Watts Aerco TAG-0072 GF-146-E Manual

Disclaimer
The information contained in this manual is subject to change without notice
from AERCO International, Inc. AERCO makes no warranty of any kind with
respect to this material, including, but not limited to, implied warranties of
merchantability and fitness for a particular application. AERCO International is
not liable for errors appearing in this manual, not for incidental or consequential
damages occurring in connection with the furnishing, performance, or use of
these materials
Operation & Maintenance Manual
AM Series
Natural Gas and Propane Gas Modulating
Condensing Boilers and Water Heaters
© 2019 AERCO
Other documents for this product include:
TAG-0072 GF-146-E Electrical Power Guide
TAG-0073 GF-146-G Gas Supply Guide
TAG-0074 GF-146-P Piping Application Guide
TAG-0075 GF-146-V Venting Guide
Applies to serial numbers:
From 18170091 and up.
OMM-0100_0F•GF-146 •11/15/2019

AM Series Boiler & Water Heater User Manual
TABLE OF CONTENTS
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Table of Contents
FOREWORD .......................................................................................................................6
SECTION 1: GENERAL INFORMATION ..............................................................................7
1.1 WARNINGS & CAUTIONS............................................................................................................................7
1.2 EMERGENCY SHUTDOWN.......................................................................................................................10
SECTION 2: FUNCTIONAL OVERVIEW ............................................................................11
2.1 INTRODUCTION.........................................................................................................................................11
2.1.1 AM Water Heaters and Boilers.............................................................................................................................. 11
2.1.2 AM Rapid Recovery (AMR) Skid Option................................................................................................................. 11
2.2 INTENDED USE –BOILERS......................................................................................................................12
2.3 INTENDED USE –WATER HEATERS.......................................................................................................12
2.4 INTENDED USE –WATER HEATERS AND BOILERS WITH AMR OPTION...........................................12
2.5 AM SERIES FUNCTIONAL SCHEMATICS ................................................................................................13
2.5.1 AM 399 / 500 Functional Schematic...................................................................................................................... 13
2.5.2 AM 750 Functional Schematic ............................................................................................................................... 14
2.5.3 AM 1000 Functional Schematic ............................................................................................................................. 15
2.5.4 AMR Functional Schematic.................................................................................................................................... 16
2.6 MAIN COMPONENTS.................................................................................................................................17
2.6.1 Burner.................................................................................................................................................................... 17
2.6.2 AM Series 199 and 250 Main Components ........................................................................................................... 19
2.6.3 AM Series 399 and 500 Main Components ........................................................................................................... 22
2.6.4 AM Series 750 and 1000 Main Components ......................................................................................................... 25
SECTION 3: INSTALLATION –SITE.................................................................................29
3.1 CHOOSING THE INSTALLATION LOCATION...........................................................................................29
3.2 BOILER AND WATER HEATER INSTALLATION LOCATION FACTORS.................................................30
3.3 SAFETY CONCERNS.................................................................................................................................31
3.4 CLOSET AND ALCOVE INSTALLATION ...................................................................................................31
3.5 CLEARANCES FOR INSTALLATION AND SERVICING ...........................................................................31
3.6 CLEARANCES TO COMBUSTIBLE MATERIAL ........................................................................................32
3.7 VENT AND COMBUSTION AIR PIPING.....................................................................................................33
3.8 PREVENTION OF COMBUSTION AIR CONTAMINATION .......................................................................33
3.9 TRANSPORTING THE UNIT ......................................................................................................................33
3.10 UNPACKING AND TRANSPORTING.......................................................................................................33
3.10.1 Transporting a Standard AM Unit........................................................................................................................ 34
3.10.2 Transporting an AMR Water Heater.................................................................................................................... 36
3.11 AMR BUFFER TANK INSTALLATION......................................................................................................37
3.11.1 AMR Buffer Tank Installation Kits........................................................................................................................ 37
3.12 AMR BUFFER TANK COMPONENTS......................................................................................................38
3.13 BUFFER TANK INSTALLATION OVERVIEW ..........................................................................................38
3.14 REMOVING THE AMR BRACING PLATE................................................................................................39
3.15 AMR 80-GALLON BUFFER TANK INSTALLATION.................................................................................39
3.16 AMR 119-GALLON BUFFER TANK INSTALLATION...............................................................................41
3.17 AM SERIES SUPPLY AND RETURN PIPING DIMENSIONS..................................................................43
3.17.1 Standard AM Supply and Return Piping Dimensions........................................................................................... 43
3.17.2 AMR Supply and Return Piping Dimensions ........................................................................................................ 44
SECTION 4: INSTALLATION –PIPING.............................................................................45
4.1 WATER INLET AND OUTLET PIPING .......................................................................................................45
4.2 WATER QUALITY .......................................................................................................................................45
4.3 SYSTEM PIPING METHODS - BOILERS...................................................................................................45

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4.4 FREEZE PROTECTION..............................................................................................................................46
4.5 FLOOR RADIANT HEATING SYSTEMS - BOILERS.................................................................................46
4.6 PIPING COMPONENTS - BOILERS...........................................................................................................46
4.7 PIPING COMPONENTS –WATER HEATERS...........................................................................................47
4.8 SAFETY RELIEF VALVE ............................................................................................................................48
4.9 LOW WATER CUTOFF (LWCO).................................................................................................................49
4.10 EXPANSION TANK AND MAKEUP WATER............................................................................................50
4.11 CIRCULATOR HEATING PUMP...............................................................................................................50
4.12 DOMESTIC HOT WATER SYSTEM PIPING WITH DIRECT WATER HEATER: WATER HEATERS....52
4.13 SCALDING –WATER HEATERS.............................................................................................................53
4.14 CONDENSATE DISPOSAL.......................................................................................................................55
SECTION 5: INSTALLATION –ELECTRICAL ...................................................................57
5.1 ELECTRICAL CONNECTIONS –BOILERS AND WATER HEATERS......................................................57
5.1.1 Power Supply Cable Connection - Boilers and Water Heaters .............................................................................. 57
5.1.2 Connecting Units in Cascade - Boilers and Water Heaters .................................................................................. 58
5.1.3 0-10 VDC Input Connections - Boilers and Water Heaters .................................................................................... 58
5.1.4 MODBUS Interface Connections –Boilers and Water Heaters ............................................................................. 59
5.2 ELECTRICAL CONNECTIONS –BOILERS ONLY....................................................................................60
5.2.1 Enable/Disable - Boilers......................................................................................................................................... 60
5.2.2 Installing the Outdoor Temperature Sensor - Boilers............................................................................................ 60
5.2.3 Indirect Water Heater Connection - Boilers .......................................................................................................... 61
5.2.4 Indirect Water Heater Priority Selection - Boilers ................................................................................................. 61
5.3 ELECTRICAL CONNECTIONS –WATER HEATERS ONLY.....................................................................62
5.3.1 Storage Tank Connection - Water Heaters ............................................................................................................ 62
5.4 AMR RAPID RECOVERY OPTION WIRING..............................................................................................62
SECTION 6: INSTALLATION –VENTING AND COMBUSTION AIR PIPING ......................65
6.1 COMBUSTION AIR CONTAMINATION PREVENTION .............................................................................65
6.2 GENERAL VENTING AND AIR PIPING SYSTEMS...................................................................................66
6.3 MIN/MAX ALLOWABLE COMBUSTION AIR AND VENT PIPING LENGTHS...........................................68
6.4 GENERAL VENTING AND COMBUSTION AIR PIPING INSTALLATION.................................................68
6.5 SPECIFIC VENT INSTALLATIONS ............................................................................................................68
6.5.1 Installations Requiring High Temperature Venting ............................................................................................... 69
6.5.2 Sealing of PVC, CPVC or ABS .................................................................................................................................. 70
6.5.3 PVC/CPVC Vent Piping Materials ........................................................................................................................... 70
6.5.4 Air Intake and Vent Starter Pieces......................................................................................................................... 71
6.5.5 Single Pipe Venting (Room Air Combustion) ......................................................................................................... 72
6.5.6 Determining Vent Termination Location............................................................................................................... 73
6.5.7 Sidewall Termination - Two pipes ......................................................................................................................... 74
6.5.8 Combustion Air and Ventilation Openings ............................................................................................................ 75
6.5.9 Two Permanent Openings Method ....................................................................................................................... 75
6.5.10 One Permanent Opening Method ....................................................................................................................... 75
6.5.11 Installing Vent and Air Piping into Sidewall ......................................................................................................... 75
6.5.12 Sidewall Termination and Fittings ....................................................................................................................... 76
6.5.13 Multiple Vent and Air Terminations .................................................................................................................... 76
6.5.14 Sidewall Termination –Concentric Vent ............................................................................................................. 77
6.5.15 Sidewall Termination Installation ........................................................................................................................ 78
6.5.16 Multi-venting Sidewall Terminations .................................................................................................................. 79
6.5.17 Determining Location of Vertical Termination .................................................................................................... 80
6.5.18 Vertical Vent and Air Roof Termination Preparation .......................................................................................... 81
6.5.19 Installing Vertical Vent and Air Roof Terminations ............................................................................................. 81
6.5.20 Installing Multiple Vent and Air Vertical Terminations ..................................................................................... 82
6.5.21 Vertical Termination –Concentric Vent .............................................................................................................. 83
6.5.22 Determining Location of Vertical Concentric Vent Termination ......................................................................... 83

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6.5.23 Multi-VentingVerticalTerminations .................................................................................................................. 83
SECTION 7: INSTALLATION –NATURAL GAS ................................................................85
7.1 GAS SUPPLY PIPING.................................................................................................................................85
7.2 CONNECTION OF GAS SUPPLY PIPING .................................................................................................85
7.3 NATURAL GAS PIPE SIZING.....................................................................................................................87
7.4 NATURAL GAS SUPPLY PRESSURE REQUIREMENTS.........................................................................87
7.5 PROPANE GAS PIPE SIZING....................................................................................................................87
7.6 PROPANE GAS SUPPLY PRESSURE REQUIREMENTS........................................................................87
7.7 CHECKING AND ADJUSTING THE UNIT INLET GAS SUPPLY PRESSURE..........................................88
7.8 HIGH ALTITUDE OPERATION...................................................................................................................88
7.9 CONVERSION FROM NATURAL GAS TO PROPANE GAS.....................................................................88
7.9.1 Gas Conversion Kit................................................................................................................................................. 88
7.9.2 Gas Conversion Instructions .................................................................................................................................. 89
SECTION 8: UNIT START-UP...........................................................................................93
8.1 INITIAL START-UP REQUIREMENTS .......................................................................................................93
8.1.1 Filling the Condensate Neutralizer ........................................................................................................................ 93
8.1.2 Filling the Heating System ..................................................................................................................................... 94
8.2 GENERAL WARNINGS CONCERNING THE GAS SUPPLY.....................................................................94
8.2.1 Confirming the Unit’s Gas Type ............................................................................................................................. 95
8.2.2 Gas Type Conversion ............................................................................................................................................. 95
8.3 IDENTIFICATION OF CONTROLS.............................................................................................................96
8.4 BOILER STARTUP PROCEDURE..............................................................................................................96
8.5 WATER HEATER STARTUP PROCEDURE..............................................................................................97
8.6 GAS SUPPLY PRESSURE TEST...............................................................................................................98
8.7 COMBUSTION CALIBRATION.................................................................................................................100
8.8 LOST IGNITION PROCEDURE................................................................................................................101
8.9 MINIMUM WATER FLOW.........................................................................................................................101
8.10 HEATING SYSTEM PRESSURE TEST..................................................................................................102
SECTION 9: OPERATION ...............................................................................................103
9.1 GENERAL OPERATION...........................................................................................................................103
9.2 FREEZE PROTECTION............................................................................................................................104
9.3 DISPLAY ENERGY SAVING MODE.........................................................................................................104
9.4 CONTROL PANEL DISPLAY....................................................................................................................104
9.5 STARTUP PROCEDURE - BOILERS.......................................................................................................105
9.6 BOILER SUMMER MODE.........................................................................................................................105
9.7 ADJUSTING THE DOMESTIC HOT WATER TEMPERATURE - BOILERS............................................106
9.8 HEATING SYSTEM TEMPERATURE ADJUSTMENT - BOILERS..........................................................106
9.9 HEATING SYSTEM TYPE SELECTION - BOILERS................................................................................106
9.10 OUTDOOR RESET ADJUSTMENT - BOILERS.....................................................................................106
9.10.1 Outdoor Reset: Setting Parameters .................................................................................................................. 107
9.10.2 Outdoor Reset Activation .................................................................................................................................. 107
9.11 BOILER DELAYS, ALARMS AND PROTECTIVE ACTIONS .................................................................108
9.12 BOILER CIRCULATOR PUMP PROTECTION.......................................................................................108
9.13 STARTUP PROCEDURE - WATER HEATERS .....................................................................................108
9.14 ADJUSTING THE STORAGE TANK TEMPERATURE (WATER HEATERS)........................................109
9.15 USER MENU...........................................................................................................................................110
9.16 INSTALLER MENU .................................................................................................................................111
9.17 FACTORY MENU....................................................................................................................................113
9.18 DIAGNOSTICS –DISPLAY MESSAGES ...............................................................................................117
9.19 DIAGNOSTICS –LOCKOUT (LOC) ERRORS.......................................................................................117

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9.20 DIAGNOSTICS –BLOCKING (ERR) ERRORS......................................................................................119
9.21 BLOCKED FLUE PRESSURE SWITCH.................................................................................................121
9.22 UNIT SHUT-DOWN.................................................................................................................................122
SECTION 10: MAINTENANCE..........................................................................................124
10.1 CHECKING FOR GAS LEAKS................................................................................................................125
10.2 FLUE AND AIR INLET PIPING INSPECTION........................................................................................125
10.3 SYSTEM PIPING, PRESSURE, AND EXPANSION TANK INSPECTION.............................................125
10.4 IGNITION AND FLAME SENSOR INSPECTION....................................................................................125
10.5 WIRING AND CONNECTIONS INSPECTION........................................................................................125
10.6 PERFORMANCE VERIFICATION INSPECTION...................................................................................125
10.7 FLAME INSPECTION..............................................................................................................................125
10.8 FLAME SIGNAL INSPECTION ...............................................................................................................126
10.9 RELIEF VALVE INSPECTION ................................................................................................................126
10.10 UNIT VICINITY INSPECTION...............................................................................................................126
10.11 PRESSURE GAUGE INSPECTION......................................................................................................126
10.12 CONDENSATE DRAIN SYSTEM INSPECTION ..................................................................................127
10.13 LOW WATER CUTOFF TEST...............................................................................................................127
10.14 REMOVING THE UNIT COVERS.........................................................................................................128
10.15 CLEANING THE BURNER AND PRIMARY HEAT EXCHANGER (FLUE/GAS SIDE)........................129
10.16 INSPECTING AND REPLACING THE HEAT EXCHANGER THERMAL INSULATION.......................133
10.17 INSPECTING AND REPLACING THE BURNER THERMAL INSULATION.........................................134
10.18 CHECKING FOR GAS LEAKS AFTER REASSEMBLY........................................................................136
10.19 IGNITION AND FLAME DETECTION SENSOR ELECTRODE POSITIONING...................................137
10.20 AIR FILTER CLEANING........................................................................................................................138
10.21 CONDENSATE TRAP AND NEUTRALIZING RESERVOIR MAINTENANCE.....................................139
10.22 CONTROL BOARD REPLACEMENT...................................................................................................141
10.23 DRAINING THE WATER FROM THE UNIT .........................................................................................142
10.24 WATER AND FLUE TEMPERATURE SENSOR..................................................................................142
10.25 OUTDOOR TEMPERATURE SENSOR (BOILERS ONLY)..................................................................143
10.26 AM RAPID RECOVERY (AMR) OPTION MAINTENANCE ..................................................................143
10.26.1 Components and Piping .................................................................................................................................. 144
10.26.2 Buffer Tank Anode Rods .................................................................................................................................. 144
10.27 MAINTENANCE KITS PART LISTS......................................................................................................145
10.27.1 Wiring Diagram................................................................................................................................................ 146
SECTION 11: TECHNICAL DATA .....................................................................................153
SECTION 12: SPARE PARTS DRAWINGS & LISTS ..........................................................155
12.1 AM 399/500 SPARE PARTS DRAWINGS..............................................................................................155
12.2 AM 399/500 SPARE PARTS LIST ..........................................................................................................158
12.3 AM 750/1000 SPARE PARTS DRAWINGS............................................................................................161
12.4 AM 750/1000 SPARE PARTS LIST ........................................................................................................164
12.5 AMR OPTION SPARE PARTS DRAWING.............................................................................................167
12.6 AM RAPID RECOVERY (AMR) OPTION SPARE PARTS LIST.............................................................168
APPENDIX A: CONTROL PANEL OPERATION CHART .....................................................169

AM Series Boiler & Water Heater User Manual
FORWARD
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FOREWORD
The Advanced Modular (AM) Series represents the latest in high efficiency, condensing boiler
and water heater technology. The AM Series has a unique modular design that provides
exceptional reliability, serviceability, and fuel savings from 399 to 1000 MBTU. Each unit is
comprised of between two and four independent thermal modules firing up to 250 MBTU each at
5:1 individual turndown. This allows for superior temperature control and low-cycling operation.
This unique design provides the multiple boiler redundancy required in a boiler plant, but in a
single unit installation with one set of water connections, one gas connection, and one vent
connection. When needed, multiple units are easily co-located to provide a boiler plant with
the highest efficiency, turndown, and redundancy in the smallest footprint. Multiple units are
sequenced through the AERCO AM Cascade Manager. Each unit is equipped for Modbus
communication to a BAS. High efficiencies and low vent temperatures mean the unit can be
vented in PVC, CPVC, Polypropylene, and AL29-4C vent materials. The front-access design also
means the unit is very simple to maintain and service.
Features:
• High Efficiency Condensing Boiler/Water Heater
• Natural Gas or Propane
• Superior Turndown 8:1 to 20:1 (depending on unit)
• Low NOx Emission <20ppm
• Direct or Conventional Vent with PVC, CPVC, Polypropylene, or AL29-4C materials
• Concentric Vent Capability
• Common Vent Capability
• Side wall common venting with no additional check valve
• Small, Doorway-Size Footprint
• Superior Reliability
• Minimal Maintenance
• Easy Front Access for Serviceability
• Zero Side Clearance
• Supports Integration to BAS System
• Modbus Communication Standard
• Integrated isolation valves, flow meters, and condensate neutralizer

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SECTION 1: GENERAL INFORMATION
1.1 Warnings & Cautions
In addition to all the requirements included in this AERCO Instruction Manual, the installation of
units MUST conform with local building codes, or, in the absence of local codes, ANSI Z223.1
(National Fuel Gas Code Publication No. NFPA-54) for gas-fired boilers and ANSI/NFPASB for
LP gas-fired boilers. Where applicable, the equipment shall be installed in accordance with the
current Installation Code for Gas Burning Appliances and Equipment, CSA B149.1, and
applicable Provincial regulations for the class; which should be carefully followed in all cases.
Authorities having jurisdiction should be consulted before installations are made.
IMPORTANT!
This Instruction Manual is an integral part of the product and must be maintained in legible
condition. It must be given to the user by the installer and kept in a safe place for future
reference.
WARNING!
Failure to comply with provisions, warnings, and cautions provided in this manual can lead to
extensive property damage and/or personal injury or death.
In the event of a breakdown and/or malfunction of the boiler, turn off the unit and do not make
any attempt to repair it. The boiler must be serviced exclusively by a Qualified installer using
original spare parts. Failure to comply with this requirement may compromise the safety of the
unit.
WARNING!
Installer: Read all instructions including this manual, before installing. Perform steps in the
order given.
User: The installation and maintenance sections of this manual are for use only by a
qualified heating installer. Refer to Chapter 9: Operation for user information.
Installation and Alterations: Only a Qualified installer must carry out the installation
and calibration of the boiler. Never modify the boiler or its components in any way.
Overheating: Should overheating occur or the gas supply fail; to shut off, do not turn off or
disconnect electrical supply to circulator. Instead, turn off the manual gas shut-off valve
external to the appliance.
Water Contamination: Do not use this appliance if any part has been under water.
Immediately call a licensed authorized technician to inspect the appliance and to replace any
part of the control system and any gas control, which has been under water.
Ensure the boiler and its controls are protected from dripping or spraying water during normal
operation or service.
Spare Parts: Only use the boiler with the accessories and spares listed in this manual.
Failure to do so can cause equipment damage or dangerous conditions.

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NOTE:
When calling or writing about the boiler, have the unit model and serial number as seen on
the unit rating plate.
CAUTION!
Do not use petroleum-based cleaning or sealing compounds in the boiler system. Gaskets
and seals in the system may be damaged. This can result in substantial property damage.
The manufacturer declines all liability, contractual or otherwise (warranty included), for any
damage to people, animals property or this same appliance, caused by:
•Incorrect installation or failure to comply with this or any other instruction provided by the
manufacturer;
•Failure to comply with the applicable local and/or national regulations in force.
•Incorrect use of this appliance.
•Inadequate or incorrect service
•Inadequate or incorrect maintenance.

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OFF.
OFF.

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1.2 Emergency Shutdown
If overheating occurs or the gas supply fails to shut off, close the manual gas shutoff valve
(Figure 1-1) located external to the unit.
NOTE:
The Installer must identify and indicate the location of the emergency shutdown manual gas
valve to operating personnel.
Figure 1-1: Manual Gas Shutoff Valve
IMPORTANT: FOR MASSACHUSETTS INSTALLATIONS:
Boiler Installations within the Commonwealth of Massachusetts must conform to the following
requirements:
•Boiler must be installed by a plumber or a gas fitter who is licensed within the
Commonwealth of Massachusetts.
•Prior to unit operation, the complete gas train and all connections must be leak tested using
a non-corrosive soap.
•The vent termination must be located a minimum of 4 feet above grade level. If side-wall
venting is used, the installation must conform to the requirements in 248 CMR 5.08 (2).
•Must be installed according to all local codes.

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CHAPTER 2: FUNCTIONAL OVERVIEW
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SECTION 2: FUNCTIONAL OVERVIEW
2.1 INTRODUCTION
2.1.1 AM Water Heaters and Boilers
Figure 2-1 shows the exterior appearance of the AM Series of boilers and water heaters. The
AM Series comes in four functionally sized models; the 399, 500, 750, and 1000. Boilers are
appended with a B (i.e. AM 1000B), and water heaters with a W (i.e. AM 1000W).
Figure 2-1: AM Boiler or Water Heater (AM 399/500 Left, AM 750/ AM 1000 Right)
2.1.2 AM Rapid Recovery (AMR) Skid Option
Figure 2-2 shows the AMR option, comprised of an AM water heater, thermal buffer tank, low
water cutoff (LWCO), recirculation loop piping, and recirculation loop pump.
Figure 2-2: AM Water Heater with Rapid Recovery Option (AM 1000RS Shown)
AM SERIES WATER HEATER
(AM750 OR AM1000)
RECIRCULATION LOOP PUMP
RECIRCULATION LOOP PIPING
HOT WATER OUTLET
AM 750 / 1000
AM 399 / AM 500
CONTROL
PANEL
THERMAL BUFFER TANK
COLD WATER INLET
SAFETY RELIEF VALVE

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2.2 Intended Use –Boilers
The gas-fired condensing AM Series boilers are designed to be used in central heating
systems. Any other use is prohibited.
Heat is always guaranteed for the production of domestic hot water since it is given priority
over space heating demands. Follow the specific procedure in Section 9.7 for boiler
adjustment for domestic hot water temperature. This boiler can be connected to an indirect
storage tank for the production of domestic hot water (Section 4.10).
This unit can be installed with a direct venting system or with a one pipe vent system and
draw combustion air from the room.
The quality of the system water is very important. Poor water quality can damage
heating systems and boilers due to scale formation and corrosion.
A heating system can be configured to function at a temperature range of between 68°F (20°C)
and 180°F (82°C).
The AM Series boiler can be connected to a room On/Off control (Section 5.2.1).
An outdoor air temperature sensor must also be connected to the boiler for an outdoor reset
supply temperature control for maximum fuel efficiency and comfort. For further information on
the outdoor-air reset, refer to Section 9.10.
2.3 Intended Use –Water Heaters
The gas fired condensing AM Series water heaters are designed to be used for domestic hot
water production. Any other use is prohibited.
The water heaters must be connected to a storage tank for the production of domestic hot
water. When connecting the water heater to the storage water heater, the installer must
consider the head loss of the water heater (see figure 4-4), the head loss of the piping system
and the head loss of the storage water heater to size adequate pumps.
This unit can be installed with a direct venting system or with a one pipe vent system and draw
combustion air from the room.
The quality of the system water is very important. Poor water quality can damage heating
systems and boilers due to scale formation and corrosion.
2.4 Intended Use –Water Heaters and Boilers with AMR Option
This option is available for AERCO AM Series water heaters and boilers. All functional
descriptions that apply to AM water heaters and boilers apply to the AMR option, except where
specifically noted.
The AMR option reduces thermal loss by using a pump to efficiently recirculate a mix of building
recirculated water (if used on site), fresh potable water, and water in the lower portion of the
tank for heating in the heat exchanger. A functional diagram may be found at the end of this
chapter.

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2.5 AM Series Functional Schematics
2.5.1 AM 399 / 500 Functional Schematic
Figure 2-3: 399 / 500 (Boiler & Water Heater) Functional Schematic

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2.5.2 AM 750 Functional Schematic
Figure 2-4: 750 (Boiler & Water Heater) Functional Schematic

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2.5.3 AM 1000 Functional Schematic
Figure 2-5: AM 1000 (Boiler & Water Heater) Functional Schematic

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2.5.4 AMR Functional Schematic
Figure 2-6: AMR Function Diagram (Buffer Tank Transparent for Clarity
MIXED BUILDING RECIRCULATION
AND MAKEUP WATER RETURN
TANK OUTLET TO
RECIRCULATION
LOOP
HOT WATER OUTLET
AM HEAT
EXCHANGER
INLET (FROM
WATER RETURN
AND TANK)
GAS INLET
AMR
RECIRCULATION
LOOP PIPING
HOT WATER OUTLET
(FROM AM HEAT
EXCHANGER TO
BUFFER TANK)
TANK INLET FROM
HEAT EXCHANGER
AM SERIES
WATER HEATER
BUFFER TANK
RECIRCULATION
LOOP PUMP
= Warm Tank Water
= Cold Return Water
= Hot Water
LWCO (LOW
WATER CUT-OFF)
= Tank and Cold Return Water

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2.6 Main Components
2.6.1 Burner
Figure 2-7: Burner Main Components

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Figure 2-8: Burner Main Components

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2.6.2 AM Series 199 and 250 Main Components
Figure 2-9: AM Series 199 and 250 Main Components

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Figure 2-10: AM Series 199 and 250 Main Components