AER Benchmark BMK 2500 User manual

Benchmark 2500 - 3000 Boilers
Installation, Operation & Maintenance Manual (IOMM)
OMM-0094_0F AERCO International, Inc. •100 Oritani Dr. •Blauvelt, NY 10913 Page 1of 207
GF-137 Ph.: 800-526-0288 09/30/2015
USER MANUAL
Installation, Operation and Maintenance
BENCHMARK
2500 / 3000
Gas-Fired Boilers
Natural Gas Modulating
& Condensing Hot Water
Boiler Models:
•BMK 2500
•BMK 3000
Applicable to Serial Numbers:
G-15-2700 and Above
Latest Update: 09/30/2015

Benchmark 2500 - 3000 Boilers
Installation, Operation & Maintenance Manual (IOMM)
Page 2of 207 AERCO International, Inc. •100 Oritani Dr. •Blauvelt, NY 10913 OMM-0094_0F
09/30/2015 Ph.: 800-526-0288 GF-137
AERCO Technical Support:
(Mon–Fri, 8am-5pm EST)
1 [phone]
www.aerco.com
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, nor for incidental or
consequential damages occurring in connection with the furnishing, performance, or use of these
materials.

Benchmark 2500 - 3000 Boilers
Installation, Operation & Maintenance Manual (IOMM)
OMM-0094_0F AERCO International, Inc. •100 Oritani Dr. •Blauvelt, NY 10913 Page 3of 207
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TABLE OF CONTENTS
FOREWORD 7
CHAPTER 1. SAFETY PRECAUTIONS .........................................................................................11
1.1 WARNINGS & CAUTIONS ...................................................................................................................11
1.2 EMERGENCY SHUTDOWN.................................................................................................................12
1.3 PROLONGED SHUTDOWN.................................................................................................................12
CHAPTER 2. INSTALLATION ........................................................................................................15
2.1 INTRODUCTION...................................................................................................................................15
2.2 RECEIVING THE UNIT.........................................................................................................................15
2.3 UNPACKING.........................................................................................................................................15
2.4 SITE PREPARATION ...........................................................................................................................16
2.4.1 Installation Clearances....................................................................................................................................16
2.4.2 Setting the Unit...............................................................................................................................................17
2.5 SUPPLY AND RETURN PIPING..........................................................................................................18
2.6 PRESSURE RELIEF VALVE INSTALLATION .....................................................................................19
2.7 CONDENSATE DRAIN & PIPING ........................................................................................................20
2.8 GAS SUPPLY PIPING..........................................................................................................................22
2.8.1 Gas Supply Specifications ...............................................................................................................................22
2.8.2 Manual Gas Shutoff Valve ..............................................................................................................................22
2.8.3 External Gas Supply Regulator........................................................................................................................22
2.9 AC ELECTRICAL POWER WIRING.....................................................................................................24
2.9.1 Electrical Power Requirements.......................................................................................................................25
2.10 FIELD CONTROL WIRING.................................................................................................................26
2.10.1 OUTDOOR AIR IN Terminal ...........................................................................................................................27
2.10.2 AIR TEMP SENSOR Terminals........................................................................................................................27
2.10.3 O2SENSOR Terminals....................................................................................................................................28
2.10.4 SPARK SIGNAL Terminals ..............................................................................................................................28
2.10.5 ANALOG IN Terminals...................................................................................................................................28
2.10.6 VALVE FEEDBACK Terminals .........................................................................................................................28
2.10.7 SHIELD Terminals ..........................................................................................................................................29
2.10.8 ANALOG OUT Terminals ...............................................................................................................................29
2.10.9 RS485 Comm Terminals................................................................................................................................29
2.10.10 RS232 Comm Terminals..............................................................................................................................29
2.10.11 VFD/BLOWER Terminals .............................................................................................................................29
2.10.12 Interlock Terminals .....................................................................................................................................29
2.10.13 FAULT RELAY Terminals ..............................................................................................................................30
2.10.14 Aux.Relay Terminals ...................................................................................................................................30
2.11 FLUE GAS VENT INSTALLATION.....................................................................................................30
2.12 COMBUSTION AIR.............................................................................................................................31
2.13 DUCTED COMBUSTION AIR.............................................................................................................31
2.14 SEQUENCING ISOLATION VALVE INSTALLATION........................................................................32
CHAPTER 3. OPERATION ..............................................................................................................35
3.1 INTRODUCTION...................................................................................................................................35
3.2 CONTROL PANEL DESCRIPTION......................................................................................................35
3.3 CONTROL PANEL MENUS..................................................................................................................39
3.3.1 Menu Processing Procedure...........................................................................................................................39
3.4 OPERATING MENU .............................................................................................................................41
3.5 SETUP MENU.......................................................................................................................................41

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3.6 CONFIGURATION MENU ....................................................................................................................42
3.7 TUNING MENU.....................................................................................................................................44
3.8 COMBUSTION CAL MENU..................................................................................................................45
3.9 BST (BOILER SEQUENCING TECHNOLOGY) MENU .......................................................................45
3.10 START SEQUENCE...........................................................................................................................48
3.11 START/STOP LEVELS.......................................................................................................................52
CHAPTER 4. INITIAL START-UP..................................................................................................53
4.1 INITIAL START-UP REQUIREMENTS.................................................................................................53
4.2 TOOLS AND INSTRUMENTATION FOR COMBUSTION CALIBRATION ..........................................53
4.2.1 Required Tools & Instrumentation .................................................................................................................54
4.2.2 Installing Gas Supply Manometer...................................................................................................................54
4.2.3 Accessing the Analyzer Probe Port .................................................................................................................56
4.3 NATURAL GAS COMBUSTION CALIBRATION..................................................................................56
4.3.1 Benchmark 2500 Combustion Calibration ......................................................................................................57
4.3.2 Benchmark 3000 Combustion Calibration ......................................................................................................60
4.4 REASSEMBLY......................................................................................................................................62
4.5 OVER-TEMPERATURE LIMIT SWITCHES.........................................................................................63
4.5.1 Over-Temperature Alarm Switch Checks and Adjustments ...........................................................................63
CHAPTER 5. MODE OF OPERATION...........................................................................................65
5.1 INTRODUCTION...................................................................................................................................65
5.2 INDOOR/OUTDOOR RESET MODE ...................................................................................................65
5.2.1 Reset Ratio......................................................................................................................................................65
5.2.2 Building Reference Temperature....................................................................................................................65
5.2.3 Outdoor Air Temperature Sensor Installation ................................................................................................65
5.2.4 Indoor/Outdoor Startup .................................................................................................................................66
5.3 CONSTANT SETPOINT MODE ...........................................................................................................66
5.3.1 Setting the Setpoint ........................................................................................................................................67
5.4 REMOTE SETPOINT MODES .............................................................................................................67
5.4.1 Remote Setpoint Field Wiring.........................................................................................................................68
5.4.2 Remote Setpoint Startup ................................................................................................................................68
5.5 DIRECT DRIVE MODES.......................................................................................................................68
5.5.1 Direct Drive Field Wiring.................................................................................................................................69
5.5.2 Direct Drive Startup ........................................................................................................................................69
5.6 AERCO CONTROL SYSTEM (ACS)....................................................................................................70
5.6.1 ACS External Field Wiring................................................................................................................................70
5.6.2 ACS Setup and Startup....................................................................................................................................70
5.7 COMBINATION CONTROL SYSTEM (CCS).......................................................................................71
5.7.1 Combination Control System Field Wiring......................................................................................................72
5.7.2 Combination Control System Setup and Startup............................................................................................72
CHAPTER 6. SAFETY DEVICE TESTING.....................................................................................73
6.1 TESTING OF SAFETY DEVICES.........................................................................................................73
6.2 LOW GAS PRESSURE FAULT TEST..................................................................................................74
6.3 HIGH GAS PRESSURE TEST .............................................................................................................75
6.4 LOW WATER LEVEL FAULT TEST.....................................................................................................77
6.5 WATER TEMPERATURE FAULT TEST..............................................................................................78
6.6 INTERLOCK TESTS.............................................................................................................................79
6.6.1 Remote Interlock Test.....................................................................................................................................79
6.6.2 Delayed Interlock Test ....................................................................................................................................79
6.7 FLAME FAULT TESTS.........................................................................................................................80

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6.8 AIR FLOW FAULT TESTS....................................................................................................................82
6.8.1 Blower Proof Switch Test................................................................................................................................82
6.8.2 Blocked Inlet Switch Test................................................................................................................................82
6.9 SSOV PROOF OF CLOSURE SWITCH...............................................................................................84
6.10 PURGE SWITCH OPEN DURING PURGE........................................................................................85
6.11 IGNITION SWITCH OPEN DURING IGNITION .................................................................................86
6.12 SAFETY PRESSURE RELIEF VALVE TEST.....................................................................................87
CHAPTER 7. MAINTENANCE.........................................................................................................89
7.1 MAINTENANCE SCHEDULE ...............................................................................................................89
7.2 IGNITER-INJECTOR ............................................................................................................................90
7.3 FLAME DETECTOR .............................................................................................................................92
7.4 O2SENSOR93
7.5 SAFETY DEVICE TESTING.................................................................................................................93
7.6 BURNER ASSEMBLY INSPECTION ...................................................................................................94
7.7 CONDENSATE DRAIN TRAP ..............................................................................................................97
7.8 AIR FILTER CLEANING & REPLACEMENT........................................................................................98
7.9 WATER CUTOFF (LWCO) CAPACITOR INTEGRITY TEST...............................................................99
7.9.1 Low Water Cutoff (LWCO) - Capacitor Electrical Short Test ...........................................................................99
7.9.2 Low Water Cutoff (LWCO) - Standard C-More Test ......................................................................................101
7.10 SHUTTING THE BOILER DOWN FOR AN EXTENDED PERIOD OF TIME...................................101
7.11 PLACING THE BOILER BACK IN SERVICE AFTER A PROLONGED SHUTDOWN.....................102
7.12 SPARK MONITOR (AC CURRENT TRANSDUCER).......................................................................102
CHAPTER 8. TROUBLESHOOTING GUIDE............................................................................. 105
8.1 INTRODUCTION.................................................................................................................................105
8.2 ADDITIONAL FAULTS WITHOUT SPECIFIC FAULT MESSAGES ..................................................117
CHAPTER 9. BOILER SEQUENCING TECHNOLOGY............................................................. 121
9.1 INTRODUCTION.................................................................................................................................121
9.1.1 Installation Notes..........................................................................................................................................122
9.2 AERCO BST QUICK START CHART.................................................................................................123
9.3 BST IMPLEMENTATION INSTRUCTION ..........................................................................................124
9.3.1 Option 1 - Constant Setpoint with DIRECT Wired Header Sensor ................................................................124
9.3.2 Option 2 - Constant Setpoint with MODBUS Wired Header Sensor.............................................................125
9.3.3 Option 3 - Outdoor Reset with DIRECT WIRED Header Sensor AND DIRECT WIRED Outdoor Sensor .........126
9.3.4 Option 4 - Outdoor Reset with MODBUS Header Sensor AND MODBUS Outdoor Sensor...........................128
9.3.5 Option 5 - Remote Setpoint with DIRECT WIRED Header Sensor AND 4-20ma Setpoint Drive ...................130
9.3.6 Option 6 - Remote Setpoint with DIRECT WIRED Header Sensor AND MODBUS Setpoint Drive.................132
9.3.7 Option 7 - Remote Setpoint with MODBUS Header Sensor AND 4-20ma Setpoint Drive ............................133
9.3.8 Option 8 - Remote Setpoint with MODBUS Header Sensor AND MODBUS Setpoint Drive .........................135
APPENDIX A: BOILER MENU ITEM DESCRIPTIONS ............................................................. 137
TABLE A-1: OPERATING MENU ITEM DESCRIPTIONS .......................................................................137
TABLE A-2: SETUP MENU ITEM DESCRIPTIONS.................................................................................138
TABLE A-3: CONFIGURATION MENU ITEM DESCRIPTIONS ..............................................................139
TABLE A-4: TUNING MENU ITEM DESCRIPTIONS...............................................................................142
TABLE A-5: COMBUSTION CALIBRATION MENU ITEM DESCRIPTIONS...........................................143
APPENDIX B: STARTUP, STATUS & DISPLAY MESSAGES .................................................. 145
APPENDIX C: SENSOR RESISTANCE/VOLTAGE CHART...................................................... 149
APPENDIX D: RECOMMENDED PERIODIC TESTING ............................................................ 151
APPENDIX E: INDOOR/OUTDOOR RESET RATIO CHARTS ............................................... 153

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APPENDIX F: DIMENSIONAL DRAWING.................................................................................. 157
APPENDIX G: CLEARANCE DRAWINGS .................................................................................... 158
APPENDIX H: PARTS LIST DRAWINGS..................................................................................... 159
APPENDIX I: C-MORE WIRING DIAGRAMS............................................................................ 171
APPENDIX J: PIPING DRAWINGS .............................................................................................. 191
APPENDIX K: C-MORE CONTROL PANEL VIEWS................................................................... 199
APPENDIX L: RECOMMENDED SPARES................................................................................... 201
APPENDIX M: KOREAN GAS TRAINS.......................................................................................... 203

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FOREWORD
The AERCO Benchmark (BMK) 2500 and 3000 Boilers are modulating and condensing units.
They represent a true industry advance that meets the needs of today's energy and
environmental concerns. Designed for application in any closed loop hydronic system, the
Benchmark's modulating capability relates energy input directly to fluctuating system loads. The
turn down ratios for these boilers is 15:1. These BMK models provide extremely high efficiency
operation and are ideally suited for modern low temperature, as well as, conventional heating
systems.
The Benchmark Model BMK 2500 and BMK 3000 operate within the following input and output
ranges:
Benchmark
Model Input Range (BTU/hr.) Output Range (BTU/hr.)
Minimum
Maximum
Minimum
Maximum
BMK 2500 167,000 (48.9 kW) 2,500,000 (732 kW) 144,000 (42.2 kW) 2,150,000 (630 kW)
BMK 3000 200,000 (58.6 kW) 3,000,000 (879 kW) 186,000 (54.5 kW) 2,790,000 (818 kW)
The output of the boiler is a function of the unit’s firing rate (valve position) and return water
temperature.
When installed and operated in accordance with this Instruction Manual, these boilers comply
with the NOx emission standards outlined in:
South Coast Air Quality Management District (SCAQMD), Rule 1146.2
Whether used in singular or modular arrangements, the BMK 2500 and BMK 3000 offer the
maximum venting flexibility with minimum installation space requirements. These Boilers are
Category II, III and IV, positive pressure appliances. Single and/or multiple breeched units are
capable of operation in the following vent configurations:
Conventional, Vertical
Conventional, Sidewall
Conventional, Direct Vent, Vertical
Sealed, Direct Vent, Horizontal
These boilers are capable of being vented utilizing Polypropylene and AL29-4C vent systems.
The Benchmark's advanced electronics are available in several selectable modes of operation
offering the most efficient operating methods and energy management system integration.
IMPORTANT
Unless otherwise specified, all descriptions and procedures provided in this
Installation, Operation & Maintenance Manual apply to the Benchmark
series of boiler.

Benchmark 2500 - 3000 Boilers
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Phrases, Abbreviations, and Acronyms
Phrase, Abbreviation or
Acronym
Meaning
A (Amp) Ampere
ACS
AERCO Control System, AERCO’s boiler management systems
ADDR Address
AGND Analog Ground
ALRM Alarm
ANSI
American National Standards Institute,
ASME American Society of Mechanical Engineers
AUX Auxiliary
BAS Building Automation System, often
used interchangeably with EMS (see
below)
Baud Rate Symbol rate, or simply the number of distinct symbol changes (signaling
events) transmitted per second. It is not equal to bits per second, unless
each symbol is 1 bit long.
BMK (Benchmark) AERCO’s Benchmark series boilers
BMS or BMS II AERCO Boiler Management Systems
BLDG (Bldg) Building
BST AERCO on-board Boiler Sequencing Technology
BTU British Thermal Unit. A unit of energy approximately equal to the heat
required to raise 1 pound (0.45 kg) of water 1°F (0.55 °C)
BTU/HR
BTUs per Hour (1 BTU/hr = 0.29 W)
CCP
Combination Control Panel
CCS Combination Control System
C-More Controller
(or Control Box)
A control system developed by AERCO and currently used in all Benchmark,
Innovation and KC1000 Series product lines.
CFH Cubic Feet per Hour (1 CFH = 0.028 m
3
/hr)
CO
Carbon Monoxide
COMM (Comm) Communication
Cal. Calibration
CNTL
Control
CPU Central Processing Unit
DBB Double Block and Bleed, a gas trains containing 2 Safety Shutoff Valves
(SSOVs) and a solenoid operated vent valve.
DIP Dual In-Line Package, a type of switch
ECU Electronic Control Unit (O2 sensor)
EMS
Energy Management System; often used interchangeably with BAS
FM Factory Mutual. Used to define boiler gas trains.
GF-xxxx Gas Fired (an AERCO document numbering system)
GND Ground
HDR
Header

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Phrase, Abbreviation or
Acronym
Meaning
Hex Hexadecimal Number (0 – 9, A – F)
HP Horse Power
HX
Heat Exchanger
Hz Hertz (Cycles Per Second)
I.D. Inside Diameter
IGN Ignition
IGST Board Ignition/Stepper Board, contained in C-More Control Box
INTLK (INTL’K) Interlock
I/O Input/Output
I/O Box Input/Output (I/O) Box currently used on Benchmark, Innovation and KC1000
Series products
IP
Internet Protocol
ISO International Organization for Standardization
Lbs. Pounds
LED Light Emitting Diode
LN
Low Nitrogen Oxide
MA (mA) Milliampere (1 thousand
th
of an ampere)
MAX (Max) Maximum
MBH
1000 BTUs per Hour
MIN (Min) Minimum
Modbus® A serial, half-duplex data transmission protocol developed by AEG Modicon
NC (N.C.) Normally Closed
NO (N.O.) Normally Open
NOx
Nitrogen Oxide
NPT National Pipe Thread
O
2
Oxygen
O.D. Outside Diameter
OMM & O&M
Operation and Maintenance Manual
OnAER
AERCO’s on-line remote monitoring system
PCB Printed Circuit Board
PMC Board
Primary Micro-Controller (PMC) board, contained in the C-More
P/N Part Number
POC
Proof of Closure
PPM Parts per Million
PSI Pounds per Square Inch (1 PSI = 6.89 kPa)
PTP
Point-to-Point (usually over RS232 networks)
P&T Pressure and Temperature
ProtoNode Hardware interface between BAS and a boiler or water heater
PVC Poly Vinyl Chloride, a common synthetic plastic
PWM Pulse Width Modulation
REF (Ref) Reference

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Phrase, Abbreviation or
Acronym
Meaning
RES. Resistive
RS232
(or EIA-232)
A standard for serial, full-duplex (FDX) transmission of data based on the
RS232 Standard
RS422
(or EIA-422) A standard for serial, full-duplex (FDX) transmission of data based on the RS422 Standard
RS485
(or EIA-485)
A standard for serial, half-duplex (HDX) transmission of data based on the
RS485 Standard
RTN (Rtn)
Return
SETPT (Setpt) Setpoint Temperature
SHLD (Shld) Shield
SPDT Single Pole Double Throw, a type of switch
SSOV
Safety Shut Off Valve
TEMP (Temp) Temperature
Terminating Resistor A resistor placed at each end of a daisy-chain or multi-drop network in order
to prevent reflections that may cause invalid data in the communication
Tip-N-Tell A device that indicates if a package was tipped during shipping
UL
A business that tests and validates products
VAC
Volts, Alternating Current
VDC Volts, Direct Current
VFD Vacuum Fluorescent Display, also Variable Frequency Drive
W
Watt
W.C. Water Column, a unit of pressure (1 W.C. = 249 Pa)
µA Micro amp (1 million
th
of an ampere)

Benchmark 2500 - 3000 Boilers
CHAPTER 1 – SAFETY PRECAUTIONS
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CHAPTER 1. SAFETY PRECAUTIONS
1.1 WARNINGS & CAUTIONS
Installers and operating personnel MUST, at all times, observe all safety regulations. The
following warnings and cautions are general and must be given the same attention as specific
precautions included in these instructions. 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.
See pages 13 and 14 for important information regarding installation of units within the
Commonwealth of Massachusetts.
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!
Do not use matches, candles, flames, or other sources of ignition to check
for gas leaks.
WARNING!
Fluids under pressure may cause injury to personnel or damage to
equipment when released. Be sure to shut off all incoming and outgoing
water shutoff valves. Carefully decrease all trapped pressures to zero
before performing maintenance.
WARNING!
Before attempting to perform any maintenance on the unit, shut off all gas
and electrical inputs to the unit.
WARNING!
The exhaust vent pipe of the unit operates under a positive pressure and
therefore must be completely sealed to prevent leakage of combustion
products into living spaces.
WARNING!
Electrical voltages up to 480 VAC may be used in this equipment.
Therefore the cover on the unit’s power box (located behind the front panel
door) must be installed at all times, except during maintenance and
servicing.

Benchmark 2500 - 3000 Boilers
CHAPTER 1 – SAFETY PRECAUTIONS
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WARNING!
A three-pole switch must be installed on the electrical supply line of the
unit. The switch must be installed in an easily accessible position to quickly
and safely disconnect electrical service. Do not affix switch to unit sheet
metal enclosures.
CAUTION
Many soaps used for gas pipe leak testing are corrosive to metals. The
piping must be rinsed thoroughly with clean water after leak checks have
been completed.
CAUTION
DO NOT use this boiler if any part has been under water. Call a qualified
service technician to inspect and replace any part that has been under
water.
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
1.3 PROLONGED SHUTDOWN
After prolonged shutdown, it is recommended that the startup procedures in Chapter 4 and the
safety device test procedures in Chapter 6 of this manual be performed, to verify all system-
operating parameters. If there is an emergency, turn off the electrical power supply to the
AERCO boiler and close the manual gas valve located upstream the unit. The installer must
identify the emergency shut-off device.
MANUAL GAS SHUT-OFF VALVE
VALVE OPEN VALVE CLOSED

Benchmark 2500 - 3000 Boilers
CHAPTER 1 – SAFETY PRECAUTIONS
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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
following requirements extracted from 248 CMR 5.08 (2):
(a) For all side wall horizontally vented gas fueled equipment installed in every dwelling,
building or structure used in whole or in part for residential purposes, including those owned or
operated by the Commonwealth and where the side wall exhaust vent termination is less than
seven (7) feet above finished grade in the area of the venting, including but not limited to decks
and porches, the following requirements shall be satisfied:
1. INSTALLATION OF CARBON MONOXIDE DETECTORS. At the time of installation of
the side wall horizontal vented gas fueled equipment, the installing plumber or gasfitter shall
observe that a hard wired carbon monoxide detector with an alarm and battery back-up is
installed on the floor level where the gas equipment is to be installed. In addition, the
installing plumber or gasfitter shall observe that a battery operated or hard wired carbon
monoxide detector with an alarm is installed on each additional level of the dwelling, building
or structure served by the side wall horizontal vented gas fueled equipment. It shall be the
responsibility of the property owner to secure the services of qualified licensed professionals
for the installation of hard wired carbon monoxide detectors.
a. In the event that the side wall horizontally vented gas fueled equipment is installed in a
crawl space or an attic, the hard wired carbon monoxide detector with alarm and battery
back-up may be installed on the next adjacent floor level.
b. In the event that the requirements of this subdivision can not be met at the time of
completion of installation, the owner shall have a period of thirty (30) days to comply with
the above requirements; provided, however, that during said thirty (30) day period, a
battery operated carbon monoxide detector with an alarm shall be installed.
2. APPROVED CARBON MONOXIDE DETECTORS. Each carbon monoxide detector as
required in accordance with the above provisions shall comply with NFPA 720 and be
ANSI/UL 2034 listed and IAS certified.
3. SIGNAGE. A metal or plastic identification plate shall be permanently mounted to the
exterior of the building at a minimum height of eight (8) feet above grade directly in line with
the exhaust vent terminal for the horizontally vented gas fueled heating appliance or
equipment. The sign shall read, in print size no less than one-half (1/2) inch in size, "GAS
VENT DIRECTLY BELOW. KEEP CLEAR OF ALL OBSTRUCTIONS".
4. INSPECTION. The state or local gas inspector of the side wall horizontally vented gas
fueled equipment shall not approve the installation unless, upon inspection, the inspector
observes carbon monoxide detectors and signage installed in accordance with the
provisions of 248 CMR 5.08(2)(a)1 through 4.
(b) EXEMPTIONS: The following equipment is exempt from 248 CMR 5.08(2)(a)1 through 4:

Benchmark 2500 - 3000 Boilers
CHAPTER 1 – SAFETY PRECAUTIONS
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1. The equipment listed in Chapter 10 entitled "Equipment Not Required To Be Vented" in
the most current edition of NFPA 54 as adopted by the Board; and
2. Product Approved side wall horizontally vented gas fueled equipment installed in a room
or structure separate from the dwelling, building or structure used in whole or in part for
residential purposes.
(c) MANUFACTURER REQUIREMENTS - GAS EQUIPMENT VENTING SYSTEM
PROVIDED. When the manufacturer of Product Approved side wall horizontally vented gas
equipment provides a venting system design or venting system components with the equipment,
the instructions provided by the manufacturer for installation of the equipment and the venting
system shall include:
1. Detailed instructions for the installation of the venting system design or the venting
system components; and
2. A complete parts list for the venting system design or venting system.
(d) MANUFACTURER REQUIREMENTS - GAS EQUIPMENT VENTING SYSTEM NOT
PROVIDED. When the manufacturer of a Product Approved side wall horizontally vented gas
fueled equipment does not provide the parts for venting the flue gases, but identifies "special
venting systems", the following requirements shall be satisfied by the manufacturer:
1. The referenced "special venting system" instructions shall be included with the appliance
or equipment installation instructions; and
2. The "special venting systems" shall be Product Approved by the Board, and the
instructions for that system shall include a parts list and detailed installation instructions.
(e) A copy of all installation instructions for all Product Approved side wall horizontally vented
gas fueled equipment, all venting instructions, all parts lists for venting instructions, and/or all
venting design instructions shall remain with the appliance or equipment at the completion of the
installation.
____________________________________________________________________________
[End of Extracted Information From 248 CMR 5.08 (2)]

Benchmark 2500 - 3000 Boilers
CHAPTER 2 – INSTALLATION
OMM-0094_0F AERCO International, Inc. •100 Oritani Dr. •Blauvelt, NY 10913 Page 15 of 207
GF-137 Ph.: 800-526-0288 09/30/2015
CHAPTER 2. INSTALLATION
2.1 INTRODUCTION
This Chapter provides the descriptions and procedures necessary to unpack, inspect and install
the AERCO Benchmark Boiler Models BMK 2500 and BMK 3000.
2.2 RECEIVING THE UNIT
Each Benchmark Boiler System is shipped as a single crated unit. The shipping weight for these
BMK models is approximately 2200 pounds (1000 kg). The unit must be moved with the proper
rigging equipment for safety and to avoid equipment damage. The unit should be completely
inspected for evidence of shipping damage and shipment completeness at the time of receipt
from the carrier and before the bill of lading is signed.
NOTE
AERCO is not responsible for lost or damaged freight. Each unit
has a Tip-N-Tell indicator on the outside of the crate. This
indicates if the unit has been turned on its side during shipment. If
the Tip-N-Tell indicator is tripped, do not sign for the shipment.
Note the information on the carrier’s paperwork and request a
freight claim and inspection by a claims adjuster before
proceeding. Any other visual damage to the packaging materials
should also be made clear to the delivering carrier.
2.3 UNPACKING
Carefully unpack the unit taking care not to damage the unit enclosure when cutting away
packaging materials
After unpacking, a close inspection of the unit should be made to ensure that there is no
evidence of damage not indicated by the Tip-N-Tell indicator. The freight carrier should be
notified immediately if any damage is detected.
The following accessories come standard with each unit and are either packed separately within
the unit’s shipping container or are factory installed on the unit:
•Pressure/Temperature Gauge
•ASME Pressure Relief Valve
•Condensate Drain Trap (P/N 24441)
•2” Gas Supply Shutoff Valve
When optional accessories are ordered, they may be packed within the unit’s shipping
container, factory installed on the unit, or packed and shipped in a separate container. Any
standard or optional accessories shipped loose should be identified and stored in a safe place
until ready for installation or use.

Benchmark 2500 - 3000 Boilers
CHAPTER 2 – INSTALLATION
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2.4 SITE PREPARATION
Ensure that the site selected for installation of the Benchmark 2500/3000 Boiler includes:
•Access to AC Input Power at 208 VAC, Three-Phase, 60 Hz @ 10 Amps OR 460 VAC,
Three-Phase, 60 Hz @ 5 Amps
•Access to Natural Gas line at a minimum pressure of 8 inches W.C. (1993 Pa) at gas
flow:
oBMK 2500 – 2,500,000 BTU/hr. (732 kW) energy input
oBMK 3000 – 3,000,000 BTU/hr. (879 kW) energy input
2.4.1 Installation Clearances
The Benchmark Model 2500 and 3000 are packaged in an enclosure having identical exterior
dimensions. The unit must be installed with the prescribed clearances for service as shown in
Figure 2-1a. The minimum clearance dimensions, required by AERCO, are listed below.
However, if Local Building Codes require additional clearances, these codes shall supersede
AERCO’s requirements. Minimum acceptable clearances required are as follows:
•Sides: 24 inches (61 cm)
•Front: 24 inches (61 cm)
•Rear: 24 inches (61 cm)
•Top: 18 inches (45.7 cm)
All gas piping, water piping and electrical conduit or cable must be arranged so that they do not
interfere with the removal of any panels, or inhibit service or maintenance of the unit.
Figure 2-1a: Benchmark Boiler Model 2500 Clearances
NOTE
Ensure that
condensate
assembly is not
located over the
housekeeping pad.
Housekeeping Pad.
FRONT
REAR

Benchmark 2500 - 3000 Boilers
CHAPTER 2 – INSTALLATION
OMM-0094_0F AERCO International, Inc. •100 Oritani Dr. •Blauvelt, NY 10913 Page 17 of 207
GF-137 Ph.: 800-526-0288 09/30/2015
WARNING!
Keep the unit area clear and free from all combustible materials and
flammable vapors or liquids.
CAUTION
While packaged in the shipping container, the unit must be moved by pallet
jack or forklift from the FRONT ONLY.
FOR MASSACHUSSETTS ONLY:
For Massachusetts installations, the unit must be installed by a plumber or
gas-fitter licensed within the Commonwealth of Massachusetts. In addition,
the installation must comply with all requirements specified in Chapter 1
Safety Precautions.
2.4.2 Setting the Unit
The unit must be installed on a concrete housekeeping pad, a minimum of 4 inches (10.2 cm)
and a maximum of 8 inches (20.3 cm) thick, to ensure proper condensate drainage. If
anchoring the unit, refer to Figure 2-1b for anchor locations.
NOTES:
1) ALL HOLES ARE FLUSH WITH THE BOTTOM SURFACE OF THE FRAME
2) ALL DIMENSIONS SHOWN ARE IN INCHES [MILLIMETERS]
Figure 2-1b: Benchmark 2500/3000 Anchor Bolt Locations
A total of 3 lifting lugs are provided at the top of the primary heat exchanger as shown in Figure
2-2. Remove the front top panel from the unit to provide access to the lifting tabs.
Remove the four (4) lag screws securing the unit to the shipping skid. Lift the unit off the
shipping skid and position it on the 4 inch to 8 inch (10.2 cm to 20.3 cm)concrete
housekeeping pad (required) in the desired location.
FRONT
REAR

Benchmark 2500 - 3000 Boilers
CHAPTER 2 – INSTALLATION
Page 18 of 207 AERCO International, Inc. •100 Oritani Dr. •Blauvelt, NY 10913 OMM-0094_0F
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WARNING!
When lifting or moving the boiler, DO NOT manipulate the boiler using
the gas train or blower.
Figure 2-2: Boiler Lifting Provisions
In multiple unit installations, it is important to plan the position of each unit in advance. Sufficient
space for piping connections and future service/maintenance requirements must also be taken
into consideration. All piping must include ample provisions for expansion.
2.5 SUPPLY AND RETURN PIPING
All Benchmark 2500 and 3000 units have one 4” (10.2 cm) 150# flanges for the water INLET
(supply) and one 4” (10.2 cm) 150# flanges for the hot water OUTLET (return) piping
connections. Some units have an optional second 4” (10.2 cm) 150# flange for the water INLET,
as shown in Figure 2-3.
The physical location of the supply and return piping connections on the rear of the unit are
shown in Figure 2-3.
LIFTING LUGS
(3 POSITIONS)
2” GAS INLET

Benchmark 2500 - 3000 Boilers
CHAPTER 2 – INSTALLATION
OMM-0094_0F AERCO International, Inc. •100 Oritani Dr. •Blauvelt, NY 10913 Page 19 of 207
GF-137 Ph.: 800-526-0288 09/30/2015
Figure 2-3: Supply and Return Locations
The optional dual inlet connections on the Benchmark 2500 and 3000 allow these units to be
configured with a separate cooler return temperature zone, rather than blending high and low
return temperature zones. Utilizing the dual return capability of these boilers can take further
advantage of the condensing capabilities of these models. When configured with a lower return
temperature zone or AERCO SmartPlates, thermal efficiency can improve by up to 10%.
If your unit includes the secondary inlet, pipe the warmer return water to the secondary (upper)
inlet and the cooler return water to the primary (lower) inlet. Contact your AERCO
representative for additional information.
2.6 PRESSURE RELIEF VALVE INSTALLATION
An ASME rated Pressure Relief Valve is supplied with each Benchmark Boiler. The pressure
rating for the relief valve must be specified on the sales order. Available pressure ratings range
from 30 psi to 160 psi (207 to 1103 kPa). The relief valve is installed on the hot water outlet of
the boiler as shown in Figure 2-4. A suitable pipe joint compound should be used on the
threaded connections. Any excess should be wiped off to avoid getting any joint compound into
the valve body. The relief valve must be piped to within 12 inches (30.5 cm) of the floor to
prevent injury in the event of a discharge. No valves, restrictions, or other blockages are
allowed in the discharge line. In multiple unit installations the discharge lines must not be
manifolded together. Each must be individually run to a suitable discharge location.
HOT WATER OUTLET
(SUPPLY)
EXHAUST
MANIFOLD
CONDENSATE
DRAIN
AIR INLET
PRIMARY WATER INLET
(COOLER WATER RETURN)
DRAIN VALVE
OPTIONAL SECONDARY
WATER INLET
(WARMER WATER RETURN)

Benchmark 2500 - 3000 Boilers
CHAPTER 2 – INSTALLATION
Page 20 of 207 AERCO International, Inc. •100 Oritani Dr. •Blauvelt, NY 10913 OMM-0094_0F
09/30/2015 Ph.: 800-526-0288 GF-137
Figure 2-4: P&T Relief Valve Location
2.7 CONDENSATE DRAIN & PIPING
The Benchmark Boiler is designed to condense water vapor from the flue products. Therefore,
the installation must have provisions for suitable condensate drainage or collection.
The condensate drain port located on the exhaust manifold (Figure 2-5) must be connected to
the condensate trap (P/N 24441) which is packed separately within the unit’s shipping container.
The condensate trap inlet features two integral O-rings and a thumbscrew to allow direct
connection of the drain port into the trap inlet. See the Condensate trap Installation instructions
and Figure 2-6 on the next page.
Figure 2-5: Condensate Drain Connection Location
A sample condensate trap installation is shown in Figure 2-6. The following general guidelines
must be observed to ensure proper condensate drainage:
•The condensate trap inlet (Figure 2-6) must be level the exhaust manifold drain port.
•The base of the condensate trap must be supported to ensure that it is level (horizontal).
•The trap must be removable for routine maintenance.
PRESSURE
RELIEF VALVE
4” HOT BOILER
WATER OUTLET
AIR INLET
PRIMARY
WATER INLET
DRAIN VALVE
CONDENSATE DRAIN PORT
1/4” ANALYZER
NPT PORT
EXHAST
MANIFOLD