AERCO BMK 2.0 LN Natural Gas User Manual
Benchmark 2.0LN Boiler GF-123
USER MANUAL
Benchmark 2.0LN Low NOx Boiler
Installation, Operation, and Maintenance
Benchmark 2.0LN
Low NOx Boiler
Installation, Operation & Maintenance Manual OMM-0046_0E
Natural Gas or Propane Fired
Modulating, Condensing,
Forced Draft, Hot Water Boiler
2,000,000 BTU/H Input
Applicable for Serial Numbers:
G-11-1861 and above.
Revised 08/20/2012
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GF-123 Benchma rk 2.0LN Boiler
Technical Support:
www.aerco.com
OMM-0046_0E Installation, Operation & Maintenance Manual
(Mon–Fri, 8am-5pm EST)
1-800-526-0288
The information containe d in this manual is subject to c hange without notice from AERCO Inter national,
Inc. AERCO makes no warranty of any kind with respect to this material, including but not limited to
implied warranties of merchantability and fitness f or a particular application. AE RCO 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 this material.
Disclaimer
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GF-123 Benchma rk 2.0LN Boiler
OMM-0046_0E Installation, Operation & Maintenance Manual
TABLE OF CONTENTS
CHAPTER 1: SAFETY PRECAUTIONS ...................................................................................................... 9
1.1 WARNINGS & CAUTIONS ................................................................................................................. 9
1.2 EMERGENCY SHUTDOWN ............................................................................................................ 10
1.3 PROLONGED SHUTDOWN ............................................................................................................ 10
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 CONDENSATE DRAIN AND PIPING ............................................................................................... 18
2.6.1 Exhaust Manifold Condensate Drain .................................................................................... 19
2.7 GAS SUPPLY PIPIN G ...................................................................................................................... 20
2.7.1 Gas Supply Specifications. ................................................................................................... 21
2.7.2 Manual Gas Shutoff Valve .................................................................................................... 21
2.7.3 External Gas Supply Regulator ............................................................................................. 21
2.7.4 IRI Gas Train Kit .................................................................................................................... 22
2.8 AC ELECTRICAL POWER WIRING ................................................................................................ 22
2.8.1 Electrical Power Requirements ............................................................................................. 22
2.9 MODES OF OPERATION AND FIELD CONTROL WIRING ........................................................... 23
2.9.1 Constant Setpoint Mode ....................................................................................................... 24
2.9.2 Indoor/Outdoor Reset Mode ................................................................................................. 24
2.9.3 Boiler Management System Mode ........................................................................................ 24
2.9.4 Remote Setpoint and Direct Drive Modes ............................................................................ 25
2.9.5 Combination Mode ................................................................................................................ 25
2.10 I/O BOX CONNECTIONS ............................................................................................................... 26
2.10.1 OUTDOOR SENSOR IN (1) .............................................................................................. 26
2.10.2 AIR TEMP. SENSOR (2) ................................................................................................... 27
2.10.3 ANALOG IN (3) .................................................................................................................. 27
2.10.4 B.M.S. (PWM) IN (4) .......................................................................................................... 27
2.10.5 SHIELD (5) ......................................................................................................................... 28
2.10.6 mA OUT (6) ........................................................................................................................ 28
2.10.7 RS-485 COMM (7) ............................................................................................................. 28
2.10.8 TxD, RxD (8) ...................................................................................................................... 28
2.10.9 VFD/BLOWER (9) .............................................................................................................. 28
2.10.10 EXHAUST SWITCH IN (11) ............................................................................................. 28
2.10.11 INTERLOCKS (10, 12) ..................................................................................................... 28
2.10.11.1 REMOTE INTERLOCK IN (10) ................................................................................ 29
2.10.11.2 DELAYED INTERLOCK IN (12) ............................................................................... 29
2.10.12 FAULT RELAY (13) .......................................................................................................... 29
2.10.13 AUXILIARY RELAY CONTACTS (14) .............................................................................. 29
2.11 FLUE GAS VENT INSTALLATION ................................................................................................. 29
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OMM-0046_0E Installation, Operation & Maintenance Manual
2.12 COMBUSTION AIR ........................................................................................................................ 30
2.12.1 Combustion Air From Outside the Building ......................................................................... 30
2.12.2 Combustion Air From Inside The Building .......................................................................... 30
2.12.3 Sealed Combustion ............................................................................................................. 30
2.12.4 Temporary Combustion Air Filtering During Construction .................................................. 30
2.13 BENCHMAR K PUM P R EL A Y OPTION.......................................................................................... 31
CHAPTER 3. CONTROL PANEL OPERATION ................................................................................ 3-33
3.1 INTRODUCTION ........................................................................................................................... 3-33
3.2 CONTROL PANEL DESCRIPTION ............................................................................................... 3-33
3.3 CONTROL PANEL MENUS .......................................................................................................... 3-36
3.3.1 Menu Processing Procedure .............................................................................................. 3-37
3.4 OPERATING MENU ...................................................................................................................... 3-38
3.5 SETUP MENU ............................................................................................................................... 3-39
3.6 CONFIGURATION MENU ............................................................................................................. 3-40
3.7 TUNING MENU ................................................................................................................................ 42
3.8 COMBUSTION CAL MENU .............................................................................................................. 42
3.9 START SEQUENCE ......................................................................................................................... 43
3.10 START/STOP LEVELS .................................................................................................................. 46
CHAPTER 4. INITIAL START-UP......................................................................................................... 49
4.1 INITIAL START-UP REQUIREMENTS ............................................................................................ 49
4.2 TOOLS AND INSTRUMENTATION FOR COMBUSTION CALIBRATION ...................................... 49
4.2.1 Required Tools & Instrumentation ........................................................................................ 50
4.2.2 Installing Gas Supply Manometer ......................................................................................... 50
4.2.3 Accessing the Analyzer Probe Port ...................................................................................... 51
4.3 RSI REGULATOR SAFE TEST ........................................................................................................ 51
4.4 NATURAL GAS COMBUSTION CALIBRATION .............................................................................. 53
4.5 PROPANE COMBUSTION CALIBRATION ..................................................................................... 58
4.6 UNIT REASSEMBLY ........................................................................................................................ 62
4.7 OVER-TEMPERATURE LIMIT SWITCHES ..................................................................................... 62
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 ........................................................................................................ 65
5.3 CONSTANT SETPOINT MODE ....................................................................................................... 66
5.3.1 Setting the Setpoint ............................................................................................................... 66
5.4 REMOTE SETPOINT MODES ......................................................................................................... 67
5.4.1 Remote Setpoint Field Wiring ............................................................................................... 67
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
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OMM-0046_0E Installation, Operation & Maintenance Manual
5.6 BOILER MANAGEMENT SYSTEM (BMS)....................................................................................... 69
5.6.1 BMS External Field Wiring .................................................................................................... 70
5.6.2 BMS Setup and Startup ........................................................................................................ 70
5.7 COMBINATION CONTROL SYSTEM (CCS) ................................................................................... 70
5.7.1 Combination Control System Field Wiring ............................................................................ 71
5.7.2 Combination Control System Setup and Startup .................................................................. 71
CHAPTER 6. SAFETY DEVICE TESTING ........................................................................................... 73
6.1 TESTING OF SAFETY DEVICES .................................................................................................... 73
6.2 LOW GAS PRESSURE FAULT TEST ............................................................................................. 73
6.3 HIGH GAS PRESSURE TEST ......................................................................................................... 74
6.4 LOW WATER LEVEL FAULT TEST ................................................................................................. 75
6.5 WATER TEMPERATURE FAULT TEST .......................................................................................... 75
6.6 INTERLOCK TESTS......................................................................................................................... 76
6.6.1 REMOTE INTERLOCK ......................................................................................................... 77
6.6.2 DELAYED INTERLOCK ........................................................................................................ 77
6.7 FLAME FAULT TESTS ..................................................................................................................... 77
6.8 AIR FLOW FAULT TESTS ............................................................................................................... 78
6.9 SSOV PROOF OF CLOSURE SWITCH .......................................................................................... 79
6.10 PURGE SWITCH OPEN DURING PURGE ................................................................................... 80
6.11 IGNITION SWITCH OPEN DURING IGNITION ............................................................................. 80
6.12 SAFETY PRESSURE RELIEF VALV E TEST ................................................................................ 81
CHAPTER 7. MAINTENANCE .............................................................................................................. 83
7.1 MAINTENANCE SCHEDULE ........................................................................................................... 83
7.2 IGNITER-INJECTOR ........................................................................................................................ 84
7.3 FLAME DETECTOR ......................................................................................................................... 86
7.4 COMBUSTION CALIBRATION & RSI REGULATOR ADJUSTMENT ............................................. 87
7.4.1 RSI Regulator Pressure ........................................................................................................ 87
7.4.1.1 RSI Regulator Pressure Test ........................................................................................ 87
7.4.1.2 RSI Regulator Calibration .............................................................................................. 88
7.5 SAFETY DEVIC E TESTING ............................................................................................................. 89
7.6 BURNER ASSEMB LY INSPECTION ............................................................................................... 89
7.7 CONDENSATE DRAIN TRAP .......................................................................................................... 92
7.8 SHUTTING THE BOILER DOWN FOR AN EXTENDED PERIOD OF TIME .................................. 93
7.9 PLACING THE BOI LE R BAC K IN SERVICE AFTER A PROLO NG ED SHU T D OWN .................... 93
CHAPTER 8. troubleshooting guide .................................................................................................. 95
8.1 INTRODUCTION ......................................................................................................................... 95
8.2 ADDITIONAL FAULTS WITHOUT SPECIFIC FAULT MESSAGES ........................................ 107
CHAPTER 9.
9.1 INTRODUCTION ............................................................................................................................ 111
9.2 RS232 COMMUNICATION SETUP ............................................................................................... 113
9.3 MENU PROCESSING UTILIZING RS232 COMMUNICATION ..................................................... 113
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RS232 COMMUNICATION ........................................................................................... 111
9.1.1 Aquiring the PuTTY Applic ation .......................................................................................... 111
9.1.2 Logging on to a Remote Machine Using PuTTY ................................................................ 111
9.1.3 Running a Command on a Remote Machine Using PuTTY ............................................... 112
GF-123 Benchma rk 2.0LN Boiler
OMM-0046_0E Installation, Operation & Maintenance Manual
9.4 DATA LOGGING ............................................................................................................................ 114
9.4.1 Fault Log ............................................................................................................................. 114
9.4.2 Operation Time Log ............................................................................................................ 114
9.4.3 Sensor Log .......................................................................................................................... 115
APPENDIX A: MENU ITEM DESCRIPTIONS ........................................................ 117
APPENDIX B: STARTUP, STATUS AND FAULT MESSAGES ............................... 123
APPENDIX C: SENSOR TEMPERATURE RESISTANCE ...................................... 127
APPENDIX D: INDOOR/OUTDOOR RESET RATIO CHART S .............................. 129
APPENDIX E: BOILER DEFAULT SETTINGS ........................................................ 133
APPENDIX F: PART AND DIMENSIONAL DRAWINGS ......................................... 135
APPENDIX G: PIPING DRAWINGS ....................................................................... 149
APPENDIX H: WIRING SCHEMATICS .................................................................. 155
APPENDIX I: RECOMMENDED PERIODI C T ESTI NG CHECK L IST ...................... 161
APPENDIX J: BENCHMARK CONTROL PANEL FEATURES ................................. 163
APPENDIX K: RECOMMENDED SPARE PARTS LISTS ....................................... 165
STANDARD WARRANTY: Benchmark Gas-Fired Hydronic Boiler.......................... 167
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GF-123 Benchma rk 2.0LN Boiler
OMM-0046_0E Installation, Operation & Maintenance Manual Foreword
Foreword
The AERCO Benchmark 2.0 Low NOx (LN) Boiler is a modulating unit. It represents 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 f luctuating system loads. The Benchmark 2.0LN, with
its 20:1 turn down ratio and condensing capability, provides extremely high efficiencies and
makes it ideally suited for modern low temperature, as well as, conventional heating systems.
The boiler operates at inputs ranging from 100,000 BTU/hr. to 2,000,000 BTU/hr. The output of
the boiler is a function of the unit’s firing rate and return water temperature. Output ranges from
99,000 BTU/hr. to 1,933,000 BTU/hr., depending on operating conditions.
When installed and operated on natural gas in accordance with this Instruction Manual, the
Benchmark 2.0LN Boiler complies 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 Benchmark 2.0LN offers the maximum
flexibility in venting with minimum installation space requirements. The Benchmark's advanced
electronics are available in several selectable modes of operation offering the most efficient
operating methods and energy management system integration.
For service or parts, contact your local sales representative or AERCO INTERNATIONAL.
NAME:
ORGANIZATION:
ADDRESS:
TELEPHONE:
INSTALLATION DATE: _____________________________________________
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Benchmark 2.0LN Low NOx Boiler GF-130
Foreword Installation, Operation & Maintenance Manual OMM-0046_0E
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GF-123 Benchmark 2.0LN Low NOx Boil e r Chapter 1
OMM-0046_00E Installation, Operation and Maintenance Manual Safety Precautions
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).
Where ASME CSD-1 is required by local jurisdiction, the installation must conform to CSD-1.
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
WARNINGS MUST BE OBSERVED TO PREVENT SERIOUS INJURY.
WARNING
BEFORE ATTEMPTING TO PER-FORM 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 THERE-FORE MUST BE COMPLETELY
SEALED TO PREVENT LEAKAGE OF COMBUSTION PRODUCTS I NTO
LIVING SPACES.
WARNING
A DOUBLE-POLE SWITCH MUST BE INST ALLED ON T HE ELECTRICAL
SUPPLY LINE OF THE UNIT. T HE SWIT CH MUST BE INSTALLED I N AN
EASILY ACCESSIBLE POSITION TO QUICKLY AND SAFELY DISCONNECT ELECTRICAL SERVICE. DO NOT AFFIX SWITCH TO UNIT
SHEET METAL ENCLOSURES.
WARNING
DO NOT USE MATCHES, CANDLES, FLAMES, OR OTHER SOURCES
OF IGNITION TO CHECK FOR GAS LEAKS.
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Chapter 1 Benchmark 2.0LN Low NOx Boil er GF-123
Safety Precautions Installation, Operation and Maintenance Manual OMM-0046_0E
WARNING
FLUIDS UNDER PRESS URE MAY CAUSE INJURY TO PERSO NNEL 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
ELECTRICAL VOLTAGES UP TO 120 VAC MAY BE USED IN THIS
EQUIPMENT. THEREFO RE 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.
CAUTIONS
Must be observed to prevent equipment damage or loss of
operating effectiveness.
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.
IMPORTANT
The Installer must identify and indicate the location of the
emergency shutdown manual gas valve to operating personnel.
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 systemoperating 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.
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GF-123 Benchmark 2.0LN Low NOx Boil e r Chapter 1
MANUAL GAS SHUTOFF
VALVE
VALVE OPEN
VALVE CLOSED
OMM-0046_00E Installation, Operation and Maintenance Manual Safety Precautions
Figure 1-1: Manual Gas Shutoff Valve
IMPORTANT – FOR MASSACHUSETTS INSTALLATIONS ONLY
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-corros ive s oap .
• If a glycol solution is used as anti-freeze protection, a backflow preventer must be installed
upstream of the Fill/Makeup Valve.
• 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 CARBO N MONOXIDE DETECTORS. At the time of inst allation
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 propert y owner to secure the services of
qualified licensed professionals for the installation of hard wired carbon monoxide
detectors.
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Chapter 1 Benchmark 2.0LN Low NOx Boil er GF-123
Safety Precautions Installation, Operation and Maintenance Manual OMM-0046_0E
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 g as 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:
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 t he manufacturer of a Product Approved side wall horizontally vented gas
fueled equipment does not provide the parts for venting the flue gases, but identifies "s pecial
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
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GF-123 Benchmark 2.0LN Low NOx Boil e r Chapter 1
OMM-0046_00E Installation, Operation and Maintenance Manual Safety Precautions
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 the Product Approved side wall horizontally vented
gas fueled equipment and all the venting instructions, parts lists and/or design instructions for
the venting system shall remain with the appliance or equipment at the completion of the
installation.
_______________ [End of Extracted Information From 248 CMR 5.08 (2)__________________
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Chapter 1 Benchmark 2.0LN Low NOx Boil er GF-123
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GF-123 Benchmark 2.0LN Low NOx Boil e r Chapter 2
OMM-0046_0E Installation, Operation and Maintenance Manual Installation
CHAPTER 2. INSTALLATION
2.1 INTRODUCTION
This Chapter provides the descriptions and procedures necessary to unpack, inspect and install
the AERCO Benchmark 2.0LN Boiler. Brief descriptions are also provided for each available
mode of operation. Detailed procedures for implementing these modes are provided in Chapter
5.
2.2 RECEIVING THE UNIT
Each Benchmark 2.0LN System is shipped as a single crated unit. The shipping weight is
approximately 1600 pounds. 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 fr om 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 damag e 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
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.
IMPORTANT
After unpacking, take off the unit top panel and remove the strap and
packing material at the top of the heat exchanger. The packing material is
located in the area of the igniter-injector and staged ignition solenoid on the
burner assembly.
The following accessories come standard with each unit and are either packed separately within
the unit’s packing container or are factory installed on the boiler:
• Pressure/Temperature Gauge
• Spare Spark Igniter-Injector
• Spare Flame Detector
• ASME Pressure Relief Valve
• Condensate Drain Trap
• 2” Gas Supply Shutoff Valve
When ordered, optional accessories may be packed separately, packed within the boiler
shipping container, or may be installed on the boiler. Any standard or optional accessories
shipped loose should be identified and stored in a safe place until ready for installation or use.
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Chapter 2 Benchmark 2.0LN Low NOx Boiler GF-123
44.5"
18"
79"
101"
4" HIGH PAD*
24"
24"
30"
24"
REAR
FRONT
*(SEE NOTE IN PARAGRAPH 2.4.2)
Installation Installation, Operation and Maintenance Manual OMM-0046_0E
2.4 SITE PREPARATION.
Ensure that the site selected for installation of the Benchmark 2.0LN Boiler includes:
• Access to AC Input Power at 120 VAC, Single-Phase, 60 Hz @ 20A
• Access to Natural Gas or Propane line at a Minimum supply gas pressure of 4" W.C.
(2000 cfh for Natural Gas, 800 cfh for Propane)..
2.4.1 Installation Clearances
The unit must be installed with the prescribed clearances for service as shown in Figure 2-1.
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:
• Sides: 24 inches
• Front : 24 inches
• Rear: 30 inches
• Top: 18 inches
All gas piping, water piping and electrical conduit or cable must be arranged so that t hey do not
interfere with the removal of any panels, or inhibit service or maintenance of the unit.
KEEP THE UNIT AREA CLEAR AND FREE FR OM ALL COMBUST IBLE
Figure 2-1: Benchmark 2.0LN Boiler Clearances
WARNING
MATERIALS AND FLAMMABLE VAPORS OR LIQUIDS.
CAUTION
While packaged in the shipping container, the boiler must be moved by
pallet jack or forklift from the FRONT ONLY.
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GF-123 Benchmark 2.0LN Low NOx Boil e r Chapter 2
LIFTING
TABS (2)
OMM-0046_0E Installation, Operation and Maintenance Manual Installation
FOR MASSACHUSSETTS ONLY:
For Massachusetts installations, the boiler must be installed by a plumber
or gas fitter who is 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 4 inch to 6 inch housekeeping pad to ensure proper condensate
drainage (see NOTE below). If anchoring the unit, refer to the dimensional drawings in Appendix
F for anchor locations. Two lifting tabs are provided at the top of the heat exchanger. Figure 2-2
shows the location of the tab on the top-left side. The second tab is located on the top-right side
of the heat exchanger. USE THESE TWO TABS TO LIFT AND MOVE THE UNIT. Remove the
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 6 inch housekeeping concrete pad (required) in the desired location.
NOTE
When using the AERCO Condensate Neutralizer Tank for proper condensate drainage, the Neutralizer Tank must be stored in a pit, OR the
boiler and AERCO Condensate Trap must be elevated higher than 4”
above the floor. See Condensate Tank instructions in TID-0074 for details.
WARNING
WHEN LIFTING OR MOVING THE BOILER:
• DO NOT MANIPULATE THE BOILER USING THE GAS TRAIN
OR BLOWER
• WHEN USING THE LIFTING TABS, ENSURE THERE IS NO
LOAD PLACED ON THE GAS TRAIN OR BLOWER
Figure 2-2: Partial Top View Showing Lifting Tab Location
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Chapter 2 Benchmark 2.0LN Low NOx Boiler GF-123
2" GAS INLET
CONNECTION
BOILER RETURN
4" – 150# FLANGE
CONNECTION
BOILER SUPPLY
4" – 150# FLANGE
CONNECTION
EXHAUST
MANIFOLD
SHELL
DRAIN
VALVE
REAR VIEW
Installation Installation, Operation and Maintenance Manual OMM-0046_0E
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.
If installing a Combination Control Panel (CCP) system, it is important to identify the
Combination Mode Boilers in advance and place them in the proper physical location. Refer to
Chapter 5 for information on Combination Mode Boilers.
2.5 SUPPLY AND RETURN PIPING
The Benchmark 2.0LN Boiler utilizes 4” 150# flanges for the water system supply and return
piping connections. The physical location of the supply and return piping connections are on the
rear of the unit as shown in Figure 2-3. Refer to Appendix F, Drawing AP-A-798 for addit ional
dimensional data.
2.6 CONDENSATE DRAIN AND PIPING
The Benchmark 2.0LN 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 pipe located on the exhaust manifold (Figure 2-4) must be connected t o a
condensate trap which is packed separately within the unit’s shipping container.
Figure 2-3: Supply and Return Locations
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GF-123 Benchmark 2.0LN Low NOx Boil e r Chapter 2
EXHAUST
MANIFOLD
1/2” NPT
CONDENSATE
DRAIN
CONNECTION
HOUSE-
KEEPING
PAD
BOILER
RETURN
OMM-0046_0E Installation, Operation and Maintenance Manual Installation
The procedure to install and connect the condensate drain is provided in paragraph 2.6.1.
Figure 2-4: Condensate Drain Connection Location
2.6.1 Exhaust Manifold Condensate Drain
NOTE
There are two slightly different types of condensate traps that may be used
in your configuration; an older style without built-in adapter, and a newer
style with a built-in adapter (see Figure 2-5). Installation is the sam e (1/4”
threads are inside built-in adapter on newer style).
A condensate drain trap (part no. 24060) is shipped loose and must be installed at the rear of
the unit. The trap inlet and outlet contain tapped 3/4” NPT ports. The actual installation details
for the condensate trap will depend on the available clearances, housekeeping pad
height/dimensions and other prevailing conditions at the site. However, the following guidelines
must be observed to ensure proper condensate trap operation:
• The condensate trap inlet (Figure 2-5) must be level with, or lower than the exhaust
manifold drain port.
• The condensate trap must be supported to ensure that its base is level (horizontal).
• The trap must be removable for routine maintenance. AERCO recommends that a
union be utilized between the exhaust manifold condensate drain port and the trap
inlet port.
While observing the above guidelines, connect the condensate trap inlet to the exhaust manifold
drain connection using the appropriate piping components (nipples, reducers, elbows, etc.) for
the boiler installation site. Connect as follows:
1. At the condensate trap outlet, install a 3/4” NPT nipple.
2. Connect a length of 1” I.D polypropylene hose to the trap outlet and secure with a hose
clamp.
3. Route the hose on the trap outlet to a nearby floor drain.
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Chapter 2 Benchmark 2.0LN Low NOx Boiler GF-123
Installation Installation, Operation and Maintenance Manual OMM-0046_0E
4. If a floor drain is not available, a condensate pump can be used to remove the condensate
to drain. The maximum condensate flow rate is 20 GPH. The condensate drain trap,
associated fittings and drain line must be removable for routine maintenance.
Figure 2-5: Condensate Trap Installation: Older (left) and Newer (right) Style
2.7 GAS SUPPLY PIPING
The AERCO Benchmark 2.0LN Gas Components and Supply Design Guide, GF-2030 must be
consulted prior to designing or installing any gas supply piping.
WARNING
NEVER USE MATCHES, CANDLES, FLAMES O R OT HER SO URCES OF
IGNITION TO CHECK FOR GAS LEAKS.
WARNING
Many soaps used for gas pipe leak testing are corrosive to metals. Therefore, piping must be rinsed thoroughly with clean water after leak checks
have been completed.
NOTE
All gas piping must be arranged so that it does not interfere with removal of
any covers, inhibit service/maintenance, or restrict access bet ween the unit
and walls, or another unit.
A 2 inch gas inlet connection is located on the rear of the unit as shown in Figure 2-3.
Prior to installation, all pipes should be de-burred and internally cleared of any scale, metal
chips or other foreign particles. Do Not install any flexible connectors or unapproved gas
fittings. Piping must be supported from the floor, ceiling or walls only and must not be supported
by the unit.
A suitable piping compound, approved for use with natural gas, should be used. Any excess
must be wiped off to prevent clogging of components.
To avoid unit damage when pressure testing gas piping, isolate the unit from the gas supply
piping. At no time should the gas pressure applied to the unit exceed 14” W.C. Leak test all
external piping thoroughly using a soap and water solution or suitable equivalent. The gas
piping used must meet all applicable codes.
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GF-123 Benchmark 2.0LN Low NOx Boil e r Chapter 2
GAS
SUPPLY
DIRT
TRAP
2" MANUAL
SHUTOFF
VALVE
GAS PRESS.
REGULATOR
(REQUIRED FOR
MASSACHUSETTS
INSTALLATIONS)
OMM-0046_0E Installation, Operation and Maintenance Manual Installation
2.7.1 Gas Supply Specifications.
The maximum static pressure to the unit must not exceed 14” W.C. The specifications for
natural gas and propane are as follows:
• Natural Gas: T he gas supply pressure to t he unit must be of sufficient capacity to provide
2000 cfh while maintaining the gas pressure at 4.0" W .C. for FM or 5.0" W.C. for IRI gas trains.
• Propane: The gas supply pressure to the unit must be of suff icient capacity to provide 800
cfh while maintaining the gas pressure at 4.0" W.C. for FM or 5.0" W.C. for IRI gas trains.
2.7.2 Manual Gas Shutoff Valve
A manual shut-off valve must be installed in the gas supply line upstream of the Boiler as shown
in Figure 2 -6. Maximum allowable gas pressure to the Boiler is 14” W.C.
NOTE
Paragraph 2.7.3 applies only to boiler installations within the
Commonwealth of Massachusetts.
2.7.3 External Gas Supply Regulator
For Massachusetts installations, a mandatory external gas supply regulator must be positioned
as shown in Figure 2-6. The gas supply regulator must be properly vented to outdoors. Consult
the local gas utility for detailed requirements concerning venting of the supply gas regulator.
NOTE
The external regulator must be capable of regulating 1,500,000 BTU/HR of
natural gas while maintaining a gas pressure of 4.0” W.C. to the boiler.
CAUTION
A lock-up style regulator MUST be used when gas supply pressure will
exceed 14” W.C.
Figure 2-6: Manual Gas Shut-Off Valve Location
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Chapter 2 Benchmark 2.0LN Low NOx Boiler GF-123
UPPER RIGHT CORNER OF FRONT PANEL
TERMINAL BLOCK
Installation Installation, Operation and Maintenance Manual OMM-0046_0E
2.7.4 IRI Gas Train Kit
The IRI gas train is an optional gas train configuration which is required in some areas for code
compliance or for insurance purposes. The IRI gas train is factory pre-piped and wired. See
Appendix F, Drawing AP-A-843 for details.
2.8 AC ELECTRICAL POWER WIRING
The AERCO Benchmark 2.0LN Electrical Power Wiring Guide, GF-2060LN, must be consulted
prior to connecting any AC power wiring to the unit. External AC power connections are made
to the unit inside the Power Box on the front panel of the unit. Remove the front door of the unit
to access the Power Box mounted directly above the Control Box. Loos en the four Power Box
cover screws and remove cover to access the AC terminal connections inside the Power Box
(Figure 2-7).
NOTE
All electrical conduit and hardware must be installed so that it does not
interfere with the removal of any unit covers, inhibit service/maintenance,
or prevent access between the unit and walls or another unit.
Figure 2-7: AC Input Terminal Block Location
2.8.1 Electrical Power Requirements
The AERCO Benchmark 2.0LN Boiler accepts 120 VAC, single-phase, 60 Hz @ 20A. The
Power Box contains a terminal block as shown in Figure 2-8. In addition, a wiring diagram
showing the required AC power connections is provided on the front cover of the Power Box.
Each Boiler must be connected to a dedicated electrical circuit. NO OTHER DEVICES
SHOULD BE ON THE SAME ELECTRICAL CIRCUIT AS THE BOILER.
A double-pole switch must be installed on the electrical supply line in an easily accessible
location to quickly and safely disconnect electrical service. DO NOT attach the switch to sheet
metal enclosures of the unit.
After placing the boiler in service, the ignition safety shutoff device must be test ed. If an exter nal
electrical power source is used, the installed boiler must be electrically bonded to ground in
accordance with the requirements of the authority having jurisdiction. In the absence of such
requirements, the installation shall conform to National Electrical Code (NEC), ANSI/ NFPA 70
and/or the Canadian Electrical Code (CEC) Part I, CSA C22.1 Electrical Code.
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GF-123 Benchmark 2.0LN Low NOx Boil e r Chapter 2
GND
NEU
L1
120 VAC, 1 PHASE
OMM-0046_0E Installation, Operation and Maintenance Manual Installation
For electrical power wiring diagrams, see the AERCO Benchmark 2.0LN Electrical Power Wiring
Guide, (GF-2060LN).
Figure 2-8: AC Terminal Block Configurations
2.9 MODES OF OPERATION AND FIELD CONTROL WIRING
The Benchmark 2.0 Boiler is available in several different modes of operation. W hile each unit
is factory configured and wired for its intended mode, some additional field wiring may be
required to complete the installation. This wiring is typically connected to the Input/Output (I/O)
Box located on the lower portion of the unit front panel (Figure 2-9) behind the removable front
door.
To access the I/O Box terminal strips shown in Figure 2-10, loosen the four cover screws and
remove the cover. All field wiring is installed from the rear of the panel by routing the wires
through one of the four bushings provided.
Refer to the wiring diagram provided on the cover of the I/O Box (Figure 2-10) when making all
wiring connections.
Brief descriptions of each mode of operation, and their wiring requirements, are provided in the
following paragraphs. Additional information concerning field wiring is provided in paragraphs
2.9.1 through 2.9.9. Refer to Chapter 5 for detailed information on the available modes of
operation.
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Chapter 2 Benchmark 2.0LN Low NOx Boiler GF-123
Installation Installation, Operation and Maintenance Manual OMM-0046_0E
Figure 2-9: Input/Output (I/O) Box Location
2.9.1 Constant Setpoint Mode
The Constant Setpoint Mode is used when it is desired to have a fixed setpoint that does not
deviate. No wiring connections, other than AC electrical power connections, are required for
this mode. However, if desired, fault monitoring or enable/disable interlock wiring can be
utilized (see paragraphs 2.9.9.1 and 2.9.10).
2.9.2 Indoor/Outdoor Reset Mode
This mode of operation increases supply water temperature as outdoor temperatures decrease.
An outside air temperature sensor (AERCO Part No. 122790) is requi red. The sensor MUST
BE wired to the I/O Box wiring terminals (see Figure 2-10). Refer to paragraph 2.10.1 for
additional information on outside air temperature sensor installation.
2.9.3 Boiler Management System Mode
NOTE
BMS Model 168 can utilize either pulse width modulation (PWM) or RS485
Modbus signaling to the Boiler. BMS II Model 5R5-384 and the AERCO
Control System (ACS) can utilize only RS485 signaling to the Boiler.
When using an AERCO BMS, BMS II, or ACS (AERCO Control System), the field wiring is
connected between the BMS/BMS II/ACS Panel and each Boiler’s I/O Box terminal strip (Figure
2-10). Twisted shielded pair wire from 18 to 22 AWG must be utilized for the connections. The
BMS Mode can utilize either pulse width modulation (PWM) signaling, or RS485 Modbus
signaling. For PWM signaling, connections are made from the AERCO Boiler Management
System to the B.M.S. (PWM) IN terminals on the I/O Box terminal strip. For RS485 Modus
signaling, connections are made from the BMS/BMS II/ACS to the RS485 COMM terminals on
the I/O Box terminal strip. Polarity must be maintained and the shield must be connected only at
the AERCO BMS/BMS II/ACS. The boiler end of the shield must be left floating.
For additional instructions, refer to Chapter 5, paragraph 5.6 in this manual. Also, refer to GF108M (BMS), GF-124 (BMS II Model 5R5-384), and GF-131 (ACS) operation manuals.
Page 24 of 170 AERCO International Inc.● 100 Oritani Dr. ● Blauvelt, NY 10913. ● Ph: 800-526-0288 PR1 08/20/12
GF-123 Benchmark 2.0LN Low NOx Boil e r Chapter 2
OMM-0046_0E Installation, Operation and Maintenance Manual Installation
2.9.4 Remote Setpoint and Direct Drive Modes
The Benchmark 2.0LN Boiler can accept several types of signal formats from an Energy
Management System (EMS), Building Automation System (BAS) or other source, to control
either the setpoint (Remote Setpoint Mode) or air/fuel valve position (Dir ect Drive Mode) of the
Boiler. These formats are:
• 4 to 20 mA/1 to 5 VDC
• 0 to 20 mA/0 to 5 VDC
• PWM – (Pulse Width Modulated signal. See para. 2.10.4)
• Network (RS485 Modbus. See para. 2.10.7)
While it is possible to control a boiler or boilers using one of the previously described modes of
operation, it may not be the method best suited for the application. Prior t o selecting one of
these modes of operation, it is recommended that you consult with your local AERCO
representative or the factory for the mode of operation that will work best with your application.
For more information on wiring the 4 to 20 mA / 1to 5VDC or the 0 to 20 mA / 0 to 5 VDC, see
paragraph 2.9.3.
2.9.5 Combination Mode
NOTE
Only BMS Model 168 and ACS can be utilized f or the Combination Mode,
not the BMS II (Model 5R5-384).
With a Combination Mode unit, field wiring is between the unit’s I/O Box wiring terminals, the
CCP (Combination Control Panel), and the BMS (Boiler Management System). For ACS
applications, the wiring is between the ACS panel, the ACS Relay panel (optional, depending on
applications), and the RS485 comm terminals in the I/O box. The wiring must be accomplished
using twisted-shielded pair wire from 18 to 22 AWG. Polarity must be maintained. For further
instructions and wiring diagrams, refer to the GF-108 Boiler Management System Operations
Guide and the CCP-1 data sheet (BMS 168 applications)/GF-131 and TAG-0050 (ACS
applications).
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Chapter 2 Benchmark 2.0LN Low NOx Boiler GF-123
Installation Installation, Operation and Maintenance Manual OMM-0046_0E
Figure 2-10. I/O Box Terminal Locations and Functions
2.10 I/O BOX CONNECTIONS
The types of input and output signals and devices to be connected to the I/O Box terminals
shown in Figure 2-10 are described in the following paragraphs.
NOTE
Older I/O PCBs are wired the same as new ones, even if silk-screen
designations differ.
NOTE
DO NOT make any connections to the I/O Box terminals labeled “NOT
USED”. Attempting to do so may cause equipment damage.
2.10.1 OUTDOOR SENSOR IN (1)
An outdoor air temperature sensor (AERCO Part No. 122790) will be required primarily for the
Indoor/Outdoor reset mode of operation. It can also be used with another mode if it is desired to
use the outdoor sensor enable/disable feature. This feature allows the boiler to be enabled or
disabled based on the outdoor air temperature.
The factory default for the outdoor sensor is DISABLED. To enable the sensor and/or select an
enable/disable outdoor temperature, see the Configuration menu in Chapter 3.
The outdoor sensor may be wired up to 200 feet from the boiler. It is connected to the
OUTDOOR SENSOR IN and SENSOR CO MMON ter m inals in the I/O Box (see Fig ur es 2-9 and
2-10). Wire the sensor using a twisted shielded pair wire from 18 to 22 AWG. There is no
polarity to observe when terminating these wires. The shield is to be connected only to the
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GF-123 Benchmark 2.0LN Low NOx Boil e r Chapter 2
OMM-0046_0E Installation, Operation and Maintenance Manual Installation
terminals labeled SHIELD in the I/O Box. The sensor end of the shield must be left free and
ungrounded.
When mounting the sensor, it must be located on the North side of the building where an
average outside air temperature is expected. The sensor must be shielded from direct sunlight
as well as impingement by the elements. If a shield is used, it must allow for free air circulation.
2.10.2 AIR TEMP. SENSOR (2)
The Air Temperature Sensor is connected to the positive (+) and negative (-) term inals of the
AIR TEMP. SENSOR on the I/O board. This sensor measures the temperature of the air input to
the Air/Fuel Valve. This temperature reading is one of the components used to calculate the
rotational speed of the blower used in the combustion Calibration process (Chapter 4).
The AIR TEMP. SENSOR terminals can be used to add an additional temperature sensor for
monitoring purposes. This input is always enabled and is a view-onl y input that can be seen in
the Operating Menu. The sensor must be wired to the positive (+) and negative (-) terminals of
the AIR TEMP. SENSOR and must be similar to AERCO BALCO wire sens or Part No. 12449.
A resistance chart for this sensor is provided in Appendix C.
2.10.3 ANALOG IN (3)
The ANALOG IN + and – terminals are used when an external signal is used to drive the air/fuel
valve position (Direct Drive Mode) or change the setpoint (Remote Setpoint Mode) of the Boiler.
Either a 4 to 20 mA /1 to 5 VDC or a 0 to 20 mA / 0 to 5 VDC signal may be used to vary the
setpoint or valve position. The factory default setting is for 4 to 20 mA / 1 to 5 VDC, however this
may be changed to 0 to 20 mA / 0 to 5 VDC using the Configuration Menu described in Chapter
3. If voltage rather than current is selected as the drive sig nal, a DIP switch must be set on the
PMC Board located inside the Control Box. Contact the AERCO factory for information on
setting DIP switches.
All of the supplied signals must be floating (ungrounded) signals. Connections between the
signal source and the Boiler’s I/O Box must be made using twisted shielded pair wire fr om 18 to
22 AWG, such as Belden 9841 (see Figure 2-10). Polarity must be maintained. The shield
must be connected only at the source end and must be left floating (not connected) at the
Boiler’s I/O Box.
Regardless of whether voltage or current is used for the drive signal, they are linearly mapped
to a 40°F to 240°F setpoint or a 0% to 100% valve position. No scaling for these signals is
provided.
2.10.4 B.M.S. (PWM) IN (4)
NOTE
Only BMS Model 168 can utilize Pulse Width Modulation (PWM), not the
BMS II or ACS (AERCO Control System).
These terminals are used to connect the AERCO Boiler Management System (BMS) to the unit.
The BMS utilizes a 12 millisecond, ON/OFF duty cycle. This duty cycle is Pulse Width
Modulated (PWM) to control valve position. A 0% valve position = a 5% ON pulse and a 100%
valve position = a 95% ON pulse.
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Chapter 2 Benchmark 2.0LN Low NOx Boiler GF-123
Installation Installation, Operation and Maintenance Manual OMM-0046_0E
2.10.5 SHIELD (5)
The SHIELD terminals are used to terminate any shields used on sensor wires connected to the
unit. Only shields must be connected to these terminals.
IMPORTANT
DO NOT USE the mA OUT output to remotely monitor Setpoint, Outlet
Temp or Fire Rate Out.
2.10.6 mA OUT (6)
These terminals provide a 4 to 20 mA output to the VFD ( if so equipped) to control the rotational
speed of the blower. This function is enabled in the Configuration Menu (Chapter 3, Table 3-4).
2.10.7 RS-485 COMM (7)
These terminals are used for RS-485 MODBUS serial communication between the unit and an
external “Master” such as a Boiler Management System (BMS), AERCO Cont ro l System (ACS) ,
Energy Management System (EMS), Building Automation System (BAS) or other suitable
device.
2.10.8 TxD, RxD (8)
These terminals provide a parallel connection to the connector on the C -More Controller front
panel, for connecting a computer or laptop.
2.10.9 VFD/BLOWER (9)
These terminals provide a 0 to 10 volt output to control t he rotational speed of the blower. This
function is enabled in the Configuration Menu (Chapter 3, Table 3-4).
2.10.10 EXHAUST SWITCH IN (11)
These terminals permit an external exhaust switch to be connected to the exhaust manif old of
the boiler. The exhaust switch should be a normally open type switch (such as AERCO Part No.
123463) that closes (trips) at 500°F.
2.10.11 INTERLOCKS (10, 12)
The unit offers two interlock circuits for interfacing with Energy Management Systems and
auxiliary equipment such as pumps or louvers. These interlocks are called the Remote Interlock
and Delayed Interlock (Figure 2-10). The wiring terminals for these interlocks are located inside
the I/O Box on the unit front panel. The I/O Box cover contains a wiring diagr am which shows
the terminal strip locations for these interlocks (REMOTE INTL’K IN and DELAYED INTL’K IN).
Both interlocks, described below, are factory wired in the closed position.
NOTE
Both the Delayed Interlock and Remote Interlock MUST be in the closed position to allow the
unit to fire.
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GF-123 Benchmark 2.0LN Low NOx Boil e r Chapter 2
OMM-0046_0E Installation, Operation and Maintenance Manual Installation
2.10.11.1 REMOTE INTERLOCK IN (10)
The remote interlock circuit is provided to remotely start (enable) and stop (disable) the Boiler, if
desired. The circuit is labeled REMOTE INTL’K IN and is located inside the I/O Box on the front
panel. The circuit is 24 VAC and is factory pre-wired in the closed (jumpered) position.
2.10.11.2 DELAYED INTERLOCK IN (12)
The delayed interlock is typically used in conjunction with the auxiliary relay described in
paragraph 2.11. This interlock circuit is located in the purge section of the start string. It can be
connected to the proving device (end switch, flow switch etc.) of an auxiliary piece of equipm ent
started by the Boiler’s auxiliary relay. The delayed interlock must be closed for the boiler to fire.
If the delayed interlock is connected to a proving device that r equires time to close (make), a
time delay (Aux Start On Dly) that holds the start sequence of the boiler long enough for a
proving switch to make can be programmed. Should the proving switch not prove within the
programmed time frame, the boiler will shut down. T he Aux Start On Dly can be programmed
from 0 to 120 seconds. This option is locate in the Configuration Menu (Chapter 3, Table 3-4).
2.10.12 FAULT RELAY (13)
The fault relay is a single pole double throw (SPDT) relay having a normally open and normally
closed set of relay contacts that are rat ed for 5 amps at 120 VAC and 5 am ps at 30 VDC. The
relay energizes when any fault condition occurs and remains energized until the f ault is cleared
and the CLEAR button is depressed. The fault relay connections are shown in Figure 2-10.
2.10.13 AUXILIARY RELAY CONTACTS (14)
Each Boiler is equipped with a single pole double throw (SPDT) relay that is energized when
there is a demand for heat and de-energized after the demand for heat is satisf ied. The relay is
provided for the control of auxiliary equipment, such as pumps and louvers, or can be used as a
Boiler status indictor (firing or not firing). Its contacts are rated for 120 VAC @ 5 amps. Refer to
Figure 2-10 to locate the AUX RELAY terminals for wiring connections.
2.11 FLUE GAS VENT INSTALLATION
The minimum allowable vent diameter for a single Benchmark 2.0LN Boiler is 8 inches.
The AERCO Benchmark Venting and Combustion Air Guide, GF-2050, must be consulted
before any flue gas vent or inlet air venting is designed or inst alled. U/L listed, posit ive pressur e,
watertight vent materials as specified in AERCO’s GF-2050, must be used for safety and code
compliance. Since the unit is capable of discharging low temper ature exhaust gases, horizontal
sections of the flue vent system must be pitched back to the unit a minimum of 1/4 inch per foot
to avoid condensate pooling and allow for proper drainage.
The combined pressure drop of vent and combustion air systems must not exceed 140
equivalent feet of 8 inch ducting. Fittings as well as pipe leng ths must be calculated as part of
the equivalent length.
For a natural draft installation the draft must not exceed ±0.25 inch W.C. These factors must be
planned into the vent installation. If the maximum allowable equivalent lengths of piping are
exceeded, the unit will not operate properly or reliably.
For Massachusetts installations, the Heatfab Division of the Selkirk Corporat ion provides vent
systems which conform to all applicable requirements for installations within the Commonwealth
of Massachusetts. Contact information for this supplier are as follows:
PR1 08/20/12 AERCO International Inc.● 100 Oritani Dr. ● Blauvelt, NY 10913. ● Ph: 800-526-0288 Page 29 of 170
Chapter 2 Benchmark 2.0LN Low NOx Boiler GF-123
Installation Installation, Operation and Maintenance Manual OMM-0046_0E
Selkirk Corporation, Heatfab Division ( www.heat-fab.com ),130 Industrial Blvd., Turners Falls,
MA 01376
Phone: 1-800-772-0739
2.12 COMBUSTION AIR
The AERCO Benchmark Venting and Combustion Air Guide, GF-2050 MUST be consulted
before any f lue or combustion supply air venting is designed or implemented. Com bustion air
supply is a direct requirement of ANSI 223.1, NFPA-54, CSA B149.1 and local codes. These
codes should be consulted before a permanent design is determined.
The combustion air must be free of chlorine, halogenated hydrocarbons, or other chemicals that
can become hazardous when used in gas-fired equipment. Common sources of these
compounds are swimming pools, degreasing compounds, plastic processing and refrigerants.
Whenever the environment contains these types of chemicals, combustion air must be supplied
from a clean area outdoors for the protection and longevity of the equipment.
The AERCO Benchmark 2.0LN Boiler is UL listed for 100% sealed combustion. It can also be
installed using room air, provided there is an adequate supply. (See para. 2.13.3 for more
information concerning sealed combustion air). If the sealed combustion air option is not being
used, an inlet screen will be attached at the air inlet on the top of the unit
The more common methods of supplying combustion air are outlined below. For more
information concerning combustion air, refer to the AERCO Benchmark Venting and Combustion Air Guide, GF-2050.
2.12.1 Combustion Air From Outside the Building
Air supplied from outside the building must be provided through two permanent openings. Each
opening must have a free area of not less than one square inch for each 4000 BTU/H boiler
input. The free area must take into account r estrictions such as louvers and bird screens. For
Canada installations, refer to the requirements specified in CSA B149.1-10, 8.4.1 and 8.4.3.
2.12.2 Combustion Air From Inside The Building
When combustion air is provided from within the building, it must be supplied through two
permanent openings in an interior wall. Each opening must have a free area of not less than
one square inch per 1000 BTU/H of total boiler input . The free area must take into ac count any
restrictions such as louvers.
2.12.3 Sealed Combustion
The AERCO Benchmark 2.0LN Boiler is UL listed for 100%-sealed combustion. For sealed
combustion installations, the screen on the air inlet duct of the unit must be removed. The inlet
air ductwork must then be attached directly to the unit’s air inlet.
In a sealed combustion air application, the combustion air ducting pressure losses must be
taken into account when calculating the total maximum allowable venting run. See the AERCO
Benchmark Venting and Combustion Air Guide, GF-2050. When using the boiler in a sealed
combustion air configuration, each unit must have a minimum 6 inch diameter connection at the
unit.
2.12.4 Temporary Combustion Air Filtering During Construction
When the Benchmark 2.0LN Boiler is used to provide heat temporarily during ongoing building
construction, accumulated drywall dust, sawdust and similar particles can accumulate in the
unit’s combustion air intake filter and block combustion air flow. In these situations, AERCO
Page 30 of 170 AERCO International Inc.● 100 Oritani Dr. ● Blauvelt, NY 10913. ● Ph: 800-526-0288 PR1 08/20/12
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