Aaon M2-005 Installation Manual

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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.

M2 Series

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

Modular Indoor Air Handling Units

Installation, Operation

& Self-Contained Units

& Maintenance

Table of Contents

Safety .............................................................................................................................................. 9

Feature String Nomenclature ........................................................................................................ 15

M2 Series Base Feature String Nomenclature .......................................................................... 16

Fan Module Description ............................................................................................................ 17

Filter Module Description ......................................................................................................... 18

Mixing Module Description ...................................................................................................... 19

Heat Module Description .......................................................................................................... 20

Blank Module Description ........................................................................................................ 22

Coil Module Description ........................................................................................................... 23

Controls Module Description .................................................................................................... 25

Energy Recovery Module Description ...................................................................................... 26

Water-Source Heat Pump Module Description ......................................................................... 27

Unit Orientation ............................................................................................................................ 29

General Information ...................................................................................................................... 30

Codes and Ordinances ............................................................................................................... 31

Receiving Unit ........................................................................................................................... 31

Storage ....................................................................................................................................... 32

Preparation for Storage .............................................................................................................. 32

Direct Expansion (DX) Units .................................................................................................... 32

Gas or Electric Heating ............................................................................................................. 34

Wiring Diagrams ....................................................................................................................... 34

Condensate Drain Pan ............................................................................................................... 34

Installation..................................................................................................................................... 36

Locating Units ........................................................................................................................... 36

Lifting the Assembled Unit ....................................................................................................... 37

Lifting the Individual Modules ................................................................................................. 40

Floor Mounted Units ................................................................................................................. 40

Suspended Units ........................................................................................................................ 40

Module Assembly ..................................................................................................................... 41

Refrigerant Piping for Split Systems ......................................................................................... 46

Determining Refrigerant Line Size ........................................................................................... 47

Equivalent Line Length ......................................................................................................... 47

Liquid Line Sizing ................................................................................................................. 47

Suction Line Sizing ................................................................................................................ 48

Hot Gas Bypass Line ............................................................................................................. 49

Hot Gas Reheat Line .............................................................................................................. 50

Refrigerant-to-Water Heat Exchanger ...................................................................................... 51

Open Loop Applications ........................................................................................................ 51

Freezing Water in the Heat Exchanger .................................................................................. 52

Water Piping .......................................................................................................................... 52

Heat Exchanger Safeties ........................................................................................................ 55

Waterside Economizer .............................................................................................................. 55

Heating Coils ............................................................................................................................. 56

Chilled Water Coils ................................................................................................................... 57

Condensate Drain Piping ........................................................................................................... 57

Blower Wheels .......................................................................................................................... 59

Electrically Commutated Motor (ECM) Air Adjustment ...................................................... 59

Banded Wheel Air Adjustment .............................................................................................. 60

Electric Heating ......................................................................................................................... 62

Electrical .................................................................................................................................... 62

Cutting Electrical Openings ................................................................................................... 62

Thermostat Control Wiring .................................................................................................... 64

Gas Fired Duct Furnace ............................................................................................................. 65

Unit Location and Clearances ................................................................................................ 65

Gas Supply, Piping and Connections..................................................................................... 65

Duct Furnace Component Identification ............................................................................... 66

Operating and Safety Instructions ......................................................................................... 67

Startup .................................................................................................................................... 68

Shutdown ............................................................................................................................... 70

Furnace Maintenance ............................................................................................................. 73

Energy Recovery Units ............................................................................................................. 74

Initial Mechanical Check and Setup ...................................................................................... 74

Routine Maintenance and Handling ...................................................................................... 75

Cleaning ................................................................................................................................. 76

Wheel Drive Components ...................................................................................................... 77

Startup Procedure ................................................................................................................... 78

Service ................................................................................................................................... 79

Startup ........................................................................................................................................... 81

Filters ......................................................................................................................................... 81

Check Out .................................................................................................................................. 81

Commissioning .......................................................................................................................... 83

Operation ................................................................................................................................... 83

Adjusting Refrigerant Charge ................................................................................................... 84

Refrigeration Troubleshooting .................................................................................................. 87

Maintenance .................................................................................................................................. 88

Fan Assembly ............................................................................................................................ 88

Bearings ..................................................................................................................................... 88

Belts ........................................................................................................................................... 89

Indoor Coils ............................................................................................................................... 90

Refrigeration Cycle ................................................................................................................... 90

Brazed Plate Heat Exchanger Cleaning .................................................................................... 90

E-Coated Coil Cleaning ............................................................................................................ 90

Electric Heating ......................................................................................................................... 92

Steam or Hot Water Heating ..................................................................................................... 92

Cleaning .................................................................................................................................... 92

Chilled Water ............................................................................................................................ 92

DX Water Source Cooling ........................................................................................................ 92

Condensate Drain Pans .............................................................................................................. 92

Duct Furnace ............................................................................................................................. 92

Lubrication ................................................................................................................................ 92

Replacement Parts ..................................................................................................................... 93

AAON-Longview Product Support ........................................................................................... 93

Phase and Brownout Protection Module ................................................................................... 94

Filter Replacement .................................................................................................................... 96

Appendix A - Heat Exchanger Corrosion Resistance ................................................................... 99

Split System Piping Diagrams .................................................................................................... 101

M2 Series Startup Form .............................................................................................................. 117

Maintenance Log ........................................................................................................................ 123

R40681 · Rev. D · 160524

(ACP 30752)

Index of Tables and Figures

Tables:

Table 1 – Electric and Gas Heating Capacities ............................................................................. 35

Table 2 - Minimum Clearances ..................................................................................................... 37

Table 3 - Glycol Freezing Points .................................................................................................. 52

Table 4 - Standard Water-Source Connections ............................................................................. 53

Table 5 - Freezing Points .............................................................................................................. 54

Table 6 – Steam Distributing Coil Connection Sizes ................................................................... 56

Table 7 – Hot Water Coil Connection Sizes ................................................................................. 56

Table 8 – Chilled Water Coil Connection Sizes ........................................................................... 57

Table 9 - Drain Trap Dimensions ................................................................................................. 58

Table 10 - Blow-Through Drain Trap Dimensions ....................................................................... 58

Table 11 - Control Wiring............................................................................................................. 64

Table 12 – Gas Inlet Pressure ....................................................................................................... 65

Table 13 - Gas Heater Troubleshooting ........................................................................................ 71

Table 14 - Gas Heater Troubleshooting Continued ...................................................................... 72

Table 15 - Acceptable Air-Cooled Refrigeration Circuit Values ................................................. 85

Table 16 - Acceptable Water-Cooled Refrigeration Circuit Values ............................................. 85

Table 17 - R-410A Refrigerant Temperature-Pressure Chart ....................................................... 86

Table 18 – Refrigeration Problems, Causes, and Solutions .......................................................... 87

Table 19 - Bearing Setscrew Torque Recommendations .............................................................. 89

Table 20 - Fan Bearing Lubrication Schedule .............................................................................. 93

Table 21 - M2-005 and M2-008 Filters ........................................................................................ 96

Table 22 - M2-011 and M2-014 Filters ........................................................................................ 96

Table 23 - M2-018 and M2-022 Filters ........................................................................................ 97

Table 24 - M2-026 Filters ............................................................................................................. 97

Table 25 - M2-032 and M2-036 Filters ........................................................................................ 97

Figures:

Figure 1 - Typical M2 Series Selection ........................................................................................ 15

Figure 2 - Unit Orientation ........................................................................................................... 29

Figure 3 - Lockable Handle .......................................................................................................... 32

Figure 4 - Service Access Clearance ............................................................................................ 37

Figure 5 - M2 Series Unit Four Point Lifting ............................................................................... 38

Figure 6 - M2 Series Unit Eight Point Lifting .............................................................................. 39

Figure 7 - M2 Series Individual Module Bottom Tier Lifting ...................................................... 40

Figure 8 - M2 Series Individual Module Top Tier Lifting ........................................................... 40

Figure 9 - Unit Suspension ........................................................................................................... 41

Figure 10 - Module Assembly Schematic ..................................................................................... 43

Figure 11 - Bolted Base Rail ......................................................................................................... 44

Figure 12 - Bar Clamp .................................................................................................................. 44

Figure 13 - Self-Tapping Screw .................................................................................................... 44

Figure 14 - Strap Types................................................................................................................. 45

Figure 15 - Strap Locations........................................................................................................... 45

Figure 16 - Strap Positioning ........................................................................................................ 45

Figure 17 - Strap Installation ........................................................................................................ 45

Figure 18 - TXV Bulb Position ..................................................................................................... 46

Figure 19 - Water-Source Heat Pump Water Piping .................................................................... 52

Figure 20 - Water-Cooled Only Water Piping .............................................................................. 53

Figure 21 – Waterside Economizer Piping ................................................................................... 55

Figure 22 - Steam Distributing Piping .......................................................................................... 56

Figure 23 - Hot Water Piping........................................................................................................ 56

Figure 24 - Chill Water Piping...................................................................................................... 57

Figure 25 - Draw-Through Drain Trap ......................................................................................... 58

Figure 26 - Blow-Through Drain Trap ......................................................................................... 58

Figure 27 – EC Motor Wiring Diagram for Controls by Others ................................................... 59

Figure 28 – Jumper for Remote Fan Speed Control ..................................................................... 59

Figure 29 – Potentiometer ............................................................................................................. 60

Figure 30 - Supply Fan Banding ................................................................................................... 61

Figure 31 - Sediment Trap for Gas Heat ....................................................................................... 66

Figure 32 –Gas Heater Horizontal Configuration ......................................................................... 66

Figure 33 –Gas Heater Vertical Configuration ............................................................................. 67

Figure 34 - Gas Valve ................................................................................................................... 67

Figure 35 - 1.2” w.c. Manifold Natural Gas ................................................................................. 69

Figure 36 - 3.5” w.c. Manifold Natural Gas ................................................................................. 69

Figure 37 - Flame Sensor Current Check ..................................................................................... 70

Figure 38 - Energy Recovery Wheel ............................................................................................ 74

Figure 39 - Cross Section of Air Seal Structure ........................................................................... 75

Figure 40 - Lifting Hole Locations ............................................................................................... 76

Figure 41 - Avoid Racking of Cassette Frame.............................................................................. 78

Figure 42 - Diameter Seal Adjustment ......................................................................................... 78

Figure 43 - Hub Seal Adjustment ................................................................................................. 78

Figure 44 - Segment Retainer ....................................................................................................... 79

Figure 45 - Segment Installation ................................................................................................... 79

Figure 46 - Belt Replacement ....................................................................................................... 80

Figure 47 - Angular Misalignment ............................................................................................... 89

Figure 48 - Parallel Misalignment ................................................................................................ 89

Figure 49 - Belt Deflection ........................................................................................................... 89

Figure 50 - Filter Layout ............................................................................................................... 98

Figure 51 - A/C Split System Piping, Suction Down ................................................................. 101

Figure 52 - A/C Split System Piping, Suction Up ...................................................................... 102

Figure 53 - A/C with Modulating Hot Gas Reheat Split System Piping, Suction Down ........... 103

Figure 54 - A/C with Modulating Hot Gas Reheat Split System Piping, Suction Up ................ 104

Figure 55 - A/C with Hot Gas Bypass Split System Piping, Suction Down .............................. 105

Figure 56 - A/C with Hot Gas Bypass Split System Piping, Suction Up ................................... 106

Figure 57 - A/C with Modulating Hot Gas Reheat and Hot Gas Bypass Split System Piping,

Suction Down.............................................................................................................................. 107

Figure 58 - A/C with Modulating Hot Gas Reheat and Hot Gas Bypass Split System Piping,

Suction Up .................................................................................................................................. 108

Figure 59 - Heat Pump Split System Piping, Suction Down ...................................................... 109

Figure 60 - Heat Pump Split System Piping, Suction Up ........................................................... 110

Figure 61 - Heat Pump with Modulating Hot Gas Reheat Split System Piping, Suction Down 111

Figure 62 - Heat Pump with Modulating Hot Gas Reheat Split System Piping, Suction Up ..... 112

Figure 63 - Heat Pump with Hot Gas Bypass Split System Piping, Suction Down ................... 113

Figure 64 - Heat Pump with Hot Gas Bypass Split System Piping, Suction Up ........................ 114

Figure 65 - Heat Pump with Modulating Hot Gas Reheat and Hot Gas Bypass Split System

Piping, Suction Down ................................................................................................................. 115

Figure 66 - Heat Pump with Modulating Hot Gas Reheat and Hot Gas Bypass Split System

Piping, Suction Down ................................................................................................................. 116

Safety

ELECTRIC SHOCK, FIRE OR EXPLOSION HAZARD

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

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

 Before servicing, disconnect all

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

 When servicing controls, label all

wires prior to disconnecting. Reconnect wires correctly.

 Verify proper operation after

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

WARNING

WHAT TO DO IF YOU SMELL GAS

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

building.

 Never test for gas leaks with an

open flame.

 Use a gas detection soap solution

and check all gas connections and shut off valves.

CAUTION

Attention should be paid to the following statements:

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

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

equipment damage, property damage, or personal injury.

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

equipment damage, property damage, personal injury or death.

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

damage, property damage, severe personal injury or death.

QUALIFIED INSTALLER

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

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

VARIABLE FREQUENCY DRIVES

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

WARNING

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.

WARNING

FIRE, EXPLOSION OR CARBON MONOXIDE POISONING HAZARD

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

WARNING

Electric 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.

CAUTION

UNIT HANDLING

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

WARNING

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

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

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

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

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.

WARNING

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

CAUTION

To prevent damage to the unit, do not use acidic chemical coil cleaners. Do not use alkaline chemical coil cleaners with a pH value greater than

8.5, after mixing, without first using an aluminum corrosion inhibitor in the cleaning solution.

CAUTION

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

WARNING

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

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

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.

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

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

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.

Ensure that sufficient dampers will be open to provide air path before fan is allowed to run.

WARNING

CAUTION

1. Startup and service must be performed

by a Factory Trained Service Technician.

2. Use only with type of the gas approved

for the furnace. Refer to the furnace rating plate.

3. 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.

4. Always install and operate furnace

within the intended temperature rise range and duct system external static pressure (ESP) as specified on the unit nameplate.

5. 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.

6. Clean furnace, duct and components

upon completion of the construction setup. Verify furnace operating conditions including input rate, temperature rise and ESP.

7. 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.

8. READ THE ENTIRE INSTALLATION,

OPERATION AND MAINTENANCE MANUAL. OTHER IMPORTANT SAFETY PRECAUTIONS ARE PROVIDED THROUGHOUT THIS MANUAL.

9. Keep this manual and all literature

safeguarded near or on the unit.

Feature String Nomenclature

Base Feature String

Individual Module Feature String

Identifies the main unit features and options.

Identifies module configurations, features and

options.

BBD-101-0-00-00000-00000-0-0

FTH-102-P-C0-20000-CE000-C-X

HRA-103-A-00-00000-00000-0-0

M2-H-026-L-2-A-A-0-C-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, CLC105-E-00-00000-610I0-0-0, is the fifth module on the first level of the unit. The exhaust fan, EDB-201-L-GI-C000-00000-00, is the first module on the second level.

Figure 1 - Typical M2 Series Selection

M2 Series Base Feature String Nomenclature

Model Options

GEN TYPE UNIT SIZE SUPPLY

AIRFLOW VOLTAGE ASSEMBLY WIRING PAINT BASE RAIL SPECIAL

- H -

011

- R - 2 - A - A - 0 - C -

M2 Series Base Feature String Nomenclature

BASE MODEL DESCRIPTION

Series and Generation

Type

H = Horizontal

Unit Size

005 = 5 ft2 Coil (1,000 – 2,700 cfm) 008 = 8 ft2 Coil (2,000 – 4,400 cfm) 011 = 11 ft2 Coil (3,100 – 6,000 cfm) 014 = 14 ft2 Coil (5,000 – 7,700 cfm) 018 = 18 ft2 Coil (6,000 – 10,300 cfm) 022 = 22 ft2 Coil (9,900 – 13,200 cfm) 026 = 26 ft2 Coil (11,500 – 15,600 cfm) 032 = 32 ft2 Coil (13,500 – 19,200 cfm) 036 = 36 ft2 Coil (15,500 – 21,600 cfm)

Supply Airflow

L = Left Hand R = Right Hand

Voltage

1 = 230V/1Φ/60Hz 2 = 230V/3Φ/60Hz 3 = 460V/3Φ/60Hz 4 = 575V/3Φ/60Hz 8 = 208V/3Φ/60Hz 9 = 208V/1Φ/60Hz

Assembly

A = Factory Assembled B = Individual Boxes

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

B = 8” High C = 6” High D = 10” High

Special

0 = None X = Special Pricing Authorization

Fan Module Feature String Nomenclature

MODULE ID POSITION MOTOR

SIZE BLOWER

ISOLATION MOTOR

TYPE

BLANK

PULLEYS SAFETY

CONTROL

BLANK BLANK SPECIAL

SFA

103

- E - B I - A

0C - 0

0000

- 0 -

Fan Module Description

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

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 2

FILTER

TYPE

FILTER BLANK FILTER

OPTIONS SPECIAL

FTA

102

- P -

A0 - 0

0000

- 0 00

00 - 0 - 0

Filter Module Description

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

Mixing Module Feature String Nomenclature

MODULE ID POSITION ACTUATOR

TYPE FILTERS SAFETY

CONTROL

BLANK BYPASS

OPENING

BLANK FILTER

OPTIONS SPECIAL

MBH

101

- A -

00 - 0

0000

- 0 0000

- 0 -

Mixing Module Description

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 ROWS

FPI

CIRCUITING

COATING HEAT

CAPACITY

STAGES

FUEL GAS

COMB

INTAKE FILTER

OPTIONS SPECIAL

PHA

101

- 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

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

Heat Capacity

0 = Hot Water Heating Coil 1 = 150 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)

Heat Module Feature String Nomenclature

MODULE ID POSITION FUNCTION FILTERS ROWS

FPI

CIRCUITING

COATING HEAT

CAPACITY

STAGES

FUEL GAS

COMB

INTAKE FILTER

OPTIONS SPECIAL

PHA

101

- 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

Blank Module Feature String Nomenclature

MODULE ID POSITION BLANK AIRWAY

TYPE SAFETY

CONTROL

BLANK BYPASS

OPENING

BLANK DRAIN PAN

TYPE SPECIAL

BBA

101

- 0 -

AR - 0

0000

- 0 0000

- 0 -

Blank Module Description

BLANK MODULE DESCRIPTION

Module ID

BBA = Small BBB = Medium BBC = Large BBD = XL BBE = XXL BBF = XXXL BBG = Extended Large CBA = Small with Drain Pan CBB = Medium with Drain Pan CBC = Large with Drain Pan CBD = XL with Drain Pan CBE = XXL with Drain Pan CBF = XXXL with Drain Pan CBG = Extended Large with Drain Pan

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

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

101

- C - 0 0 - 0

00 0 0 - 4

F 0 - S -

Coil Module Description

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 = None C = Chilled Water F = DX R-410A G = DX R-410A + Hot Gas Bypass

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) 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

FPI

00 = No Cooling Coil 08 = 8 Fins Per Inch 10 = 10 Fins Per Inch 12 = 12 Fins Per Inch

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

101

- C - 0 0 - 0

00 0 0 - 4

F 0 - S -

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 -

Controls Module Description

CONTROLS MODULE DESCRIPTION

Module ID

TRA = Small TRB = Medium TRC = Large TRD = XL TRE = XXL TRF = XXXL

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 WHEEL

SIZE RECOVERY

TYPE BLANK BLANK VFD

CONTROL SPECIAL

HRA

101

- A -

00 - 00000

00000

- 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 CAPACITY COMP

STAGING

BLANK REFRIG

OPTIONS

REFRIG

ACCESS

BLANK

WATER

SIDE

HEAT

EXCHANGER

BLANK SPECIAL

WHP

101

- 0 -

25 - D K 000

- D A 0 B

0 - 0 - 0

Water-Source Heat Pump Module Description

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

Capacity

03 = 3 tons 04 = 4 tons 05 = 5 tons 06 = 6 tons 07 = 7 tons 08 = 8 tons 10 = 10 tons 11 = 11 tons 13 = 13 tons 15 = 15 tons 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

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

Blank

000 = Standard

Refrigeration Options

0 = Standard A = Hot Gas Bypass [HGB] - Lead & Lag Stage C = HGB Lag D = Modulating Hot Gas Reheat [MHGR] F = HGB - Lead & Lag Stage + MHGR G = HGB - Lag Stage + MHGR

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

Water-Source Heat Pump Module Feature String Nomenclature

MODULE ID POSITION REVISION CAPACITY COMP

STAGING

BLANK REFRIG

OPTIONS

REFRIG

ACCESS

BLANK

WATER

SIDE

HEAT

EXCHANGER

BLANK SPECIAL

WHP

101

- 0 -

25 - D K 000

- D A 0 B

0 - 0 - 0

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

Consider the airflow to be

hitting the back of your head.

M2 Series

Top View

Return Air

“Back”

Supply Air

“Front”

Left Hand Side

Right Hand Side

Connections & service

AIRFLOW

Filter

Coil

Supply Fan

Unit Orientation

Determine left hand or right hand orientation/connections:

access on left side for

left hand orientation

Figure 2 - Unit Orientation

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

WARNING

These units must not be used as a “construction heater” 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

CAUTION

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.

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.

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

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

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

WARNING

CAUTION

c. Certified with refrigerant R-410A coils

or with chilled water cooling coils.

Codes and Ordinances

M2 Series units have been tested and certified, by ETL, in accordance with the UL Safety Standard 1995/CSA C22.2 No.

236.

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

Installation of 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.

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-Longview Warranty Department for assistance with handling damaged goods, repairs, and freight claims: (903) 236-4403.

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

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. If the unit is stored on the ground, take the following additional precautions:

 Make sure that the unit is well

supported along the length of the base rails.

 Make sure that the unit is level and

not twisting or on an uneven surface.

 Provide proper drainage around the

unit to prevent flooding in the equipment.

 Provide adequate protection from

vandalism, mechanical contact, etc.

 Make sure all doors remain securely

closed and all latches closed.

Preparation for Storage

Blower wheels and fans

 Depending on local climate

conditions, condensation may collect on components inside the units. To prevent surface rust and discoloration, spray all bare metal parts with a rust preventive compound.

Cabinet Sections

 Once a month, open a door on each

section and verify that no moisture or debris is accumulating in the unit.

Control Compartment

 It is recommended that any

electronic control equipment in the unit be stored in a 5% to 95% RH (non-condensing) environment.

 It may be necessary to put a heat

source (light bulb) in the main control panel to prevent the accumulation of condensate within the panel. The location and wattage of the heat source is dependent on local environmental conditions.

 Check the control compartment

every two weeks to confirm that the heat source is functional and is adequate for current conditions.

Direct Expansion (DX) Units

All factory-assembled packaged DX refrigeration systems are leak tested, charged with refrigerant, and run tested. Field-assembled 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.

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.

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

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

CAUTION

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.

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 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.

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

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.

CAUTION

Note: Low Ambient Operation

Air-cooled DX units without a low ambient option, such as condenser fan cycling, ECM driven condenser fans or the 0°F low ambient option, will not operate in the cooling mode of operation properly when the outdoor temperature is below 55°F. Low ambient and/or economizer options are recommended if cooling operation below 55°F is expected.

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.

If unit has not been selected as a 100% outside air unit (make up air unit) the return air duct must be sealed to the unit and the return air temperature must be maintained between 55F and 80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.

Table 1 – Electric and Gas Heating Capacities

When locating gas fired units, it is recommended the unit be installed so that the flue discharge vents are located at least 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

WARNING

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.

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.

Depending on natural gas and propane heating module orientations, the combustion air inlets or vent (flue) gas discharges may be located in the unit roof or sides. There must be 6 feet of clearance between these roofs/sides and building walls, parapets, or equipment. If equipment is for replacement

and required clearances are not available, contact AAON for recommendations.

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 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.

Unit Size

Minimum Required

Service Clearance

X =

M2-005

50”

M2-008

50”

M2-011

62”

M2-014

62”

M2-018

84”

M2-022

84”

M2-026

84”

M2-032

96”

M2-036

96”

UNIT HANDLING

Incorrect lifting can cause damage to the unit.

Coil

Energy

Recovery

Wheel

Module

Energy

Recovery

Wheel

Coil Module

Fan

CAUTION

Figure 4 - Service Access Clearance

Table 2 - Minimum Clearances

Point Lifting Figure and the M2 Series Unit Eight Point Lifting Figure.

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.

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 on a skid, the recommended method of lifting is to insert a 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 the M2 Series Unit Four

Figure 5 - M2 Series Unit Four Point Lifting

Figure 6 - M2 Series Unit Eight Point Lifting

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.

allow for proper drainage of the condensate line. Standard units are built with a 6” base, but an optional base can be shorter. Other installation provisions may be necessary according to job specifications.

Suspended Units

Some M2 Series units can be suspended. Only single path units of size M2-005 to M2-014 can be suspended.

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

Floor Mounted Units

Dual path units, self-contained units and units over size M2-014 must be floor mounted. Make sure the unit is level, and

installed with a minimum height of 6” to

Figure 9 - Unit Suspension

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 FTF101-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-Longview Product Support.

After identifying modules and determining module arrangement, modules can be prepared for final assembly.

Configuration Schematic can

be found in unit literature packet

CONFIGURATION:

HRA

PEC

FTE

CLF

FTF

SFA

Table provides required

service access clearances

203

104

201

101

102

103

Arrows

airflow

Base model

number

Module

numbers

Note: Energy recovery wheel module will have a 100 series number, but will span both tiers, also utilizing a 200 series space.

Figure 10 - Module Assembly Schematic

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

configuration

indicate

for applicable modules

5/16” Hex Head

2. Connect Modules

Modules are to be connected with nuts and bolts through the base rail and 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 insert bolts through the bolt holes in the base rails of two adjacent modules. Secure with nuts to pull the bases of the two modules together tightly.

Figure 11 - Bolted Base Rail

Use bar clamps or other non-destructive winching device to pull the tops of the modules together tightly.

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 predrilled 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.

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 predrilled holes and adhesive backing already

Figure 12 - Bar Clamp

1”

Self-Tapping Screws

Provided with Unit

Figure 13 - Self-Tapping Screw

Side

Angle

Top

Strap

Angle

Strap

Angle

Strap

Side

Strap

Put straps in position,

Strap

Figure 14 - Strap Types

Figure 17 - 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. 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.

Figure 15 - Strap Locations

5. Final Sealing

It is very important to keep air from infiltrating the unit cabinet. Seal all piping penetrations with Armaflex, Permagum or

hold in place and attach

with self-tapping sheet

metal screws.

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.

Figure 16 - Strap Positioning

This section is for information only and is not intended to provide all details required by the designer or installer of the refrigerant piping

between the condenser or

condensing unit and the air handling unit. AAON is not responsible for interconnecting refrigerant piping. Consult ASHRAE Handbook – Refrigeration and ASME Standards.

CAUTION

WARNING

Refrigerant Piping for Split Systems

(See back of the manual for refrigerant piping diagrams.)

Piping from the condensing unit to the air handling unit is the responsibility of the installing contractor.

The Split System Configurator or Refrigerant Piping Calculator in AAONEcat32 should be used to determine acceptable refrigerant line sizes.

The pipe sizes must be selected to meet the actual installation conditions and not simply based on the connection sizes at the evaporator or condensing unit.

Only clean ACR tubing should be used. Piping should conform to generally accepted practices and codes.

The air handling unit coils are pressurized. The copper caps must be punctured to permit a gradual escape of the pressure prior to un-sweating 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.

When piping is completed interconnecting piping and air handling unit must be evacuated to 500 microns or less and leak checked. Condenser shutoff

valves can then be opened to allow refrigerant to flow to the air handling unit.

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 7/8” OD, mount in the 12 o’clock position. On suction lines greater than 7/8” OD, mount in either the 4 o’clock or 8

o’clock position.

Figure 18 - TXV Bulb Position

Refrigerant lines should be fastened and supported according to local codes.

Unit should be charged based on determination of sub-cooling and superheat.

Line sizes must be selected to meet actual installation conditions, not simply based on the connection sizes at the condensing unit or air handling unit.

CAUTION

See Adjusting Refrigerant Charge section for more information.

Refrigerant reheat coil for the modulating hot gas reheat option is factory installed. Liquid line receiver should be installed at the condensing unit on the same circuit as the reheat coil. Care must be taken not to cross circuits in reheat systems.

Determining Refrigerant Line Size

The piping between the condenser and evaporator must ensure:

1. Minimum pressure drop, and

2. Continuous oil return, and

3. Prevention of liquid refrigerant slugging, or carryover

Minimizing the refrigerant line size is favorable from an economic perspective, reducing installation costs, and reducing the potential for leakage. However, as pipe diameters narrow, pressure-reducing frictional forces increase.

Excessive suction line pressure drop causes loss of compressor capacity and increased power usage resulting in reduced system efficiency. Excessive pressure drops in the liquid line can cause the liquid refrigerant to flash, resulting in faulty TXV operation and improper system performance. In order to operate efficiently and cost effectively, while avoiding malfunction, refrigeration systems must be designed to minimize both cost and pressure loss.

Equivalent Line Length

All line lengths discussed in this manual, unless specifically stated otherwise, are Equivalent Line Lengths. The frictional pressure drop through valves, fittings, and accessories is determined by establishing the equivalent length of straight pipe of the same diameter. Always use equivalent line lengths when calculating pressure drop. Special piping provisions must be taken when lines are run underground, up vertical risers, or in excessively long line runs.

Liquid Line Sizing

When sizing the liquid line, it is important to minimize the refrigerant charge to reduce installation costs and improve system reliability. This can be achieved by minimizing the liquid line diameter. However, reducing the pipe diameter will increase the velocity of the liquid refrigerant which increases the frictional pressure drop in the liquid line, and causes other undesirable effects such as noise.

Maintaining the pressure in the liquid line is critical to ensuring sufficient saturation temperature, avoiding flashing upstream of the TXV, and maintaining system efficiency. Pressure losses through the liquid line due to frictional contact, installed accessories, and vertical risers are inevitable. Maintaining adequate subcooling at the condenser to overcome these losses is the only method to ensure that liquid refrigerant reaches the TXV.

Liquid refrigerant traveling upwards in a riser loses head pressure. If the evaporator is below the condenser, and the liquid line does not include risers, the gravitational force will increase the pressure of the liquid refrigerant. This will allow the refrigerant to withstand greater frictional losses without the occurrence of flashing prior to the TXV.

A moisture-indicating sight glass may be field installed in the liquid line to indicate the occurrence of premature flashing or moisture in the line. The sight glass should not be used to determine if the system is properly charged. Use temperature and

pressure measurements to determine liquid sub-cooling, not the sight glass.

Liquid Line Routing

Care should be taken with vertical risers. When the system is shut down, gravity will pull liquid down the vertical column, and back to the condenser when it is below the evaporator. This could potentially result in compressor flooding. A check valve can be installed in the liquid line where the liquid column rises above the condenser to prevent this. The liquid line is typically pitched along with the suction line, or hot gas line, to minimize the complexity of the configuration.

Liquid Line Insulation

When the liquid line is routed through regions where temperature losses are expected, no insulation is required, as this may provide additional sub-cooling to the refrigerant. When routing the liquid line through high temperature areas, insulation of the line is appropriate to avoid loss of subcooling through heat gain.

Liquid Line Guidelines

In order to ensure liquid at the TXV, frictional losses must not exceed available sub-cooling. A commonly used guideline to consider is a system design with pressure losses due to friction through the line not to exceed a corresponding 1-2°F change in saturation temperature.

If the velocity of refrigerant in the liquid line is too great, it could cause excessive noise or piping erosion. The recommended

maximum velocities for liquid lines are 100 fpm from the condenser to a receiver tank to discourage fluid backup, and 300 fpm from receiver tank to the evaporator to minimize valve induced liquid hammer.

Liquid Line Accessories

The total length equivalent of pressure losses through valves, elbows and fittings must be considered when adding additional components in the field. It is a good practice to utilize the fewest elbows that will allow the mating units to be successfully joined.

Suction Line Sizing

The suction line is more critical than the liquid line from a design and construction standpoint. More care must be taken to ensure that adequate velocity is achieved to return oil to the compressor at minimum loading conditions. However, reducing the piping diameter to increase the velocity at minimal load can result in excessive pressure losses, capacity reduction, and noise at full load. The suction line also dictates the position of the TXV sensing bulb for proper operation of the TXV.

Suction Line Routing

Pitch the suction line in the direction of flow (about 1 foot per 100 feet of length) to maintain oil flow towards the compressor, and keep it from flooding back into the evaporator. Make sure to provide support to maintain suction line positioning, and insulate completely between the evaporator and condensing unit. It is important to consider part load operation when sizing suction lines. At minimum capacity, refrigerant velocity may not be adequate to return oil up the vertical riser. Decreasing the diameter of the vertical riser will increase the velocity, but also the frictional loss.

Circuits with variable capacity scroll compressors require suction riser traps every 10 feet.

CAUTION

A double suction riser can be applied to the situation of part load operation with a suction riser. A double suction riser is designed to return oil at minimum load while not incurring excessive frictional losses at full load. A double suction riser consists of a small diameter riser in parallel with a larger diameter riser, and a trap at the base of the large riser. At minimum capacity, refrigerant velocity is not sufficient to carry oil up both risers, and it collects in the trap, effectively closing off the larger diameter riser, and diverting refrigerant up the small riser where velocity of the refrigerant is sufficient to maintain oil flow.

At full load, the mass flow clears the trap of oil, and refrigerant is carried through both risers. The smaller diameter pipe should be sized to return oil at minimum load, while the larger diameter pipe should be sized so that flow through both pipes provides acceptable pressure drop at full load.

Suction Line Insulation

The entire suction line should be insulated. This prevents condensation from forming on the line, and reduces any potential loss in capacity associated with heat gain.

Suction Line Guidelines

For proper performance, suction line velocities less than a 4,000 fpm maximum are recommended. The minimum velocity required to return oil is dependent on the pipe diameter, however, a general guideline of 1,000 fpm minimum may be applied.

In a fashion similar to the liquid line, a common guideline to consider is a system design with pressure losses due to friction through the line not to exceed a corresponding 1-2°F change in saturation temperature.

At points where small pipe size can be used to provide sufficient velocity to return oil in vertical risers at part loads, greater pressure losses are incurred at full loads. This can be compensated for by over sizing the horizontal runs and vertical drop sections. This will however require additional refrigerant charge.

Circuits with variable capacity scroll compressors require suction riser traps every 10 feet.

Suction Line Accessories

If the job requirements specify suction accumulators, they must be separately purchased and field installed.

Hot Gas Bypass Line

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.

Hot Gas Bypass Piping Considerations for Evaporator above Condensing Unit

Pitch the hot gas bypass (HGB) line downward in the direction of refrigerant flow, toward the evaporator.

When installing hot gas bypass risers, a drain leg must be provided at the lowest point in the system. The drain leg must be vertical, its diameter should be the same as the diameter of the riser, and it should be 1 foot long. Install a sight glass in the drain leg for observation. Run an oil return line, using 1/8 inch capillary tube, 10 feet in length, from the drain leg to the suction line. Connect the oil return line below the sight glass and 1 inch above the bottom of the drain leg.

HGB valves are adjustable. Factory HGB valve settings will be sufficient for most applications, but may require slight adjustments for some applications, including some make up air applications.

Insulate the entire length of the HGB line with a minimum 1 inch thick Armaflex insulation.

Hot Gas Bypass Piping Considerations for Evaporator below Condensing Unit

The line must slope downward from the HGB valve toward the evaporator.

Hot Gas Bypass Line Guidelines

Choose a small size line to ensure oil return, and minimize refrigerant charge.

Maintain velocities below a maximum of 4,000 fpm. A general minimum velocity guideline to use is approximately 1,000 fpm.

Hot Gas Reheat Line

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.

Discharge lines should be sized to ensure adequate velocity of refrigerant to ensure oil return, avoid excessive noise associated with velocities that are too high, and to minimize efficiency losses associated with friction.

Pitch the hot gas line in the direction of flow for oil return.

When installing hot gas reheat risers, a drip leg must be provided at the lowest point in the system. The drip leg must be vertical, its diameter should be the same as the diameter of the riser, and it should be 1 foot long. Run a drip line, using 1/8 inch capillary tube, 10 feet in length, from the drip leg to the suction line. Connect the drip line a minimum of 1-inch above the bottom of the drain leg.

Insulate the entire length of the hot gas line with a minimum 1 inch thick Armaflex insulation.

Hot Gas Reheat Guidelines

Maintain velocities below a maximum of 3,500 fpm. A general minimum velocity guideline is 2,000 fpm.

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.

OPEN LOOP APPLICATIONS

SMO 254 brazed plated refrigerantto-water 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.

WARNING

Cleaning the cooling tower or condenser water loop with harsh chemicals such as hydrochloric acid (muriatic acid), chlorine or other chlorides, can damage the refrigerant-to-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.

CAUTION

WARNING

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 43°F with an entering water loop temperature of 70°F.

CAUTION

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.

WATER-SOURCE HEAT PUMP

APPLICATIONS

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.

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.

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.

% Glycol

Ethylene

Glycol

Propylene

Glycol

18°F

19°F

7°F

9°F

-7°F

-6°F

-28°F

-27°F

WATER FREEZING

WARNING

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 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.

Unit is capable of operating with Entering Water Temperatures (EWT) as low as 50°F during heat pump heating mode without the need for head pressure control. If the EWT is expected to be lower than 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 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

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 water- cooled 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 19 - Water-Source Heat Pump Water

Piping

Tonnage

Supply and Return

Connection Size

003, 004

1" FPT

005

1 1/4" FPT

006, 007, 008,

010, 011, 013

1 1/2" Sch 80

015, 016, 018,

020

2" Sch 80

025, 030, 040,

050

2 1/2" Sch 80

060, 070

3" Sch 80

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 water piping. Supply water connection may require a backflow preventer to prevent supply makeup water from backing up into the public water system.

WARNING

CAUTION

Installing Contractor is responsible for proper sealing of the water piping entries into the unit. Failure to seal the entries may result in damage to the unit and property.

CAUTION

The water-cooled only units have water supply to the bottom of the heat exchanger and the return to the top.

Figure 20 - Water-Cooled Only Water

Piping

WATER PRESSURE

Condenser water connections range in size from 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

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.

% Glycol

Ethylene

Glycol

Propylene

Glycol

18°F

19°F

7°F

9°F

-7°F

-6°F

-28°F

-27°F

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.

Each heat exchanger is equipped with a refrigerant pressure relief device to relieve pressure should excessive condensing pressures (>675 psig) occur. Codes may require installing contractor to connect and route relief piping outdoors. The relief valve has a 5/8” male flare outlet connection.

CAUTION

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.

Unit is capable of operating with Entering Water Temperatures (EWT) as low as 50°F without the need for head pressure control. If the EWT is expected to be lower than 50°F or more stable operation is desired, a field provided water regulating valve may be used.

Table 5 - Freezing Points

Piping systems should not exceed 10 ft/sec velocity to ensure tube wall integrity and reduce noise.

Do not exceed recommended condenser fluid flow rates. Serious damage to or erosion of the heat exchanger tubes could occur.

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.

CAUTION

FIELD PROVIDED

Heat Exchanger Safeties

Electronic freeze protection and water flow safeties should be field installed or factory provided. If the leaving water temperature drops below 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 6” from the drain connection. See the previous section on condensate drain piping for additional p-trap and drain information.

DRAIN PAN CONNECTION

Figure 21 – 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.

Model (M2-)

Supply and Return

Connection Size

005 - 036

2 1/8"

Model (M2-)

Supply and Return

Connection Size

005

1 3/8"

008

1 5/8"

011, 014, 018

2 1/8"

022, 026, 032, 036

2 5/8"

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.

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 water-source 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.

Table 6 – Steam Distributing Coil

Connection Sizes

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 7 – Hot Water Coil Connection Sizes

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

Figure 22 - Steam Distributing Piping

Figure 23 - Hot Water Piping

Water coils should not be subjected to entering air temperatures below 38°F to prevent coil freeze-up. If air temperature

Model (M2-)

Supply and Return

Connection Size

005

1 5/8"

008, 011

2 1/8"

014, 018, 022

2 5/8"

026, 032, 036

3 1/8"

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.

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

CAUTION

WARNING

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 8 – Chilled Water Coil Connection

Sizes

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 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.

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

Figure 24 - 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.

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.

Draw-Through

Drain Pan Pressure

Trap Dimensions

Negative Static

X/2

(inches of water)

(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

Blow-Through

Drain Pan Pressure

Trap Dimension

Positive Static

(inches of water)

(inch)

0.5

1.5

1.0

2.0

1.5

2.5

2.0

3.0

2.5

3.5

3.0

4.0

3.5

4.5

4.0

5.0

Note: The drain pan connection is a 1” MPT fitting.

Figure 25 - Draw-Through Drain Trap

Table 9 - Drain Trap Dimensions

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.

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

Figure 26 - Blow-Through Drain Trap

Table 10 - Blow-Through Drain Trap

Dimensions

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. 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 blow-through 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.

Figure 27 – EC Motor Wiring Diagram for

Controls by Others

Referencing the figure above, 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.

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.

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.

Figure 30 - Supply Fan Banding

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.

WARNING

The foam insulation releases dangerous fumes when it is burnt. Do not cut a foam part with a cutting torch or plasma cutter. Do not weld to a foam filled part.

WARNING

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.

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.

Note: Locations for field cut electrical entries are marked on the unit. Field cut openings must be a minimum of 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.

Three phase voltage imbalance will cause motor overheating and premature failure.

Installing Contractor is responsible for proper sealing of the electrical and gas entries into the unit. Failure to seal the entries may result in damage to the unit and property.

CAUTION

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.

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.

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 2.0%.

Voltage imbalance is defined as 100 times the sum of the deviation of the three voltages from the average divided by the average voltage.

Example: (221V+230V+227V)/3 = 226V, then 100*(226V-221V)/226V = 2.2%, 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

Wire Size (Stranded)

- Copper Conductors Only

Total Wire Distance Allowable 20 AWG

200 ft

18 AWG

350 ft

16 AWG

500 ft

14 AWG

750 ft

12 AWG

1250 ft

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 type AWM insulated conductors.

Thermostat Control Wiring

If a thermostat is used for unit control, thermostat should be located on an inside wall 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 11 - Control Wiring

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 Inlet

Pressures (“wc)

Natural

Gas

Propane

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

WARNING

Gas Fired Duct Furnace

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 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 Duct furnaces require a minimum inlet gas pressure of 5.0” w.c. and limited to a maximum inlet gas pressure of 13.5” w.c. with the furnace operating.

Table 12 – Gas Inlet Pressure

1. When pressure testing at 1/2 psi or less, close the manual shutoff valve on the appliance before testing.

2. When pressure testing gas supply line at 1/2 psi or higher, close manual gas valve and disconnect heater from supply line to be tested. Cap or plug the supply line.

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

4. A 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.

Duct Furnace Component Identification

Figure 31 - Sediment Trap for Gas Heat

Figure 32 –Gas Heater Horizontal

Configuration

Horizontal Airflow Configuration

1. Airflow may be from either right or left for heater as shown, without any difference in system performance.

2. Typically no condensate drain attachment is necessary in “Heat” only applications. Condensation should not occur during heating cycle. However, in applications operating at low temperature rise or with 50% or more outside air, condensation may occur early in the heating cycle. In these applications connection of a condensate drain line is recommended, to avoid

condensate buildup and possible heat exchanger damage.

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 1/4 inch NPT connection is provided for attachment of condensate drain line to remove condensate from heat exchanger.

Figure 33 –Gas Heater Vertical

Configuration

Vertical Airflow Configuration

1. Airflow may be either upflow or downflow for heater as shown, without any difference in system performance.

2. In this configuration, condensate due to operation of air conditioning system would drain through the open heat exchanger tubes near base of heater. An optional condensate drain pan is available for these applications, if none is incorporated integral to the unit.

3. Some condensation may occur in the flue collector box, and it is recommended that a

drain tube be connected to the lower condensate drain fitting as well.

Gas Valve

Figure 34 - Gas Valve

Input

The correct heat capacity of the furnace is controlled by the burner orifices and the gas manifold pressure. The manifold pressure is factory set but should be checked at the time of start-up.

Operating and Safety Instructions

1. This duct furnace does not have a pilot. It is equipped with a direct spark ignition device that automatically lights the gas burner. DO NOT try to light burners by hand.

2. BEFORE OPERATING, leak test all gas piping up to heater gas valve. Smell around the unit area for gas. DO NOT attempt to place heater in operation until source of gas leak is identified and corrected.

3. Use only hand force to push and turn the

gas control knob to the “ON” position.

NEVER use tools. If knob does not operate by hand, replace gas valve prior to staring the unit. Forcing or attempting to repair the gas valve may result in fire or explosion.

4. Do not attempt to operate unit if there is indication that any part or control has been under water. Any control or component that has been under water must be replaced prior to trying to start the unit.

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

WARNING

Startup

1. Turn thermostat or temperature controller to its lowest setting.

2. Turn off gas supply at the manual shut-off valve (supplied by others).

3. Turn off power to the unit at the disconnect switch.

4. Open door to unit module housing the gas heater.

5. Move gas control knob to “OFF” position.

6. Install a tapped fitting for attachment to a manometer or other gauge suitable for 14.0”

w.c. in the inlet pressure tap, and for 10.0”

w.c. in the manifold pressure tap.

7. Wait 5 minutes for any gas to clear out. If you smell gas, turn off gas supply at the manual shut-off valve (field installed). If

you don’t smell gas or have corrected any

leaks, go to the next step.

8. Turn gas control knob to “ON” position.

9. Open all manual gas valves (supplied by others).

10. Turn power on at disconnect switch.

11. Set thermostat or controller to its highest position to initiate call for heat and maintain operation of unit.

12. Draft inducer will run for a 15 to 30 second pre-purge period.

13. At the end of the pre-purge the direct spark will be energized and gas valve will open.

Check and Adjust Manifold Pressure

For 2 stage (TS) and modulating control (MD) systems manifold pressure should be

1.2” w.c. Adjust Lo Regulator on 2 stage gas

valve, if necessary. The controls are design to hold operation at this pressure for 2 minutes. After that time manifold pressure

should increase to 3.5” w.c.(10.0”wc for LP

gas) within 30 to 45 seconds. For On/Off units the manifold pressure should be 3.5” w.c (10.0”wc for LP gas).

Failure to Ignite

1. For the initial start-up, or after unit has been off long periods of time, the first ignition trial may be unsuccessful due to need to purge air from manifold at start-up.

2. If ignition does not occur on the first trial, the gas and spark are shut-off by the ignition control and the control enters an inter-purge period of 15 to 90 seconds, during which the draft inducer continues to run.

3. At the end of the inter-purge period, another trial for ignition will be initiated.

4. Control will initiate up to three ignition trials on a call for heat before lockout of control occurs.

5. Control can be brought out of lockout by turning thermostat or controller to its lowest position and waiting 5 seconds and then turning back up to call for heat. Some controls provided will automatically reset after one hour and initiate a call for heat.

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

WARNING

Burner Flames

Prior to completing the start-up, check the appearance of the main burner flame. See Figure 35 - 1.2” w.c. Manifold and Figure 36 - 3.5” w.c. Manifold for flame characteristics of properly adjusted natural gas systems.

Figure 35 - 1.2” w.c. Manifold Natural Gas

Figure 36 - 3.5” w.c. Manifold Natural Gas

1. The burner flame should be predominately blue in color and well defined and centered at the tube entry as shown inFigure 35 - 1.2” w.c. Manifold and Figure 36 - 3.5” w.c. Manifold. Distorted flame or yellow tipping of natural gas flame, or a long yellow flame on propane, may be caused by lint and dirt accumulation inside burner or at burner ports, at air inlet between burner and manifold pipe, or debris in the main burner orifice. Soft brush or vacuum clean affected areas after performing Shutdown procedure.

2. Poorly defined, substantially yellow flames, or flames that appear lazy, indicate poor air supply to burners or excessive burner input. Verify gas supply type and manifold pressure with rating plate.

3. Poor air supply can be caused by obstructions or blockage in heat exchanger tubes or vent discharge pipe. Inspect and clean as necessary by to eliminate blockage. Vacuum any dirt or loose debris found in the tubes or vents. Clean heat exchanger tubes with stiff brush after performing Shutdown procedure. Poor flame characteristics can also be caused by undersized combustion air openings or flue gas recirculation into combustion air supply. Increase air opening size or re-direct flue products to prevent recirculation.

4. Reduced air delivery can also be the result of fan blade slippage, dirt accumulation the fan blade or low voltage to draft inducer motor. Inspect draft fan assembly and be sure fan blade is secure to motor shaft. Check line voltage to heater.

Shutdown

1. Set thermostat or controller to lowest setting.

2. Turn off electrical supply to unit at disconnect switch.

3. Turn off manual gas supply (supplied by others).

4. Disconnect manifold and inlet pressure taps and re-install pipe plugs.

5. Close module door.

Normal Operation

1. Turn on electrical supply to unit at disconnect switch.

2. Turn on manual gas supply (supplied by others).

3. Set Thermostat or Temperature controller to desired temperature.

Figure 37 - Flame Sensor Current Check

Service Checks

Flame current is the current which passes through the flame from the sensor to ground. The minimum flame current necessary to keep the system from lockout is 0.7 microamps. To measure flame current, connect an analog DC microammeter to the

FC- and FC+ terminals per figure. Meter should read 0.7 uA or higher. If the meter

reads below “0” on scale, meter leads are

reversed. Disconnect power and reconnect meter leads for proper polarity.

Air Pressure Switch

An air pressure switch is provided as part of the control system to verify airflow through draft inducer by monitoring the difference in pressure between the draft inducer and the atmosphere. If sufficient negative pressure is not present, indicating lack of proper air movement through heat exchanger, the switch opens shutting off gas supply though the ignition control module. On units with two speed draft inducer operation, a dual air pressure switch is used, monitoring high and low speed pressures. The air pressure switches have fixed settings and are not adjustable.

Rollout Switch (Manual Reset)

The duct furnace is equipped with manual reset rollout switches in the event of burner flame rollout. The switch will open on temperature rise and shut-off gas supply through the ignition control module. Flame rollout can be caused by insufficient airflow for the burner firing rate (high gas pressure), blockage of the vent system or in the heat exchanger. The duct furnace should not be placed back in operation until the cause of rollout condition is identified. The rollout switch can be reset by pressing the button on the top of the switch.

High Limit Switch

The duct furnace is equipped with a fixed temperature high limit switch mounted on the vestibule panel that shuts off gas to the heater through the ignition control module in the event of reduced circulating airflow over the heat exchanger. Reduced airflow can be caused by motor failure of the circulating air blower, dirty or blocked filters or restriction

LED

Code

System

Description

Actions

None

No Power to

On call for heat nothing happens

1. Check for open fuse or circuit breaker.

2. Check for poor wiring connection.

3. Check for failed 24V transformer.

Open Limit

Switch

Thermostat call for heat. No power

across terminals V1 / V2 control.

1. Check for proper operation of circulating air supply system and for air filter blockage.

2. Check manifold pressure when limit cools and closes. Natural gas 3.5” w.c / LP gas 10.0” w.c.

3. Low combustion blower air output. Flue gas temp exceeds 550ºF. Inspect for debris accumulation, proper wheel attachment, and proper voltage to blower.

Steady

Internal

Control Fault

(No Operation)

24VAC across Terminal 24VAC /

V2-Gnd when Thermostat calling for

heat

Control fault – Replace ignition control.

Flash

Combustion

Air Flow Fault

Pressure switch contacts in closed

position for 30 seconds with no

output to Combustion blower.

Remains in this mode with

combustion blower off.

1. Check for short in wiring to pressure switch.

2. Check pressure switch for closed contacts (with leads disconnected).

3. Replace pressure switch

Open pressure switch or flame

rollout switch when inducer (IND

terminal) is energized. If switch remains open for more than 30

seconds after combustion blower is

energized, control will remain in this

mode with IND terminal (blower)

energized.

1. Failed Combustion blower.

2. Check connections and air tube from draft inducer to air switch for leaks.

3. Check rollout switch manual reset - depress reset.

4. Check supply tube from draft inducer housing to pressure switches for condensate - drain line and re-connect.

5. Check pressure switch for condensate accumulation

6. Replace pressure switch

of the air inlet or outlet to the unit. The high limit switch will automatically reset when the temperature drops to 15ºF below the set point. Determine the cause of the reduced air flow and correct.

Table 13 - Gas Heater Troubleshooting

Ignition Control Diagnostics and Service Guide (Fenwal 35-61 Series). LED flashes on for ¼ second, and off for ¼ second during fault condition. Pause between fault codes is 3 seconds.

LED

Code

System

Description

Actions

Flash

Flame Fault

(No Call for

Heat)

Flame sense failure / flame present

with no call for heat.

1. Check for voltage to gas valve with thermostat in off position. Valve should not be powered.

2. If valve is not energized, check for gas flow (manifold pressure reading greater than 0). If gas flow, turn off main shut-off valve and replace gas valve.

Flash

Ignition

Lockout

Failure to light and or carryover.

Loss of flame or flame signal during

ignition or operation cycle.

Control will initiate up to 3 ignition

re-trials before lockout.

1. Verify gas supply available and operation of gas valve - manifold pressure at start of ignition cycle. Check for power to valve terminals LO & COM while spark is energized.

2. Is spark present? - If not check igniter for debris between electrodes, cracked ceramic and check ignition wire for short to ground.

3. Check flame sensor wiring connections to electrode and control and for any abrasions.

4. Check for cracked ceramic on flame sensor or grounded sensor rod.

5. Verify that ample air supply and proper venting of flue gases occurs during operating cycle.

6. Check for circulating air leaks into burner compartment during operation.

7. Check for re-circulation of flue gases into combustion air supply.

8. If all conditions satisfactory – replace ignition control.

Table 14 - Gas Heater Troubleshooting Continued

WARNING

If any original wiring needs to be replaced it must be replaced with wiring materials suitable for 105ºC.

Label all wires prior to disconnection when servicing unit. Wiring errors can cause improper or dangerous operation. Verify proper operation after servicing.

CAUTION

WARNING

Operating Control Systems

Two Stage (TN) - Low / High Fire / High Speed Inducer Only

Modulating (MD) - Modulating (25 to 100%) / 2 Speed Draft Inducer - Mid-Fire Start (55%)

Modulating (MH) - Modulating (25 to 100%) / 2 Speed Draft Inducer - High Fire Start (100%)

Refer to unit wiring diagrams located in unit door.

Furnace Maintenance

Duct Furnace Inspection

1. The duct furnace should be inspected annually by a qualified service agency. The condition of the burners, heat exchanger, draft inducer, vent system, operating controls and wiring should be determined. Check for obvious signs of deterioration, accumulation of dirt and debris and any heat or water related damage. Any damaged or deteriorated parts should be replaced before the unit is put back into service.

2. Clean burners, heat exchanger, draft inducer and vent ducts with a soft brush or vacuum.

3. Check Heat Exchanger for cracks. If any are present, replace heat exchanger before putting unit back into service.

4. Check the attachment point of the duct furnace to the cabinet or ducts to verify that they are air tight.

5. Check the automatic gas valve to insure that the gas valve seat is not leaking.

Duct Furnace Operation Check

1. Turn on power to the unit and set thermostat or heat controller to call for heat, allowing duct furnace to operate.

2. Check for proper start-up and ignition as outlined in Start-Up section.

3. Check the appearance of the burner flame.

4. Check that the circulating air fan is operating and verify the proper airflow through duct furnace.

5. Return thermostat or heat controller to normal setting.

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 38 - 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

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.

WARNING

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 39 - Cross Section of Air Seal

Structure

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

.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.

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 40 - 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 “selfcleaning” 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.

Do Not use acid based cleaners, aromatic solvents, steam or temperatures in excess of 170°F; damage to the wheel may occur!

CAUTION

Air Seals

Four adjustable diameter seals are provided on each cassette to minimize transfer of air between the counter flowing airstreams.

To adjust diameter seals, loosen diameter seal adjusting screws and back seals away from wheel surface. Rotate wheel clockwise until two opposing spokes are hidden behind the bearing support beam. Using a folded piece of paper as a feeler gauge, position paper between the wheel surface and diameter seals.

Adjust seals towards wheel surface until a slight friction on the feeler gauge (paper) is detected when gauge is moved along the length of the spoke. Retighten adjusting screws and recheck clearance with “feeler” gauge.

Wheel Drive Components

The wheel drive motor bearings are prelubricated and no further lubrication is necessary.

The wheel drive pulley is secured to the drive motor shaft by a combination of either a key or D slot and set screw.

The set screw is secured with removable locktite to prevent loosening. Annually confirm set screw is secure. The wheel drive belt is a urethane stretch belt designed to provide constant tension through the life of the belt. No adjustment is required. Inspect the drive belt annually for proper tracking and tension. A properly tensioned belt will

turn the wheel immediately after power is applied with no visible slippage during startup.

Installation Considerations

Energy recovery cassettes are incorporated within the design of packaged units, packaged air handlers and energy recovery ventilators. In each case, it is recommended that the following considerations be addressed:

Accessibility

The cassette and all its operative parts; i.e.: motor, belt, pulley, bearings, seals and energy transfer segments must be accessible for service and maintenance. This design requires that adequate clearance be provided outside the enclosure.

Orientation & Support

The Energy Recovery Cassette may be mounted in any orientation. However, Care must be taken to make certain that the cassette frame remains flat and the bearing beams are not racked.

To verify, make certain that the distance between wheel rim and bearing beam is the same at each end of the bearing beam, to within 1/4 of an inch (dimension A & B). This amount of racking can be compensated for by adjusting the diameter seals.

If greater than 1/4 inch (dimension C), racking must be corrected to ensure that drive belt will not disengage from wheel.

Bearing beams shown racked

Frame

Bearing beams (2)

Flat surface

Keep hands away from rotating wheel! Contact with rotating wheel can cause physical injury.

CAUTION

Figure 41 - Avoid Racking of Cassette

Frame

Operation

Startup Procedure

1. By hand, turn wheel clockwise (as viewed from the pulley side), to verify wheel turns freely through 360º rotation.

2. Before applying power to drive motor, confirm wheel segments are fully engaged in wheel frame and segment retainers are completely fastened. (See Segment Installation Diagram).

3. With hands and objects away from moving parts, activate unit and confirm wheel rotation. Wheel rotates clockwise (as viewed from the pulley side).

4. If wheel has difficulty starting, turn power off and inspect for excessive interference between the wheel surface and each of the four (4) diameter seals. To correct, loosen diameter seal adjusting screws and back

adjustable diameter seals away from surface of wheel, apply power to confirm wheel is free to rotate, then re-adjust and tighten hub and diameter seals, as shown in hub seal adjustment diagram.

5. Start and stop wheel several times to confirm seal adjustment and to confirm belt is tracking properly on wheel rim

(approximately 1/4” from outer edge of

rim).

Figure 42 - Diameter Seal Adjustment

Figure 43 - Hub Seal Adjustment

Disconnect electrical power before servicing energy recovery cassette. Always keep hands away from bearing support beam when installing or removing segments. Failure to do so could result in severe injury to fingers or hand.

CAUTION

Service

Segment Installation & Replacement

Wheel segments are secured to the wheel frame by a Segment Retainer which pivots on the wheel rim and is held in place by a Segment Retaining Catch.

Figure 44 - Segment Retainer

To install wheel segments follow steps one through five below. Reverse procedure for segment removal.

1. Unlock two segment retainers (one on each side of the selected segment opening.

2. With the embedded stiffener facing the motor side, insert the nose of the segment between the hub plates.

Figure 45 - Segment Installation

3. Holding segment by the two outer corners, press the segment towards the center of the wheel and inwards against the spoke flanges. If hand pressure does not fully seat the segment, insert the flat tip of a screw driver between the wheel rim and outer corners of the segment and apply downward force while guiding the segment into place.

4. Close and latch each Segment Retainer under Segment Retaining Catch.

5. Slowly rotate the wheel 180º. Install the second segment opposite the first for counterbalance. Rotate the two installed segments 90º to balance the wheel while the third segment is installed. Rotate the wheel 180º again to install the fourth segment opposite the third. Repeat this sequence with the remaining four segments.

Wheel Drive Motor and Pulley Replacement

1. Disconnect power to wheel drive motor.

2. Remove belt from pulley and position temporarily around wheel rim.

3. Loosen set screw in wheel drive pulley using a hex head wrench and remove pulley from motor drive shaft.

Protect hands and belt from possible sharp edges of hole in Bearing Support Beam.

CAUTION

4. While supporting weight of drive motor in one hand, loosen and remove (4) mounting bolts.

5. Install replacement motor with hardware kit supplied.

6. Install pulley to dimension as shown and secure set screw to drive shaft.

7. Stretch belt over pulley and engage in groove.

8. Follow start-up procedure.

Belt Replacement

1. Obtain access to the pulley side bearing access plate if bearing access plates are provided. Remove two bearing access plate retaining screws and the access plate.

2. Using hexagonal wrench, loosen set screw in bearing locking collar. Using light hammer and drift (in drift pin hole) tap collar in the direction of wheel rotation to unlock collar. Remove collar.

3. Using socket wrench with extension, remove two nuts which secure bearing housing to the bearing support beam. Slide bearing from shaft. If not removable by hand, use bearing puller.

4. Form a small loop of belt and pass it through the hole in the bearing support beam. Grasp the belt at the wheel hub and pull the entire belt down.

Note: Slight hand pressure against wheel rim will lift weight of wheel from inner race of bearing to assist bearing removal and installation.

5. Loop the trailing end of the belt over the shaft (belt is partially through the opening).

6. Reinstall the bearing onto the wheel shaft, being careful to engage the two locating pins into the holes in the bearing support beam. Secure the bearing with two self-locking nuts.

7. Install the belts around the wheel and pulley according to the instructions provided with the belt.

8. Reinstall diameter seals or hub seal and tighten retaining screws. Rotate wheel in clockwise direction to determine that wheel rotates freely with slight drag on seals.

9. Reinstall bearing locking collar. Rotate collar by hand in the direction the wheel rotates (see label provided on each cassette for wheel rotation).

10. Lock in position by tapping drift pin hole with hammer and drift. Secure in position by tightening set screw.

11. Reinstall Bearing Access Cover.

12. Apply power to wheel and ensure that the wheel rotates freely without interference.

Figure 46 - Belt Replacement

Improper installation, adjustment, alteration, service or maintenance can cause property damage, personal injury or loss of life. Installation and service must be performed by a trained, qualified installer. A copy of this IOM should be kept with the unit.

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

WARNING

Startup

(See back of the manual for startup form)

During startup, it is necessary to perform routine checks on the performance of the unit. This includes checking of the air flow, the air filters, condenser water flow and refrigerant charge.

Filters

Do not operate the unit without filters in place. Operation of the equipment without filters in place can result in clogged coils. Units are shipped with the selected filters installed. If filters have been removed during installation, open the filter access door and re-install the correct filters with the airflow indicator arrows pointing in the direction of airflow.

Filters should be checked after a few days of operation after the unit has been started up as dust and debris from construction may cause premature filter loading. Replace the filters if necessary.

Check Out

Equipment should be thoroughly checked for loose wiring, a free spinning blower wheel, and well-fitting access panels. Air handlers should not be operated without proper ductwork and access panels installed, except as required during start-up and air balancing.

1. Check all electrical connections to be

sure they are tight.

2. Open all access panels, and remove

all shipping screws, or restraints.

3. Clean out any debris that may have

been left.

4. Check belt alignment and tightness

of fan drives.

5. Check bearing locking collars and

fan wheel set screws for tightness.

6. Turn fan wheels to assure free

rotation.

7. Ensure electrical supply matches the

unit nameplate.

8. Ensure condensate lines are

connected, glued, and sloped toward building drain.

9. Check local codes for any special

provisions.

10. Attach or close all access doors and

panels.

11. Ensure that all ductwork dampers are

open.

12. Check electrical phasing to ensure

the fan rotates in the proper direction.

Electric Heating Section Procedures:

1. Perform final visual inspection.

Check all equipment, ductwork, and piping to verify that all work is complete and equipment is properly installed and mounted. Improperly installed equipment or ductwork can affect readings.

2. Ensure there is no construction

debris in the unit.

3. Check the unit for external damage.

4. Note all accessories installed.

5. Install new filters of the proper size

and type.

6. Check all terminal blocks, fuses, fuse

blocks, and contactors for correctness.

7. Check all high and low voltage

wiring connections for correctness and tightness.

8. Check unit for correct incoming

voltage per the data plate.

9. Check the security of the locking

system on all blower bearings

10. Turn the unit power on.

11. Turn the unit blower on and check

for correct rotation.

12. If correct, take blower amp readings

and compare to see if the amp draw is within the safety factor area of the motor. Once correct, turn blower off.

13. Turn on the first stage of heating  Check amp draw of each

element of each stage

 Ensure blower started w/

electric heat

 Check for temperature rise

across heating section while all stages are on

 If temperature rise is within

range, turn all heating calls off

 Check to see that blower

stops

Refrigerant (DX) Cooling Section Procedures:

1. Perform final visual inspection.

Check all equipment, ductwork, and piping to verify that all work is complete, and equipment is properly installed and mounted. Improperly

installed equipment, or ductwork can affect readings.

2. Perform condenser start-up checks in

addition to these air handler checks according to the condenser manufacturer’s instructions.

3. Ensure there is no construction

debris in the unit.

4. Check the unit for external damage.

5. Note all accessories installed.

6. Ensure that drain P-trap is properly

installed.

7. Check all terminal blocks, fuses, fuse

blocks, and contactors for correctness.

8. Check all high and low voltage

wiring connections for tightness. Check unit for correct incoming voltage per the data plate.

9. Check the security of the locking

system on all blower bearings

10. Turn the unit power on.

11. Turn the unit blower on and check

for correct rotation.

12. If correct, take blower amp readings

and compare to see if the amp draw is within the safety factor area of the motor.

13. Check and record ambient

temperature.

14. Check for Guaranteed Off Timers

(GOT) and Time Delay Relays (TDR).

15. Start the first stage cooling circuit

and blower circuit.

16. After all stages of cooling have been

on for at least five minutes, record the return air temperature and supply air temperature.

17. Check the temperature difference

across the evaporator coil.

Gas Heating Section Procedures:

1. Turn thermostat or temperature

controller to its lowest setting.

2. Turn off gas supply at the manual

shut-off valve (supplied by others).

3. Turn off power to the unit at the

disconnect switch.

4. Open door to unit module housing

the gas heater.

5. Move gas control knob to “OFF”

position.

6. Install a tapped fitting for attachment

to a manometer or other gauge

suitable for 14.0” w.c. in the inlet pressure tap, and for 10.0” w.c. in

the manifold pressure tap.

7. Wait 5 minutes for any gas to clear

out. If you smell gas, turn off gas supply at the manual shut-off valve

(field installed). If you don’t smell

gas or have corrected any leaks, go to the next step.

8. Turn gas control knob to “ON”

position.

9. Open all manual gas valves (supplied

by others).

10. Turn power on at disconnect switch.

11. Set thermostat or controller to its

highest position to initiate call for heat and maintain operation of unit.

12. Draft inducer will run for a 15 to 30

second pre-purge period.

13. At the end of the pre-purge the direct

spark will be energized and gas valve will open.

Commissioning

The commissioning of an air conditioning system is the process of achieving, verifying, and documenting the performance of that system to meet the operational needs of the building. This may not be a formal process in smaller structures, but some form of owner acceptance will occur. Adjustments made during the commissioning phase may include air or water balancing, or configuration of controls and operational sequences.

Air Balancing

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 operating characteristics. Professional air balance specialists should be employed to establish actual operating conditions and to configure the air delivery system for optimal performance.

Water Balancing

A hydronic specialist with a complete working knowledge of water systems, controls, and operation must be employed to properly balance the entire system. Unqualified personnel should not attempt to manipulate temperatures, pressures, or flow rates, as all systems have unique operating characteristics and improper balancing can result in undesirable noises and operation.

Controls

A variety of controls and electrical accessories may be provided with the equipment.

Identify the controls on each unit by consulting appropriate submittal and 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.

Operation

Immediately following building occupancy, the air conditioning system requires a maintenance schedule to assure continued successful operation. Routine maintenance of this equipment is necessary in order to provide continued efficient and reliable operation for the owner. See the

The Clean Air Act of 1990 bans the intentional venting of refrigerant

(CFC’s and HCFC’s) as of July 1,

1992. Approved methods of recovery, recycling or reclaiming must be followed. Fines and/or incarceration may be levied for non-compliance.

CAUTION

Maintenance List provided later in this manual.

Adjusting Refrigerant Charge

Adjusting the charge of a system in the field must be based on determination of liquid sub-cooling and evaporator superheat. On a system with a TXV liquid sub-cooling is more representative of the charge than evaporator superheat but both measurements must be taken.

Before Charging

Unit being charged must be at or near full load conditions before adjusting the charge.

Units equipped with hot gas reheat must be charged with the hot gas reheat valves closed while the unit is in cooling mode to get the proper charge. After charging, unit should be operated in reheat (dehumidification) mode to check for correct operation.

After adding or removing charge the system must be allowed to stabilize, typically 10-15 minutes, before making any other adjustments.

The type of unit and options determine the ranges for liquid sub-cooling and evaporator superheat. Refer to the tables below when determining the proper sub-cooling.

Checking Liquid Sub-Cooling

Measure the temperature of the liquid line as it leaves the condenser.

Read the gauge pressure at the liquid line close to the point where the temperature was taken. Use liquid line pressure as it will vary from discharge pressure due to condenser pressure drop.

Convert the pressure obtained to a saturated temperature using the appropriate refrigerant temperature-pressure chart.

Subtract the measured liquid line temperature from the saturated temperature to determine the liquid sub-cooling.

Compare calculated sub-cooling to the table below for the appropriate unit type and options.

Checking Evaporator Superheat

Measure the temperature of the suction line close to the compressor.

Read gauge pressure at the suction line close to the compressor.

Convert the pressure obtained to a saturated temperature using the appropriate refrigerant temperature-pressure chart.

Subtract the saturated temperature from the measured suction line temperature to determine the evaporator superheat.

Compare calculated superheat to the table below for the appropriate unit type and options.

Air-Cooled

Condenser

Sub-Cooling

12-18°F

Sub-Cooling with

Hot Gas Reheat

15-22°F

Superheat

8-15°F

Water-Cooled

Condenser

Sub-Cooling

6-10°F

Sub-Cooling with

Hot Gas Reheat

8-12°F

Superheat

8-15°F

Refrigerant overcharging leads to excess refrigerant in the condenser coils resulting in elevated compressor discharge pressure.

CAUTION

Thermal expansion valve must be adjust to approximately 8-15°F of suction superheat. Failure to have sufficient superheat will damage the compressor and void the warranty.

CAUTION

Table 15 - Acceptable Air-Cooled

Refrigeration Circuit Values

DO NOT OVERCHARGE!

Table 16 - Acceptable Water-Cooled

Refrigeration Circuit Values

Adjusting Sub-Cooling and Superheat Temperatures

The system is overcharged if the sub-cooling temperature is too high and the evaporator is fully loaded (low loads on the evaporator result in increased sub-cooling) and the evaporator superheat is within the temperature range as shown in the table above (high superheat results in increased sub-cooling).

Correct an overcharged system by reducing the amount of refrigerant in the system to lower the sub-cooling.

The system is undercharged if the superheat is too high and the sub-cooling is too low

Correct an undercharged system by adding refrigerant to the system to reduce superheat and raise sub-cooling.

If the sub-cooling is correct and the superheat is too high, the TXV may need adjustment to correct the superheat. Before adjusting the TXV, verity the sensing bulb is in the correct position according to Figure 18 and follows the guidelines below.

1. The suction line is clean where the sensing bulb is attached.

2. The entire length of the sensing bulb is in contact with the suction line.

3. The sensing bulb should be placed several inched downstream of the equalizer line.

4. The sensing bulb is fully insulated.

5. If the sensing bulb is installed on a vertical portion of the suction line, the sensing bulb should be placed upstream of a suction line trap.

°F

PSIG

°F

PSIG

°F

PSIG

°F

PSIG

°F

PSIG

78.3

134.7

213.7

101

321.0

128

463.2

80.0

137.2

217.1

102

325.6

129

469.3

81.8

139.7

220.6

103

330.2

130

475.4

83.6

142.2

224.1

104

334.9

131

481.6

85.4

144.8

227.7

105

339.6

132

487.8

87.2

147.4

231.3

106

344.4

133

494.1

89.1

150.1

234.9

107

349.3

134

500.5

91.0

152.8

238.6

108

354.2

135

506.9

92.9

155.5

242.3

109

359.1

136

513.4

94.9

158.2

246.0

110

364.1

137

520.0

96.8

161.0

249.8

111

369.1

138

526.6

98.8

163.8

253.7

112

374.2

139

533.3

100.9

166.7

257.5

113

379.4

140

540.1

102.9

169.6

261.4

114

384.6

141

547.0

105.0

172.5

265.4

115

389.9

142

553.9

107.1

175.4

269.4

116

395.2

143

560.9

109.2

178.4

273.5

117

400.5

144

567.9

111.4

181.5

277.6

118

405.9

145

575.1

113.6

184.5

281.7

119

411.4

146

582.3

115.8

187.6

285.9

120

416.9

147

589.6

118.1

190.7

290.1

121

422.5

148

596.9

120.3

193.9

294.4

122

428.2

149

604.4

122.7

197.1

298.7

123

433.9

150

611.9

125.0

200.4

303.0

124

439.6

127.4

203.6

307.5

125

445.4

129.8

207.0

311.9

126

451.3

132.2

210.3

100

316.4

127

457.3

Table 17 - R-410A Refrigerant Temperature-Pressure Chart

Refrigeration Troubleshooting

Problem

Possible Cause

Solutions

Frosted evaporator coil, low suction pressure

Restricted air flow Low fan speed Reversed blower rotation Low refrigerant charge

Clean, or replace filters Check fan drives Correct wiring Add refrigerant

Unit runs, but supplies warm air

Loss of refrigerant Faulty expansion valve element Plugged filter-drier

Check leaks, add refrigerant Replace valve element Replace filter-drier

Compressor starts, but opens high pressure control

Refrigerant over-charged Air in condenser coil Condenser fan faulty Condenser coil dirty

Remove some refrigerant Evacuate and recharge refrigerant Replace fan motor Clean condenser coil

High suction pressure, but low superheat

Oversized expansion valve Poor sensing bulb location Low superheat adjustment

Replace with correct expansion valve Relocate sensing bulb, secure to suction line Adjust expansion valve

Unit operates continuously

Low refrigerant charge Unit undersized

Check and recharge to nameplate Decrease load or resize unit Thermostat set too low, increase temperature setting

Table 18 – Refrigeration Problems, Causes, and Solutions

Maintenance

(See back of the manual for maintenance log.)

At least once each year, a trained, qualified service technician should check out the unit. Fans, evaporator coils, and filters should be inspected at least monthly.

One week after start-up:

 Check operating pressures.  Adjust belt tension on all fan drives.  Check filters for cleanliness. Measure

pressure loss if applicable. Replace if necessary.

 Check cycling of compressors, fans, and

valves. Correct unusual cycling.

Monthly:

 Lubricate bearings if operating

continuously at 1500 rpm, or higher, or in other extreme conditions.

 Check cleanliness of filters and replace

if necessary.

 Check cooling coil drain pan to assure

proper drainage.

 Inspect all coils. Clean if dirty or

obstructed in any way.

Quarterly:

 Lubricate bearings if operating at 1000

rpm, or less, and in temperatures less than 150F, or other extreme conditions.

 Check damper operation for freedom of

movement. Correct any binding that may occur.

 Check belts and pulleys on fan drives for

tension and unusual wear.

 Check operation of heating and cooling

sections.

 Check inlet and outlet air temperatures.

Annually:

 Clean the coils with water or non-

corrosive coil cleaner.

 Clean the drain line, “P” trap, and

condensate pan.

 Check refrigerant pressures and

temperatures every Spring.

 Check heating section every Fall. Check

all electrical connections for tightness and check heater elements for indications of overheating.

Fan Assembly

M2 Series units use backward curved fan wheels which are non-overloading, energy efficient and easy to clean. Cleaning the wheels is necessary to reduce electrical use, maintain capacity, and reduce stress on the unit. The wheel and fan section need to be inspected periodically and cleaned of dust or debris.

To inspect and clean the blower, set thermostat to the “OFF” position. Turn the

electrical power to the unit to the “OFF”

position at the disconnect switch. Clean the assembly. Check the bearings. Inspect the belt condition and tightness. Check screws for tightness. Rotate blower wheels while listening closely to each bearing to check for noise or roughness in the bearing, which can indicate a failing bearing.

Bearings

AAON uses pre-lubricated bearings, and bearings that have been sized for an average failure rate of 50% after 200,000 hours, or

22.8 years, of operation (see heading “Lubrication” in this section for more information). The bearing sizing tables below are based on rotational speeds and radial loading. However, the alignment of the bearing to the shaft and the security of the bearing inner race to the shaft will greatly affect bearing life. Even though the manufacturer is responsible for bearing tolerances and mounting design, the

servicer is advised to regularly check the security of the bearing locking system.

Shaft Size

(inches)

Setscrew Locking

Thread

Torque

(in-lbs.)

1/4 - 28

66 - 85

1 3/16

1/4 - 28

66 - 85

1 7/16

5/16 - 24

126 - 164

1 7/8

3/8 - 24

228 - 296

Shaft Size

(inch)

Skewzloc Locking

Thread

Torque

(in-lbs.)

8 - 32

63 - 70

1 3/16

8 - 32

63 - 70

1 7/16

10 - 24

81 - 90

1 7/8

1/4 - 20

162 - 180

Sheave Centers

Force

Deflection = 1/64th in. per inch of length

Straightedge

Pulley

Belt

Straightedge

Pulley

Belt

Table 19 - Bearing Setscrew Torque

Recommendations

Belts

Belt drive misalignment is one of the most common causes of premature belt failure. A belt can be destroyed in a matter of days if the drives have been aligned incorrectly.

The most common tool for measuring misalignment is a straightedge. Hold the straightedge flush across one pulley to gauge the degree of misalignment of the two sheaves. The maximum allowed misalignment is one half degree of angular misalignment, and 1/10th of an inch per foot between sheave centers for parallel misalignment.

Figure 47 - Angular Misalignment

Correct by moving the position of the motor.

Figure 48 - Parallel Misalignment

Correct by adjusting sheaves on one, or both shafts.

Frequent belt tensioning is highly recommended. Most belt manufacturers would suggest a re-tensioning after as little as 8 hours of operation. A simplified method of adjusting tension is to gauge the amount of force required to deflect the belt by 1/64th of an inch per inch of distance between sheave centers. For example, if the sheaves are 20 inches apart, then the amount of deflection with the forces listed below is 20/64th (5/16th) of an inch.

Deflection required for

“A” belts: 4-6 lbs. “B” belts: 6-10 lbs. “C” belts: 10-18 lbs.

Figure 49 - Belt Deflection

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

WARNING

Indoor Coils

Indoor cooling/evaporator coils must be cleaned regularly to maintain unit efficiency and operation. Dirty evaporator coils will eventually freeze up and often result in a time consuming and expensive service call. Clean filters will help to prevent dirt from accumulating on cooling coils, however cooling coils should be cleaned at least annually by an HVAC professional.

Refrigeration Cycle

Satisfactory performance of the refrigeration cycle can be determined by measuring suction line superheat. In order to determine if refrigerant flowing from the evaporator is dry, ensure that the system has enough refrigerant to produce liquid line subcooling, but not so much to cause abnormally high condensing temperatures (and pressures). Refrigerant cycle analysis is best performed in conditions that approach the conditions where the air conditioner will be expected to operate.

Brazed Plate Heat Exchanger Cleaning

Because of a normally high degree of turbulence in brazed plate heat exchangers, for many applications the heat exchanger channels are self-cleaning. For applications that are not self-cleaning (i.e. hard water at high temperatures, etc.) or applications where additional cleaning is desired, it is possible to clean the brazed plate heat exchanger by circulating a cleaning liquid.

Use a tank with weak acid, 5% phosphoric acid (H3PO4) or, if the exchanger is frequently cleaned, 5% oxalic acid (H2C2O4). Pump the cleaning liquid through the exchanger. For optimum cleaning, the cleaning solution flow rate should be a minimum of 1.5 times the normal flow rate, preferably in a back-flush mode. After cleaning, the heat exchanger must be rinsed with clean water. A solution of 1-2% sodium hydroxide (NaOH) or sodium bicarbonate (NaHCO) before the last rinse ensures that all acid is neutralized.

E-Coated Coil Cleaning

Documented routine cleaning of e-coated coils is required to maintain coating warranty coverage.

Surface loaded fibers or dirt should be removed prior to water rinse to prevent restriction of airflow. If unable to back wash the side of the coil opposite of the coils entering air side, then surface loaded fibers or dirt should be removed with a vacuum cleaner. If a vacuum cleaner is not available, a soft non-metallic bristle brush may be used. In either case, the tool should be applied in the direction of the fins. Coil surfaces can be easily damaged (fin edges bent over) if the tool is applied across the fins.

Use of a water stream, such as a garden hose, against a surface loaded coil will drive the fibers and dirt into the coil. This will make cleaning efforts more difficult. Surface loaded fibers must be completely removed prior to using low velocity clean water rinse.

A monthly clean water rinse is recommended for coils that are applied in coastal or industrial environments to help to remove chlorides, dirt, and debris. It is very important when rinsing, that water temperature is less than 130°F and pressure is than 900 psig to avoid damaging the fin edges. An elevated water temperature (not to exceed 130°F) will reduce surface tension, increasing the ability to remove chlorides and dirt.

High velocity water from a pressure washer or compressed air should only be used at a very low pressure to prevent fin and/or coil damages. The force of the water or air jet may bend the fin edges and increase airside pressure drop. Reduced unit performance or nuisance unit shutdowns may occur.

Harsh chemicals, household bleach, or acid cleaners should not be used to clean outdoor or indoor e-coated coils. These cleaners can be very difficult to rinse out of the coil and can accelerate corrosion and attack the e-coating. If there is dirt below the surface of the coil, use the recommended coil cleaners.

CAUTION

Quarterly cleaning is essential to extend the life of an e-coated coil and is required to maintain coating warranty coverage.

Coil cleaning shall be part of the unit’s

regularly scheduled maintenance procedures. Failure to clean an e-coated coil will void the warranty and may result in reduced efficiency and durability.

For routine quarterly cleaning, first clean the coil with the below approved coil cleaner. After cleaning the coils with the approved cleaning agent, use the approved chloride remover to remove soluble salts and revitalize the unit.

Recommended Coil Cleaner

The following cleaning agent, assuming it is

used in accordance with the manufacturer’s

directions on the container for proper mixing and cleaning, has been approved for use on e-coated coils to remove mold, mildew,

dust, soot, greasy residue, lint and other particulate:

Enviro-Coil Concentrate, Part Number HEC01.

Recommended Chloride Remover

CHLOR*RID DTS™ should be used to remove soluble salts from the e-coated coil, but the directions must be followed closely. This product is not intended for use as a degreaser. Any grease or oil film should first be removed with the approved cleaning agent.

Remove Barrier - Soluble salts adhere themselves to the substrate. For the effective use of this product, the product must be able to come in contact with the salts. These salts may be beneath any soils, grease or dirt; therefore, these barriers must be removed prior to application of this product. As in all surface preparation, the best work yields the best results.

Apply CHLOR*RID DTS - Apply directly onto the substrate. Sufficient product must be applied uniformly across the substrate to thoroughly wet out surface, with no areas missed. This may be accomplished by use of a pump-up sprayer or conventional spray gun. The method does not matter, as long as the entire area to be cleaned is wetted. After the substrate has been thoroughly wetted, the salts will be soluble and is now only necessary to rinse them off.

Rinse - It is highly recommended that a hose be used, as a pressure washer will damage the fins. The water to be used for the rinse is recommended to be of potable quality, though a lesser quality of water may be used if a small amount of CHLOR*RID DTS is added. Check with CHLOR*RID International, Inc. for recommendations on lesser quality rinse water.

Electric Heating

Set thermostat in the heat mode; call for heat to engage all electric heat strips. Check blower for proper rotation and voltage. Measure the amperage and voltage. Compare them to the nameplate data.

If applicable, check remote heat pump

condenser as per the manufacturer’s

recommendations.

Steam or Hot Water Heating

Set thermostat in the heat mode. Observe supply blower for proper rotation and voltage. Check boiler or hot water operation

according to the manufacturer’s instructions.

Check control flow valves for correct operation and settings per the manufacturer’s instructions.

Cleaning

Inspect and clean unit interior at the beginning of each heating and cooling season and as operating conditions require.

Chilled Water

Check remote chiller operations as per the

manufacturer’s instructions. Check coolant

flow valves for correct operation and settings.

DX Water Source Cooling

Set unit controls to cooling mode of operation with supply fans on. Check the fan for correct operating direction, amperage, and voltage. Check compressor operation, rotation, amperage, and voltage to the unit nameplate (check the amperage on the load side of the compressor contactor).

Condensate Drain Pans

Drain pans will have moisture present and require periodic cleaning to prevent microbial growth. Cleaning of the drain pans will also prevent any possible plugging of the drain lines and overflow of the pan itself. Cleaning of the drain pans and inside of the unit should be done only by a qualified service technician.

Duct Furnace

The duct furnace should be inspected annually by a qualified service agency. The condition of the burners, heat exchanger, draft inducer, vent system, operating controls and wiring should be determined. Check for obvious signs of deterioration, accumulation of dirt and debris and any heat or water related damage. Any damaged or deteriorated parts should be replaced before the unit is put back into service. Check the automatic gas valve to insure the gas valve seat is not leaking. Check wiring connections to be sure they are secure and inspect wiring for any deterioration.

Lubrication

Most motors and bearings are permanently lubricated. Some applications may require that bearings be re-lubricated periodically. The schedule will depend on the operating duty, temperature variations, and other atmospheric conditions.

For bearings equipped with lubrication fittings, the lubrication schedule is dependent on operating temperatures and rotational speeds as shown in the table below. Lithium based grease conforming to an NLGI grade No. 2 consistency is recommended. This medium viscosity, low torque grease is rust inhibiting and waterresistant. It is satisfactory for operating temperatures in the range of –10F to 250F.

Bearings should only be re-lubricated when at normal operating temperatures and not running. Rotate the fan shaft by hand, adding only enough grease to purge the seals. A one-inch bearing has a total grease capacity of only .25 ounces. Added grease should be limited to .09 ounces.

DO NOT OVER LUBRICATE.

Recommended greases are: SHELL OIL - DOLIUM R CHEVRON OIL - SRI No. 2 TEXACO INC. - PREMIUM RB

Fan

Speed

Temp.

Environ.

Greasing

Interval

500

rpm

Up to

150 F

Clean

2 to 6

months

1000

rpm

Up to

210 F

Clean

2 weeks to

2 months

1500

rpm

Up to

210 F

Clean

Monthly

Any

Speed

Up to

150 F

Dirty

1 week to

1 month

Any

Speed

210 -

250 F

Dirty

Weekly

Table 20 - Fan Bearing Lubrication

Schedule

In the event the unit is not functioning correctly and a service company is required, only a company with service technicians qualified and experienced in both commercial heating and air conditioning should be permitted to service the systems in order to keep warranties in effect. The service tech may call the factory if assistance is required.

Replacement Parts

Parts for AAON equipment may be obtained from your local AAON representative. When ordering parts, reference the unit serial number and part number.

AAON-Longview Product Support

203 Gum Springs Road Longview, TX 75602 Ph: 903-236-4403 Fax: 903-236-4463 www.aaon.com

Note: Before calling, technician should have model and serial number of the unit available for the service department to help answer questions regarding the unit.

Line Voltage

460VAC, 3Ø

Over & Undervoltage

±10%

Trip Time Delay

5 Seconds

Re-Start Time Delay

2 Minutes

Phase Imbalance

Phase and Brownout Protection Module

The DPM is a Digital Phase Monitor that monitors line voltages from 200VAC to 240VAC 1ɸ and 200VAC to 600VAC 3ɸ. The DPM is 50/60 Hz self-sensing. DPM should be wired according to unit specific wiring diagram include in the control compartment

When the DPM is connected to the line voltage, it will monitor the line and if everything is within the setup parameters, the output contacts will be activated. If the line voltages fall outside the setup parameters, the output relay will be deenergized after the trip delay.

Once the line voltages recover, the DPM will re-energize the output relay after the restart time delay. All settings and the last 4 faults are retained, even if there is a complete loss of power.

DPM Setup Procedure

With the supply voltage active to the

module, you can setup all of the DPM’s

settings without the line voltage connected.

To change the setpoint parameters use the right arrow key to advance forward through the setpoint parameters and the left arrow to backup if needed. When each parameter is displayed use the up/down keys to change and set the parameter.

After adjustments are made or if no adjustments are made it will take 2 to 4 minutes before the DPM energizes the output relay unless there is an out of tolerance issue with the incoming line voltage.

Recommended Default Set-up

VAvg

Imb

460

off

A-B

B-C

C-A

460

459

461

200,

1Ø;

208,

1Ø;

220,

1Ø;

230,

1Ø;

240,

1Ø;

200,

3Ø;

208,

3Ø;

220,

3Ø;

230,

3Ø;

240,

3Ø;

380,

3Ø;

415,

3Ø;

440,

3Ø;

460,

3Ø;

480

3Ø;

575,

3Ø;

600,

3Ø;

10%

11%

12%

13%

14%

15%

2S,

3S,

4S,

5S,

6S,

27S,

8S,

9S & 10S

Manual,

2S,

3S,

4S,

5S,

6S,

7S,

8S,

9S,

10S,

30S,

1M,

2M,

3M & 4M

9% & 10%

“Phase a Loss”

(There is no voltage sensed on 3-L1/S)

“Voltage Low”

(Average line voltage is less than selected Undervoltage Percentage)

“Voltage High”

(Average line voltage is more than selected Overvoltage Percentage)

“Imbalance”

(One phase is lower than the average voltage by more than the Imbalance percentage)

“Phase Loss

(One phase is more than 30% below the Line Voltage selection)

“Bad Rotation”

(The phase rotation sequence is reversed)

“Bad Freq”

(Line frequency out of allowable range of 45 to 65 Hz)

Screens

Manufacturer’s Screen

R-K Electronics DPM v0.0.00

Average Voltage Screen

Default – the default screen shows the real time voltage detected in each of the 3 phases:

Voltage Selection Screen (Vertical Format) Default = 460V, 3Ø

Over/Under voltage Percentage Screen (Vertical Format) Default = 10%

Trip Time Delay Screen (Vertical Format) Default = 5 sec

Re-Start Time Delay Screen (Vertical Format) Default = 2 sec

Phase Imbalance Percentage Screen (Vertical Format) Default = 5%

Fault Screen (Vertical Format)

“0” most recent faults, “1” previous fault “2” third oldest fault & “3” fourth oldest fault.

Fault Words:

Filter Type

(Quantity) Size

M2-005

M2-008

2” Pleated - 30% Eff, MERV 8

(2) 20” x 20”

(4) 16” x 20”

4” Pleated - 30% Eff (MERV 8), 65% Eff

(MERV 11), 85% Eff (MERV 13),

or 95% Eff (MERV 14)

12” Cartridge - 65% Eff (MERV 11),

85% Eff (MERV 13),

or 95% Eff (MERV 14)

Filter Type

(Quantity) Size

M2-011

M2-014

2” Pleated - 30% Eff, MERV 8

(2) 16” x 20” and

(4) 20” x 20”

4” Pleated - 30% Eff (MERV 8), 65% Eff

(MERV 11), 85% Eff (MERV 13),

or 95% Eff (MERV 14)

12” Cartridge - 65% Eff (MERV 11),

85% Eff (MERV 13),

or 95% Eff (MERV 14)

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

WARNING

Filter Replacement

Monthly air filter inspection is required to maintain optimum unit efficiency. It is strongly recommended that filter media be replaced monthly. Open access panel and pull filters straight out to inspect all of the filters. Replace filters with the size indicated on each filter. Arrow on the replacement filters must point towards the blower.

Table 21 - M2-005 and M2-008 Filters

Table 22 - M2-011 and M2-014 Filters

Filter Type

(Quantity) Size

M2-018

M2-022

2” Pleated - 30% Eff, MERV 8

(8) 20” x 20”

(4) 25” x 20” (4) 20” x 20”

4” Pleated - 30% Eff (MERV 8), 65% Eff

(MERV 11), 85% Eff (MERV 13),

or 95% Eff (MERV 14)

12” Cartridge - 65% Eff (MERV 11),

85% Eff (MERV 13),

or 95% Eff (MERV 14)

Filter Type

(Quantity) Size

M2-026

2” Pleated - 30% Eff, MERV 8

(4) 16” x 20” (8) 20” x 20”

4” Pleated - 30% Eff (MERV 8), 65% Eff

(MERV 11), 85% Eff (MERV 13),

or 95% Eff (MERV 14)

12” Cartridge - 65% Eff (MERV 11),

85% Eff (MERV 13),

or 95% Eff (MERV 14)

Filter Type

(Quantity) Size

M2-032

M2-036

2” Pleated - 30% Eff, MERV 8

(6) 16” x 20” and

(9) 20” x 20”

4” Pleated - 30% Eff (MERV 8), 65% Eff

(MERV 11), 85% Eff (MERV 13),

or 95% Eff (MERV 14)

12” Cartridge - 65% Eff (MERV 11),

85% Eff (MERV 13),

or 95% Eff (MERV 14)

Table 23 - M2-018 and M2-022 Filters

Table 24 - M2-026 Filters

Table 25 - M2-032 and M2-036 Filters

Figure 50 - Filter Layout

(Viewed from the Upstream Side of the Cooling Coil)

*M2-032 and M2-036 are designed with a face load filter rack.

Water

Containing

Concentration

(mg/l or ppm)

Time Limits -

Analyze Before

AISI

316

SMO

254

Copper

Alloy

Nickel

Alloy

Alkalinity

(HCO

)

< 70

Within 24 Hours

+ + 0 + 70-300

+ + + + > 300

+ + 0/+

Sulfate (SO

)

< 70

No Limit

+ + + + 70-300

+ + 0/- + > 300

0 0 -

HCO

/ SO

> 1.0

No Limit

+ + + + < 1.0

+ + 0/-

Electrical

Conductivity

< 10µS/cm

No Limit

+ + 0 + 10-500 µS/cm

+ + + + > 500 µS/cm

+ + 0

< 6.0

Within 24 Hours

0 0 0 + 6.0-7.5

0/+ + 0 + 7.5-9.0

+ + + + > 9.0

+ + 0

Ammonium

(NH

)

< 2

Within 24 Hours

+ + + + 2-20

+ + 0 + > 20

+ + -

Chlorides (Cl-)*

< 300

No Limit

+ + + + > 300

0 + 0/+

Free Chlorine

(Cl2)

< 1

Within 5 Hours

+ + + + 1-5

+ + 0

> 5

0/+ + 0/-

Hydrogen

Sulfide (H2S)

< 0.05

No Limit

+ + + + > 0.05

+ + 0/-

Free (aggressive)

Carbon Dioxide

(CO

< 5

No Limit

+ + + + 5-20

+ + 0 + > 20

+ + -

Appendix A - Heat Exchanger Corrosion Resistance

Corrosion Resistance of Copper and Stainless Steel in Brazed Plate Heat Exchangers

- Points to Measure and Check in a Water Analysis

The resistance guide provides the corrosion resistance of stainless steel type AISI 316 and pure Copper (99.9%) in water, to a number of important chemical factors. The actual corrosion is a very complex process influenced by many different factors in combination.

Explanations: + Good resistance under normal conditions 0 Corrosion problems may occur especially when more factors are valued 0

- Use is not recommended

*See Chloride Content Table

Water

Containing

Concentration

(mg/l or ppm)

Time Limits -

Analyze Before

AISI

316

SMO

254

Copper

Alloy

Nickel

Alloy

Total Hardness

(°dH)

4.0-8.5

No Limit

+ + +

Nitrate (NO3)

< 100

No Limit

+ + + + > 100

+ + 0

Iron (Fe)

< 0.2

No Limit

+ + + + > 0.2

+ + 0

Aluminum (Al)

< 0.2

No Limit

+ + + + > 0.2

+ + 0

Manganese (Mn)

< 0.1

No Limit

+ + + + > 0.1

+ + 0

Chloride Content

Maximum Temperature

60°C (140°F)

80°C (176°F)

120°C (248°F)

130°C (266°F)

= 10 ppm

SS 304

SS 316

= 25 ppm

SS 304

SS 316

= 50 ppm

SS 304

SS 316

Ti / SMO 254

= 80 ppm

SS 316

Ti / SMO 254

= 150 ppm

SS 316

Ti / SMO 254

= 300 ppm

SS 316

Ti / SMO 254

> 300 ppm

Ti / SMO 254

Chloride Content

100

Aaon M2-005 Installation Manual

Specifications and Main Features

Frequently Asked Questions

User Manual