AAON M2 Series Modular Indoor Air Handling Units and Self Contained Units Owner's Manual

It is crucial to follow all safety warnings provided to prevent serious injury, death, or property damage. Make sure to read and understand the installation, operation, and service instructions in the manual.

Installation:

Proper installation is necessary to avoid injury, death, or property damage. Only a qualified installer should perform installation, adjustment, alteration, service, or maintenance. Keep a copy of the installation, operation, and maintenance manual with the unit at all times.

Operation:

Before starting the unit, ensure that there are no flammable vapors or liquids stored nearby. If you smell gas, do not try to light any appliance. Leave the building immediately and call your gas supplier or the fire department for instructions.

Maintenance:

Startup and service must be conducted by a Factory Trained Service Technician. When servicing, disconnect all electrical power to the unit and label wires before disconnecting controls. Verify proper operation after servicing and secure all doors with key-lock or nut and bolt.

FAQ

Q: What should I do if I smell gas?
- A: If you smell gas, do not try to turn on the unit. Shut off the main gas supply, do not touch any electric switch, and leave the building immediately. Call your gas supplier from a neighbor’s phone for instructions. If you cannot reach your gas supplier, call the fire department.

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WARNING 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.

WARNING
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.

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.

WARNING
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.
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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.
CAUTION
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. Leave the building immediately. Immediately call your gas supplier
from a neighbor’s phone. Follow the gas supplier’s instructions. If you cannot reach your gas supplier, call the fire department.

WARNING
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
CARBON-MONOXIDE POISONING HAZARD
Failure to follow instructions could result in severe personal injury or death due to carbon-monoxide poisoning, if combustion products infiltrate into the building.
Check that all openings in the outside wall around the vent (and air intake) pipe(s) are sealed to prevent infiltration of combustion products into the building.
Check that furnace vent (and air intake) terminal(s) are not obstructed in any way during all seasons.
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
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
ROTATING COMPONENTS
Unit contains fans with moving parts that can cause serious injury. Do not open door containing fans until the power to the unit has been disconnected and fan wheel has stopped rotating.
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.
9

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.
CAUTION
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.
WARNING
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 61 cm (24 inches) high to verify proper center of gravity lift point to avoid unit damage, injury or death.
10

CAUTION

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
Failure to properly drain and vent coils when not in use during freezing temperature may result in coil and equipment damage.

WARNING
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
This appliance is not intended for use by persons with reduced physical, sensory or mental capabilities, or lack of experience and knowledge, unless they have been given supervision or instruction concerning use of the appliance by a person responsible for their safety. Children must be supervised around this appliance.

WARNING
WATER PRESSURE
Prior to connection of condensing water supply, verify water pressure is less than maximum pressure shown on unit nameplate. To prevent injury or death due to instantaneous release of high pressure water, relief valves should be field supplied on system water piping.
WARNING
Always use a pressure regulator, valves and gauges to control incoming pressures when pressure testing a system. Excessive pressure may cause line ruptures, equipment damage or an explosion which may result in injury or death.
CAUTION
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.
WARNING
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.

CAUTION
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.
CAUTION
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

Cleaning the cooling tower or the

condenser water loop with harsh

chemicals, such as hydrochloric acid

(muriatic acid) or chlorine, can

damage the water-cooled condenser.

Care should be taken to avoid

allowing chemicals to enter the water-

cooled condenser. See Appendix A –

Heat

Exchanger

Corrosion

Resistance for more information.

CAUTION
In order to avoid a hazard due to inadvertent resetting of the THERMAL CUT-OUT, this appliance must not be supplied through an external switching device, such as a timer, or connected to a circuit that is regularly switched on and off by the utility.
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WARNING
OPEN LOOP APPLICATIONS
Failure of the condenser as a result of chemical corrosion is excluded from coverage under AAON Inc. warranties and the heat exchanger manufacturer’s warranties.
WARNING
WATER FREEZING
Failure of the condenser due to freezing will allow water to enter the refrigerant circuit and will cause extensive damage to the refrigerant circuit components. Any damage to the equipment as a result of water freezing in the condenser is excluded from coverage under AAON warranties and the heat exchanger manufacturer warranties.
WARNING
HOT PARTS
Disconnect all power, close all isolation valves and allow equipment to cool before servicing equipment to prevent serious injury. Equipment may have multiple power supplies. Electric resistance heating elements and hot water or steam heating coils may have automatic starts. Hot water will circulate even after power is off.

CAUTION
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.
WARNING
Do not weld or cut foam panel with plasma cutters or a cutting torch When burnt the foam produces dangerous fumes.
WARNING
Do not work in a closed area where refrigerant or nitrogen gases may be leaking. A sufficient quantity of vapors may be present and cause injury or death.
WARNING
Never attempt to open an access door or remove a panel while the unit is running. Pressure in the unit can cause excessive force against the panel.

WARNING
Ensure that sufficient dampers will be open to provide air path before fan is allowed to run.
CAUTION
COMPRESSOR CYCLING
5 MINUTE OFF TIME To prevent motor overheating, compressors must cycle off for a
minimum of 5 minutes.
5 MINUTE 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

Units

with

VFD

driven

motors/compressors have adjustable

overload settings. These are set by

the AAON factory for the protection of

these motors/compressors and must

not be adjusted over this factory

setpoint or bypassed.

1. Startup and service must be performed by a Factory Trained Service Technician.
2. The unit is for indoor use only. See General Information section for more unit information.
3. Use only with type of the gas approved for the furnace. Refer to the furnace rating plate.
4. Install this furnace only in a location and position as specified in the Installation section of this manual. The gas heat module must be installed on the positive pressure side of the supply fan.
5. Provide adequate combustion ventilation air to the furnace. If a vent duct extension is used, a class III approved vent is required. See the Locating Units and Gas Heating sections of the Installation section of the manual.
6. Combustion products must be discharged to the outdoors. Connect the furnace to an approved vent system. See the General Venting section of this manual.
7. Never test for gas leaks with an open flame. Use a commercially available soap solution made specifically for the detection of leaks to check all connections.
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8. Always install and operate furnace within the intended temperature rise range and duct system external static pressure (ESP) as specified on the unit nameplate.
9. The supply and return air ducts must be derived from the same space. It is recommended ducts be provided with access panels to allow inspection for duct tightness. When a down flow duct is used with electric heat, the exhaust duct should be an L shaped duct.
10. Clean furnace, duct and components upon completion of the construction setup. Verify furnace operating conditions including input rate, temperature rise and ESP.
11. 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.
12. READ THE ENTIRE INSTALLATION, OPERATION AND MAINTENANCE MANUAL. OTHER IMPORTANT SAFETY PRECAUTIONS ARE PROVIDED THROUGHOUT THIS MANUAL.
13. Keep this manual and all literature safeguarded near or on the unit.
14

Feature String Nomenclature

Base Feature String Identifies the main unit features and options.

Individual Module Feature String Identifies module configurations, features and
options.

M2-H-026-L-2-A-A-0-C-0

BBD-101-0-00-00000-00000-0-0 FTH-102-P-C0-20000-CE000-C-X HRA-103-A-00-00000-00000-0-0 MBH-104-A-00-00000-0000-0-0 CLC-105-E-00-00000-610I0-S-0 SDB-106-M-EI-C0000-00000-0-0 PHG-107-H-00-00000-C0M0A-0-0 EDB-201-L-GI-C0000-00000-0-0 MBD-203-A-A0-00000-B0000-0-0

Complete Feature String

A complete unit feature string consists of a base model feature string followed by a series of individual module feature strings. The first three letters of the individual module model number identify the type of module (fan, filter, coil, etc). The three numbers after the three letters indicate the position of the module in unit assembly. If the module is on the bottom level, the first number is 1 while the first number in the top level is 2. The last

number increases in value from the return/outside air section to the discharge air section. In the below example, the cooling coil module in Figure 1, CLC-105-E-0000000-610I0-0-0, is the fifth module on the first level of the unit. The exhaust fan, EDB201-L-GI-C000-00000-0-0, is the first module on the second level.

Figure 1 – Typical M2 Series Selection 15

M2 Series Base Feature String Nomenclature
Model Options

GE N TYPE UNIT SIZE SUPPL Y AIRFLOW VOLTAGE ASSEMBLY WIRING PAINT BASE RAIL SPECIAL

M2 – H – 011 – R – 2 – A – A – 0 – C – 0

M2 Series Base Feature String Nomenclature
BASE MODEL DESCRIPTION
Series and Generation M2
Type H = Horizontal
Unit Size 018 = 18 ft2 Coil (3800 9800) 026 = 26 ft2 Coil (5200-14800) 036 = 36 ft2 Coil (7000-21000)
Supply Airflow L = Left Hand R = Right Hand
Voltage 2 = 230V/3/60Hz 3 = 460V/3/60Hz 4 = 575V/3/60Hz 8 = 208V/3/60Hz

Assembly A = Factory Assembled B = Individual Boxes
Wiring 0 = No Factory Wiring A = Control Wiring in Fan Box B = Control Wiring in Control Box
Paint 0 = None – Standard A = Indoor Unit with Exterior Corrosion Protection B = Indoor Unit with Interior and Exterior Corrosion Protection E = Shipping Shrink Wrap F = Indoor Unit with Exterior Corrosion Protection + Shipping Shrink Wrap G = Indoor Unit with Interior and Exterior Corrosion Protection + Shipping Shrink Wrap
Base Rail C = 6″ High
Special 0 = None X = Special Pricing Authorization

Fan Module Feature String Nomenclature

MODULE ID POSITION MOTOR SIZ E BLOWER ISOLATION MOTOR TYPE BLANK PULLEYS SAFETY CONTROL BLANK BLANK SPECIAL

SDD – 103 – J – B I – F 00 00 – A 0000 – 0 – 0

Fan Mo dule Descriptio n
FAN MODULE DESCRIPTION
Module ID SFA = Belt Driven Supply SFC = Belt Drive Supply, Top Discharge SFD = Belt Driven Supply, No Control Panel SDB = Direct Drive Supply SDD = Direct Drive Supply, Top Discharge SDM = Dual Fan Direct Drive Supply SDN = Dual Fan Direct Drive Supply, Top Discharge PEA = Belt Driven Power Exhaust PEC = Belt Driven Power Exhaust, Top Discharge EDB = Direct Drive Power Exhaust EDD = Direct Drive Power Exhaust, Top Discharge RFA = Belt Driven Power Return RDB = Direct Drive Power Return RDM = Dual Fan Direct Drive Power Return
Position ### = Level and Position of Module in Air Handling Unit
Motor Size E = 1 hp F = 2 hp G = 3 hp H = 5 hp J = 7.5 hp K = 10 hp L = 15 hp M = 20 hp N = 25 hp P = 30 hp Q = 1.0 kW (1.3 hp) S = 1.7 kW (2.3 hp) T = 3.0 kW (4.0 hp) U = 5.4 kW (8.0 hp)
Blower A = 15″ Backward Curved Plenum B = 18″ Backward Curved Plenum C = 22″ Backward Curved Plenum D = 27″ Backward Curved Plenum E = 30″ Backward Curved Plenum F = 33″ Backward Curved Plenum G = 37″ Backward Curved Plenum H = 24″ Backward Curved Plenum

Blower Continued J = 15″ BC Plenum – 50% Width K = 18″ BC Plenum – 30% Width L = 2 x 18″ Backward Curved Plenum M = 2 x 22″ Backward Curved Plenum N = 2 x 24″ Backward Curved Plenum P = 2 x 27″ Backward Curved Plenum Q = 14″ ECM Backward Curved Plenum R = 16″ ECM Backward Curved Plenum S = 18″ ECM Backward Curved Plenum T = 18″ ECM Backward Curved Plenum
Isolation 0 = Standard I = Fan Isolation
Motor Type A = Standard Efficiency 1760 rpm B = Premium Efficiency 1760 rpm C = Premium Eff. 1760 rpm with VFD D = Premium Eff. 1760 rpm with VFD and Bypass E = Premium Efficiency 1170 rpm F = Premium Eff. 1170 rpm with VFD G = EC Motor
Blank 00 = Standard
Pulleys ## = Pulley Combination
Safety Control 0 = None A = Phase & Brownout Protection
Blank 0000 = Standard
Blank 0 = Standard
Special 0 = None X = Special Pricing Authorization

Filter Module Feature String Nomenclature

MODULE ID POSITION FILTER TYPE FILTERS SAFETY CONTROL BLANK 2ND FILTER TYPE 2ND FILTER BLANK FILTER OPTIONS SPECIAL

FTA – 102 – P – A0 – 0 0000 – 0 00 00 – 0 – 0

Filter Module Descriptio n
FILTER MODULE DESCRIPTION
Module ID FTA = Small Flat Filter FTC = Cartridge Filter FTE = Medium Flat Filter FTF = Large Flat Filter FTH = Cartridge Filter with Flat Pre-Filter FTK = Extra Large Flat Filter
Position ### = Level and Position of Module in Air Handling Unit
Filter Type P = Pleated C = Cartridge
Filters A0 = 2″ Pleated, 30% Eff. B0 = 4″ Pleated, 30% Eff. C0 = 4″ Pleated, 65% Eff. or 12″ Cartridge, 65% Eff. D0 = 4″ Pleated, 85% Eff. or 12″ Cartridge, 85% Eff. E0 = 4″ Pleated, 95% Eff. or 12″ Cartridge, 95% Eff.
Safety Control 0 = Standard 2 = Firestat

Blank 0000 = Standard
Second Filter Type 0 = Standard – None C = Cartridge
Second Filter 00 = Standard – None C0 = 12″ Cartridge, 65% Eff. D0 = 12″ Cartridge, 85% Eff. E0 = 12″ Cartridge, 95% Eff.
Blank 00 = Standard
Filter Options 0 = Standard – None A = Magnehelic Gauge B = Clogged Filter Switch C = Magnehelic Gauge & Clogged Filter Switch
Special 0 = None X = Special Pricing Authorization

MODULE ID POSITION ACTUATOR TYPE FILTERS SAFETY CONTROL BLANK BYPASS OPENING BLANK FILTER OPTIONS SPECIAL

Mixing Module Feature String Nomenclature

MBH – 101 – A – 00 – 0 0000 – 0 0000 – 0 – 0

Mixin g Mod ule Descriptio n
MIXING MODULE DESCRIPTION
Module ID MBA = Vertical Damper MBB = Horizontal Top Damper MBC = Vertical & Horizontal Bottom Damper MBD = Vertical Damper with Filter MBE = Horizontal Top Damper with Filter MBF = Horizontal Bottom Damper MBH = Vertical & Horizontal Top Damper MBI = Horizontal Bottom Damper with Filter MBJ = Vertical & Horizontal Top Damper with Filter MBK = Vertical & Horizontal Bottom Damper with Filter
Position ### = Level and Position of Module in Air Handling Unit
Actuator Type 0 = Standard – None A = Two Position Actuator B = DDC Actuator
Filters 00 = Standard – None A0 = 2″ Pleated, 30% Eff. B0 = 4″ Pleated, 30% Eff. C0 = 4″ Pleated, 65% Eff. D0 = 4″ Pleated, 85% Eff. E0 = 4″ Pleated, 95% Eff.
Safety Control 0 = Standard 2 = Firestat

Blank 0000 = Standard
Bypass Opening 0 = Standard – None A = Top Open B = Bottom Open
Blank 0000 = Standard
Filter Options 0 = Standard – None A = Magnehelic Gauge B = Clogged Filter Switch C = Options A + B
Special 0 = Standard – None X = Special Pricing Authorization

Heat Module Feature String Nomenclature

MODULE ID POSITION FUNCTION FILTERS ROW S FPI CIRCUITING COATING HEAT CAPACIT Y STAGES FUEL GAS COMB INTAKE FILTER OPTIONS SPECIAL

PHA – 104 – H – 00 – 0 00 0 0 – E 02 0 0 – 0 – 0

Heat Module Description
HEAT MODULE DESCRIPTION
Module ID PHA = Electric Heat PHB = Hot Water Coil PHC = Hot Water Coil with Filter PHD = Electric Heat with Filter PHG = Gas Heat
Position ### = Level and Position of Module in Air Handling Unit
Function B = Heating + Dehumidification D = Dehumidification H = Heating
Filters 00 = None A0 = 2″ Pleated, 30% Eff. B0 = 4″ Pleated, 30% Eff. C0 = 4″ Pleated, 65% Eff. D0 = 4″ Pleated, 85% Eff. E0 = 4″ Pleated, 95% Eff.
HEATING COIL Rows 0 = No Hot Water Heating 1 = 1 Row 2 = 2 Rows
FPI 00 = No Hot Water Heating 08 = 8 Fins Per Inch 10 = 10 Fins Per Inch 12 = 12 Fins Per Inch
Circuiting 0 = No Hot Water Heating F = Single Serpentine H = Half Serpentine Q = Quarter Serpentine

Coating 0 = Standard H = Stainless Steel Coil Casing & Copper Fins P = Polymer E-Coating S = Stainless Steel Coil Casing K = Stainless Steel Coil Casing & Polymer ECoating
Heat Capacity 0 = Hot Water Heating Coil 1 = 50 MBH input 2 = 75 MBH input 3 = 100 MBH input 4 = 125 MBH input 5 = 150 MBH input 6 = 175 MBH input 7 = 200 MBH input 8 = 250 MBH input A = 300 MBH input OR 7 kW (5.3 kW @ 208V) B = 350 MBH input OR 14 kW (10.5kW @ 208V) C = 400 MBH input OR 21 kW (15.8 kW @ 208V) D = 28 kW (21 kW @ 208V) E = 42 kW (31.5 kW @ 208V) F = 56 kW (42 kW @ 208V) G = 70 kW (52.2 kW @ 208V) H = 35 kW (26.3 kW @ 208V) J = 84 kW (63 kW @ 208V) K = 112 kW (84.1 kW @ 208V) L = 126 kW (94.6 kW @ 208V) M = 168 kW (126.2 kW @ 208V) N = 10 kW (7.5 kW @ 208V) P = 20 kW (15 kW @ 208V) Q = 30 kW (22.5 kW @ 208V) R = 40 kW (30 kW @ 208V) S = 50 kW (37.5 kW @ 208V) T = 80 kW (60.1 kW @ 208V) U = 100 kW (75.1 kW @ 208V) V = 120 kW (90.1 kW @ 208V) W = 160 kW (120.1 kW @ 208V)

MDULE ID POSITION FUNCTION FILTERS ROW S FPI CIRCUITING COATING HEAT CAPACIT Y STAGES FUEL GAS COMB INTAKE FILTER OPTIONS TYPE

Heat Module Feature String Nomenclature

PHA – 104 – H – 00 – 0 00 0 0 – E 02 0 0 – 0 – 0

Stages 00 = Hot Water Heating Coil 01 = 1 Stage 02 = 2 Stage 03 = 3 Stage 04 = 4 Stage 0M = Modulating 5:1 Stage Natural Gas
Modulating 3:1 Stage LP Gas
Fuel Gas 0 = Natural Gas [Hot Water/Electric Heat] A = LP Gas
Combustion Intake 0 = Open Combustion [Hot Water/Electric Heat] A = Separated Combustion

Filter Options 0 = Standard A = Magnehelic Gauge B = Clogged Filter Switch C = Options A + B
Special 0 = None X = Special Pricing Authorization S = Steam Heating

MODULE ID POSITION BLANK AIRWAY TYPE SAFETY CONTROL BLANK BYPASS OPENING BLANK DRAIN PAN TYPE SPECIAL

Blank Module Feature String Nomenclature

BBA – 101 – 0 – AR – 0 0000 – 0 0000 – 0 – 0

Blank M odule Description
BLANK MODULE DESCRIPTION
Module ID BBA = Small BBC = Large BBD = XL BBE = XXL
Position ### = Level and Position of Module in Air Handling Unit
Blank 0 = Standard
Airway Type 00 = Standard AR = Top Open, Right Hand End Panel AL = Top Open, Left Hand End Panel
Safety Control 0 = None 2 = Firestat

Blank 0000 = Standard
Bypass Opening 0 = None A = Top Opening B = Bottom Opening
Blank 0000= Standard
Drain Pan Type 0 = None A = Auxiliary
Special 0 = None X = Special Pricing Authorization

Cooling Coil Module Feature String Nomenclature

MODULE ID POSITION COOLING TYPE ELECTRIC HEAT kW ELEC HEAT STAGES HEATING COIL ROWS HEATING COIL FPI HEATING COIL CKT HEAT COIL COATING COOLING COIL ROWS COOLING COIL FPI COOLING COIL CKT COOL COIL COATING DRAIN PAN TYPE SPECIAL

CLC – 103 – F – 0 0 – 0 00 0 0 – 6 10 I P – S – 0

Coil Modu le Description
COOLING COIL MODULE DESCRIPTION
Module ID CLB = Chilled Water or DX CLC = DX + Hot Gas Reheat CLF = Hot Water + Chilled Water or DX CLG = Electric Heat + Chilled Water or DX CLI = Hot Water, Chilled Water, or DX with Face and Bypass Dampers CLM = Chilled Water or DX, Shorter Length
Position ### = Level and Position of Module in Air Handling Unit
Cooling Type 0 = No Cooling A =R-410A Hot Gas Bypass [HGB] Lead + HGB Lag B = R-410A HGB Non-Variable Compressors [HGBNV] C = Chilled Water F = DX R-410A G = R-410A HGB Lead H = R-410A Heat Pump J = R-410A HGB Lead + Heat Pump K = R-410A HGB Lead + HGB Lag + Heat Pump L = R-410A HGBNV + Heat Pump M =R-454B DX N =R-454B HGB Lead P =R-454B Hot Gas Bypass [HGB] Lead + HGB Lag Q = R-454B HGB Non-Variable Compressors [HGBNV] R = R-454B Heat Pump S = R-454B HGB Lead + Heat Pump T = R-454B HGB Lead + HGB Lag + Heat Pump U = R-454B HGBNV + Heat Pump
ELECTRIC HEAT Capacity 0 = No Electric Heat A = 7 kW (5.3 kW) B = 14 kW (10.5 kW) C = 21 kW (15.8 kW) D = 28 kW (21.0 kW) H = 35 kW (26.3 kW) E = 42 kW (35.0 kW) F = 56 kW (42.0 kW)

ELECTRIC HEAT Capacity (continued) G = 70 kW (52.5 kW) J = 84 kW (63.1 kW) K = 112 kW (84.1 kW) L = 126 kW (94.6 kW) M = 168 kW (126.2 kW)
Stages 0 = Standard – None 1 = 1 Stage 2 = 2 Stage 3 = 3 Stage 4 = 4 Stage
HEATING COIL Rows 0 = No Hot Water Heating 1 = 1 Row 2 = 2 Rows
FPI 00 = No Hot Water Heating 08 = 8 Fins Per Inch 10 = 10 Fins Per Inch 12 = 12 Fins Per Inch 14 = 14 Fins Per Inch
Circuiting 0 = No Hot Water Heating F = Single Serpentine H = Half Serpentine Q = Quarter Serpentine
Coating 0 = Standard P = Polymer E-Coating S = Stainless Steel Coil Casing H = Stainless Steel Coil Casing & Copper Fins K = Stainless Steel Coil Casing & Polymer ECoating
COOLING COIL Rows 0 = No Cooling Coil 4 = 4 Rows 6 = 6 Rows 8 = 8 Rows
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Cooling Coil Module Feature String Nomenclature

CLC – 103 – F – 0 0 – 0 00 0 0 – 6 10 I P – S – 0

FPI 00 = No Cooling Coil 08 = 8 Fins Per Inch 10 = 10 Fins Per Inch 12 = 12 Fins Per Inch
Circuiting 0 = No Cooling Coil D = Double Serpentine F = Single Serpentine H = Half Serpentine Q = Quarter Serpentine S = DX Single Circuit I = DX Dual Circuit, Interlaced
Coating 0 = Standard P = Polymer E-Coating S = Stainless Steel Coil Casing

H = Stainless Steel Coil Casing & Copper Fins K = Stainless Steel Coil Casing & Polymer ECoating
Drain Pan 0 = No Drain Pan S = Stainless Steel
Special 0 = None X = Special Pricing Authorization S = Steam Heating

Controls Module Feature String Nomenclature

MODULE ID POSITION BLANK BLANK SAFETY CONTROL BLANK BLANK BLANK SPECIAL

TRA – 101 – 0 – 00 – 0 0000 – 00000 – 0 – 0

Controls Mo dule Description
CONTROLS MODULE DESCRIPTION
Module ID TRA = Small TRC = Large
Position ### = Level and Position of Module in Air Handling Unit
Blank 0 = Standard
Blank 00 = Standard

Safety Control 0 = Standard 2 = Firestat
Blank 0000 = Standard
Blank 00000 = Standard
Blank 0 = Standard
Special 0 = None X = Special Pricing Authorization

Energy Recovery Module Feature String Nomenclature

MODULE ID POSITION WHEE L SIZ E RECOVERY TYPE BLANK BLANK VF D CONTROL SPECIAL

HRA – 102 – A – 00 – 00000 – 00000 – 0 – 0

Energy Recovery Module Description
ENERGY RECOVERY MODULE DESCRIPTION
Module ID HRA = AAONAIRE® Energy Recovery Wheel
Position ### = Level and Position of Module in Air Handling Unit
Wheel Size A = Standard
Recovery Type 00 = Total Energy Recovery 0A = Total Energy Recovery + 1% Purge A0 = Sensible Only Energy Recovery AA = Sensible Only Energy Recovery + 1% Purge

Blank 00000 = Standard
Blank 00000 = Standard
VFD Control 0 = Standard A = VFD Controlled Wheel
Special 0 = None X = Special Pricing Authorization

Water-Source Heat Pump Module Feature String Nomenclature

MODULE ID POSITION REVISION CAPACIT Y COMP STAGING BLANK REFRIG OPTIONS REFRIG ACCESS BLANK WATER SIDE
HEA T EXCHANGER
BLANK SPECIAL

WHP – 204 – A – 25 – D K 000 – D A 0 H 0 – 0 – 0

Water-Source Heat Pump Mod ule Descriptio n
WATER-SOURCE HEAT PUMP MODULE DESCRIPTION
Module ID WHP = Water-Source Heat Pump WCC = Water-Cooled Condenser (A/C only)
Position ### = Level and Position of Module in Air Handling Unit
Revision A
Capacity 16 = 16 tons 18 = 18 tons 20 = 20 tons 25 = 25 tons 30 = 30 tons 40 = 40 tons 50 = 50 tons 60 = 60 tons 70 = 70 tons
Compressor Style A = R-410A Scroll Compressor B = R-410A 2-Step Capacity Scroll Compressor D = R-410A Variable Capacity Scroll Compressor E = R-410A Tandem Scroll Compressor G = R-410A Tandem Variable Capacity Scroll Compressor J = R-454B 2 step Scroll M = R-454B Tandem Scroll Compressor N = R-454B Tandem Variable Capacity Scroll Compressor
Staging G = 1 On/Off Refrigeration System H = 1 Variable Capacity Refrigeration System J = 2 On/Off Refrigeration Systems K = Lead Variable Capacity Refrigeration System + Lag On/Off Refrigeration System L = 2 Variable Capacity Refrigeration Systems M = 2 Two Step Refrig System N = 1 Variable Refrig System + 1 Two Step Refrig System

Blank 000 = Standard
Refrigeration Options 0 = Standard A = Hot Gas Bypass [HGB] – Lead B = HGB Lead + HGB Lag C = HGB Lag
Refrigeration Accessories 0 = Standard A = Sight Glass B = Compressor Isolation Valves C = Sight Glass + Compressor Isolation Valves
Blank 0 = Standard
Water-Side Options 0 = Standard A = Balancing Valves B = Water Flow Switch C = Motorized Shut-off Valve D = 2 Way Head Pressure Control E = 3 Way Head Pressure Control F = Options B + A G = Options B + C H = Options B + D J = Options B + E K = Options B +A + C L = Options B + A + D M = Options B + A + E P = Options A + C Q = Options A + D R = Options A + E
Heat Exchanger Type 0 = Standard A = SMO 254 Brazed Plate Heat Exchanger B = Cupronickel Coaxial Heat Exchanger
Blank 0 = Standard
Special 0 = None X = Special Pricing Authorization

Unit Orientation

Determine left hand or right hand orientation/connections:
M2 Series

Top View

Right Hand Side

Supply Air “Front”

AIRFLOW

Supply Fan

Coil

Filter

Return Air “Back”

Connections & service access on left side for left hand orientation

Left Hand Side

Consider the airflow to be hitting the back of your head.
Figure 2 – Unit Orientation

General Information

M2 Series modular indoor air handling units and self-contained units have been designed for indoor installation. Flexible connectors are required on all duct connections to minimize air leaks.
M2 Series units are designed for safe operation when installed, operated and maintained within design specifications and the instructions in this manual. It is necessary to follow these instructions to avoid personal injury or damage to equipment or property during equipment installation, startup, operation and maintenance.
WARNING
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.
CAUTION
These units must not be used for heating or cooling at any time during any phase of construction. Very low return air temperatures, harmful vapors, and misplacement of the filters will damage the unit and its efficiency.

CAUTION
This equipment is protected by a standard limited warranty under the condition that initial installation, service, startup and maintenance is performed according to the instructions set forth in this manual. This manual should be read in its entirety prior to installation and before performing any service or maintenance work.
Equipment described in this manual is available with many optional accessories. If you have questions after reading this manual in its entirety, consult other factory documentation or contact your AAON Sales Representative to obtain further information before manipulating this equipment or its optional accessories
Certification of Gas Heat Models a. Certified as a Category III forced air
furnace with or without cooling. b. Certified for indoor installation.
Certification of Steam or Hot Water Heat Models a. Certified as a forced air heating system
with or without cooling. b. Certified for indoor installation.
Certification of Electric Heat Models a. Certified as an electric warm air furnace
with or without cooling. b. Certified for indoor installation.
Certification of Cooling Models a. Certified as a commercial central air
conditioner. b. Certified for indoor installation. c. Certified with refrigerant R-410A coils or
with chilled water cooling coils.
29

Codes and Ordinances M2 Series units have been tested and certified, by ETL, in accordance with UL60335-2-40 4th edition.
System should be sized in accordance with the American Society of Heating, Refrigeration and Air Conditioning Engineers Handbook.
Installation of M2 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. In the absence of local codes installation must conform to the current (United States) National Fuel Gas Code ANSI-Z223.1/NFPA 54 or the current (Canada) National Fuel & Propane Installation Code CSA B149.1 or B149.2, and Mechanical Refrigeration Code CSA B52. 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.
WARNING
Failure to observe the following instructions will result in premature failure of your system and possible voiding of the warranty.
CAUTION
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.

WARNING
Coils and sheet metal surfaces present sharp edges and care must be taken when working with equipment.
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 the AAON Technical Support for assistance with handling damaged goods, repairs, and freight claims: 918-382-6450.
Note: Upon receipt check shipment for items that ship loose such as filters and remote sensors. Consult order and shipment documentation to identify potential looseshipped items. Loose-shipped items may have been placed inside unit cabinet for security. Installers and owners should secure all doors with locks or nuts and bolts to prevent unauthorized access.

Figure 3 – Lockable Handle
Storage This equipment is not suitable for outdoor use of 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.
Direct Expansion (DX) Units All factory-assembled packaged DX refrigeration systems are leak tested, charged with refrigerant, and run tested. Fieldassembled and split system DX refrigeration systems are charged with a nitrogen holding charge instead of refrigerant.
All packaged water-source DX refrigerant systems include an evaporator, condenser, liquid line filter driers, thermal expansion valves (TXV) and scroll compressors.

WARNING
COMPRESSOR CYCLING
5 MINUTE OFF TIME To prevent motor overheating, compressors must cycle off for a
minimum of 5 minutes.
5 MINUTE 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.
Never cut off the main power supply to the unit, except for servicing, emergency, or complete shutdown of the unit. When power is cut off from the unit, crankcase heaters cannot prevent refrigerant migration into the compressors. 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.
CAUTION
CRANKCASE HEATER OPERATION
Some 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.
If power to the unit must be off for more than an hour, turn the thermostat system switch to “OFF”, or turn the unit off at the control
31

panel, and leave the unit off until the main power switch has been turned on again 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 started.
Always control the unit from the thermostat, or control panel, never at the main power supply, except for servicing, emergency or complete shutdown of the unit.
During the cooling season, if the air flow is reduced due to dirty air filters or any other reason, the cooling coils can get too cold which will cause excessive liquid to return to the compressor. As the liquid concentration builds up, oil is washed out of the compressor, leaving it starved for lubrication.
The compressor life will be seriously shorted by reduced lubrication and the pumping of excessive amounts of liquid oil and refrigerant.
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.
Note: Low Ambient Operation Air-cooled DX units without a low ambient option, such as condenser fan cycling, ECM driven condenser fans or the -17.8°C (0°F) low ambient option, will not operate in the cooling mode of operation properly when the outdoor temperature is below 12.8°C (55°F). Low ambient and/or economizer options are recommended if cooling operation below 12.8°C (55°F) is expected.
32

Note: Multiple Units with Multiple Thermostats When several heating and cooling units are used to condition a space, all unit thermostat switches must be set in either heating mode, cooling mode, or off. Do not leave part of the units switched to the opposite mode. Cooling only units should be switched off at the thermostat during the heating season.
Gas or Electric Heating The unit is designed to heat a given amount of air while operating. If this amount of air is greatly reduced, approximately 1/3 during the heating season, the gas heat exchanger or electric heating coil may overheat, and may cut the burner or heater off entirely by action of the safety high temperature limit devices which are factory mounted at the heat exchanger and supply fan areas.
Airflow should be adjusted after installation to obtain an air temperature rise within the range specified on the unit rating plate at the required external static pressure.
Should overheating occur with a gas heat exchanger, or the gas supply fail to shut off, shut off the manual gas valve to the furnace before shutting off the electrical supply.
Prolonged overheating of the heat exchanger will shorten its life.
The maximum supply air temperature is 60°C (140°F).
Wiring Diagrams Unit specific wiring diagrams are laminated and affixed inside the controls compartment door.
Condensate Drain Pan Unit requires drain traps to be connected to the condensate drain pan of the unit.

For condensate drain lines, the line should be the same pipe size or larger than the drain connection, include a p-trap, and pitch downward toward drain. An air break should be used with long runs of condensate lines. See Installation section of this manual for more information.
CAUTION

CAUTION
An auxiliary / emergency drain pan is recommended for all indoor applications where there is a risk of water damage to surrounding structure or furnishings. Refer to local codes.

Unit should not be operated without a p-trap. Failure to install a p-trap may result in overflow of condensate water.

Table 1 Electric and Gas Heating Capacities

Installation

The M2 can either be shipped assembled or shipped in individual modules. See the Module Assembly section of this document for instructions on individual modules.
WARNING
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.
Locating Units Verify foundation or mounting frame can support the total unit weight, including accessory weights.
Before setting the unit into place, caution must be taken to provide clearance for unit doors that must be accessible for periodic service. These areas contain the controls, safety devices, refrigerant or water piping, shut-off valves and filters.
A minimum clearance equal to the width of the unit is required on the access panel side of the unit to ensure there is enough room to slide out coils and energy recovery wheels, and to access filters, fans and other internal components.

WARNING
When locating gas fired units, it is recommended the unit be installed so that the flue discharge vents are located at least 305 cm (120 inches) away from any opening through which combustion products could enter the building.
WARNING
Distances from adjacent public walkways, adjacent buildings, operable windows and building openings, shall conform to local codes and/or the National Fuel Gas Code, ANSI Z223.1/NFPA 54, or the National Gas & Propane Code, CSA B149.1
For gas fired unit, do not position flue opening to discharge into a fresh air intake of any other piece of equipment. Unit should also be installed so that the flow of combustion intake air is not obstructed from reaching the furnace.
Flue gas is dangerously hot and contains containments. The user is responsible for determining if vent gases may degrade building materials.
The National Gas and Propane Installation Code, B149.1 specifies a 1.8 m (6 ft) horizontal vent terminal clearance to gas and electric meters and relief devices.

Local codes may supersede or further place restrictions on vent termination locations.

Energy Recovery
Wheel

Energy Recovery
Wheel Module
Coil Module

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 61 cm (24 inches) high to verify proper center of gravity lift point to avoid unit damage, injury or death.

Coil Fan
X

Figure 4 – Service Access Clearance

Table 2 – Minimum Clearances

Minimum Required

Unit Size

Service Clearance

X =

M2-018

84″

M2-026

84″

M2-036

96″

Lifting the Assembled Unit Units may be delivered as separate modules or completely factory assembled with all modules connected. In the latter case, if the unit was received fully assembled, the recommended method of lifting is to insert a 38.1 mm (1-1/2″) steel pipe through the lifting lugs along the entire length of the unit, then pick the unit up using a spreader bar assembly. Refer to Figure 5 – M2 Series Unit Four Point Lifting and Figure 6 – M2 Series Unit Eight Point Lifting.

If cables or chains are used to hoist the unit they must be the same length. 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.
CAUTION
Incorrect lifting can cause damage to the unit.

Figure 5 – M2 Series Unit Four Point Lifting 36

Figure 6 – M2 Series Unit Eight Point Lifting 37

Lifting the Individual Modules The bottom tier individual modules have lifting lugs built into the base. Individual bottom tier modules can be lifted by securing hooks and cables at all four lugs provided on the module.
Figure 7 – M2 Series Individual Module Bottom Tier Lifting
The top tier individual modules are shipped on individual wooden pallets and do not have base lifting lugs. They can be lifted by wrapping a strap around each side of the module or using a forklift truck.

Floor Mounted Units Dual path units, self-contained units and units over size M2-018 must be floor mounted. Make sure the unit is level, and installed with a minimum height of 15.25 cm (6″) to allow for proper drainage of the condensate line. Standard units are built with a 15.25 cm (6″). Other installation provisions may be necessary according to job specifications.
A ceiling suspended mounting frame must be provided for unit suspension. It is the responsibility of the engineer or installing contractor to design and build a suitable structure based on the load distribution of individual modules. C-channels, or similar structural members, are suggested to be placed parallel to airflow under each base rail of the unit, with appropriate structural cross members as required by weight and design. A 4″ minimum c-channel size is recommended. The unit is not designed to be suspended directly from the base rails. An appropriate structural support is required for suspension.
The air handling unit must be installed level as the internal drain pan is manufactured with a slope toward the drain. Other installation provisions may be necessary according to job specifications and requirements.

Figure 8 – M2 Series Individual Module Top Tier Lifting

Module Assembly Although M2 Series modular units are shipped factory assembled as standard, the unit may be ordered as individual modules for certain applications such as for assembly in existing structures where modules must be manipulated separately. If the unit was ordered as individual modules, then they must be connected in the field.
Locate the configuration schematic in the equipment’s literature packet. The schematic will have CONFIGURATION written in the top left hand corner followed by the unit model number and then the module configuration numbers listed in order.
1. Identify and Situate Modules Use the Feature String descriptions at the beginning of this manual or in the M2 Engineering Catalog for assistance identifying module types by their three-letter codes.
It is advisable to situate all required modules in the installation location as near as possible to the order in which they will be connected. Be sure to leave enough space to work between modules before connection.
Identify each module by the configuration number on its label. For example, if a module has a configuration number of FTF-101-P-

A0-00000-00000-0-0, then it is a large flat filter module “FTF”, and should be placed in the first position “101” of the lower tier – the bottom left as you face the access side of a right hand unit, or the bottom right as you face the access side of a left hand unit.
Although the schematic should be available, the configuration numbers have been created so that correct assembly order can be determined without the need for a schematic.
Modules are arranged in order with 100 series modules on the first tier and 200 series modules on the second tier. Module 101 will always be located on the end of the bottom tier – the bottom left as you face the access side of a right hand unit, or the bottom right as you face the access side of a left hand unit. Module 201 will always be located on the end of the top tier – the top left as you face the access side of a right hand unit, or the top right as you face the access side of a left hand unit. Therefore, it is possible to identify the exact module arrangement even without knowing the module type, and without a configuration schematic.
If, for any reason, a module or its position in final assembly is unidentifiable, then consult the project engineer, AAON sales representative, or AAON Technical Support 918-382-6450.
After identifying modules and determining module arrangement, modules can be prepared for final assembly.
39

Base model number
CONFIGURATION: M2-H-011-R-2-A-A-0-C-0
FTF-101-P-A0-00000-00000-0-0 HRA-102-A-00-00000-00000-0-0 CLF-103-C-00-210F0-610F0-S-0 SFA-104-K-C0-A0000-00000-0-0 PEC-201-K-BI-A0000-00000-0-0 FTE-203-P-B0-00000-00000-0-0
Module configuration
numbers
Table provides required service access clearances
for applicable modules

Configuration Schematic can be found in unit literature packet
Arrows indicate airflow

201
Note: Energy recovery wheel module will have a 100 series number, but will span both tiers, also utilizing a 200 series space.
101
Figure 9 – Module Assembly Schematic
40

PEC

FTE

HRA

FTF

CLF

203 SFA

104 102
103

2. Connect Modules Modules are to be connected with nuts and bolts through the base rail with a strong metal casing around the bolt. (see Figure 11 below). The walls and roof are connected with metal strapping over module joints. Metal straps have adhesive backs and are to be additionally fastened to the unit case with sheet metal screws. All connection hardware is shipped with the unit. Align modules and place the metal support bolt casing in the middle of the two bases. Insert bolts through the bolt hole, through the metal support casing, and through the second bolt hole in the base rails of two adjacent modules. Secure with nuts to pull the bases of the two modules together tightly.
Figure 10 – Bolted Base Rail Use bar clamps or other non-destructive winching device to pull the tops of the modules together tightly.
Figure 11 – Bar Clamp

There should now be an airtight joint that needs to be permanently secured in position.
3. Secure Module Joints The metal straps are to be used to secure module joints in order to maintain the airtight seal. Straps are provided with pre-drilled holes and adhesive backing already affixed. Self-tapping sheet metal screws are provided to attach the straps to the unit cabinet. Leave bar clamps in place until strap is secure.
Peel away backing from adhesive side of a strap.
Place the strap over a module joint with the adhesive side of the strap against the unit case.
Ensure that strap completely covers the joint and that it is square with the unit casing.
Apply pressure to the strap to affix the adhesive and to hold strap in place.
Insert self-tapping screws through pre-drilled holes in strap and secure screws into unit casing using a power drill. For best results, use the lowest effective power drill torque setting. Be careful not to over tighten the screws.
Remove bar clamps and repeat for all remaining module joints.
1″
5/16″ Hex Head Self-Tapping Screws
Provided with Unit
Figure 12 – Self-Tapping Screw

Top Strap

Side Strap

Figure 13 – Strap Types

Top Strap

Angle Strap
Angle Strap

Figure 16 – Strap Installation
4. Run Power and Control Wiring M2 Series units are equipped with an internal wiring chase, located along the inside top of each module. Wire is provided for power and control wiring inside the unit.

Side Strap
Angle Strap
Figure 14 – Strap Locations
Put straps in position, hold in place and attach with self-tapping sheet
metal screws.

Figure 17 – Power and Control Wiring
The control wiring uses quick connects so a female quick connect from one module will connect to a male quick connect from the adjacent module. Some modules will have two sets of connection, so make sure the correct wire colors match up from one quick connect to the other.

Figure 15 – Strap Positioning 42

Figure 18 – Quick Connects

Wire from the unit to external controls and power sources must be provided in the field.
A color-coded wiring diagram is laminated and affixed to the inside of the control compartment access door. M2 Series units are equipped with a single point power connection.
5. Final Sealing It is very important to keep air from infiltrating the unit cabinet. Seal all piping penetrations with Armaflex, Permagum or other suitable sealant. Also seal around drain connections, electrical connections and all other inlets where air may enter the cabinet. This is especially important when the unit is installed in an unconditioned area.
Evaporator Coils The air handling unit coils are pressurized. The copper caps must be punctured to permit a gradual escape of the pressure prior to unsweating those caps. Immediately couple the tubing to the indoor unit to avoid exposing the coils to moisture. A properly sized filter drier is furnished in the condenser. When making solder connections, make sure dry nitrogen flows through the lines, when heating the copper, to prevent oxidization inside of the copper. Field piping between the condensing unit and the air handler is required.
Thermal expansion valve bulbs should be mounted with good thermal contact on a horizontal section of the suction line close to the evaporator, but outside the cabinet, and well insulated. On suction lines less than or equal to 22 mm (7/8″) OD, mount in the 12 o’clock position. On suction lines greater than 22 mm (7/8″), mount in either the 4 o’clock or 8 o’clock position.

Figure 19 – TXV Bulb Position
Hot Gas Reheat Hot Gas Reheat (HGRH) is available for use with DX systems that need humidity control. The AAON modulating hot gas reheat system diverts hot discharge gas from the condenser to the air handling unit through the hot gas line.
Field piping between the condensing unit and the air handler is required. Connect the hot gas line from the outdoor unit to the upper stub-out connection of the reheat coil in the air handling unit.
The line delivers the hot discharge gas to the reheat coil and/or the hot gas bypass valve, so it is sized as a discharge line.
Hot Gas Bypass Hot Gas Bypass (HGB) is available for use with DX systems that may experience low suction pressure during the operating cycle. This may be due to varying load conditions associated with VAV applications or units supplying a large percentage of outside air. Hot Gas Bypass is not necessary in units with variable capacity compressors. The system is designed to divert refrigerant from the compressor discharge to the low pressure side of the system in order to keep the evaporator from freezing and to maintain adequate refrigerant velocity for oil return at minimum load.

Hot discharge gas is redirected to the evaporator inlet via an auxiliary side connector (ASC) to false load the evaporator when reduced suction pressure is sensed. Field piping between the condensing unit and the evaporator is required.
Refrigerant-to-Water Heat Exchanger Condenser water pump, condenser water piping, cooling tower, pressure gauges, strainers and all components of the waterside piping must be field installed.
CAUTION
WATER-SOURCE HEAT PUMP APPLICATIONS
Water-source heat pump units using 100% outside air must have electric preheat if the application has a potential for heat pump heating operation with air entering the indoor coil below 4.4°C (43°F) with an entering water loop temperature of 21.1°C (70°F).
Open Loop Applications This product contains one or more refrigerant-to-water heat exchangers made of 316 Stainless Steel. 316 Stainless Steel is subject to severe corrosion and failure when exposed to chlorides.
WARNING
OPEN LOOP APPLICATIONS
Failure of the condenser as a result of chemical corrosion is excluded from coverage under AAON Inc. warranties and the heat exchanger manufacturer’s warranties.

Do not allow water containing any form of chlorides to enter this heat exchanger.
Common forms of chlorides include:
1. Sea water mist entering an open cooling tower system. 2. Contaminated make-up water containing salt water. 3. Disinfection the water loop with solutions containing sodium hypochlorite.
Chlorides will result in a premature failure of the condenser.
WARNING
OPEN LOOP APPLICATIONS
SMO 254 brazed plated refrigerant-towater heat exchangers are recommended with all open loop applications. Failure to use a SMO 254 heat exchanger may result in premature failure of your system and possible voiding of the warranty.
Failure of the condenser as a result of chemical corrosion is excluded from coverage under AAON warranties and the heat exchanger manufacturer warranties.
Failure of the condenser will allow water to enter the refrigerant circuit and will cause extensive damage to the refrigerant circuit components. Any damage to the equipment as a result of condenser failure from chemical corrosion due the fluid in the condenser is excluded from coverage under AAON warranties and the heat exchanger manufacturer warranties.

CAUTION
Cleaning the cooling tower or condenser water loop with harsh chemicals such as hydrochloric acid (muriatic acid), chlorine or other chlorides, can damage the refrigerantto-water heat exchanger. Care should be taken to avoid allowing chemicals to enter the refrigerant-to-water heat exchanger. See Appendix A – Heat Exchanger Corrosion Resistance for more information.
Freezing Water in the Heat Exchanger This product contains one or more refrigerant-to-water heat exchangers. A refrigerant-to-water heat exchanger contains refrigerant in one passage and water in another passage. Water is subject to freezing at 0°C (32°F). When water freezes in a heat exchanger significant forces are exerted on the components of the heat exchanger where the water is confined.
WARNING
WATER FREEZING
Failure of the condenser due to freezing will allow water to enter the refrigerant circuit and will cause extensive damage to the refrigerant circuit components. Any damage to the equipment as a result of water freezing in the condenser is excluded from coverage under AAON warranties and the heat exchanger manufacturer warranties.

Unit is capable of operating with Entering Water Temperatures (EWT) as low as 13.9 °C (57°F) during cooling mode without the need for head pressure control. If the EWT is expected to be lower than 13.9 °C (57°F) or more stable operation is desired, a factory provided head pressure control water valve option is available.

Glycol solution should be used if ambient temperatures are expected to fall below freezing or if the loop water temperature is below 10°C (50°F) while operating in the heating mode (heat pump units only). Adding glycol to condenser water causes an increase in pressure drop resulting in a decrease in unit performance. A minimum concentration of 20% glycol solution is recommended.

Table 3 – Glycol Freezing Points

% Glycol Ethylene

Propylene

Glycol

[°C (°F)] [°C (°F)]

-7.8 (18)

-7.2 (19)

-13.9 (7)

-12.8 (9)

-21.7 (-7)

-21.1 (-6)

-33.3 (-28) -32.8 (-27)

Water loop piping runs through unheated areas or outside the building should be insulated.

Water Piping All water-source heat pump units are built with a water flow switch. Some watercooled units may not have a water flow switch. This sensor provides a signal to the unit controller that water flow is present in the heat exchanger and the compressors can operate without damaging unit components. Installing contractor must ensure a differential pressure switch is installed between the condenser water supply and return connections if the unit does not have a water flow switch installed at the factory.

The water connections will differ depending on whether the unit is water-cooled only or if it is water-source heat pump. The watersource heat pump units have water supply to the top of the heat exchanger and the return to the bottom.
Figure 20 – Water-Source Heat Pump Water Piping
The water-cooled only units have water supply to the bottom of the heat exchanger and the return to the top.
Figure 21 – Water-Cooled Only Water Piping

Condenser water connections range in size from 25.4-76.2 mm (1″-3″) OD copper or black pipe. Only use approved water pipe material. Avoid using galvanized material for water lines/fittings as the material is corrosive and may cause fouling of the water system.

Table 4 – Standard Water-Source

Connections

Tonnage

Supply and Return Connection Size

016, 018, 020 51mm (2″) SCH 40

black pipe

025, 030, 040, 63.5mm (2-1/2″)

050

SCH 40 black pipe

060, 070

76mm (3″) SCH 40

black pipe

Condenser water pump must be field sized and installed between the cooling tower and self-contained unit. System should be sized in accordance with the ASHRAE Handbook. Use engineering guidelines to maintain equal distances for supply and return piping and limit bend radiuses to maintain balance in the system. Balancing valves, permanent thermometers and gauges may be required.

CAUTION
Proper sealing of the water piping entries into the unit must be ensured before operation. Failure to seal the entries may result in damage to the unit and property.
CAUTION
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
WATER PIPING
Follow national and local codes when installing water piping. Connections to the unit should incorporate vibration eliminators to reduce noise and vibration and shutoff valves to facilitate servicing. Supply and return water piping must be at least as large as the unit connections and larger depending on length of runs, rise and bends.
Before connection to the unit the condenser water system should be flushed to remove foreign material that could cause condenser fouling. Install a screen strainer with a

minimum of 20 Mesh ahead of the condenser inlet to prevent condenser fouling and internal tube damage.
Mineral content of the condenser water must be controlled. All make-up water has minerals in it and as the water is evaporated in the cooling tower, these minerals remain. As the mineral content of the water increases, the conductivity of the water increases.
Field provided and installed water treatment program must be compatible with stainless steel, copper, aluminum, ABS plastic, and PVC. Batch feed processes should never be used as concentrated chemicals can cause corrosion. Never use hydrochloric acid (muriatic acid) or chlorine as it will corrode stainless steel.
CAUTION
Each heat exchanger is equipped with a refrigerant pressure relief device to relieve pressure should excessive condensing pressures (>4654 kpa [675 psig]) occur. Codes may require installing contractor to connect and route relief piping outdoors. The relief valve has a 16 mm (5/8″) male flare outlet connection.
Unit is capable of operating with Entering Water Temperatures (EWT) as low as 10°C (50°F) without the need for head pressure control. If the EWT is expected to be lower than 10°C (50°F) or more stable operation is desired, a field provided water regulating valve may be used.
Glycol solution should be used if ambient temperatures are expected to fall below freezing or if the loop water temperature is below 10°C (50°F) while operating in the

heating mode (heat pump units only). Adding glycol to condenser water causes an increase in pressure drop resulting in a decrease in unit performance. A minimum concentration of 20% glycol solution is recommended. Reference Table 3.
Piping systems should not exceed 10 ft/sec velocity to ensure tube wall integrity and reduce noise.
CAUTION
Do not exceed recommended condenser fluid flow rates. Serious damage to or erosion of the heat exchanger tubes could occur.
Heat Exchanger Safeties Electronic freeze protection and water flow safeties should be field installed or factory provided. If the leaving water temperature drops below 3.3 °C (38°F) or water flow has ceased the 24VAC control circuit will be broken to disable the cooling system.
Waterside Economizer Cooling and pre-cooling waterside economizer coil is factory installed upstream of the evaporator coil. An optional field installed water piping kit includes three fully modulating water valves (the economizer valve, economizer bypass valve, and a threeway head pressure control valve). The water piping between the waterside economizer and the water-cooled condenser must be field provided. See the waterside economizer piping figure for recommended piping.
A p-trap must be installed on the coil drain outlet, not to exceed 15.25 cm (6″) from the drain connection. See the previous section on condensate drain piping for additional p-trap and drain information.

FIELD PROVIDED

CAUTION
DRAIN PAN CONNECTION With a waterside economizer coil a separate drain connection is included. Failure to use this separate drain connection may result in water backup and overflow of drain pan.
Figure 22 Waterside Economizer Piping The waterside economizer circuit can operate in three modes: waterside economizer only, waterside economizer with mechanical cooling, and mechanical cooling only. During waterside economizer only mode of operation, condenser water flows through the waterside economizer coil with modulating valves maintaining supply air temperature setpoint. The condenser water completely bypasses the water-cooled condenser.

During waterside economizer with mechanical cooling mode of operation, 100% of the condenser water flows through the waterside economizer coil. The condenser water then passes through the water-cooled condenser and the three-way valve modulates to maintain head pressure.
During mechanical cooling only mode of operation, condenser water flows around the waterside economizer coil with the waterside economizer bypass valve fully open. The condenser water then passes through the water-cooled condenser and the valves modulate to maintain head pressure.
Mineral content of the condenser water must be controlled. All make-up water has minerals in it and as the water is evaporated in the cooling tower, these minerals remain. As the mineral content of the water increases, the conductivity of the water increases.
Field provided and installed water treatment program must be compatible with stainless steel, copper, aluminum, ABS plastic, and PVC. Batch feed processes should never be used as concentrated chemicals can cause corrosion. Never use hydrochloric acid (muriatic acid) or chlorine as it will corrode stainless steel.
Heating Coils One or two row hot water heating coils can be factory mounted. These coils are supplied from a building hot water source. The hot water coil is not connected to the watersource condenser piping. All controls for heating operation are field supplied and field installed. Always connect the steam heating supply to the top of the coil and the return to the bottom.

Figure 23 – Steam Distributing Piping

Table 5 Steam Distributing Coil Sweat

Connection Sizes (OD)

Model (M2-)

Supply and Return Connection Size

018- 036

54mm (2 1/8″)

Air handling units with steam heating coils MUST BE installed high enough to allow for a minimum of 1 foot condensate drop leg off of the steam coil, or as recommended by the steam trap manufacturer. Lines should be insulated with approved insulation and be properly fastened, sloped, and supported according to local code requirements.

Table 6 Hot Water Coil Sweat Connection Sizes (OD)

Model (M2-)

Supply and Return Connection Size

018

54 mm (2 1/8″)

026, 036

67 mm (2 5/8″)

Always connect the hot water heating supply to the bottom of the coil and return to the top.

Figure 24 – Hot Water Piping

Water coils should not be subjected to entering air temperatures below 3.3°C (38°F) to prevent coil freeze-up. If air temperature across the coil is going to be below this value, use a glycol solution to match the coldest air expected.

Water supply lines must be insulated, properly fastened, drained, and supported according to local code requirements.

Chilled Water Coils Four, six, or eight row chilled water cooling coils can be factory mounted. These coils are supplied from a building chilled water source. The chill water coil is not connected to the water-source condenser piping. All controls for the cooling coil are field supplied and field installed.

Table 7 Chilled Water Coil Sweat Connection Sizes (OD)

Model (M2-)

Supply and Return Connection Size

018,

67 mm (2 5/8″)

026, 036

79.4 mm (3 1/8″)

Always connect the chilled water supply to the bottom of the coil and return to the top.

Figure 25 – Chill Water Piping
Water supply lines must be insulated with closed cell type pipe insulation or insulation that includes a vapor barrier. Lines should be properly fastened, drained and supported according to local code requirements, and job specifications.
WARNING
Piping shall be in accordance with national and local codes. Pressure limiting devices, backflow preventers and all other safety requirements are the sole responsibility of the installing contractor.
Condensate Drain Piping Unit may be equipped with more than one condensate drain pan connection. A p-trap and drain line must be installed on every drain connection, with the p-trap not to exceed 15.25 cm (6″) from the drain connection. The lines should be the same pipe size or larger than the drain connection, include a p-trap, and pitch downward toward drain. An air break should be used with long runs of condensate lines.

CAUTION
Unit should not be operated without ptraps. Failure to install a p-trap may result in overflow of condensate water.
Draw-through cooling coils will have a negative static pressure in the drain pan area. This will cause an un-trapped drain to back up due to air being pulled up through the condensate drain piping. Blow-through coils will have a positive static pressure in the drain pan. The condensate piping on these drain pans must be trapped to prevent pressure loss through the drain. Condensate drain trapping and piping should conform to all applicable governing codes. Note: The drain pan connection is a 25 mm (1″) MPT fitting.
Figure 26 – Draw-Through Drain Trap

Table 8 Draw-Through and Blow-Through

Drain Trap Dimensions (Metric)

Draw-Through

Drain Pan Pressure

Trap Dimensions

Negative Static

X/2

(mmHg)

(millimeters) (millimeters)

-0.93

38.1

19.1

-1.87

50.8

25.4

-2.80

63.5

31.8

-3.74

76.2

38.1

-4.67

88.9

44.5

-5.60

101.6

50.8

-6.54

114.3

57.2

-7.47

127

63.5

Table 9 Draw-Through and Blow-Through

Drain Trap Dimensions (Imperial)

Draw-Through

Drain Pan Pressure Trap Dimensions

Negative Static

X/2

(inches of water) (inch) (inch)

-0.50

1.50 0.75

-1.00

2.00 1.00

-1.50

2.50 1.25

-2.00

3.00 1.50

-2.50

3.50 1.75

-3.00

4.00 2.00

-3.50

4.50 2.25

-4.00

5.00 2.50

The X dimension on the draw-through trap should be at least equal to the absolute value of the negative static pressure in the drain pan plus one inch. To calculate the static pressure at the drain pan add the pressure drops of all components upstream of the drain pan, including the cooling coil, and add the return duct static pressure. Include the dirt allowance pressure drop for the filters to account for the worst-case scenario.

The height from top of the bottom bend of the trap to the bottom of the leaving pipe must be at least equal to one half of the X dimension. This ensures that enough water is stored in

the trap to prevent losing the drain seal during unit startup
Note: The absolute value of the fan inlet pressure will always be greater than or equal to the absolute value of the static pressure in the drain pan on draw-through units, so the fan inlet pressure is a safe value to use for the drain pan static pressure.
Figure 27 – Blow-Through Drain Trap
The Y dimension of blow-through traps should be at least equal to the value of the positive pressure in the drain pan plus one inch. Reference Table 9 and Table 10 for trap dimensions based on positive static value. This ensures that there will be enough water stored in the trap to counter the static pressure in the drain pan. To find the pressure subtract any pressure drops between the drain pan and the supply blower from the blower discharge pressure. The worst-case scenario for blowthrough coils is the minimum pressure drop, so do not include dirt allowance pressure drops for filters.
The bottom of the leaving pipe should be at least one half inch lower than the bottom of the drain pan connection. This ensures proper drainage when the unit is not running.
Note: It may be necessary to fill the trap manually, or the trap can be filled

automatically by operating the unit until enough condensate collects to fill the trap. The trap will then be filled when the unit is turned off.
Blower Wheels M2 Series units are equipped with backward curved blower wheels that are set to deliver the air volume specified according to unit size and/or job requirements. This is done with air volume bands in the blower wheels, with variable frequency drives, with electrically commutated motors, or with belt drive blowers. Field airflow adjustment is required at startup.
Electrically Commutated Motor (ECM) Air Adjustment One blower option is ECM blowers. These blowers can read a 0-10V signal for modulating air flow or they can be operated at one speed using a potentiometer. Units ordered with controls by others will include the potentiometer wired to a terminal block so that either option can be used in the field.
If the application is for the motor to run at a constant speed, the potentiometer can be utilized without any change. If the application is to vary the motor speed for changing conditions, remove the jumper indicated on the terminal strip (red wire).
Figure 28 Jumper for Remote Fan Speed Control

Figure 29 Potentiometer
Note, the potentiometer is still active in the electrical loop. The potentiometer dial should be set for the maximum fan speed for a particular application. Maximum fan speed is determined by the ECat submittal. Typically, this max speed will be the rpm set at the factory.
The fan speed can be modulated using the 010 VDC input signal.
To check fan output from the factory, the potentiometer can be dialed to 100%. By sending a 5V signal*, for instance, the rpm can be measured and this reading can be converted to cubic feet of air moved by the fan.
It is advised that a medium range signal* be utilized for this procedure. The highest signal sent by the controller should then be determined by adjustment.

The air band is sized according to the air delivery specifications and can be ordered from the factory for field installation.
The related photos of the wheel are provided for practical guidelines only in order to identify the air band location in the wheel. Actual field installation of the air band into the wheel will require access into and through the blower wheel venturi.
Air volume bands are made of aluminum, sized and equipped with easy bend tabs that are to be inserted into pre-punched slots provided on the wheel. Once the band has been inserted into the slots, it MUST BE secured by bending the tabs over from the back side of the wheel and also MUST BE secured from the inside by connecting the ends together with a pop-rivet in the holes provided on the ends of the band.
If the band is to be field installed, a hand held pop-rivet tool is recommended for connecting the band ends together. Caution must be taken to assure that the band is tightly installed and no damage, denting, or alteration to the wheel or blades occurs during the installation.

Banded Wheel Air Adjustment In the event that reduced air volume is required, an air volume band can be installed within the blower wheel to reduce the amount of air delivery. If the unit is factory equipped with the air band but additional air delivery is needed, the band can be removed from the wheel.

Figure 30 – Supply Fan Banding 54

Electric Heating Heating is accomplished by passing electrical current through a specified amount of resistance heaters which will produce the required heat. The indoor fan motor will energize at the same time as the heaters. Wiring to the air handling unit must be done in accordance with local electrical codes and standards. Check specified electrical rating and install with proper wire size.

Electrical Verify the unit name plate agrees with power supply. M2 Series units are provided with single point power wiring connections. Connection terminations are made to the main terminal block. A complete set of unit specific wiring diagrams, showing factory and field wiring are laminated in plastic and located inside the controls compartment door.

Table 10 – Nameplate Voltage Markings

Voltage Feature

Nameplate Voltage Marking

Min/Max VAC

1 230V/1/60Hz

230 197/252

2 230V/3/60Hz

230 197/252

3 460V/3/60Hz

460 456/504

4 575V/3/60Hz

575 570/630

8 208V/3/60Hz

208 197/228

9 208V/1/60Hz

208 197/228

All units require a field supplied electrical overcurrent and short circuit protection. Device must not be sized larger than the Maximum Overcurrent Protection (MOP) shown on the unit nameplate.
Codes may require a disconnect switch be within sight of the unit.
Note: Do not install the required field installed overcurrent protection or disconnect switch on the unit!
Electrical supply can enter through the bottom or side of the controls compartment. Entry must be field cut into panels of the unit.
A single point connection to a terminal block is provided. Split units may require connection between the units. High voltage conductors should enter the control panel in a separate opening and separate conduit than 24V low voltage conductors.
WARNING
The foam insulation releases dangerous fumes when it is burned. Do not cut a foam part with a cutting torch or plasma cutter. Do not weld to a foam filled part.

WARNING
Disconnect all electrical power sources before servicing the unit. More than one power source may be provided. Failure to do so may result in injury or death from electrical shock or entanglement in moving parts.

Note: Locations for field cut electrical entries are marked on the unit. Field cut openings must be a minimum of 15.25 cm (6 inches) away from all components and wiring to prevent damage due to drilling or cutting.
To pass wires through the wall or roof of the unit, a hole should be cut and conduit passed through it. Use the following procedure to cut a round hole in a foam panel.

Cutting Electrical Openings
1. Locate the placement of the hole. Be sure that the conduit will not interfere with the operation of any component or prevent access of any door or removable panel.
2. Drill a pilot hole all the way through the foam panel.
3. Using a hole saw cut the hole through the metal on both sides of the foam part.
4. With a knife cut the foam out of the hole.
5. After the conduit is installed in the hole caulk the entire perimeter of the hole on both sides with an industrial grade silicone sealant or a duct seal compound.
CAUTION
Proper sealing of the electrical and gas entries into the unit must be ensured before unit operation. Failure to seal the entries may result in damage to the unit and property.
If a larger cut-out is needed for additional duct connections not provided by the factory, or for any other reason, it is very important that the foam be completely sealed. Insulation covers should be fabricated from sheet metal to cover the foam at the cut. The edges and corners that are not covered should be sealed using silicone caulking. If a reciprocating saw is used to make the cut out, take care that the metal skins of the foamed part do not separate from the foam, this would result in reduced structural integrity of the part.
Size supply conductors based on the unit Minimum Current Ampacity (MCA) rating.

Supply conductors must be rated a minimum of 75°C (167°F).
Protect the branch circuit in accordance with code requirements. The unit 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.
Wire power leads to the unit’s terminal block or main disconnect. All wiring beyond this point has completed at the factory.
CAUTION
Three phase voltage imbalance will cause motor overheating and premature failure.
Supply voltage must be within the min/max range shown on the unit nameplate. Available short circuit current should not exceed the SCCR rating shown on the unit nameplate.
Three phase voltage imbalance will cause motor overheating and premature failure. The maximum allowable imbalance is 5%.
Voltage imbalance is defined as 100 times the maximum deviation from the average voltage divided by the average voltage.
Example: (218V+237V+235V)/3 = 230V, then 100*(230V-218V)/230V = 5.2%, which exceeds the allowable imbalance.
Check voltage imbalance at the unit disconnect switch and at the compressor terminal. Contact your local power company for line voltage corrections.

Installing contractor must check for proper motor rotation and check blower motor amperage listed on the motor nameplate is not exceeded. Motor overload protection may be a function of the variable frequency drive (VFD) and must not be bypassed.
Note: All units are factory wired for 208/230V, 460V, or 575V. If unit is to be connected to a 208V supply, the transformer must be rewired to 208V service. For 208V service interchange the yellow and red conductor on the low voltage control transformer. Red-Black for 208V Yellow-Black for 230V
CAUTION
Rotation must be checked on all MOTORS AND COMPRESSORS 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
Wire control signals to the unit’s low voltage terminal block located in the controls compartment.
If any factory installed wiring must be replaced, use a minimum 105°C (221°F) type AWM insulated conductors.

Fuses and Circuit Breakers The interrupting rating of fuses and circuit breakers is to be determined based on the KAIC rating of the unit. Refer to the wiring diagram for fuse sizing.

Table 11 35 KAIC Fuse Sizing

35 KAIC Construction

Component

Description

Interrupting Rating (kA)

Fuse

Class CC, 600V, 0.5A – 30A

200

Fuse

Class J, 600V, 35A – 600A

200

Disconnect

3P, 600V, 15A 600A

Table 12 65 KAIC Fuse Sizing

65 KAIC Construction

Component

Description

Interrupting Rating (kA)

Fuse

Class CC, 600V, 0.5A – 30A

200

Fuse

Class J, 600V, 35A – 600A

200

Disconnect

3P, 600V, 15A – 600A

Thermostat Control Wiring If a thermostat is used for unit control, thermostat should be located on an inside wall 1.2-1.5 meters (4-5 feet) above the floor where it will not be subjected to drafts, sun exposure, or heat from electrical fixtures of appliances. Control wiring must deliver adequate voltage to components to assure proper operation. Control voltage returning from controller circuit must be a minimum of 21 VAC. To assure proper wiring use the following chart to determine the allowable wiring distances.

Table 13 – Control Wiring

Wire Size (Stranded) Total Wire Distance

– Copper Conductors Allowable

Only

20 AWG

60.96 m 200 ft

18 AWG

106.7 m 350 ft

16 AWG

152.4 m 500 ft

14 AWG

228.6 m 750 ft

12 AWG

381.0 m 1250 ft

Total Wire Distance Allowable = (Quantity of Control Wires) x (Control Wire Distance)

Take the total wire distance allowable and divide by the number of wires to be connected. This indicates the distance allowable for that size wire. The wiring to the unit must not exceed the total wire distance allowable. If the voltage at the connectors is less than 21 VAC, isolation relays must be installed. If under external control 21 VAC must be field verified.

All external devices must be powered via a separate external power supply.

Example: A total of 8 wires must be pulled 75ft to a control the unit. What size wire should be used?

According to the Table 2, 16 AWG allows for 63ft (500 ft/8 wires) and 14 AWG allows for 94ft (750 ft/8 wires). Thus, 14 AWG should be used.

Gas Fired Furnace
WARNING
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.
Inspection on Arrival 1. Inspect unit upon arrival for any damage that may have occurred during shipping. 2. Prior to installation locate rating plate and verify that furnace is equipped for the available fuel supply and power supply at point of installation.
Unit Location and Clearances 1. Be sure unit is located with respect to building construction and other equipment to provide ready access and clearance to access panels or doors that must be opened to permit adjustment and servicing of the heating module. 2. The heating unit provided is listed for installation on the positive side of the circulating air blower only. 3. Locate unit to insure an adequate supply of fresh air to replace air used in the combustion and ventilation process. 4. When locating units, it is important to consider the exhaust vent piping connected to the outside atmosphere. Location should minimize the number of elbows or turns in vent pipe. 5. Do not install unit where it may exposed to potentially explosive or flammable vapors.

6. Do not locate unit in areas where corrosive vapors (such as chlorinated, halogenated, or acidic) are present in the atmosphere or can be mixed with combustion air entering heater.

Gas Supply, Piping and Connections Gas piping must be installed in accordance with local codes, or in the absence of local code, installation must conform to the current (United States) National Fuel Gas Code ANSI-Z223.1/NFPA 54 or the current (Canada) National Fuel & Propane Installation Code CSA B149.1 or B149.2.

1. Gas piping must be sized for the total Btu input of all units (heaters) serviced by a single supply. Individual heat module gas supply pipe connection size is 19 mm (¾”) NPT for gas inputs up to 400 MBH & 1″NPT for 401-600 MBH.

2. Ensure that gas regulators servicing more than one heater have the proper pipe and internal orifice size for the total input of all heaters serviced by the regulator.

3. Natural Gas furnaces require a minimum inlet gas pressure of 9.34 mmHg (5.0″ w.c.) and limited to a maximum inlet gas pressure of 25.2 mmHg (13.5″ w.c.) with the furnace operating.

Table 14 Gas Inlet Pressure (Metric)

Gas Inlet Pressures (mmHg)

Natural Gas (mmHg)

Propane Gas (LP)
(mmHg)

Minimum (50-400 MBH)

9.34

20.55

Minimum

(400-600

11.21

22.42

MBH)

Maximum

25.22

Table 15 Gas Inlet Pressures (Imperial)

Gas Inlet

Natural Propane

Pressures (“wc) Gas Gas (LP)

Minimum (50-400 MBH)

5.0″wc

11.0″wc

Minimum (400-600 MBH)

6.0″wc

12.0″wc

Maximum

13.5″wc 13.5″wc

4. A 3.2mm (1/8″) NPT tap is provided on the inlet side of the gas valve to the heater. A fitting suitable for connection to a pressure gauge capable of measuring gas pressure should be connected to each heater serviced by a single regulator so that gas pressure at each heater can be measured with all heaters in operation.
5. A drip leg (sediment trap) and a manual shut off valve must be provided immediately upstream of the gas control on the heating unit. To facilitate servicing of unit, installation of a union is recommended.
6. All gas supply and heater connections must be leak tested prior to placing equipment in service.

WARNING
1. All field gas piping must be pressure/ leak tested prior to operation. NEVER use an open flame to check for leaks. Use a soap solution or other leak detecting solution for testing.
2. Gas pressure to appliance controls must never exceed 13.5″ w.c. (1/2 psi)
WARNING
1. When pressure testing at 13.5″ w.c. (1/2 psi) or less, close the manual shutoff valve on the appliance before testing.
2. When pressure testing gas supply line at 13.5″ w.c. (1/2 psi) or higher, close manual gas valve and disconnect heater from supply line to be tested. Cap or plug the supply line.

Figure 31 – Sediment Trap for Gas Heat

Gas Furnace Component Identification

Figure 32 Gas Heater Component Identification

Horizontal Airflow Configuration 1. Airflow may be from either right or left for heater as shown, without any difference in system performance. 2. In applications with modulating controls, temperature rises below 4.4°C (40°F), or with outside air make-up air, some condensation may occur in the heating cycle. Flue gas condensate is corrosive and will result in shortened heat exchanger life. In these

applications, connection of a condensate drain line is required to avoid condensate buildup and possible heat exchanger damage. If condensate drain lines are run through unheated spaces, apply heat tape to prevent condensate from freezing. 3. If heating section is located downstream of a refrigeration system or cooling coil, condensation can occur during operation of the air conditioning,

resulting in condensation from warm, moist air in the heat exchanger tubes and flue collector. This condensate is not harmful to the heat exchanger provided it is drained continuously. For these applications a .64 cm (1/4 inch) NPT connection is provided for attachment of condensate drain line to remove condensate from heat exchanger. 4. Disposal of condensate is subject to local codes and ordinances. Some municipalities require that the acidic condensate produced be neutralized before being discharged into the sanitary sewer. If a condensate neutralizer kit is field installed, it must be installed where it can be easily accessed for inspection and maintenance.
General Venting Safe operation of indirect-fired gas furnaces requires a properly operating vent system which exhausts all the products of combustion (flue gases) to the outside atmosphere.
Venting must be in accordance with local codes and the National Fuel Gas Code NFPA54 / ANSI Z223.1 in the United States or CSA B149.1 Natural and Propane Installation Code in Canada. Local requirements typically supersede national requirements.
WARNING
FURNACE VENTING
Failure to provide proper venting affects furnace performance and may result in a health hazard which could cause serious personal injury or death.

A collar is provided on each furnace for attachment of vent piping as listed
Table 16 Vent Pipe Connection Size Input Rating (MBH) For Vent Pipe
Diameter 75.0 149.9 MBH 12.7cm (5″) 150.0 400.0 MBH 15.25cm (6″) 401.0 600.0 MBH 17.8 cm (7”)
Vertically Vented 1. Refer to Table 13.1 (a) in ANSI Z223.1 or Table C.1 in CSA B149.1 for vent pipe sizing. HD furnaces are fanassisted. Use “FAN” column for maximum and minimum input base on vertical and lateral vent pipe runs.
2. Maximum vent lengths are based on total equivalent length of pipe which must include fittings and elbows. Equivalent length of 12.7 or 17.8 cm (5 or 6 inch) elbows is 1.5 m (5 ft), and for a 17.8 cm (7 inch) elbow is 2.1 m (7 feet).
3. The top of the vent pipe must extend at least two .6 (2) meters (feet) above the highest point on the roof.
4. Horizontal runs should be pitched upward .64 cm (¼”) per foot and should be supported at .9 m (3 foot) maximum intervals.
5. Install a tee fitting at the low point of the vertical section with a drip leg and cleanout cap.
6. Vent must terminate in a Listed, weatherproof vent cap.
7. Vent connectors serving Category 1 heaters must not be connected into any portion of a mechanical draft system operating under positive pressure. Dampers must not be used in vent piping runs. Spillage of flue gases into the occupied space could result.

Horizontally Vented Vent pressures in horizontally vented furnaces are positive and therefore are classified as Category III venting systems in accordance with ANSI standards. All vent pipe joints must be sealed to prevent leakage of flue gases into the heated space.
Use only Category III vent materials listed to UL1738 / ULC S636 for vent pipe and fittings.
All field installed vent pipe and fittings must be from the same manufacturer. DO NOT intermix vent system parts from different vent manufacturers. Follow instruction provided with approved venting materials used.
Seal joint at connection to flue collar with a high temperature silicone sealant with temperature rating of 260°C (500°F).
The total equivalent length of vent pipe must not exceed 15.2 m (50 ft). Equivalent length of 12.7 or 17.8 cm (5 or 6 inch) 90° elbows is 1.5 m (5 ft), and for a 17.8 cm (7 inch) 90° elbow is 2.1 m (7 feet). 45° Elbows are half of the equivalent length of 90°.
The vent system must also be installed to prevent collection of condensate. Pitch horizontal pipe runs downward .64 cm (¼ in.) per foot toward the outlet to permit condensate drainage. Maintain 6 in. clearance between vent pipe and combustible materials.
EACH DUCT FURNACE MUST HAVE ITS OWN INDIVIDUAL VENT PIPE AND TERMINAL. Do not connect vent system from horizontally vented units to other vent systems or a chimney.
1. A Tee Fitting termination or Vent Cap listed for horizontal venting must be provided.

2. Termination fitting inlet diameter must be same as the required vent pipe diameter. The vent terminal must be at least 30.5 cm (12 in.) from any exterior wall to prevent degradation of building material by flue gases.
3. The vent terminal must be located at least 0.9 m (3 ft) above grade, or in snow areas, above snow line to prevent blockage. Additionally, the vent terminal must be installed with a minimum horizontal clearance of 1.2 m (4 ft) from electric meters, gas meters, regulators or relief equipment.
4. Through the wall vents shall not terminate over public walkways, or over an area where condensate or vapor could create a nuisance or hazard.
Two-Pipe Separated Combustion Venting The furnace must be mounted with the burner section in a reasonably airtight vestibule compartment, as these systems provide combustion air from outside the heated space and vent the products of combustion outdoors. Additionally the heating unit must include the following:
1. For vent pipe and fittings conveying flue gases, use only Category III vent materials listed to UL1738 / ULC S636 from same vent manufacturer. DO NOT intermix vent system parts from different vent manufacturers. Follow instruction provided with approved venting materials used.
2. For combustion air piping, use of 24 gauge galvanized steel single wall pipe is acceptable. Tape joints with aluminum foil tape and secure with corrosion resistant screws.
3. Inlet air pipe must be same size as exhaust vent pipe based on input ratings.

4. Exhaust and vent piping must not exceed a combined 50 equivalent feet in length.
5. See Figure 36 and Figure 37 for recommend vent terminations and air inlet fittings for venting configuration. Proper installation of air inlet and flue gas exhaust piping are essential to proper operation of the heat module. NOTE: The inlet and outlet terminals must be located in the same pressure zone to provide for safe appliance operation.
Separated combustion systems may not be common vented. Each heater must have its own individual air supply and flue gas exhaust vent. If vent system application does not meet the criteria outlined in the diagrams and information provided, contact a manufacturer of venting systems and materials for assistance with system design. If vent cap terminations are used, be sure that the vent cap used is approved for horizontal application. Certain vent terminals are approved for vertical installation only.
64

Figure 33 Indoor Vertical Venting (Category I)
Figure 34 Indoor Horizontal Venting (Category III) 65

Figure 35 Indoor Vertical Venting Separated Combustion
Figure 36 Indoor Horizontal Venting Separated Combustion 66

Energy Recovery Units AAONAIRE® units have been equipped with an energy recovery wheel. This section is provided to assure the energy recovery feature will be properly setup to perform in accordance with the job specifications for your particular application.
Figure 37 – Energy Recovery Wheel
The Energy Recovery Cassette consists of a frame wheel, wheel drive system, and energy transfer segments. Segments are removable for cleaning or replacement. The segments rotate through counter flowing exhaust and outdoor air supply streams where they transfer heat and/or water vapor from the warm, moist air stream to the cooler and/or drier air stream.
The initial setup and servicing of the energy recovery wheel is very important to maintain proper operation efficiency and building occupant comfort.
Normal maintenance requires periodic inspection of filters, the cassette wheel, drive belts, air seals, wheel drive motor, and its electrical connections.
Wiring diagrams are provided with each motor. When wired according to wiring diagram, motor rotates clockwise when viewed from the shaft/pulley side.

By carefully reviewing the information within this section and following the instructions, the risk of improper operation and/or component damage will be minimized.
It is important that periodic maintenance be performed to help assure trouble free operation.
Initial Mechanical Check and Setup Outdoor air intake adjustments should be made according to building ventilation, or local code requirements.
After the unit installation is complete, open the cassette access door and determine that the energy wheel rotates freely when turned by hand. Apply power and observe that the wheel rotates at approximately 30 RPM. If the wheel does not rotate when power is applied, it may be necessary to readjust the “diameter air seals”.
Air Seal Adjustments Pile type air seals across both sides of the energy wheel diameter are factory adjusted to provide close clearance between the air seal and wheel. Racking of the unit or cassette during installation, and/or mounting of the unit on a non-level support or in other than the factory orientation can change seal clearances. Tight seals will prevent rotation.
Figure 38 – Cross Section of Air Seal Structure
67

Wheel to Air Seal Clearance To check wheel to seal clearance; first disconnect power to the unit, in some units the energy recovery wheel assembly can be pulled out from the cabinet to view the air seals. On larger units, the energy recovery wheel may be accessible inside the walk-in cabinet.
A business card or two pieces of paper can be used as a feller gauge, (typically each .1mm (.004″) thick) by placing it between the face of the wheel and pile seal.
Using the paper, determine if a loose slip fit exist between the pile seal and wheel when the wheel is rotated by hand.
To adjust air seal clearance, loosen all seal plate retaining screws holding the separate seal retaining plates to the bearing support channels and slide the seals plates away from the wheel. Using the paper feeler gauge, readjust and retighten one seal plate at a time to provide slip fit clearance when the wheel is rotated by hand.
Confirm that the wheel rotates freely. Apply power to the unit and confirm rotation.
Airflow Balancing and Checking High performance systems commonly have complex air distribution and fan systems. Unqualified personnel should not attempt to adjust fan operation, or air circulation, as all systems have unique operations characteristics. Professional air balance specialists should be employed to establish actual operating conditions, and to configure the air delivery system for optimal performance.
Controls A variety of controls and electrical accessories may be provided with the equipment. Identify the controls on each unit

by consulting appropriate submittal, or order documents, and operate according to the control manufacturer’s instructions. If you cannot locate installation, operation, or maintenance information for the specific controls, then contact your sales representative, or the control manufacturer for assistance.
WARNING
Do not alter factory wiring. Deviation from the supplied wiring diagram will void all warranties, and may result in equipment damage or personal injury. Contact the factory with wiring discrepancies.
Routine Maintenance and Handling Handle cassettes with care. All cassettes should be lifted by the bearing support beam. Holes are provided on both sides of the bearing support beams to facilitate rigging as shown in the following illustration.
Figure 39 – Lifting Hole Locations Routine maintenance of the Energy Recovery Cassettes includes periodic cleaning of the

Energy Recovery Wheel as well as inspection of the Air Seals and Wheel Drive Components as follows:
Cleaning The need for periodic cleaning of the energy recovery wheel will be a function of operating schedule, climate and contaminants in the indoor air being exhausted and the outdoor air being supplied to the building.
The energy recovery wheel is “self-cleaning” with respect to dry particles due to its laminar flow characteristics. Smaller particles pass through; larger particles land on the surface and are blown clear as the flow direction is reversed. Any material that builds up on the face of the wheel can be removed with a brush or vacuum. The primary need for cleaning is to remove oil based aerosols that have condensed on energy transfer surfaces. A characteristic of all dry desiccants, such films can close off micron sized pores at the surface of the desiccant material, reducing the efficiency by which the desiccant can adsorb and desorb moisture and also build up so as to reduce airflow.
In a reasonably clean indoor environment such as a school or office building, measurable reductions of airflow or loss of sensible (temperature) effectiveness may not occur for several years. Measurable changes in latent energy (water vapor) transfer can occur in shorter periods of time in applications such as moderate occupant smoking or cooking facilities. In applications experiencing unusually high levels of occupant smoking or oil based aerosols such as industrial applications involving the ventilation of machine shop areas for example, annual washing of energy transfer may be necessary to maintain latent transfer efficiency. Proper cleaning of the energy recovery wheel will restore latent effectiveness to near original performance.

To clean, gain access to the energy recovery wheel and remove segments. Brush foreign material from the face of the wheel. Wash the segments or small wheels in a 5% solution of non-acid based coil cleaner or alkaline detergent and warm water.
Soak in the solution until grease and tar deposits are loosened (Note: some staining of the desiccant may remain and is not harmful to performance). Before removing, rapidly run finger across surface of segment to separate polymer strips for better cleaning action. Rinse dirty solution from segment and remove excess water before reinstalling in wheel.
CAUTION
Do Not use acid based cleaners, aromatic solvents, steam or temperatures in excess of 76.7°C (170°F); damage to the wheel may
Air Seals Four adjustable diameter seals are provided on each cassette to minimize transfer of air between the counter flowing airstreams.

Documents / Resources

AAON M2 Series Modular Indoor Air Handling Units and Self Contained Units [pdf] Owner's Manual
M2 Series Modular Indoor Air Handling Units and Self Contained Units, M2 Series, Modular Indoor Air Handling Units and Self Contained Units, Air Handling Units and Self Contained Units, Handling Units and Self Contained Units, Self Contained Units, Contained Units, Units

References

User Manual

AAON M2 Series Modular Indoor Air Handling Units and Self Contained Units

Product Usage Instructions

FAQ

Safety

Feature String Nomenclature

Unit Orientation

General Information

Installation

Documents / Resources

References

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