System Matching
Modulating Head Pressure Control
Single Point Power
High Density Foam Compressor Sound
Suppression Blanket
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

6
ELECTRIC SHOCK
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.
WARNING
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
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.
WARNING

7
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
LIVE ELECTRICAL
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.
WARNING
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.
WARNING
ROTATING COMPONENTS
Unit contains fans with moving parts
that can cause serious injury. Do not
remove grill containing fans until the
power to the unit has been
disconnected and fan has stopped
rotating.
WARNING
3-PHASE ROTATION
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

8
Compartments containing hazardous
voltage or rotating parts are equipped
with a panel requiring tooled access.
Always re-install screws on the panel
after installation or service is
completed.
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.
WARNING
LEAK TESTING
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
COMPRESSOR LUBRICANT
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
PVC PIPING
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
COIL CLEANERS
To prevent damage to the unit, do not
use acidic chemical coil cleaners. Do
not use alkaline chemical coil
cleaners with a pH value greater than
8.5, after mixing, without first using
an aluminum corrosion inhibitor in the
cleaning solution.
CAUTION
COIL CLEANERS
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

9
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
unit 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.
COIL CLEANING
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
ENCLOSED AREA
Do not work in an enclosed area
where refrigerant or nitrogen gases
may be leaking. A sufficient quantity
of vapors may be present and cause
injury or death.
WARNING
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

CB Series Feature String Nomenclature
Model Options
:
Unit Feature Options
GEN
MJREV
UNIT SIZE
VLT
COMP
CKTS
1
2
3
4
5
6
7
CB
-
B
-
060
-
3
-
B
-
1
:
B
D
0
0
D
A
0
10
CB Base Model and FeaturesDe scription
BASE MODEL
SERIES AND GENERATION
CB
REVISION
B = Design Sequence
UNIT SIZE
024 = 24 MBH - 2 Ton - Vertical Discharge
036 = 36 MBH - 3 Ton - Vertical Discharge
048 = 48 MBH - 4 Ton - Vertical Discharge
060 = 60 MBH - 5 Ton - Vertical Discharge
VOLTAGE
1 = 230V/1Φ/60Hz
2 = 230V/3Φ/60Hz
3 = 460V/3Φ/60Hz
4 = 575V/3Φ/60Hz
8 = 208V/3Φ/60Hz
9 = 208V/1Φ/60Hz
COMPRESSOR TYPE
B = R-410A Two Step Scroll Compressor
D = R-410A Variable Capacity Scroll Compressor
F = R-410A Two Step Scroll Compressor with Sound
Blanket
H = R-410A Variable Capacity Scroll Compressor
with Sound Blanket
NUMBER OF CIRCUITS
1 = One Circuit
FEATURE 1: AMBIENT CONTROL
0 = Standard (55°F Ambient)
B = Adjustable Fan Cycling (35°F Ambient)
D = Modulating Fan Pressure Control (35°F
Ambient)
F = Flooded Condenser Ambient Controls (0°F) +
Option B
G = Flooded Condenser Ambient Controls (0°F) +
Option D
FEATURE 2: REFRIGERATION
OPTIONS
0 = Standard - Split System Air Conditioner
A = External Hot Gas Bypass
B = Split System Heat Pump
D = Modulating Hot Gas Reheat
F = Options A + D
G = Options B + D
FEATURE 3: CONTROLS
0 = Standard - Terminal Block
A = Suction Pressure Transducer (F1- Wattmaster
Reheat)
H = Control Circuit Transformer
S = Suction Pressure Transducer (Not F1 -
Wattmaster Controls)
T = Control Circuit Transformer w/ Suction Pressure
Transducer
FEATURE 4: COIL PROTECTION
0 = Standard
A = Polymer E-Coated Coil
FEATURE 5: CABINET OPTIONS
D = Standard –Louvered Panels + 2500 Hour Salt-
Spray Tested Exterior Paint
G = Wire Grille + 2500 Hour Salt-Spray Tested
Exterior Paint
FEATURE 6: WARRANTY
0 = Standard
A = Second to Fifth Year Extended Compressor
Warranty
FEATURE 7: TYPE
0 = Standard
X = Special Pricing Authorization