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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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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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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
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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
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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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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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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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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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Page 18
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.
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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
2.9.4 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
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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:
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Chapter 2 Benchmark 2.0LN Low NOx Boiler GF-123
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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
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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
recommends that a disposable air intake filter be installed, temporarily, above the boiler
combustion air inlet.
AERCO recommends that the temporary air filter be cut from a McMaster-Carr part no.
2122K315 Polyester Air Filter Roll Tackfield, ½” thick, 16” wide, or equivalent. Cover the
Benchmark 2.0LN air inlet with the blue side of the filter material facing outward to hold the dust
on the outside surface. Maximize the surface area of the filter covering the 8" diameter opening
by creating a dome out of the filter material.
Cover the flared duct opening with the blue side facing outward. During construction check the
filter for dust accumulation and replace it when the accumulation becomes noticeable.
2.13 BENCHMARK PUMP RELAY OPTION
An optional Benchmark pump relay allows the user to turn a pump on/off and open/close a
motorized valve as the boiler cycles on and off on demand. The Pump Delay Timer feature
allows the user to keep the pump running and keep the motorized valve open for up to 30
minutes after the boiler has shut down and the demand is satisfied.
The Benchmark pump relay (SPDT) contact is rated for:
• 10 A Resistive @ 277 VAC/28 VDC
• 1/3 HP N/O @ 120/240 VAC
• 1/6 HP N/C @ 120/240 VAC
• 480 VA Pilot Duty @ 240-277 VAC
If pump/valve load exceeds the above contact ratings, use a separate contact relay.
See Diagrams 2-1a and 2-1b.
To identify if the boiler is equipped with the BMK Pump Relay Option (part no. 69102), look for
the label and relay as shown in Figure 2-12.
Diagram 2-1a: Schematic – System Pump Start usi ng Boi l er Pump Relay
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Chapter 2 Benchmark 2.0LN Low NOx Boiler GF-123
Installation Installation, Operation and Maintenance Manual OMM-0046_0E
Diagram 2-1b: Schematic – System Pump Start using a Separate Contact Relay
Figure 2-11: Identifying the Presence of BMK Pump Relay Option 69102
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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 3. CONTROL PANEL OPERATION
3.1 INTRODUCTION
The information in this Chapter provides a guide to the operation of the Benchmark 2.0LN
Boiler using the Control Panel mounted on the front of the unit. It is imperative that the initial
startup of this unit be performed by factory trained personnel. Operation prior to initial
startup by factory trained personnel will void the equipment warranty. In addition, the
following WARNINGS and CAUTIONS must be observed at all times.
IMPORTANT!
All of the installation procedures in Chapter 2 must be completed before
attempting to start the unit.
WARNING
ELECTRICAL VOLTAGES IN THIS SYSTEM MAY INCLUDE 460, 208
AND 24 VOLTS AC. IT MUST BE SERVICED only BY FACTORY
CERTIFIED SERVICE TECHNICIANS
WARNING
DO NOT ATTEMPT TO DRY FIRE THE BOILER. STARTING THE
UNIT WITHOUT A FULL W ATER LEVEL CAN SERIOUSLY DA MAGE
THE UNIT AND MAY RESULT IN INJURY TO PERSONNEL OR
PROPERTY DAMAGE. THIS SITUATION WILL VOID ANY
WARRANTY.
3.2 CONTROL PANEL DESCRIPTION
The Benchmark 2.0LN Control Panel shown in Figure 3-1 contains all of the controls,
indicators and displays necessary to operate, adjust and troubleshoot the Benchmark 2.0LN
Boiler. These operating controls, indicators and displays are listed and described in Table
3-1. Additional information on these items is provided in the individual operating procedures
provided in this Chapter.
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Chapter 2 Benchmark 2.0LN Low NOx Boiler GF-123
1
2
3
4
5
6
7
8
9
10
11
12
Installation Installation, Operation and Maintenance Manual OMM-0046_0E
Figure 3-1: Control Panel Front View
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GF-123 Benchmark 2.0LN Low NOx Boil e r Chapter 2
FUNCTION
8
OMM-0046_0E Installation, Operation and Maintenance Manual Installation
Table 3-1 Operating Controls, Indicators and Displays
ITEM
NO.
CONTROL, INDICATOR
OR DISPLAY
1 LED Status Indicators
COMM
MANUAL
REMOTE
DEMAND
OUTLET
2
TEMPERATURE
Display
3 VFD Display
RS-232 Port
4
FAULT Indicator
5
CLEAR Key
6
READY Indicator
7
Four Status LEDs indicate the current operating status as
follows:
Lights when RS-232 communication is occurring
Lights when the unit is being controlled using the front panel
keypad.
Lights when the unit is being controlled by an external signal
from an Energy Management System
Lights when there is a demand for heat.
3–Digit, 7–Segment LED display continuously displays the
outlet water temperature. The °F or °C LED next to the
display lights to indicate whether the displayed temperature is
in degrees Fahrenheit or degrees Celsius. The °F or °C blinks
when operating in the Deadband Mode.
Vacuum Fluorescent Display (VFD) consists of 2 lines each
capable of displaying up to 16 alphanumeric characters. The
information displayed includes:
Startup Messages
Fault Messages
Operating Status Messages
Menu Selection
Port permits a Laptop Computer or External Modem to be
connected to the unit’s Control Panel.
Red FAULT LED indicator lights when a boiler alarm
condition occurs. An alarm message will appear in the VFD.
Turns off the FAULT indicator and clears the alarm message
if the alarm is no longer valid. Lockout type alarms will be
latched and cannot be cleared by simply pressing this key.
Troubleshooting may be required to clear these types of
alarms.
Lights ON/OFF switch is set to ON and all Pre-Purge
conditions have been satisfied.
ON/OFF Switch
LOW WATER LEVEL
9
TEST/RESET
Switches
Enables and disables boiler operation.
Allows operator to test operation of the water level monitor.
Pressing TEST opens the water level probe circuit and
simulates a Low Water Level alarm.
Pressing RESET resets the water level monitor circuit.
Pressing the CLEAR key (item 6) resets the display.
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Chapter 2 Benchmark 2.0LN Low NOx Boiler GF-123
DISPLAY
Bargraph
Installation Installation, Operation and Maintenance Manual OMM-0046_0E
Table 3-1 Operating Controls, Indicators and Displays (Continued)
ITEM
NO.
CONTROL,
INDICATOR OR
MENU Keypad
MENU
BACK
▲ (UP) Arrow
10
▼ (DOWN) Arrow
CHANGE
ENTER
AUTO/MAN Switch
11
12
VALVE POSITION
FUNCTION
Consists of 6 keys which provide the following functions for
the Control Panel Menus:
Steps through the main menu categories shown in Figure 3-
2. The Menu categories wrap around in the order shown.
Allows you to go back to the previous menu level without
changing any information. Continuously pressing this key
will bring you back to the default status display in the VFD.
Also, this key allows you to go back to the top of a main
menu category.
When in one of the main menu categories (Figure 3-2),
pressing the ▲ arrow key will select the displayed menu
category. If the CHANGE key was pressed and the menu
item is flashing, pressing the ▲ arrow key will increment the
selected setting.
When in one of the main menu categories (Figure 3-2),
pressing this key will select the displayed menu category. If
the CHANGE key was pressed and the menu item is
flashing, pressing the ▼ arrow key will decrement the
selected setting.
Permits a setting to be changed (edited). When the
CHANGE key is pressed, the displayed menu item will begin
to flash. Pressing the ▲ or ▼ arrow key when the item is
flashing will increment or decrement the displayed setting.
Saves the modified menu settings in memory. The display
will stop flashing.
This switch toggles the boiler between the Automatic and
Manual modes of operation. When in the Manual (MAN)
mode, the front panel controls are enabled and the
MANUAL status LED lights.
When in the Automatic (AUTO) mode, the MANUAL status
LED will be off and the front panel controls disabled.
20 segment red LED bargraph continuously shows the
Air/Fuel Valve position in 5% increments from 0 to 100%
3.3 CONTROL PANEL MENUS
The Control Panel incorporates an extensive menu structure which permits the operator to
set up, and configure the unit. The menu structure consists of five major menu cat egories
which are applicable to this manual. These categories are shown in Figure 3-2. Each of the
menus shown, contain options which permit operating parameters to be viewed or changed.
The menus are protected by a password levels to prevent unauthorized use.
Prior to entering the correct password, the options contained in the Operation, Setup,
Configuration and Tuning Menu categories can be viewed. However, with the exception of
Internal Setpoint Temperature (Configuration Menu), none of the viewable menu options can
be changed.
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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
Once the valid level 1 password (159) is entered, the options listed in the Setup.
Configuration and Tuning Menus can be viewed and changed, if desired. The Com bustion
Cal Menu is protected by the level 2 password which is used in Chapter 4 to perform
combustion calibration prior to service use.
3.3.1 Menu Processing Procedure
Accessing and initiating each menu and option is accomplished using the Menu Keys shown
in Figure 3-1. Therefore, it is imperative that you be thoroughly fam iliar with the following
basic steps before attempting to perform specific menu procedures.
1. The Control Panel will normally be in the Operating Menu and the VFD will display the
current unit status. Pressing the ▲ or ▼ arrow key will display the other available data
items in the Operating Menu.
2. Press the MENU key. The display will show the Setup Menu, which is the next menu
category shown in Figure 3-2. This menu contains the Password option which must be
entered if other menu options will be changed.
3. Continue pressing the MENU key until the desired menu is displayed.
4. With the desired menu displayed, press the ▲ or ▼ arr ow key. The first option in the
selected menu will be displayed.
5. Continue to press the ▲ or ▼ arrow key until the desired menu option is displayed.
Pressing the ▲ arrow key will display the available menu options in the Top-Down
sequence. Pressing the ▼ arrow key will display the options in the Bottom-Up
sequence. The menu options will wrap-around after the first or last available option is
reached.
6. To change the value or setting of a displayed menu option, press the CHANGE key. T he
displayed option will begin to f lash. Press the ▲ or ▼ arrow key to scroll through the
available menu option choices for the option to be changed. The menu option choices
do not wrap around.
7. To select and store a changed menu item, press the ENTER key.
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Chapter 2 Benchmark 2.0LN Low NOx Boiler GF-123
OPERATING
SETUP
CONFIGURATION
TUNING
COMBUSTION CAL
CALIBRATION
(NOT USED IN THIS O & M)
LEVEL 2 PWD
LEVEL 1 PWD
DIAGNOSTICS
(NOT USED IN THIS O & M)
Installation Installation, Operation and Maintenance Manual OMM-0046_0E
Figure 3-2: Control Panel Menu Structure
NOTE
The following paragraphs provide brief descriptions of the options contained in each menu.
Refer to Appendix A for detailed descriptions of each menu option. Refer to Appendix B for
listings and descriptions of displayed startup, status and error messages.
3.4 OPERATING MENU
The Operating Menu displays a number of key operating parameters for the unit as listed in
Table 3-2. This menu is “Read-Only” and does not allow personnel to change or adjust any
displayed items. Since this menu is “Read-Only”, it can be viewed at any time without
entering a password. Pressing the ▲ arrow key to display the menu items in the order listed
(Top-Down). Pressing the ▼ arrow key will display the menu items in reverse order
(Bottom-Up).
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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
NOTE
The Outdoor Temp display item shown with an asterisk in Table 3-2 will
not be displayed unless the Outdoor Sensor function has been enabled
in the Configuration Menu (Table 3-4).
Table 3-2: Operating Menu
Available Choices or Limits
Menu Item Display Minimum Maximum Default
Status Message
Active Setpoint
AIR Temp
Outdoor Temp*
Valve Position In
40°F 240°F
-70°F 245°F
-70°F 130°F
0%
100% Valve
Position
Flame Strength
Run Cycles
Run Hours
Fault Log
0% 100%
0 999,999,999
0 999,999,999
0 19
0
3.5 SETUP MENU
The Setup Menu (Table 3-3) permits the operator to enter the unit password (159) which is
required to change the menu options. To prevent unauthorized use, the password will timeout after 1 hour. Therefore, the correct password must be reentered when required. In
addition to permitting password entries, the Setup Menu is also used to enter date and time,
units of temperature measurements and entries required for external communication and
control of the unit via the RS-232 port. A view-only software version display is also provided
to indicate the current Control Box software version.
Table 3-3. Setup Menu
Available Choices or Limits
Menu Item Display Minimum Maximum Default
Passsword
Language
Time
Date
Unit of Temp
Comm Address
Baud Rate
Software Version
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0 9999 0
English English
12:00 am 11:59 pm
01/01/00 12/31/99
Fahrenheit or Celsius Fahrenheit
0 127 0
2400, 4800, 9600, 19.2K 9600
Ver 0.00 Ver 9.99
Page 40
Chapter 2 Benchmark 2.0LN Low NOx Boiler GF-123
Available Choices or Limits
Menu Item Display
Minimum
Maximum
Default
Installation Installation, Operation and Maintenance Manual OMM-0046_0E
3.6 CONFIGURATION MENU
The Configuration Menu shown in Table 3-4 permits adjustment of the Internal Setpoint
(Setpt) temperature regardless of whether the valid password has been entered. Setpt is
required for operation in the Constant Setpoint mode. The remaining options in this menu
require the valid password to be entered, prior to changing existing entries. This menu
contains a number of other configuration settings which may or may not be displayed,
depending on the current operating mode setting.
NOTE
The Configuration Menu settings shown in Table 3-4 are Factory-Set in accordance with the
requirements specified for each individual order. Therefore, under normal operating
conditions, no changes will be required.
Table 3-4. Configuration Menu
Internal Setpt Lo Temp Limit Hi Temp Limit 130°F
Unit Type KC Boiler, KC Boiler LN,
BMK Boiler, BMK Boiler LN,
BMK Boiler Dual, KC Water
Heater, KC Water Heater LN,
Water Heater 2010
Unit Size 0.5 MBTU, 1.0 MBTU
1.5 MBTU, 2.0 MBTU
3.0 MBTU, 3.5 MBTU
4.0 MBTU, 5.0 MBTU
6.0 MBTU
Fuel Type Natural Gas, Propane Natural Gas
Boiler Mode Constant Setpoint,
Remote Setpoint,
Direct Drive
Combination
Outdoor Reset
Remote Signal
(If Mode = Remote
Setpoint, Direct Drive
or Combination)
Bldg Ref Temp
(If Mode = Outdoor
Reset)
4 – 20 mA/1 – 5V
0 -20 mA/0 – 5V
PWM Input (BMS)
Network
40°F 230°F 70°F
BMK Boiler
LN
2.0 MBTU
Constant
Setpoint
4 – 20 mA,
1-5V
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GF-123 Benchmark 2.0LN Low NOx Boil e r Chapter 2
Available Choices or Limits
Menu Item Display
Minimum
Maximum
Default
OMM-0046_0E Installation, Operation and Maintenance Manual Installation
Table 3-4. Configuration Menu - Continued
Reset Ratio
(If Mode = Outdoor
Reset)
Outdoor Sensor Enabled or Disabled Disabled
System Start Tmp
(If Outdoor Sensor =
Enabled)
Setpt Lo Limit 40°F Setpt Hi Limit 60°F
Setpt Hi Limit Setpt Lo Limit 195°F 195°F
Temp Hi Limit 40°F 210°F 195°F
Max Valve Position 40% 100% 100%
Pump Delay Timer 0 min. 30 min. 0 min.
Pump Delay Timer 0 min. 30 min. 0 min.
Aux Start On Dly 0 sec. 120 sec. 0 sec.
Failsafe Mode Shutdown or Constant Setpt Shutdown
*Analog Output
(See CAUTION at
end of Table 3-4 )
Low Fire Timer 2 sec. 600 sec. 2 sec.
Setpt Limiting Enabled or Disabled Disabled
0.1 9.9 1.2
30°F 100°F 60°F
Off, Setpoint, Outlet Temp,
Valve Position 4-20 mA,
Valve Position 0-10V
*Valve
Position
0-10V
Setpt Limit Band 0°F 10°F 5°F
Network Timeout 5 Sec 999 Sec 30 Sec
HI DB Setpt EN 0% 100% 30%
Demand Offsert 0 25 10
Deadband High 0 25 2
Deadband Low 0 25 2
*CAUTION: DO NOT CHANGE the Analog Output Menu Item from its Default setting
(Valve Position 0-10V).
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Chapter 3 Benchmark 2.0LN Low NOx Boiler GF-123
Operation Installation, Operation and Maintenance Manual OMM-0046_0E
*CAUTION!
DO NOT CHANGE the Analog Output Menu Item from its Default setting
(Valve Position 0-10V).
3.7 TUNING MENU
The Tuning Menu items in Table 3-5 are Factory set for each individual unit. Do not change
these menu entries unless specifically requested to do so by Factory-Trained personnel.
3.8 COMBUSTION CAL MENU
The Combustion Cal (Calibration) Menu items in Table 3-6 are used to vary the speed of the
unit’s blower motor based on air temperature and air density at prescribed Air/Fuel Valve
positions (% open). This is accomplished by providing a DC drive voltage to t he motor which
adjusts the rotational speed of the blower to maximize combustion efficiency and ensure the unit
conforms to the Nitrogen Oxide (NOx) and Carbon Monoxide (CO) emissions specified in
Chapter 4. The valve positions (%) and default drive voltag es are listed in Table 3-6.
Table 3-5: Tuning Menu
Menu Item Display
Prop Band
Integral Gain
Derivative Time
Reset Defaults?
Available Choices or Limits
Default
Minimum Maximum
1°F 120°F 70°F
0.00 2.00 1.00
0.0 min 2.00 min 0.00 min
Yes, No, Are You Sure? No
Table 3-6: Combustion Cal Menu
Menu Item Display
CAL Voltage 16%
CAL Voltage 30%
CAL Voltage 45%
CAL Voltage 60%
Available Choices or Limits
Default
Minimum Maximum
.25 8.20 1.80v
.25 8.20 3.20v
.25 8.20 3.70v
.25 8.20 3.80
CAL Voltage 80%
CAL Voltage 100%
SET Valve Position
Blower Output
.25 8.20 4.60
.25 8.20 6.00
0% 100% 0%
Monitor Blower Output
.00
Voltage
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GF-123 Benchmark 2.0LN Low NOx Boil e r Chapter 3
OMM-0046_0E Installation, Operation and Maintenance Manual Operation
3.9 START SEQUENCE
When the Control Box ON/OFF switch is set to the O N position, it checks all pre-purge safety
switches to ensure they are closed. These switches include:
• Safety Shut-Off Valve Proof of Closure (POC) switch
• Low Water Level switch
• High Water Temperature switch
• High Gas Pressure switch
• Low Gas Pressure switch
• Blowe r Proof swit ch
• Blocked Inlet switch
If all of the above switches are closed, the READY light above the ON/OFF switch will lig ht and
the unit will be in the Standby mode.
When there is a demand for heat, the following events will occur:
NOTE
If any of the Pre-Purge safety device switches are open, the appropriate fault message will be
displayed. Also, the appropriate fault messages will be displayed throughout the start
sequence, if the required conditions are not observed.
1. The DEMAND LED status indicator will light.
2. The unit checks to ensure that the Proof of Closure (POC) switch in the downstream Safety
Shut-Off Valve (SSOV) is closed. See Figure 3-3 for SSOV location.
3. With all required safety device switches closed, a purge cycle will be initiated and the
following events will occur:
(a) The Blower relay energizes and turns on blower.
(b) The Air/Fuel Valve rotates to the full-open purge position and closes purge position
switch. The dial on the Air/Fuel Valve (Figure 3-4) will read 100 to indicate that it is fullopen (100%).
(c) T he VALVE POSITION bargraph will show 100%.
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Chapter 3 Benchmark 2.0LN Low NOx Boiler GF-123
SSOV
TO AIR/FUEL
MANUAL SHUT-OFF VALVE
Operation Installation, Operation and Maintenance Manual OMM-0046_0E
GAS
INLET
VALVE
Figure 3-3: SSOV Location
4. Next, the blower proof switch on the Air/Fuel Valve (Figure 3-5) closes. The display will
show Purging and indicate the elapsed time of the purge cycle in seconds.
5. Upon completion of the purge cycle, the Control Box initiates an ignition cycle and the
following events occur:
(a) The Air/Fuel Valve rotates to the low-fire ignition position and closes t he ignition switch.
The dial on the Air/Fuel Valve (Figure 3-6) will read between 25 and 35 to indicate that
the valve is in the low-fire position.
(b) The ig niter relay is activated and provides ignition spark.
(c) T he gas Safety Shut-Off Valve (SSOV) is energized (opened) allowing gas to flow into
the Air/Fuel Valve.
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GF-123 Benchmark 2.0LN Low NOx Boil e r Chapter 3
100
DETAIL “A”
TO BLOWER
AIR IN
DIAL
(DETAIL “A”)
STEPPER
MOTOR
OMM-0046_0E Installation, Operation and Maintenance Manual Operation
Figure 3-4: Air/Fuel Valve In Purge Position
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Figure 3-5: Blower Proof Switch
Page 46
Chapter 3 Benchmark 2.0LN Low NOx Boiler GF-123
25
TO BLOWER
AIR IN
DIAL
(DETAIL “A”)
STEPPER
MOTOR
DETAIL “A”
Operation Installation, Operation and Maintenance Manual OMM-0046_0E
6. Up to 7 seconds will be allowed for ignition to be detected. The igniter relay will be turned
7. After 2 seconds of continuous flame, Flame Proven will be displayed and the flame strength
8. With the unit firing properly, it will be controlled by the temperature controller circuitry. The
Once the demand for heat has been satisfied, the Control Box will turn off the dual SSOV gas
valves. The blower relay will be deactivated and the Air/Fuel Valve will be closed. Standby will
be displayed.
3.10 START/STOP LEVELS
The start and stop levels are the Air/Fuel Valve positions (% open) that start and stop the unit,
based on load. These levels are Factory preset as follows:
Natural Gas:
Figure 3-6: Air/Fuel Valve In Ignition Position
off one second after flame is detected.
will be indicated. After 5 seconds, the current date and time will be displayed in place of the
flame strength.
boiler’s VALVE POSITION will be continuously displayed on the front panel bargraph.
• Start Level: 22%
• Stop Level: 18%
Propane:
Normally, these settings should not require adjustment.
Page 46 of 170 AERCO International Inc.● 100 Oritani Dr. ● Blauvelt, NY 10913. ● Ph: 800-526-0288 PR1 08/20/12
• Start Level: 24%
• Stop Level: 20%
Page 47
GF-123 Benchmark 2.0LN Low NOx Boil e r Chapter 3
0 0 0
10% 0 0
18%
(Stop Level)
5.0%
20%
134,000
7%
30%
349,000
17%
40%
631,000
32%
50%
893,000
45%
60%
1,150,000
58%
70%
1,410,000
71%
80%
1,610,000
81%
90%
1,830000
92%
100%
2,000,000
100%
OMM-0046_0E Installation, Operation and Maintenance Manual Operation
Note that the energy input of the boiler is not linearly related to the Air/Fuel Valve position. Refer
to Table 3-7 for the relationship between the energy input and Air/Fuel Val ve position for a unit
running on natural gas.
Table 3-7. Relationship Between Air/Fuel Valve Position and Energy Input For
Unit Running On Natural Gas
Air/Fuel Valve Position
(% Open)
Energy Input
(BTU/Hr)
100,000
Boiler Energy Input
(% of Full Capacity)
PR1 08/20/12 AERCO International Inc.● 100 Oritani Dr. ● Blauvelt, NY 10913. ● Ph: 800-526-0288 Page 47 of 170
Page 48
Chapter 3 Benchmark 2.0LN Low NOx Boiler GF-123
Operation Installation, Operation and Maintenance Manual OMM-0046_0E
(This page is intentionally blank)
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Page 49
GF-123 Benchmark 2.0LN Low NOx Boil e r Chapter 4
OMM-0046_0E Installation, Operation and Maintenance Manual Initial Start-Up
CHAPTER 4. INITIAL START-UP
4.1 INI TIAL START-UP REQUIREMENTS
The requirements for the initial start-up of the Benchmark 2.0LN Boiler consists of the following:
• Complete installation (Chapter 2)
• Set proper controls and limits (Chapter 3)
• Perform combustion calibration (Chapter 4)
• Set up mode of operation (Chapter 5)
• Test safety devices (see Chapter 6)
All applicable Installation procedures in Chapter 2 must be fully completed before performing
initial start-up. The initial start-up must be successfully completed prior to putting the unit into
service. Starting a unit without the proper piping, venting, or electrical systems can be
dangerous and may void the product warranty. The following start-up instructions should be
followed precisely in order to operate the unit safely and at a high thermal eff iciency, with low
flue gas emissions.
Initial unit start-up is to be performed ONLY by AERCO factory trained start-up and service
personnel. After performing the start-up procedures in this Chapter, it will be necessary to
perform the Mode of Operation settings in Chapter 5, and the Safety Device Testing procedures
in Chapter 6 to complete all initial start-up requirements.
AERCO Gas Fired Startup Sheets, included with each Benchmark Boiler, must be completed for
each unit for warranty validation. A copy of these sheets must be returned promptly to AERCO
at:
AERCO International, Inc.
159 Paris Ave.
Northvale, NJ 07647
WARNING
DO NOT ATTEMPT TO DRY FIRE T HE BOILER. STARTING T HE UNIT
WITHOUT A FULL WATER LEVEL CAN SERIOUSLY DAMAGE THE
UNIT AND MAY RESULT IN I NJURY TO PERSONNEL OR PROPERTY
DAMAGE. THIS SITUATION WILL VOID ANY WARRANTY.
NOTE
All applicable installation procedures in Chapter 2 must be completed
before attempting to start the unit.
4.2 TOOLS AND INSTRUMENTATION FOR COMBUSTION CALIBRATION
To properly perform combustion calibration, the proper instruments and tools must be used and
correctly attached to the unit. The following paragraphs outline the necessary tools and
instrumentation as well as their installation.
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Page 50
Chapter 4 Benchmark 2.0LN Low NOx Boiler GF-123
TO AIR/FUEL
MANUAL
RSI GAS
(Shown Closed)
RSI
REGULATOR
1/4” NPT PLUG
1/4” NPT PLUG
Calibration)
Initial Start-Up Installation, Operation and Maintenance Manual OMM-0046_0E
4.2.1 Required Tools & Instrumentation
The following tools and instrumentation are necessary to perform combustion calibration of the
unit:
• Digital Combustion Analyzer: Oxygen accuracy to ± 0.4%; Carbon Monoxide (CO) and
Nitrogen Oxide (NOx) resolution to 1PPM.
• 16 inch W.C. manometer or equivalent gauge and plastic tubing.
• 1/4" NPT-to-barbed fittings for use with gas supply manometer or gauge.
• Small and large flat blade screwdrivers.
• Tube of silicone adhesive
4.2.2 Installing Gas Supply Manometer
The gas supply manometer (or gauge) is used to calibrate the gas pressure to be monitored on
the downstream side of the SSOV during the Combustion Calibration procedures described in
paragraph 4.4.
The gas supply manometer is installed at the downstream location on the 1/4” NPT port shown
in Figure 4-1. Note that a 1/4” plug must be removed from the port in order to install the
manometer.
GAS
INLET
(Install manometer
SSOV
VALVE
(Install manometer here for
RSI Regulator Calibration)
here for Combustion
Figure 4-1: Manometer Installation Location
NOTE
If a second 16” W.C. manometer is available, it can be installed in the
SSOV downstream location to provide continuous monitoring at both the
upstream and downstream ports of the SSOV. However, if only one is
available, the RSI Regulator must be calibrated first, prior to moving the
manometer to the downstream location.
VALVE
SHUT-OFF
(Shown open)
VALVE
Page 50 of 170 AERCO International Inc.● 100 Oritani Dr. ● Blauvelt, NY 10913. ● Ph: 800-526-0288 PR1 08/20/12
Page 51
GF-123 Benchmark 2.0LN Low NOx Boil e r Chapter 4
EXHAUST
MANIFOLD
1/2” NPT
CONDENSATE
DRAIN
CONNECTION
BOILER
RETURN
ANALYZER
PROBE PORT
OMM-0046_0E Installation, Operation and Maintenance Manual Initial Start-Up
Install the 16” W.C. manometer(s) as described in the following steps:
1. Turn off the main gas supply upstream of the unit.
2. Remove the top panel and left or right side panel from the boiler to access the gas train
components.
3. Perform the RSI regulator Safe Test as described in paragraph 4.3. If test shows a
successful RSI ignition, proceed to the next step. If RSI ignition is not successful, follow
instructions in paragraph 4.3 before attempting Combustion Calibration.
4. To monitor the gas pressure on the downstream side of the SSOV during Combustion
Calibration (paragraph 4.4), remove the 1/4” NPT plug from the leak detection ball valve on
the downstream side of the SSOV as shown in Figure 4-1.
5. install a NPT-to-barbed fitting into the tapped plug port.
6. Attach one end of the plastic tubing to the barbed fitting and the other end to the 16” W.C.
manometer.
4.2.3 Accessing the Analyzer Probe Port
The unit contains NPT plugs on the left and right side of the exhaust manifold at the rear of the
unit as shown in Figure 4-1. Prepare the port for the combustion analyzer probe as follows:
1. Remove the plug from the probe port on the left or r ight side of the exh aust manifold.
2. If necessary, adjust the stop on the combustion analyzer probe so that it will extend mid-way
into the flue gas flow. DO NOT install the probe at this time.
Figure 4.2: Analyzer Probe Hole Location
4.3 RSI REGULATOR SAFE TEST
The Benchmark 2.0LN contains a RSI regulator in the Regulated Staged Ignition (RSI) line of
the unit. The RSI regulator is calibrated prior to shipm ent, however the RSI system should be
safe tested prior to performing the Combustion Calibration Procedure to ensure it is working
properly. RSI regulator safe testing is performed as follows:
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Page 52
Chapter 4 Benchmark 2.0LN Low NOx Boiler GF-123
AIR/FUEL
VALVE
STAGED
IGNITION
ASSEMBLY
FLAME
DETECTOR
IGNITOR-
INJECTOR
BLOWER
BURNER
PLATE
BURNER
Observation Port
Initial Start-Up Installation, Operation and Maintenance Manual OMM-0046_0E
1. Close the main gas supply shut-off valve upstream of the unit.
2. Refer to Figure 4.1 and CLOSE the following valves in the unit’s gas train:
• RSI gas valve
• RSI Bleed-off Valve
• Manual shut-off valve to Air/Fuel Valve.
3. OPEN the main gas supply upstream of the unit.
4. Turn ON electrical power to the system.
5. Slowly OPEN the RSI Gas Valve.
6. Turn on the external gas supply to the unit.
7. Slowly open the RSI gas supply valve.
8. Start the boiler in MANUAL Mode.
9. Look into the observation port in the top head (see Figure 4-3) and ensure that you observe
the orange glow of the RSI flame during the ignition trial period.
10. Conduct at least three safe RSI ignitions while looking int o the observation port in the top
head. Assure the igniter lights immediately with a strong orange flame after the Staged
Ignition Solenoid Valve opens, and then proceed with the Combustion Calibration procedure
described in Section 4.4.
NOTE
Clear any Flame Loss During Ignition messages during the tests by
pressing The CLEAR key on control panel.
IMPORTANT!
If you do NOT see the orange glow from the RSI ignition in the observation
port, refer to Paragraph 7.4.1.2 to calibrate the RSI regulator. Do NOT
proceed with Combustion Calibration until the RSI is igniting properly.
Page 52 of 170 AERCO International Inc.● 100 Oritani Dr. ● Blauvelt, NY 10913. ● Ph: 800-526-0288 PR1 08/20/12
Figure 4-3: Observation Port Location
Page 53
GF-123 Benchmark 2.0LN Low NOx Boil e r Chapter 4
BRASS HEX
HEAD CAP
(REMOVE TO
ACCESS GAS
PRESSURE
ADJUSTMENT
SCREW)
SSOV ACTUATOR
OMM-0046_0E Installation, Operation and Maintenance Manual Initial Start-Up
4.4 NATURAL GAS COMBUSTION CALI BRATION
The Benchmark 2.0LN Boiler is combustion calibrated at the factory prior to shipping. However,
recalibration as part of initial start-up is necessary due to changes in the local altitude, g as BTU
content, gas supply piping and supply regulators. Factory Test Data sheets are shipped with
each unit. These sheets must be filled out and returned to AERCO for proper Warranty
Validation.
It is important to perform the following procedure as outlined. This will keep readjustments to a
minimum and provide optimum performance.
1. Open the water supply and return valves to the unit and ensur e that the system pumps are
running.
2. Open the natural gas supply valve(s) to the unit.
3. Set the control panel ON/OFF switch to the OFF position.
4. Turn on external AC power to the unit. The display will show LOSS OF POWER and the
time and date.
5. Set the unit to the Manual Mode by pressing the AUTO/MAN key. A flashing Manual Valve
Position message will be displayed with the present r ate in %. Also, the MANUAL L ED will
light.
6. Adjust the air/fuel valve position to 0% by pressing the ▼ arrow key.
7. Ensure that the leak detection ball valve down-stream of the SSOV is open.
8. Set the ON/OFF switch to the ON position.
9. Change the valve position to 29% using the ▲ arrow key. The unit should begin its start
sequence and fire.
10. Next, verify that the gas pressure downstream of the SSOV is 2.8” W.C. for both FM and IRI
gas trains. If gas pressure adjustment is required, remove the brass hex nut on the
downstream SSOV actuator (IRI gas train) to access the gas pressure adjustment screw
(Figure 4-4). Make gas pressure adjustments using a flat-tip screwdriver to obtain 2.8” W.C.
Figure 4-4: Gas Pressure Adjustment Screw Location
11. Increase the valve open position to 100% and verify that the gas pressure downstream of
the SSOV remains at 2.8” W.C. Readjust pressure if necessary.
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Page 54
Chapter 4 Benchmark 2.0LN Low NOx Boiler GF-123
Inlet Air
Temp
Oxygen %
± 0.2
Carbon
Monoxide
NOx
>100°F
4.8 %
<100 ppm
<30 ppm
90°F
5.0 %
<100 ppm
<30 ppm
80°F
5.2 %
<100 ppm
<30 ppm
<70°F
5.3 %
<100 ppm
<30 ppm
AIR
INLET
IRIS AIR
DAMPER
(SEE VIEW
“A”)
USE 1/2"
WRENCH TO
INCREASE
(CW) OR
DECREASE
(CCW) INLET
AIR
IRIS
ADJUSTMENT
VIEW A - A
Initial Start-Up Installation, Operation and Maintenance Manual OMM-0046_0E
12. With the valve position at 100%, insert the combustion analyzer probe into the flue probe
opening and allow enough time for the combustion analyzer reading to stabilize.
13. Compare the measured oxygen level to the oxygen range for the inlet air temperature
shown in Table 4-1. Also, ensure that the carbon monoxide (CO) and nitrogen oxide (NOx)
readings do not exceed the values shown.
Table 4-1: Combustion Oxygen Levels for a
100%
Air/Fuel Valve Position
14. If necessary, adjust the iris air damper shown in Figure 4-5 until the oxygen level is within
the range specified in Table 4-1.
15. Once the oxygen level is within the specified range at 100%, lower the valve position to
80%.
Page 54 of 170 AERCO International Inc.● 100 Oritani Dr. ● Blauvelt, NY 10913. ● Ph: 800-526-0288 PR1 08/20/12
Figure 4-5: Iris Air Damper Location/Adjustment
Page 55
GF-123 Benchmark 2.0LN Low NOx Boil e r Chapter 4
Oxygen %
± 0.2
5.2 %
<100 ppm
<30 ppm
OMM-0046_0E Installation, Operation and Maintenance Manual Initial Start-Up
NOTE
The remaining combustion calibration steps are performed using
the Combustion Cal Menu included in the C-More Control System.
The combustion calibration control functions will be used to adjust
the oxygen level (%) at air/fuel valve positions of 80%, 60%, 45%,
30% and 16% as described in the following steps. These steps
assume that the inlet air temperature is within the range of 50°F to
100°F.
16. Press the MENU key on the front panel of the C-MORE and access the Setup menu. Enter
password 6817 and then press the ENTER key.
17. Press the MENU key on the front panel of the C-MORE until Combustion Cal Menu appears
on the C-More display.
18. Press the ▲ arrow key until SET Valve Position appears on the C-MORE display.
19. Press the CHANGE key. SET Valve Position will begin to flash.
20. Press the ▲ arrow key until the SET Valve Position reads 80%. Press the ENTER key.
21. Next, press the down (▼) arrow key until CAL Voltage 80% is displayed.
22. Press the CHANGE key and observe that CAL Voltage 80% is flashing.
23. The oxygen level at the 80% valve position should be as shown below. Also, ensure that the
carbon monoxide (CO) and nitrogen oxide (NOx) readings do not exceed the values shown.
Table 4-2: Combustion Oxygen Levels for a 80% Air/Fuel Valve Position
Carbon Monoxide NOx
24. If the oxygen level is not within the specified range, adjust the level using the ▲ and ▼
arrow keys. This will adjust the output voltage to the blower motor as indicated on the
display. Pressing the ▲ arrow key increases the oxygen level and pressing the down ▼
arrow key decreases the oxygen level.
25. Once the oxygen level is within the specified range at 80%, press the ENTER key to store
the selected blower output voltage for the 80% valve position.
NOTE
The remaining steps basically repeat the procedures in steps 18 through
25 for valve positions of 60%, 45%, 30% and 16%. However, since oxygen
levels vary, these steps are repeated in their entirety. When performing
these steps, also ensure that the carbon monoxide (CO) and nitrogen oxide
(NOx) readings do not exceed the values shown for each valve position.
26. Press the ▲ arrow key until SET Valve Position appears on the C-MORE display.
27. Press the CHANGE key. SET Valve Position will begin to flash.
28. Press the ▼ arrow key until the SET Valve Position reads 60% and press the ENTER key.
29. Press the down ▼ arrow key until CAL Voltage 60% is displayed.
30. Press the CHANGE key. CAL Voltage 60% will begin to flash.
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Page 56
Chapter 4 Benchmark 2.0LN Low NOx Boiler GF-123
Oxygen %
± 0.2
5.7 %
<50 ppm
<30 ppm
Oxygen %
± 0.2
7.2 %
<50 ppm
<30 ppm
Oxygen %
± 0.2
8.0 %
<50 ppm
<30 ppm
Initial Start-Up Installation, Operation and Maintenance Manual OMM-0046_0E
31. The oxygen level at the 60% valve position should be as shown below. Also, ensure that the
carbon monoxide (CO) and nitrogen oxide (NOx) readings do not exceed the values shown.
Table 4-3: Combustion Oxygen Levels for a 60% Air/Fuel Valve Position
Carbon Monoxide NOx
32. If the oxygen level is not within the specified range, adjust the level using the ▲ and ▼
arrow keys. This will adjust the output voltage to the blower motor as indicated on the
display. Pressing the ▲ arrow key increases the oxygen level and pressing the ▼ arrow key
decreases the oxygen level.
33. Once the oxygen level is within the specified range at 60%, press the ENTER key to store
the selected blower output voltage for the 60% valve position.
34. Press the ▲ arrow key until SET Valve Position appears on the C-MORE display.
35. Press the CHANGE key. SET Valve Position will begin to flash.
36. Press the ▼ arrow key until the SET Valve Position reads 45%, then press the ENTER key.
37. Press the ▼ arrow key until CAL Voltage 45% is displayed.
38. Press the CHANGE key. CAL Voltage 45% will begin to flash.
39. The oxygen level at the 45% valve position should be as shown below. Also, ensure that the
carbon monoxide (CO) and nitrogen oxide (NOx) readings do not exceed the values shown.
Table 4-4: Combustion Oxygen Levels for a 45% Air/Fuel Valve Position
Carbon Monoxide NOx
40. If the oxygen level is not within the specified range, adjust the level using the ▲ and ▼
arrow keys. This will adjust the output voltage to the blower motor as indicated on the
display. Pressing the ▲ arrow key increases the oxygen level and pressing the ▼ arrow key
decreases the oxygen level.
41. Once the oxygen level is within the specified range at 45%, press the ENTER key to store
the selected blower output voltage for the 45% valve position.
42. Press the ▲ arrow key until SET Valve Position appears on the C-MORE display.
43. Press the CHANGE key. SET Valve Position will begin to flash.
44. Press the ▼ arrow key until the SET Valve Position reads 30%, then press the ENTER key.
45. Press the ▼ arrow key until CAL Voltage 30% is displayed.
46. Press the CHANGE key. CAL Voltage 30% will begin to flash.
47. The oxygen level at the 30% valve position should be as shown in Table 4-5. Also, ensure
that the carbon monoxide (CO) and nitrogen oxide (NOx) readings do not exceed the values
shown.
Table 4-5: Combustion Oxygen Levels for a 30% Air/Fuel Valve Position
Carbon Monoxide NOx
Page 56 of 170 AERCO International Inc.● 100 Oritani Dr. ● Blauvelt, NY 10913. ● Ph: 800-526-0288 PR1 08/20/12
Page 57
GF-123 Benchmark 2.0LN Low NOx Boil e r Chapter 4
Oxygen %
± 0.2
8.0 %
<50 ppm
<30 ppm
OMM-0046_0E Installation, Operation and Maintenance Manual Initial Start-Up
48. If the oxygen level is not within the specified range, adjust the level using the ▲ and ▼
arrow keys. This will adjust the output voltage to the blower motor as indicated on the
display. Pressing the ▲ arrow key increases the oxygen level and pressing the ▼ arrow key
decreases the oxygen level.
49. Once the oxygen level is within the specified range at 30%, press the ENTER key to store
the selected blower output voltage for the 30% valve position.
50. Press the ▲ arrow key until SET Valve Position appears on the C-MORE display.
51. Press the CHANGE key. SET Valve Position will begin to flash.
52. Press the ▼ arrow key until the SET Valve Position reads 16%, then press the ENTER key.
53. Press the ▼ arrow key until CAL Voltage 18% is displayed.
54. Press the CHANGE key. CAL Voltage 18% will begin to flash.
55. The oxygen level at the 18% valve position should be as shown below. Also, ensure that the
carbon monoxide (CO) and nitrogen oxide (NOx) readings do not exceed the values shown.
Table 4-6: Combustion Oxygen Levels for a 18% Air/Fuel Valve Position
Carbon Monoxide NOx
56. If the oxygen level is not within the specified range, adjust the level using the ▲ and ▼
arrow keys. This will adjust the output voltage to the blower motor as indicated on the
display. Pressing the ▲ arrow key increases the oxygen level and pressing the ▼ arrow key
decreases the oxygen level.
57. Once the oxygen level is within the specified range at 16%, press the ENTER key to store
the selected blower output voltage for the 16% valve position.
58. This completes the Natural Gas Combustion Calibration procedure.
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Page 58
Chapter 4 Benchmark 2.0LN Low NOx Boiler GF-123
Initial Start-Up Installation, Operation and Maintenance Manual OMM-0046_0E
IMPORTANT
The unit is shipped from the factory set up for either Natural
Gas or Propane as specified by the Style No. on the Sales
Order.
Since the required gas pressures and oxygen (O
) levels for
2
Propane differ from those required for Natural Gas, the Propane Combustion Calibration procedures are repeated in
paragraph 4.5.
4.5 PROPANE COMBUSTION CALIBRATION
The Benchmark 2.0LN Boiler is combustion calibrated at the factory prior to shipping. However,
recalibration as part of initial start-up is necessary due to changes in the local altitude, g as BTU
content, gas supply piping and supply regulators. Factory Test Data sheets are shipped with
each unit. These sheets must be filled out and returned to AERCO for proper Warranty
Validation.
Prior to starting these procedures, ensure that the Benchmark 2.0LN has been set up as
specified in paragraphs 4.2 through 4.2.3.
It is important to perform the following procedure as outlined. This will keep readjustments to a
minimum and provide optimum performance.
1. Open the water supply and return valves to the unit and ensur e that the system pumps are
running.
2. Open the propane supply valve(s) to the unit.
3. Set the control panel ON/OFF switch to the OFF position.
4. Turn on external AC power to the unit. The display will show LOSS OF POWER and the
time and date.
5. Set the unit to the Manual Mode by pressing the AUTO/MAN key. A f lashing Manual Valve
Position message will be displayed with the present rat e in %. Also, the MANUAL LED will
light.
6. Adjust the valve position to 0% by pressing the ▼ arrow key.
7. Ensure that the leak detection ball valve (Figure 4-1) down-stream of the SSOV is open.
8. Set the ON/OFF switch to the ON position.
9. Change the valve position to 29% using the ▲ arrow key. The unit should begin its start
sequence and fire.
10. Next, verify that the gas pressure downstream of the SSOV is 2.3” W.C. for both FM and IRI
gas trains. If gas pressure adjustment is required, remove the brass hex nut on the SSOV
actuator (IRI gas train) containing the gas pressure regulator (Figure 4-3). Make gas
regulator adjustments using a flat-tip screwdriver to obtain 2.3” W.C.
11. Raise the valve position to 100% and verify that the gas pressure downstream of the SSOV
remains at 2.3” W.C. Readjust pressure if necessary.
12. With the valve position at 100%, insert the combustion analyzer probe into the flue probe
opening and allow enough time for the combustion analyzer to stabilize.
13. Compare the measured oxygen % level to the range shown below. Also, ensure that the
carbon monoxide (CO) and nitrogen oxide (NOx) readings do not exceed the values shown.
Page 58 of 170 AERCO International Inc.● 100 Oritani Dr. ● Blauvelt, NY 10913. ● Ph: 800-526-0288 PR1 08/20/12
Page 59
GF-123 Benchmark 2.0LN Low NOx Boil e r Chapter 4
Oxygen %
± 0.2
4.8 %
<100 ppm
<100 ppm
Oxygen %
5.0 %
<100 ppm
<30 ppm
OMM-0046_0E Installation, Operation and Maintenance Manual Initial Start-Up
Table 4-7: Combustion Oxygen Levels for a
100%
Valve Position
Carbon Monoxide
NOx
14. If necessary, adjust the iris air damper shown in Figure 4-4 until the oxygen level is within
the range specified in Table 4-2.
15. Once the oxygen level is within the specified range at 100%, lower the valve position to
80%.
NOTE
The remaining combustion calibration steps are performed using the
Combustion Cal Menu included in the C-More Control System. The
combustion calibration control functions will be used to adjust the oxygen
level (%) at valve positions of 80%, 60%, 45%, 30% and 20% as described
in the following steps. These steps assume that the inlet air temperature is
within the range of 50°F to 100°F.
16. Press the MENU key on the front panel of the C-MORE and access the Setup menu. Enter
password 6817 and then press the ENTER key.
17. Press the MENU key on the front panel of the C-MORE until Combustion Cal Menu appears
on the C-More display.
18. Press the ▲ arrow key until SET Valve Position appears on the C-MORE display.
19. Press the CHANGE key. SET Valve Position will begin to flash.
20. Press the ▲ arrow key until the SET Valve Position reads 80%. Press the ENTER key.
21. Next, press the down (▼) arrow key until CAL Voltage 80% is displayed.
22. Press the CHANGE key and observe that CAL Voltage 80% is flashing.
23. The oxygen level at the 80% valve position should be as shown below. Also, ensure that the
carbon monoxide (CO) and nitrogen oxide (NOx) readings do not exceed the values shown.
80%
Table 4-8: Combustion Oxygen Level at
Valve Position
Carbon Monoxide NOx
± 0.2
24. If the oxygen level is not within the specified range, adjust the level using the ▲ and ▼
arrow keys. This will adjust the output voltage to the blower motor as indicated on the
display. Pressing the ▲ arrow key increases the oxygen level and pressing the down ▼
arrow key decreases the oxygen level.
25. Once the oxygen level is within the specified range at 80%, press the ENTER key to store
the selected blower output voltage for the 80% valve position.
PR1 08/20/12 AERCO International Inc.● 100 Oritani Dr. ● Blauvelt, NY 10913. ● Ph: 800-526-0288 Page 59 of 170
Page 60
Chapter 4 Benchmark 2.0LN Low NOx Boiler GF-123
Oxygen %
± 0.2
4.7 %
<50 ppm
<30 ppm
Oxygen %
± 0.2
6.0 %
<50 ppm
<30 ppm
Initial Start-Up Installation, Operation and Maintenance Manual OMM-0046_0E
NOTE
The remaining steps basically repeat the procedures in steps 18
through 25 for valve positions of 60%, 45%, 30% and 16%.
However, since oxygen levels vary, these steps are repeated in
their entirety. When performing these steps, also ensure that the
carbon monoxide (CO) and nitrogen oxide (NOx) readings d o not
exceed the values shown for each valve position.
26. Press the ▲ arrow key until SET Valve Position appears on the C-MORE display.
27. Press the CHANGE key. SET Valve Position will begin to flash.
28. Press the ▼ arrow key until the SET Valve Position reads 60% and press the ENTER key.
29. Press the down ▼ arrow key until CAL Voltage 60% is displayed.
30. Press the CHANGE key. CAL Voltage 60% will begin to flash.
31. The oxygen level at the 60% valve position should be as shown below. Also, ensure that the
carbon monoxide (CO) and nitrogen oxide (NOx) readings do not exceed the values shown.
Table 4-9: Combustion Oxygen Level at
Carbon Monoxide NOx
32. If the oxygen level is not within the specified range, adjust the level using the ▲ and ▼
arrow keys. This will adjust the output voltage to the blower motor as indicated on the
display. Pressing the ▲ arrow key increases the oxygen level and pressing the ▼ arrow key
decreases the oxygen level.
33. Once the oxygen level is within the specified range at 60%, press the ENTER k ey to store
the selected blower output voltage for the 60% valve position.
34. Press the ▲ arrow key until SET Valve Position appears on the C-MORE display.
35. Press the CHANGE key. SET Valve Position will begin to flash.
36. Press the ▼ arrow key until the SET Valve Position reads 45%, then press the ENTER key.
37. Press the ▼ arrow key until CAL Voltage 45% is displayed.
38. Press the CHANGE key. CAL Voltage 45% will begin to flash.
39. The oxygen level at the 45% valve position should be as shown below. Also, ensure that the
carbon monoxide (CO) and nitrogen oxide (NOx) readings do not exceed the values shown.
Table 4-10: Combustion Oxygen Level at
60%
Valve Position
45%
Valve Position
Carbon Monoxide NOx
40. If the oxygen level is not within the specified range, adjust the level using the ▲ and ▼
arrow keys. This will adjust the output voltage to the blower motor as indicated on the
display. Pressing the ▲ arrow key increases the oxygen level and pressing the ▼ arrow key
decreases the oxygen level.
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Oxygen %
± 0.2
8.0 %
<50 ppm
<30 ppm
Oxygen %
± 0.2
8.6 %
<50 ppm
<30 ppm
OMM-0046_0E Installation, Operation and Maintenance Manual Initial Start-Up
41. Once the oxygen level is within the specified range at 45%, press the ENTER key to store
the selected blower output voltage for the 45% valve position.
42. Press the ▲ arrow key until SET Valve Position appears on the C-MORE display.
43. Press the CHANGE key. SET Valve Position will begin to flash.
44. Press the ▼ arrow key until the SET Valve Position reads 30%, then press the ENTER key.
45. Press the ▼ arrow key until CAL Voltage 30% is displayed.
46. Press the CHANGE key. CAL Voltage 30% will begin to flash.
47. The oxygen level at the 30% valve position should be as shown below. Also, ensure that the
carbon monoxide (CO) and nitrogen oxide (NOx) readings do not exceed the values shown.
30%
Table 4-11: Combustion Oxygen Level at
Carbon Monoxide NOx
48. If the oxygen level is not within the specified range, adjust the level using the ▲ and ▼
arrow keys. This will adjust the output voltage to the blower motor as indicated on the
display. Pressing the ▲ arrow key increases the oxygen level and pressing the ▼ arrow key
decreases the oxygen level.
Valve Position
49. Once the oxygen level is within the specified range at 30%, press the ENTER key to store
the selected blower output voltage for the 30% valve position.
50. Press the ▲ arrow key until SET Valve Position appears on the C-MORE display.
51. Press the CHANGE key. SET Valve Position will begin to flash.
52. Press the ▼ arrow key until the SET Valve Position reads 20%, then press the ENTER key.
53. Press the ▼ arrow key until CAL Voltage 16% is displayed.
54. Press the CHANGE key. CAL Voltage 20% will begin to flash.
55. The oxygen level at the 20% valve position should be as shown below. Also, ensure that the
carbon monoxide (CO) and nitrogen oxide (NOx) readings do not exceed the values shown.
20%
Table 4-12: Combustion Oxygen Level at
Valve Position
Carbon Monoxide NOx
56. If the oxygen level is not within the specified range, adjust the level using the ▲ and ▼
arrow keys. This will adjust the output voltage to the blower motor as indicated on the
display. Pressing the ▲ arrow key increases the oxygen level and pressing the ▼ arrow key
decreases the oxygen level.
57. Once the oxygen level is within the specified range at 20%, press the ENTER key to store
the selected blower output voltage for 20% valve position.
58. This completes the Propane Combustion Calibration procedure.
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4.6 UNIT REASSEMBLY
Once the combustion calibration adjustments are properly set, the unit can be reassembled for
service operation.
1. Set the ON/OFF switch in the OFF position.
2. Disconnect AC power from the unit.
3. Shut off the gas supply to the unit.
4. Remove the manometer and barbed fittings and reinstall the NPT plug using a suitable pipe
thread compound.
5. Remove the combustion analyzer probe from the vent hole. Replace the NPT plug in the
vent hole using a suitable pipe joint compound.
6. Replace the unit’s side panels and front door.
4.7 OVER-TEMPERATURE LIMIT SWITCHES
The unit contains both automatic and manual reset over-temperature limit switches. These
switches are mounted on a plate as shown in Figure 4-6. The switches can be accessed by
opening the front panel door of the unit. The manual reset switch is not adjustable and is
permanently fixed at 200°F. This switch will shut down and lock out the boiler if the water
temperature exceeds 200°F. Following an over-temperature condition, it must be manually reset
by pressing the RESET button before the boiler can be restarted. The automatic reset overtemperature switch is adjustable and allows the boiler to restart, once the temperature drops
below its temperature setting. Set the automatic over-temperature switch to the desired setting.
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GF-123 Benchmark 2.0LN Low NOx Boil e r Chapter 4
FRONT VIEW
ADJUSTABLE
TEMPERATURE
LIMIT SWITCH
RESET BUTTON
FOR MANUAL
TEMPERATURE
LIMIT SWITCH
SEE
DETAIL “A”
DETAIL “A”
OMM-0046_0E Installation, Operation and Maintenance Manual Initial Start-Up
Figure 4-5: Over Temperature Limit Switch Locations
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CHAPTER 5. MODE OF OPE RATION
5.1 INTRODUCTION
The boiler is capable of being operated in any one of six different modes. The following
paragraphs in this Chapter provide descriptions of each of these operating modes. Each boiler
is shipped from the factory tested and configured for the ordered mode of operation. All
temperature related parameters are at their factory default values which work well in most
applications. However, it may be necessary to change certain parameters to customize the unit
to the system environment. A complete listing and descriptions of the temperature related
parameters are included in Appendix A. Factory defaults are listed in Appendix E. After reading
this chapter, parameters can be customized to suit the needs of the specific application.
5.2 INDOOR/OUTDOOR RESET MODE
This m ode of operation is based on outside air temperatures. As the outside air temperature
decreases, the supply header temperature will increase and vice versa. For this mode, it is
necessary to install an outside air sensor as well as select a building reference temperature and
a reset ratio.
5.2.1 Reset Ratio
Reset ratio is an adjustable number from 0.1 to 9.9. Once adjusted, the supply header
temperature will increase by that number for each degree that the outside air temperature
decreases. For instance, if a reset ratio of 1.6 is used, for each degree that outside air
temperature decreases the supply header temperature will increase by 1.6 degrees.
5.2.2 Building Reference Temperature
This is a temperature from 40°F to 230°F. Once selected, it is the temperature that the system
references to begin increasing its temperature. For instance, if a reset ratio of 1.6 is used, and
we select a building reference temperature of 70°F, then at an outside temperature of 69°F, the
supply header temperature will increase by 1.6° to 71.6°F.
5.2.3 Outdoor Air Temperature Sensor Installation
The outdoor air temperature sensor must be mounted on the North side of the building in an
area where the average outside air temperature is expected. The sensor must be shielded from
the sun's direct rays, as well as direct impingement by the elements. If a cover or shield is used,
it must allow free air circulation. The sensor may be mounted up to two hundred feet from the
unit. Sensor connections are made at the Input/Output (I/O) Box on the front of the boiler.
Connections are made at the terminals labeled OUTDOOR SENSOR IN and SENSOR
COMMON inside the I/O Box. Use shielded 18 to 22 AWG wire for connections. A wiring
diagram is provided on the cover of the I/O Box. Refer to Chapter 2, paragraph 2.9.1 for
additional wiring information.
5.2.4 Indoor/ Outdoor Startup
Startup in the Indoor/Outdoor Reset Mode is accomplished as follows:
1. Refer to the Indoor/Outdoor reset ratio charts in Appendix D.
2. Choose the chart corresponding to the desired Building Reference Temperature.
3. Go down the left column of the chart to the coldest design outdoor air temperature expected
in your area.
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NOTE
A design engineer typically provides design outdoor air temperature and
supply header temperature data.
4. Once the design outdoor air temperature is chosen, go across the chart to the desired
supply header temperature for the design temperature chosen in step 3.
5. Next, go up that column to the Reset Ratio row to find the corresponding reset ratio.
6. Access the Configuration Menu and scroll through it until the display shows Bldg Ref Temp.
(Building Reference Temperature).
7. Press the CHANGE key. The display will begin to flash.
8. Use the ▲ and ▼ arrow keys to select the desired Building Reference Temperature.
9. Press ENTER to save any changes.
10. Next, scroll through the Configuration Menu until the display shows Reset Ratio.
11. Press the CHANGE key. The display will begin to flash.
12. Use the ▲ and ▼ arrow keys to select the Reset Ratio determined in step 5.
13. Press ENTER to save the change.
Refer to paragraph 3.3 for detailed instructions on menu changing.
5.3 CONSTANT SETPOINT MODE
The Constant Setpoint mode is used when a fixed header temperature is desired. Common
uses of this mode of operation include water source heat pump loops, and indirect heat
exchangers for potable hot water systems or processes.
No external sensors are required to operate in this mode. While it is necessary to set the
desired setpoint temperature, it is not necessary to change any other temperature-related
functions. The unit is factory preset with settings that work well in most applications. Prior to
changing any temperature-related parameters, other than the setpoint, it is suggested that an
AERCO representative be contacted. For descriptions of temperature-related functions and their
factory defaults, see Appendices A and E.
5.3.1 Setting the Setpoint
The setpoint temperature of the unit is adjustable from 40°F to 240°F. To set the unit for
operation in the Constant Setpoint Mode, the following menu settings must be made in the
Configuration Menu:
MENU OPTION SETTING
Boiler Mode Constant Setpoint
Internal Setpt Select desired setpoint
using ▲ and ▼ arrow
keys (40°F to 240°F)
Refer to paragraph 3.3 for detailed instructions on changing menu options.
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5.4 REMOTE SETPOINT MODES
The unit’s setpoint can be remotely controlled by an Energy Management System (EMS) or
Building Automation System (BAS). The Remote Setpoint can be driven by a current or voltage
signal within the following ranges:
• 4-20 mA/1-5 Vdc
• 0-20 mA/0-5 Vdc
The factory default setting for the Remote Setpoint mode is 4 - 20 mA/1 - 5 Vdc. W ith this
setting, a 4 to 20 mA/1 to 5 Vdc signal, sent by an EMS or BAS, is used to chang e the unit's
setpoint. The 4 mA/1V signal is equal to a 40°F setpoint while a 20 mA /5V signal is equal to a
240°F setpoint. When a 0 to 20 mA/0 to 5 Vdc signal is used, 0 mA is equal to a 40°F setpoint.
In addition to the current and voltage signals described above, the Remote Setpoint mode can
also driven by a RS485 Modbus Network signal from an EMS or BAS.
The Remote Setpoint modes of operation can be used to drive single as well as multiple units.
NOTE
If a voltage, rather than current signal is used to control the remote
setpoint, a DIP switch adjustment must be made on the CPU Board located
in the Control Panel Assembly. Contact your local AERCO representative
for details.
In order to enable the Remote Setpoint Mode, the following menu setting must be made in the
Configuration Menu:
MENU OPTION SETTING
Boiler Mode Remote Setpoint
Remote Signal 4-20mA/1-5V,
0-20mA/0-5V, or
Network
Refer to paragraph 3.3 for detailed instructions on changing menu options.
If the Network setting is selected for RS485 Modbus operation, a valid C omm Address must be
entered in the Setup Menu. Refer to Modbus Communication Manual GF-114 for additional
information.
While it is possible to change the settings of temperature related functions, the unit is factory
preset with settings that work well in most applications. It is suggested that an AERCO
representative be contacted, prior to changing any temperature related function settings. For
descriptions of temperature-related functions and their factory defaults, refer to Appendices A
and E.
5.4.1 Remote Setpoint Field Wiring
The only wiring connections necessary for the Remote Setpoint mode are connection of the
remote signal leads from the source to the unit’s I/O Box. The I/O Box is located on the front
panel of the boiler. For either a 4-20mA/0-5V or a 0-20mA/0-5V setting, the connections are
made at the ANALOG IN terminals in the I/O Box. For a Network setting, the connections are
made at the RS-485 COMM terminals in the I/O Box. The signal must be f loat ing, (ungr ounded)
at the I/O Box and the wire used must be a two wire shielded pair from 18 to 22 AWG. Polarity
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must be observed. The source end of the shield must be connected at the source. When driving
multiple units, each unit’s wiring must conform to the above.
5.4.2 Remote Setpoint Startup
Since this mode of operation is factory preset and the setpoint is being externally controlled, no
startup instructions are necessary. In this m ode, the REMOTE LED will light when the external
signal is present.
To operate the unit in the Manual mode, press the AUTO/MAN switch. The REMOTE LED will
go off and the MANUAL LED will light.
To change back to the Remote Setpoint mode, simply press the AUTO/MAN switch. The
REMOTE LED will again light and the MANUAL LED will g o of f.
5.5 DIRECT DRIVE MODES
The unit’s air/fuel valve position (% open) can be changed by a remote signal which is typically
sent from an Energy Management System (EMS) or from a Building Automation System (BAS).
The Direct Drive mode can be driven by a current or voltage signal within the following ranges:
• 4-20 mA/1-5 Vdc
• 0-20 mA/0-5 Vdc
The factory default setting for the Direct Drive mode is 4-20 mA/1-5 Vdc. With this setting, a 4
to 20 mA signal, sent by an EMS or BAS is used to change the unit’s valve position from 0% to
100%. A 4 mA/1V signal is equal to a 0% valve position, while a 20 mA /5V sig nal is equal to a
100% valve position. When a 0-20 mA/0-5 Vdc signal is used, zero is equal to a 0% valve
position.
In addition to the current and voltage signals described above, the Direct Drive mode can also
driven by a RS485 Modbus Network signal from an EMS or BAS.
When in a Direct Drive mode, the unit is a slave to the EMS or BAS and does not have a role in
temperature control. Direct Drive can be used to drive single, or multiple units.
NOTE
If a voltage, rather than current signal is used to control the remote
setpoint, a DIP switch adjustment must be made on the CPU Board located
in the Control Box Assembly. Contact your local AERCO representative for
details.
To enable the Direct Drive Mode, the following menu setting must be made in the Conf iguration
Menu:
MENU OPTION SETTING
Boiler Mode Direct Drive
Remote Signal 4-20mA/1-5V,
0-20mA/0-5V, or
Network
Refer to paragraph 3.3 for instructions on changing menu options.
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If the Network setting is selected for RS485 Modbus operation, a valid C omm Address must be
entered in the Setup Menu. Refer to Modbus Communication Manual GF-114 for additional
information.
5.5.1 Direct Drive Field Wiring
The only wiring connections necessary for Direct Drive mode are connection of the remote
signal leads from the source to the unit’s I/O Box. For either a 4-20mA/0-5V or a 0-20mA/0-5V
setting, the connections are made at the ANALOG IN terminals in the I/O Box. For a Network
setting, the connections are made at the RS-485 COMM terminals in the I/O Box. The sig nal
must be floating, (ungrounded) at the I/O Box and the wire used must be a two wire shielded
pair from 18 to 22 AWG. Polarity must be observed. The source end of the shield must be
connected at the source. When driving multiple units, each unit’s wiring must conform to the
above.
5.5.2 Direct Drive Startup
Since this mode of operation is factory preset and the valve position is being externally
controlled, no startup instructions are necessary. In this mode, the REMOTE LED will light when
the signal is present.
To operate the unit in manual mode, press the AUTO/MAN s witch. The REMOTE LE D will go
off and the MANUAL LED will light .
To change back to the Direct Drive mode, simply press the AUTO/MAN switch. The REMOTE
LED will again light and the MANUAL LED will g o of f.
5.6 BOILER MANAGEMENT SYSTEM (BMS)
NOTE
BMS Model 168 can utilize either pulse width modulation (PWM)
or RS485 Modbus signaling to the Boiler. The BMS II and the ACS
(AERCO Control System) can utilize only RS485 signaling to the
Boiler.
The BMS mode of operation is used in conjunction with an AERCO Boiler Management System
(BMS or BMS II) and the AERCO Control System (ACS). The BMS mode is used when it is
desired to operate multiple units in the most efficient manner possible. For this mode of
operation, a BMS Header Sensor must be installed between 2 and 10 feet downstream of the
LAST boiler in the boiler plant's supply water header. The BMS can control up to 40 boilers; 8
via pulse width modulation (PWM) and up to 32 via Modbus (RS485) net work communication.
For BMS/BMS II/ACS programming, operation, and Header Sensor installation details, see GF108M (BMS Model 168), GF-124 (BMS II Model 5R5-384), and GF-131 (ACS) Operations
Manuals. For operation via an RS485 Modbus network, refer to Modbus Communication
Manual, GF-114.
To enable the BMS Mode, the following menu settings must be made in the Configuration
Menu:
MENU OPTION SETTING
Boiler Mode Direct Drive
Remote Signal BMS (PWM Input) or
Network (RS485)
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Refer to paragraph 3.3 for instructions on changing menu options.
5.6.1 BMS External Field Wiring
Wiring connections for BMS control using PWM signaling are made between connector J P2 on
the BMS panel (boilers 1 through 8), and the B.M.S. (PWM) IN terminals in the I/O Box on the
front of the boilers. Refer to the wiring diagram provided on the cover of the I/O Box.
Wiring connections for RS485 Modbus control are made between connector JP11 on the BMS
(boilers 9 through 40) or JP6 on BMS II/ACS (boilers 1-32) and the RS485 COMM terminals in
the I/O Box on the front of the boilers.
Wire the units using shielded twisted pair wire between 18 and 22 AWG. Observe the proper
polarity for the B.M.S. (PWM) IN and/or RS485 COMM wiring connections. Shields should be
terminated only at the BMS/BMS II/ACS and the boiler end must be left floating. Each unit’s
wiring must conform to the above.
5.6.2 BMS Setup and Startup
This mode of operation is factory preset and the AERCO BMS/BMS II/ACS controls the firing
rate (air/fuel valve % open position). There are no setup instructions for each individual unit.
To operate the unit in manual mode, press the AUTO/MAN s witch. The REMOTE LE D will go
off and the MANUAL LED will light
To change back to the BMS mode, simply press the AUTO/MAN switch. The REMOTE LED
will again light and the MANUAL LED will go off.
5.7 COMBINATION CONTROL SYSTEM (CCS)
NOTE
Only the BMS and ACS can be utilized for the Combination Mode,
but not the BMS II.
A Combination Control System (CCS) is one that uses multiple boilers to cover both spaceheating and domestic hot water needs. An AERCO Boiler Management System (BMS) Model
168 and a Combination Control Panel (CCP) or an ACS and an ACS Relay Panel (optional,
depending on applications) are necessary to configure this system. Typically, an adequate
number of boilers are installed to cover the space-heating load on the design day, however one
or more units are used for the domestic hot water load.
The theory behind this type of system is that the maximum space-heating load and the
maximum domestic hot water load do not occur simultaneously. T herefore, boilers used for the
domestic hot water are capable of switching between constant setpoint and BMS modes of
operation. These boilers are the combination units and are referred to as the combo boilers. The
combo boilers heat water to a constant setpoint temperature. That water is then circulated
through a heat exchanger in a domestic hot water storage tank.
When t he space-heating load is such that all the space-heating boilers are at the 100% valve
position, the BMS/ACS will then operate the domestic boilers to become space-heating boilers,
provided the domestic hot water load is satisfied. If the domestic hot water load is not satisfied,
the combo boiler(s) remain on the domestic hot water load. If the combo boilers switch over to
space heating, but there is a call for domestic hot water, the combo units will resum e heating
water for domestic needs.
When the combo units are satisfying the domestic load they are in con stant setpoint mode of
operation. When the combo units switch over to space heating, their mode of operation changes
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to the BMS mode. For more information concerning the operation of the Combination Control
Panel see the AERCO CCP-1 literature (BMS 168 applications) and TAG-0050 (ACS).
5.7.1 Combination Control System Field Wiring
Wiring for this system is between the BMS Model 168 panel, the CCP and the B.M.S. (PWM) IN
terminals in the I/O Box. For ACS applications, the wiring is between the ACS panel, the ACS
Replay Panel (optional, depending on application), and the RS485 Comm terminals in the I/O
box. Wire the units using a shielded twisted pair of 18 to 22 AWG wire. W hen wiring multiple
units, each unit’s wiring must conform to the above. For a complete CCP system-wiring diagram
see the AERCO CCP-1 literature (BMS 168 applications) and TAG-0050 (ACS).
5.7.2 Combination Control System Setup and Startup
Setup for the Combination Mode requires entries to be made in the Configuration Menu for
boiler mode, remote signal type and setpoint. The setpoint is adjustable from 40°F to 240°F.
Enter the following settings in the Configuration Menu:
MENU OPTION
Boiler Mode Combination Combination
Remote Signal BMS (PWM Input) Network (RS485)
Internal Setpt 40°F to 240°F 40°F to 240°F
Refer to paragraph 3.3 for instructions on changing menu options.
While it is possible to change other temperature-related f unctions for combination mode, thes
functions are preset to their factory default values. These default settings work well in most
applications. It is suggested that AERCO be contacted prior to changing settings ot her than the
unit’s setpoint. For a complete listing of temperature related function defaults, see Appendix E.
To set the unit to the manual mode, press the AUTO/MAN switch. The MANUAL LED will light.
To set the unit back to the auto mode, pr es s t he AUTO/MAN switch. T he MANUAL LED will go
off and the REMOTE LED will light.
When the boiler is switched to BMS mode, the AERCO BMS/ACS controls the valve position.
There are no setup requirements to the boiler(s) in this mode.
SETTINGS
BMS 168 Applications ACS Applications
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OMM-0046_0E Installation, Operation and Maintenance Manual Safety Device Tests
CHAPTER 6. SAFETY DEVICE TESTING
6.1 TESTING OF SAFETY DEVICES
Periodic safety device testing is required to ensure that the control system and safety devices
are operating properly. The boiler control system comprehensively monitors all combustionrelated safety devices before, dur ing and after the start sequence. The following tests check to
ensure that the system is operating as designed.
Operating controls and safety devices should be tested on a regular basis or following service or
replacement. All testing must conform to local codes such as ASME CSD-1.
NOTE
MANUAL and AUTO modes of operation are required to perform the
following tests. For a complete explanation of these modes, see Chapter 3.
NOTE
It will be necessary to remove the front door and side panels from the unit
to perform the following tests.
WARNING!
ELECTRICAL VOLTAGES IN THI S SYSTEM MAY INCLUDE 12 0 AND 24
VOLTS AC. POWER MUST BE REMOVED PRIOR TO PERFORMING
WIRE REMOVAL OR OTHER TEST PROCEDURES T HAT CAN RESULT
IN ELECTRICAL SHOCK.
6.2 LOW GAS PRESSURE FAULT TEST
Refer to Figure 6-1 and ensure that the leak detection ball valve located at the high gas
pressure switch is closed.
1. Remove the 1/4“ plug from the ball valve at the low gas pressure switch shown in the lower
portion of Figure 6-1.
2. Install a 0 – 16 “ W.C. manometer or a W.C. gauge where the 1/4" plug was removed.
3. Slowly open the ball valve near the low gas pressure switch.
4. Place the unit in Manual Mode and adjust the air/fuel valve position (% open) between 25
and 30%.
5. While the unit is firing, slowly close the external manual gas shut-off valve.
6. The unit should shut down and display a LOW GAS PRESSURE fault message at
approximately 2.6” W.C. The FAULT indicator should also start flashing.
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Chapter 6 Benchmark 2.0LN Low NOx Boiler GF-123
TO
VALVE
MANUAL
1/4” NPT PLUG
GAS PRESSURE TEST)
HIGH
PRESSURE SWITCH
1/4” LEAK DETECTION
1/4” NPT PLUG
GAS PRESSURE TEST)
1/4” BALL VALVE
PRESSURE SWITCH
Safety Device Tests Installation, Operation and Maintenance Manual OMM-0046_0E
GAS
INLET
(Shown Closed)
(Install manometer here for
LOW
LOW GAS
SSOV
(Install manometer here for
HIGH
GAS
VALVE (Shown Closed)
AIR/FUEL
SHUT-OFF
VALVE (Shown
Open)
Figure 6-1: Low & High Gas Pressure Testing
7. Fully open the external manual gas shut-off valve and press the CLEAR button on the
Control Box.
8. The fault message should clear and the FAULT indicator should go off. The unit should
restart.
9. Upon test completion, close the ball valve and remove the manometer. Replace the 1/4“
plug removed in step 1.
6.3 HIGH GAS PRESSURE TEST
To simulate a high gas pressure fault, refer to Figure 6-1 and proceed as follows:
1. Remove the 1/4“ plug from the leak detection ball valve shown in Figure 6-1.
2. Install a 0 – 16” W.C. manometer (or W.C. gauge) where the 1/4” plug was removed.
3. Slowly open the leak detection ball valve
4. Start the unit in Manual mode at a valve position (firing rate) between 25 and 30%.
5. Slowly increase the gas pressure using the adjustment screw on the SSOV (see Figure 4-3).
6. The unit should shut down and display a HIGH GAS PRESSURE fault message when the
gas pressure exceeds 4.7” W.C. The FAULT indicator should also start flashing.
7. Reduce the gas pressure back to 3.0” W.C.
8. Press the CLEAR button on the Control Box to clear the fault.
9. The fault message should clear and the FAULT indicator should go off. The unit should
restart.
10. Upon test completion, close the ball valve and remove the manometer. Replace the
1/4“ plug removed in step 1.
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GF-123 Benchmark 2.0LN Low NOx Boil e r Chapter 6
OMM-0046_0E Installation, Operation and Maintenance Manual Safety Device Tests
6.4 LOW WATER LEVEL FAULT TEST
To simulate a low water level fault:
1. Set the ON/OFF switch to the OFF position
2. Close the water shut-off valves in the supply and return piping to the unit.
3. Slowly open the drain valve on the rear of the unit. If necessary the unit’s relief valve may
be opened to aid in draining.
4. Continue draining the unit until a LOW WATER LEVEL fault message is displayed and the
FAULT indicator flashes.
5. Place the unit in the Manual Mode and raise the valve position above 30%.
6. Set the ON/OFF switch to the ON position. The READY light should remain off and the unit
should not start. If the unit does start, shut the unit off immediately and refer fault to
qualified service personnel.
7. Close the drain and pressure relief valve used in draining the unit.
8. Open the water shut-off valve in the return piping to the unit.
9. Open the water supply shut-off valve to the unit to refill.
10. After the shell is full, press the LOW WATER LEVEL RESET button to reset the low water
cutoff.
11. Press the CLEAR button to reset the FAULT LED and clear the displayed error message.
12. Set the ON/OFF switch to the ON position. The unit is now ready for operation.
6.5 WATER TEMPERATURE FAULT TEST
A high water temperature fault is simulated by adjusting the automatic over-temperature switch.
This switch is accessible from the front of the unit as shown in Figure 6-2.
1. Start the unit in the normal operating mode. Allow the unit to stabilize at its setpoint.
2. Lower the adjustable over-temperature switch setting to match the displayed OUTLET
TEMPERATURE.
3. Once the adjustable over-temperature switch setting is approximately at, or just below, the
actual outlet water temperature, the unit should shut down. The FAULT indicator should
start flashing and a HIGH WATER TEMP SWITCH OPEN fault message should be
displayed. It should not be possible to restart the unit.
4. Reset the adjustable over-temperature switch to its original setting.
5. The unit should start once the adjustable temperature limit switch setting is above the actual
outlet water temperature.
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Chapter 6 Benchmark 2.0LN Low NOx Boiler GF-123
FRONT VIEW
ADJUSTABLE
TEMPERATURE
LIMIT SWITCH
RESET BUTTON
FOR MANUAL
TEMPERATURE
LIMIT SWITCH
SEE
DETAIL “A”
DETAIL “A”
Safety Device Tests Installation, Operation and Maintenance Manual OMM-0046_0E
Figure 6-2: Temperature Limit Switch Setting
6. Once the adjustable over-temperature switch setting is approximately at, or just below, the
actual outlet water temperature, the unit should shut down. The FAULT indicator should
start flashing and a HIGH WATER TEMP SWITCH OPEN fault message should be
displayed. It should not be possible to restart the unit.
7. Reset the adjustable over-temperature switch to its original setting.
8. The unit should start once the adjustable temperature limit switch setting is above the actual
outlet water temperature.
6.6 INTERLOCK TESTS
The unit is equipped with two interlock circuits called the Remote Interlock and Delayed
Interlock. Terminal connections for these circuits are located in the I/O Box (Figure 2-9) and are
labeled REMOTE INTL’K IN and DELAYED INTL’K IN. These circuits can shut down the unit in
the event that an interlock is opened. These interlocks are shipped from the factory jumpered
(closed). However, each of these interlocks may be utilized in the field as a remote stop and
start, an emergency cut-off, or to prove that a device such as a pump, gas booster, or louver is
operational.
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GF-123 Benchmark 2.0LN Low NOx Boil e r Chapter 6
OMM-0046_0E Installation, Operation and Maintenance Manual Safety Device Tests
6.6.1 REMOTE INTERLOCK
1. Remove the cover from the I/O Box and locate the REMOTE INTL’K IN terminals.
2. Start the unit in the Manual Mode and set the valve position between 25% and 30%.
3. If there is a jumper across the REMOTE INTL’K IN terminals, remove one side of the
jumper. If the interlock is being controlled by an external device, either open the interlock
via the external device or disconnect one of the wires leading to the external device.
4. The unit should shut down and display INTERLOCK OPEN.
5. Once the interlock connection is reconnected, the INTERLOCK OPEN message should
automatically clear and the unit should restart.
6.6.2 DELAYED INTERLOCK
1. Remove the cover from the I/O Box and locate the DELAYED INTL’K IN terminals.
2. Start the unit in the Manual Mode at a valve position between 25% and 30%.
3. If there is a jumper across the DELAYED INTL’K IN terminals, remove one side of the
jumper. If the interlock is connected to a proving switch of an external device, disconnect
one of the wires leading to the proving switch.
4. The unit should shut down and display a DELAYED INTERLOCK OPEN fault message.
The FAULT LED should be flashing.
5. Reconnect the wire or jumper removed in step 3 to restore the interlock.
6. Press the CLEAR button to reset the fault
7. The unit should start.
6.7 FLAME FAULT TESTS
Flame faults can occur during ignition or while the unit is already running. To simulate each of
these fault conditions, proceed as follows:
1. Set the ON/OFF switch to the OFF position.
2. Place the unit in the Manual Mode and set the valve position between 25% and 30%.
3. Close the manual gas shutoff valve located between the Safety Shut-Off Valve (SSOV) and
the Air/Fuel Valve (see Figure 6-3).
4. Set the ON/OFF switch to the ON position to start the unit.
5. The unit should shut down after reaching the Ignition cycle and display FLAME LOSS
DURING IGN.
6. Open the valve previously closed in step 3 and press the CLEAR button.
7. Restart the unit and allow it to prove flame.
8. Once flame is proven, close the manual gas valve located between the SSOV (Figure 6-3)
and the Air/Fuel Valve.
9. The unit should shut down and execute an IGNITION RETRY cycle by performing the
following steps:
(a) The unit will execute a shutdown purge cycle for a period of 15 seconds and display
WAIT FAULT PURGE.
(b) The unit will execute a 30 second re-ignition delay and display WAIT RETRY PAUSE.
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Chapter 6 Benchmark 2.0LN Low NOx Boiler GF-123
SSOV
BLOWER
PROOF
SWITCH
BLOCKED
INLET
SWITCH
AIR
INLET
AIR/FUEL
VALVE
MANUAL
GAS SHUTOFF VALVE
PARTIAL LEFT SIDE VIEW
Safety Device Tests Installation, Operation and Maintenance Manual OMM-0046_0E
(c) The unit will then execute a standard ignition sequence and display WAIT IGNITION
RETRY.
10. Since the manual gas shutoff valve is still closed, the unit will fail the ig nit ion retry sequence.
Therefore, it will shut down and display FLAME LOSS DURING IGNITION following the
failed ignition retry cycle.
11. Open the valve previously closed in step 8.
12. Press the CLEAR button. The unit should restart and fire.
Figure 6-3: Manual Gas Shut-Off Valve Location
6.8 AIR FLOW FAULT TESTS
These tests check the operation of the Blower Proof Switch and Blocked Inlet Switch shown in
Figure 6-3.
1. Disable the blower output drive voltage as follows:
(a) Press the MENU key until CONFIGUR-ATION MENU is displayed.
(b) Press the ▲ arrow key until the ANA-LOG OUTPUT f unction is displayed, then press
the CHANGE key.
(c) Press the ▼ arrow key until OFF is displayed, then press the ENTER key.
2. Start the unit in the Manual Mode at a valve position between 25% and 30%.
3. The unit should shut down and execute an IGNITION RETRY cycle by performing the
following steps:
(a) The unit will execute a 30 second re-ignition delay and display WAIT RETRY PAUSE.
(b) The unit will then execute a standard ignition sequence and display WAIT IGNITION
RETRY.
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GF-123 Benchmark 2.0LN Low NOx Boil e r Chapter 6
OMM-0046_0E Installation, Operation and Maintenance Manual Safety Device Tests
4. The unit should perform one IGNITION RETRY cycle and then shut down, since the blower
is disabled. The unit will then display AIRFLOW FAULT DURING PURGE.
5. Re-enable the blower output drive voltage by performing the following steps:
(a) Press the MENU key until CONFIGUR-ATION MENU is displayed.
(b) Press the ▲ arrow key until the ANA-LOG OUTPUT f unction is displayed, then press
the CHANGE key.
(c) Press the ▲ arrow key until VALVE POSITION 0-10V is displayed, then press the
ENTER key.
6. Once the unit has proved flame, turn off the blower by going to the Configuration Menu,
Analog Output menu item and select OFF.
7. The Blower Proof Switch will open and the blower should stop. The unit should shut down
and display AIRFLOW FAULT DURING RUN.
8. Go to the Configuration Menu, Analog Output item and select VALVE POSITION 0-10v.
9. Press the CLEAR button. The unit should restart.
10. Next, check the Blocked Inlet Switch by first noting the current position of the Iris Air Damper
and then closing the Damper to position 8.
11. .The unit should shut down and again display AIRFLOW FAULT DURING RUN.
12. Return the Iris Air Damper to its previous setting.
13. Press the CLEAR button. The unit should restart.
6.9 SSOV PROOF OF CLOSURE SWITCH
The SSOV shown in Figure 6-1 contains the proof of closure switch. The proof of closure switch
circuit is checked as follows:
1. Set the unit’s ON/OFF switch to the OFF position.
2. Place the unit in Manual Mode and set the valve position between 25% and 30%
3. Refer to Figure 6-1 and locate the SSOV.
4. Remove the cover from the SSOV by loosening the screw shown in Figure 6-4. Lift off the
cover to access the terminal wiring connections.
5. Disconnect wire #148 from the SSOV to “open” the proof of closure switch circuit.
6. The unit should fault and display SSOV SWITCH OPEN.
7. Replace wire #148 and press the CLEAR button.
8. Set the ON/OFF switch to ON to start the unit.
9. Remove the wire again when the unit reaches the purge cycle and PURGING is displayed.
10. The unit should shut down and display SSOV FAULT DURING PURGE.
11. Replace the wire on the SSOV and press the CLEAR button. The unit should restart.
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Chapter 6 Benchmark 2.0LN Low NOx Boiler GF-123
ACTUATOR
COVER
SCREW
SSOV
ACTUATOR
COVER
Safety Device Tests Installation, Operation and Maintenance Manual OMM-0046_0E
Figure 6-4: SSOV Actuator Cover Location
6.10 PURGE SWITCH OPEN DURING PURGE
The Purge Switch (and Ignition Switch) is located on the Air/Fuel Valve. To check the switch,
proceed as follows:
1. Set the unit’s ON/OFF switch to the OFF position. Place the unit in manual mode and set the
valve position between 25% and 30%.
2. Remove the Air/Fuel Valve cover by rotating the cover counterclockwise to unlock it and
then lift up (see Figure 6-5).
3. Remove one of the two wires (#171 or #172) from the Purge Switch (Figure 6-6).
4. Initiate a unit start sequence.
5. The unit should begin it’s start sequence, then shut down and display PRG SWITCH OPEN
DURING PURGE.
6. Replace the wire on the Purge Switch and depress the CLEAR button. The unit should
restart.
6.11 IGNITION SWITCH OPEN DURING IGNITION
The Ignition Switch (and the Purge Switch) is located on the Air/Fuel Valve. To check the
switch, proceed as follows:
1. Set the unit’s ON/OFF switch to the OFF position.
2. Place the unit in Manual Mode and set the valve position between 25% and 30%.
3. Remove the Air/Fuel Valve cover (Figure 6-5) by rotating the cover counterclockwise to
unlock and lift up to remove.
4. Remove one of the two wires (#169 or #170) from the Ignition Switch (Figure 6-6).
5. Initiate a unit start sequence.
6. The unit should begin its start sequence and then shut down and display IGN SWITCH
OPEN DURING IGNITION.
7. Replace the wire on the Ignition Switch and press the CLEAR button. The unit should
restart.
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GF-123 Benchmark 2.0LN Low NOx Boil e r Chapter 6
AIR/FUEL VALVE COVER
(ROTATE CCW TO REMOVE)
STEPPER
MOTOR
DIAL
172
171
169
170
IGNITION
POSITION
SWITCH
PURGE
POSITION
SWITCH
AIR
IN
TO
BLOWER
OMM-0046_0E Installation, Operation and Maintenance Manual Safety Device Tests
Figure 6-5: Air/Fuel Valve Cover Location
Figure 6-6: Air/Fuel Valve Purge and Ignition Switch Locations
6.12 SAFETY PRESSURE REL IEF VALVE TEST
Test the safety Pressure Relief Valve in accordance with ASME Boiler and Pressure Vessel
Code, Section VI.
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Chapter 6 Benchmark 2.0LN Low NOx Boiler GF-123
Safety Device Tests Installation, Operation and Maintenance Manual OMM-0046_0E
(This Page Is Intentionally Blank)
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Page 83
GF-123 Benchmark 2.0LN Low NOx Boil e r Chapter 7
Labor
Time
Igniter-Injector
(58023)
Flame Detector
(66006)
Combustion Calibration &
RSI Regulator Adjustment
Inspect &
Clean
OMM-0046_0E Installation, Operation and Maintenance Manual Maintenance
CHAPTER 7. MAINTENANCE
7.1 MAINTENANCE SCHEDULE
The unit requires regular routine maintenance to keep up efficiency and reliability. For best
operation and life of the unit, the following routine maintenance procedures should be performed
in the time periods specified in Table 7-1. See Appendix I for a complete CSD-1 inspection
check list.
In order to perform the maintenance tasks specified in Table 7-1, the following maintenance k it s
are available through your local AERCO Sales Representative:
• Annual Maintenance Kit, Part No. 58025-01
• 24-Month Waterside/Fireside Inspection Kit, Part No. 58025-06 (See NOTE below)
NOTE
The 24-Month Waterside/Fireside Inspection Kit also includes the items
contained in the Annual Maintenance Kit. Therefore, only Kit Part No.
58025-06 is required when performing the waterside/fireside inspections.
Appendix K contains recommended spare parts lists for maintenance of the boiler.
WARNING
TO AVOID PERSONAL INJURY, PRI OR TO SERVICING ENSURE T HAT
THE FOLLOWING GUIDELINES ARE STRICTLY OBSERVED:
• DISCONNECT THE AC SUPPLY BY TURNING OFF THE
SERVICE SWITCH AND AC SUPPLY CIRCUIT BREAKER.
• SHUT OFF THE GAS SUPPLY AT THE MANUAL SHUT-
OFF VALVE PROVIDED WITH THE UNIT
• ALLOW THE UNIT TO COOL TO A SAFE WATER
TEMPERATURE TO PREVENT BURNING OR SCALDING
Table 7-1: Maintenance Schedule
Paragraph Item 6 Mos. 12 Mos. 24 Mos.
7.2
7.3
7.4
7.5 Testing of Safety Devices -
*Inspect Inspect Replace 15 mins.
*Inspect Inspect Replace 15 mins.
*Check Check - 1 hr.
See CSD-1
Chart in
Appendix I
- 20 mins.
7.6 Burner - - Inspect 2 hrs.
7.7 Condensate Drain Trap *Inspect
*Only performed after initial 6 month period after initial startup.
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- 30 mins.
Page 84
Chapter 7 Benchmark 2.0LN Low NOx Boiler GF-123
AIR/FUEL
VALVE
STAGED
IGNITION
ASSEMBLY
FLAME
DETECTOR
IGNITOR-
INJECTOR
BLOWER
BURNER
PLATE
BURNER
Maintenance Installation, Operation and Maintenance Manual OMM-0046_0E
7.2 IGNITER-INJECTOR
The igniter-injector (part no. 58023) is located on the burner plate at the top of the boiler. In
addition to providing the ignition spark required to light the burner, the igniter-injector also
contains a gas injector tube which connects to the staged ignition assembly. Figure 7-1 shows
the complete burner assembly removed from the boiler and indicates the location of the igniterinjector flame detector and other related components.
The igniter-injector may be hot, therefore, care should be exercised to avoid burns. It is easier to
remove the igniter-injector from the unit after the unit has cooled to room temperature.
Figure 7-1: Benchmark 2.0LN Burner Assembly (Shown Removed from Boiler )
To inspect/replace the Igniter:
1. Set the ON/OFF switch on the control panel, to the OFF position. Disconnect AC power
from the unit
2. Remove the side and top panels from the unit.
3. Disconnect the cable from the igniter-injector (Figure 7-1).
4. Refer to the partial exploded view in Figure 7-2. Using a 7/16” open-end wrench, disconnect
the compression nut securing the gas injector tube of the igniter-injector to the elbow of the
staged ignition assembly. Disconnect the staged ignition assembly from the igniter-injector.
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GF-123 Benchmark 2.0LN Low NOx Boil e r Chapter 7
STAGED
IGNITION
ASSEMBLY
FLAME
DETECTOR
IGNITOR-
INJECTOR
BURNER
PLATE
COMPRESSION
FITTING & ELBOW
FLAME
DETECTOR
GASKET
INDEXING
WASHERS
(QTY = 0-3
AS REQ’D)
OMM-0046_0E Installation, Operation and Maintenance Manual Maintenance
IMPORTANT
Prior to removing the igniter-injector, note the position of the gas injector
tube relative to the burner plate and blower. This is necessary to ensure
that the igniter injector is reinstalled in the proper orientation when it is
reconnected to the staged ignition assembly.
Figure 7-2: Igniter-Injector & Flame Detector Mounting Details
5. Next, loosen and remove the igniter-injector from the burner plate using a 1" open-end
wrench.
6. Check the igniter-injector for evidence of erosion or carbon build-up. If there is evidence of
substantial erosion or carbon build-up, the igniter-injector should be replaced. If carbon
build-up is present, clean the component using fine emery cloth. Repeated carbon build-up
is an indication that the combustion settings of the unit should be check ed. Ref er to Chapter
4 for combustion calibration procedures.
7. Prior to reinstalling the igniter-injector, a high temperature, conductive, anti-seize compound
must be applied to the threads.
NOTE
If a replacement igniter-injector (part no. 58023) is being installed, a
compression nut containing a built-in ferrule will be included with the
replacement part. If needed, three indexing washers are also included
These washers may be needed to properly position the gas injector tube of
the igniter-injector within the 120° angle range shown in Figure 7-3.
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Chapter 7 Benchmark 2.0LN Low NOx Boiler GF-123
120
IGNITOR-
INJECTOR
GAS
INJECTOR
TUBE
BLOWER
BURNER
PLATE
Maintenance Installation, Operation and Maintenance Manual OMM-0046_0E
Figure 7-3: Igniter-Injector Orientation
8. Reinstall the igniter-injector in the burner plate. Torque to 15 ft-lbs. Do not over tighten.
9. Connect the staged ignition assembly to the gas injector tube of the igniter-injector by
securing the compression nut to the elbow of the staged ignition assembly.
10. Reconnect the igniter-injector cable.
11. Reinstall the side and top panels on the unit.
7.3 FLAME DETECTOR
The flame detector (part no. 66006) is located on the burner plate at the top of the unit (see
Figures 7-1 and 7-2). The flame detector may be hot. Allow the unit to cool sufficiently before
removing the flame detector.
To inspect or replace the flame detector:
1. Set the ON/OFF switch on the control panel, to the OFF position. Disconnect AC power from
the unit.
2. Remove the side and top panels from the unit.
3. Disconnect the flame detector lead wire.
4. Remove the two (2) screws securing the flame detector to the plate (Figure 7-2 on previous
5. Remove the flame detector and gasket from the burner plate.
page). The flame detector is secured to the burner plate with one (1) #10-32 screw and one
(1) #8-32 screw.
6. Thoroughly inspect the flame detector. If eroded, the detector should be replaced.
Otherwise clean the detector with a fine emery cloth.
7. Reinstall the flame detector and flame detector gasket.
8. Reconnect the flame detector lead wire.
9. Reinstall the side and top panels on the unit.
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GF-123 Benchmark 2.0LN Low NOx Boil e r Chapter 7
OMM-0046_0E Installation, Operation and Maintenance Manual Maintenance
7.4 COMBUSTION CALIBRATION & RSI REGUL ATOR ADJUSTMENT
The Combustion Calibration settings and RSI Regulator adjustment must be checked at the
intervals shown in Table 7-1 as part of the maintenance requirements. Ref er to Chapter 4 for
combustion calibration instructions. Refer to paragraph 7.4.1, below, for RSI regulator test and
calibration instructions.
7.4.1 RSI Regulator Pressure
The BMK2.0LN unit has a RSI (Regulated Staged Ignition) system in the gas train that should
be pressure tested annually. If the pressure is above 5.0” w.c. or below 3.0” w.c., then the RSI
pressure regulator must be recalibrated per paragraph 7.4.1.2.
7.4.1.1 RSI Regulator Pressure Test
The RSI regulator test is performed as follows:
1. Ensure that gas supply shut-off valve upstream of the unit is still turned OFF.
2. Turn OFF electrical power to the system.
3. CLOSE the following valves in the unit’s gas train (refer to Figure 7-4):
4. RSI Gas Supply Valve
5. RSI Bleed-off Valve
6. Manual Shut-off Valve (between the Air/Fuel Valve and the SSOV).
7. Remove the pipe plug from the 1/4” NPT port on the outlet side of the RSI regulator and
insert a NPT-to-barbed adapter fitting (see Figure 7-4).
8. Attach one end of the plastic tubing to the barbed fitting and the other end to the 16” W.C.
manometer.
9. Remove the cap from the RSI Pressure Regulator and rotate the regulator adjustment
(beneath cap) counterclockwise (CCW) to its lowest possible pressure setting t hat will allow
the cap to be installed.
10. OPEN the main gas supply upstream of the unit.
11. Turn ON electrical power to the system.
12. Slowly OPEN the RSI Gas Supply Valve and observe the reading on the manometer. It
should have a reading of less than 8.0” w.c.
13. Start the boiler in MANUAL Mode. Observe the manometer pressure when the RSI solenoid
“clicks” open after purge. It should now provide a reading of less than 5.0” w.c., but not less
than 3.0” w.c..
14. Look into the observation port in the top head and ensure that you observe the orange g low
of the RSI flame during the ignition trial period.
15. If the pressure is within specifications, return the unit to service. Make sure t hat the unit is
operating in AUTO Mode. The “MAN” light in the upper left of t he c ontrol box should NO T be
lit when in AUTO Mode.
16. If the RSI regulator is NOT within specifications, proceed to paragraph 7.4.1.2, RSI
Regulator Calibration, and initiate the pressure calibration procedures.
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Chapter 7 Benchmark 2.0LN Low NOx Boiler GF-123
Maintenance Installation, Operation and Maintenance Manual OMM-0046_0E
7.4.1.2 RSI Regulator Calibration
RSI regulator calibration is performed as follows:
1. Ensure that gas supply shut-off valve upstream of the unit is still turned OFF.
2. Turn OFF electrical power to the system.
3. CLOSE the following valves in the unit’s gas train (refer to Figure 7-4):
• RSI Gas Supply Valve
• RSI Bleed-off Valve
• Manual Shut-off Valve (between the Air/Fuel Valve and the SSOV).
4. Remove the pipe plug from the 1/4” NPT port on the outlet side of the RSI regulator, insert
NPT-to-barbed adapter fitting, and insert tube from the 16” w.c. manometer.
5. Remove the cap from the RSI Pressure Regulator and rotate the regulator adjustment
(beneath cap) counter-clockwise (CCW) to its lowest possible pressure setting that will allow
the cap to be installed.
6. OPEN the main gas supply upstream of the unit.
7. Turn ON electrical power to the system.
8. Slowly OPEN the RSI Gas Supply Valve and observe the reading on the manometer. It
should have a reading of less than 8.0” w.c.
9. Start the boiler in MANUAL Mode. Observe the manometer pressure when the RSI solenoid
“clicks” open after purge. The manometer should now provide a readin g of less than 5.0”
w.c.
10. Look into the observation port in the top head and ensure that you observe the orange glow
of the RSI flame during the ignition trial period.
NOTE
If you don’t see the orange glow, contact AERCO technical
support to ascertain the problem. If you DO see it, proceed to
the next step.
11. If the manometer reading is less than 3.0” w.c., increase the regulator setting by rotating the
adjustment screw clockwise (CW).
12. Repeat steps 8 through 11 until the gas pressure at the outlet of the RSI regulator reads
between 3.0” w.c. and 4.0” w.c. on the monometer.
13. Once the pressure reading is between 3.0” w.c. and 4.0” w.c., conduct at least three safe
RSI ignitions while observing the observation port. Assure the ig niter lights immediately with
a strong orange flame after the Staged Ignition Solenoid Valve opens.
NOTE
Clear any Flame Loss During Ignition messages during the
tests by pressing The CLEAR key on control panel.
14. Close the external gas supply and RSI Staged Ignition Gas Valves. Disconnect the
manometer, tubing and barbed fitting from the 1/4” NPT port hole.
15. Bleed off any remaining pressure using the RSI bleed-off valve, then ensure this valve is
closed.
16. Replace the 1/4” plug in place of the barbed fitting.
17. OPEN the gas supply upstream of the unit.
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GF-123 Benchmark 2.0LN Low NOx Boil e r Chapter 7
RSI Gas Supply Valve
Step 3: Remove this
RSI Bleed-off
RSI Pressure
Regulator
To Air/Fuel Valve
Manual Shut-Off
OMM-0046_0E Installation, Operation and Maintenance Manual Maintenance
18. Ensure power is restored and Boiler turned on in MANUAL Mode.
19. Open the Manual Shut-off Gas Valve (to the Air/Fuel Valve) and assure a smooth light off.
Perform this test three times.
20. Leak test the RSI line after the first solenoid valve.
21. Refer to paragraph 4.4 in Chapter 4, Initial Start-up to perform the Combustion Calibration
procedure.
22. Return the unit to service. Make sure that the unit is operating in AUTO Mode. The “MAN”
light in the upper left of the control box should NOT be lit in AUTO Mode.
(shown in open position)
Valve (shown in
closed position).
1/4” NPT plug to
reveal tap hole for
installing manometer.
Valve (shown in
open position)
Figure 7-4: RSI Manometer Installation Location
7.5 SAFETY DEVICE TESTING
Systematic and thorough tests of the operating and safety devices should be performed to
ensure that they are operating as designed. Certain code requirements, such as ASME CSD-1,
require that these tests be performed on a scheduled basis. Test schedules must conform to
local jurisdictions. The results of the tests should be recorded in a log book. See Chapter 6Safety Device Testing Procedures.
7.6 BURNER ASSEMBLY INSPECTION
The burner assembly (part no. 24176) is located at the top of the unit's heat exchanger. The
burner assembly may be hot. Therefore, allow the unit to cool sufficiently before removing the
burner assembly. It should be noted that the complete burner assembly also includes the blower
and air/fuel valve in addition to the Benchmark 2.0 Low NOx burner. The following parts will be
required for reassembly after burner inspection:
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Page 90
Chapter 7 Benchmark 2.0LN Low NOx Boiler GF-123
Part No.
Description
81101
Burner Gaskets (2)
81048
Flame Detector Gasket
81068
Blower Gasket
IGNITOR-
INJECTOR
3/8-16
NUTS (8)
BLOWER
BURNER
PLATE
AIR/FUEL
VALVE
FLAME
DETECTOR
STAGED
IGNITION
ASSEMBLY
1/2” BOLTS & NUTS (4)
CONNECT AIR/FUEL VALVE
TO GAS TRAIN
GROUNDING
SCREW
(10-32 x 1/2" LG.)
Maintenance Installation, Operation and Maintenance Manual OMM-0046_0E
To inspect or replace the burner assembly:
1. Set the ON/OFF switch on the control panel, to the OFF position. Disconnect AC power from
the unit and turn off the gas supply.
2. Remove the side and top panels from the unit.
3. Disconnect the lead wire from the flame detector installed on the burner plate. See Figure 7-
5.
4. Remove the two (2) screws securing the flame detector to the plate. T he flame detector is
secured to the burner plate with one (1) #10-32 screw and one (1) #8-32 screw.
5. Remove the flame detector and gasket from the burner plate.
6. Disconnect the cable from the igniter-injector.
7. Using a 7/16” open-end wrench, disconnect the compression nut securing the gas injector
tube of the igniter-injector to the elbow of the staged ignition assembly (see Figure 7-2).
Disconnect the staged ignition assembly from the igniter-injector.
Prior to removing the igniter-injector, note the position of the gas injector
tube relative to the burner plate and blower. This is necessary to ensure
that the igniter injector is reinstalled in the proper orientation when it is
reconnected to the staged ignition assembly.
Page 90 of 170 AERCO International Inc.● 100 Oritani Dr. ● Blauvelt, NY 10913. ● Ph: 800-526-0288 PR1 08/20/12
Figure 7-5: Burner Assembly Mounting Details
IMPORTANT
Page 91
GF-123 Benchmark 2.0LN Low NOx Boil e r Chapter 7
BLOWER
PROOF
SWITCH
BLOCKED
INLET
SWITCH
AIR/FUEL
VAVLE
STAGED
IGNITION
ASSEMBLY
FLAME
DETECTOR
BURNER
PLATE
HEX NUTS &
WASHERS (6)
BLOWER
GASKET
IGNITOR-
INJECTOR
BURNER
BLOWER
BURNER
GASKET
BURNER
GASKET
OMM-0046_0E Installation, Operation and Maintenance Manual Maintenance
8. Next, loosen and remove the igniter-injector from the burner plate using a 1" open-end
wrench.
9. Disconnect the unit wiring harness connectors from the air/fuel valve and blower motor.
10. Disconnect the wire leads connected to the blower proof switch and blocked inlet switch
(Figures 7-6).
11. Remove the 10-32 x 1/2" long grounding screw from the burner plate (Figures 7-4).
12. Disconnect the gas train from the air/fuel valve by removing the four (4) 1/2” bolts and nuts
(Figure 7-5).
13. Disconnect the inlet air flex hose from the air/fuel valve by loosening the hose clamp.
14. Remove the six (6) 1/4-20 hex nuts and flat washers securing the blower to the burner plate
(Figure 7-6).
15. Remove the blower and air/fuel valve from the burner plate by lifting straight up. Also,
remove the blower gasket, which will be replaced with a new gasket.
16. Remove the eight (8) 3/8-16 nuts from the burner flange (Figure 7-5) using a 9/16” wrench.
Figure 7-6: Burner Assembly Exploded View
The burner assembly is heavy, weighing approximately 30 pounds.
17. Remove the burner assembly from burner flange by pulling straight up.
18. Remove and replace the two (2) burner gaskets.
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NOTE
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Chapter 7 Benchmark 2.0LN Low NOx Boiler GF-123
Maintenance Installation, Operation and Maintenance Manual OMM-0046_0E
NOTE
During reassembly, apply high-temperature, anti-seize lubricant to the
threads of the igniter-injector and grounding screw. Also, ensure that the
igniter-injector is properly positioned as indicated in Figure 7-3. Torque t he
igniter-injector to 15 ft-lbs.
19. Beginning with the burner assembly removed in step 17, reinstall all the components in the
reverse order that they were removed. During re-assembly, replace the gaskets for the
blower and flame detector with new ones.
20. Be sure to align the igniter-injector and flame detector tapped holes in the burner plate with
the heat exchanger top head.
21. Check to ensure that the grounding screw is installed.
7.7 CONDENSATE DRAIN TRAP
The Benchmark 2.0LN Boiler contains a condensate trap as shown in Chapter 2, Figure 2-5.
The trap is located external to the unit and attached to the drain pipe from the exhaust manifold.
This trap should be inspected and, if necessary, cleaned to ensure proper operation.
NOTE
There are two slightly different types of condensate traps that may be used
in your configuration; an older style without an inlet adapter, and a newer
style with a built-in inlet adapter (see Figure 7.5). Maintenance is the same,
except that the newer style does not need an orifice gasket (Step 6).
To inspect and clean the trap, proceed as follows:
1. Disconnect the external condensate trap by loosening the union pipe connection between
the trap and the exhaust manifold drain pipe.
2. Remove the connections on the inlet and outlet sides of the condensate trap shown in
Figure 7-7.
3. Loosen the four (4) thumbscrews securing the cover on the condensate trap. Remove the
cover.
4. Remove the float from the condensate trap.
5. Remove the orifice gasket from the trap.
6. Thoroughly clean the trap, float and gasket. Also inspect the drain piping for blockage. If the
trap cannot be thoroughly cleaned, replace the trap.
7. After the above items have been inspected and thoroughly cleaned, replace the orifice
gasket and float in the condensate trap and replace the trap cover.
8. Reassemble all piping and hose connections to the condensate trap inlet and outlet.
Reconnect trap to exhaust manifold drain.
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GF-123 Benchmark 2.0LN Low NOx Boil e r Chapter 7
OMM-0046_0E Installation, Operation and Maintenance Manual Maintenance
Figure 7-7: External Condensate Trap
7.8 SHUTTING THE BOILER DOWN FOR AN EXTENDED PERIOD OF TIME
If the boiler is to be taken out of s ervice for an extended period of time (one year or more) , the
following instructions must be followed.
1. Set ON/OFF switch on the front panel to the OFF position to shut down the boiler’s
operating controls.
2. Disconnect AC power from the unit.
3. Close the water supply and return valves to isolate boiler.
4. Close external gas supply valve.
5. Open relief valve to vent water pressure.
7.9 PLACING THE BOILER BACK IN SERVICE AFTER A PROLONGED
SHUTDOWN
After a prolonged shutdown (one year or more), the following procedures must be followed:
1. Review installation requirement s included in Chapter 2.
2. Inspect all piping and connections to the unit.
3. Inspect exhaust vent, air duct (if applicable).
4. Perform initial startup per Chapter 4.
5. Perform safety device testing and scheduled maintenance procedures per Chapters 6 and 7
of this manual.
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Maintenance Installation, Operation and Maintenance Manual OMM-0046_0E
(This page intentionally blank)
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GF-123 Benchmark 2.0LN Low NOx Boil e r Chapter 8
OMM-0046_0E Installation, Operation and Maintenance Manual Troubleshooting
CHAPTER 8. TROUBLESHOOTING GUIDE
8.1 INTRODUCTION
This troubleshooting guide is intended to aid service/maintenance personnel in isolating the
cause of a fault in a Benchmark 2.0LN Boiler. The tr oubleshoot ing proc edures cont ained her ein
are presented in tabular form on the following pages. These tables are comprised of three
columns labeled: Fault Indication, Probable Cause and Corrective Action. The numbered items
in the Probable Cause and Corrective Action columns correspond to each other. For example,
Probable Cause No. 1 corresponds to Corrective Action No. 1, etc.
NOTE
The front panel of the C-More Control Box contains an RS232 port which
can be interfaced to a laptop computer or other suitable device. This
RS232 communication feature permits service personnel to view menu
items and data logs which can be useful in isolating faults. Refer to Chapter
9 of this manual for detailed RS232 communication set-up and procedures.
When a fault occurs in the Benchmark Boiler, proceed as follows to isolate and corr ect the fault:
1. Observe the fault messages displayed in the Control Box display.
2. Refer to the Fault Indication column in Troubleshooting Table 8-1 which follows and locate
the Fault that best describes the existing conditions.
3. Proceed to the Probable Cause column and start with the first item (1) listed for the Fault
Indication.
4. Perform the checks and procedures listed in the Corrective Action column for the first
Probable Cause candidate.
5. Continue checking each additional Probable Cause for the existing fault until the fault is
corrected.
6. Paragraph 8.2 and Table 8-2 contain additional troubleshooting information which may apply
when no fault message is displayed.
7. If the fault cannot be corrected using the information provided in the Troubleshooting
Tables, contact your local AERCO Representative.
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Page 96
Chapter 8 Benchmark 2.0LN Low NOx Boil er GF-123
INDICATION
Troubleshooting Installation, Operation and Maintenance Manual OMM-0046_0E
TABLE 8-1. BOILER TROUBLESHOO TING
FAULT
PROBABLE CAUSES CORRECTIVE ACTION
AIRFLOW FAULT
DURING IGNITION
1. Blower stopped running due to thermal or
current overload
2. Blocked Blower inlet or inlet ductwork
3. Blocked Blower Proof switch
4. Blocked Air inlet switch
5. Defective Blower Proof switch
6. Defective blocked-air inlet switch
7. Loose temperature to AUX connection in I/O
Box
8. Defective temperature sensor
9. Loose wire connection between the 0-10V
signal from I/O box to the Blower Motor
input.
1. Check combustion blower for signs of excessive heat or high current
drain that may trip thermal or current overload devices.
2. Inspect the inlet to the combustion blower including any ductwork
leading up to the combustion blower for signs of blockage.
3. Remove the Blower Proof switch and inspect for signs of blockage,
clean or replace as necessary.
4. Remove the Blocked-Air Inlet switch and inspect for signs of
blockage, clean or replace as necessary.
5. Measure the Blower Proof switch for continuit y with the combustion
blower running. If there is an erratic resistance reading or the
resistance reading is greater than zero ohms, replace the switch.
6. Measure the blocked-air inlet switch for continuity with the
combustion blower running. If there is an erratic resistance reading
or the resistance reading is greater than zero ohms, replace the
switch.
7. Check the actual inlet air temperature and measure voltage at AUX
input in the I/O Box. Verify that the voltage conforms to the values
shown in the tabular listing provided in Appendix C.
8. Refer to CORRECTIVE ACTION 7 and verify that the voltage
conforms to the values shown in Appendix C.
9. Check wire connection from I/O Box 0-10V signal to the Blower
Motor.
10. Defective I/O box
11. Wrong 0-10V output selection on the
control box
12. Defective Air/Fuel potentiometer
10. Measure voltage at the I/O box 0-10V output. A voltage of 8.2V
equates to a 100% open valve position.
11. Check the Analog Out option on the C-More Configuration Men u.
Valve Position 0-10V should be select.
12. Check Air/Fuel Valve position at 0%, 50% and 100% open
positions. The positions on the VALVE POSITION bargraph should
match the dial readings on the Air/Fuel Valve dial.
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GF-123 Benchmark 2.0LN Low NOx Boil e r Chapter 8
INDICATION
OMM-0046_0E Installation, Operation and Maintenance Manual Troubleshooting
TABLE 8-1. BOILER TROUBLESHOOTING (Continued)
FAULT
PROBABLE CAUSES CORRECTIVE ACTION
AIRFLOW FAULT
DURING PURGE
1. Blower not running or running too slow
2. Defective Air Flow Switch
3. Blocked Air flow Switch
4. Blocked Blower inlet or inlet ductwork.
5. No voltage to switch from control box.
6. PROBABLE CAUSES from 3 to 12 for
AIRFLOW FAULT DURING IGNITION applies
for this fault
1. Start the unit. If the blower does not run check the blower solid
state relay for input and output voltage. If the relay is okay, check
the blower.
2. Start the unit. If the blower runs, check the airflow switch for
continuity. Replace the switch if there is no continuity.
3. Remove the air flow switch and inspect for signs of blockage,
clean or replace as necessary.
4. Inspect the inlet to the combustion blower including any ductwork
leading up to the combustion blower for signs of blockage.
5. Measure for 24 VAC during start sequence from each side of the
switch to ground. If 24VAC is not present refer to qualified
service personnel.
6. See CORRECTIVE ACTIONS from 3 to 12 for AIRFLOW FAULT
DURING IGNITION.
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Page 98
Chapter 8 Benchmark 2.0LN Low NOx Boil er GF-123
INDICATION
for this fault
functional. (jumper ma y be temporar il y installed to test interlock)
Troubleshooting Installation, Operation and Maintenance Manual OMM-0046_0E
TABLE 8-1. BOILER TROUBLESHOOTING (Continued)
FAULT
PROBABLE CAUSES CORRECTIVE ACTION
AIRFLOW FAULT
DURING RUN
DELAYED
INTERLOCK OPEN
1. Blower stopped running due to thermal or
current overload
2. Blocked Blower inlet or inlet ductwork
3. Blocked airflow switch
4. Defective airflow switch
5. Combustion oscillations
6. PROBABLE CAUSES from 3 to 16 for
AIRFLOW FAULT DURING IGNITION applies
1. Delayed Interlock Jumper not installed or
removed.
2. Device proving switch hooked to interlocks is
not closed
1. Check combustion blower for signs of excessive heat or high
current draw that may trip thermal or current overload devices.
2. Inspect the inlet to the combustion blower including any ductwork
leading up to the combustion blower for signs of blockage.
3. Remove the airflow switch and inspect for signs of blockage,
clean or replace as necessary.
4. Measure the airflow switch for continuity with the combustion
blower running. If there is an erratic resistance reading or the
resistance reading is greater than zero ohms, replace the switch.
5. Run unit to full fire. If the unit rumbles or runs rough, perform
combustion calibration.
6. See CORRECTIVE ACTIONS from 3 to 16 for AIRFLOW FAULT
DURING IGNITION.
1. Check for a jumper properly installed across the delayed
interlock terminals in the I/O box.
2. If there are 2 external wires on these terminals, check to see if an
end switch for a device such as a pump, louver, etc. is tied these
interlocks. Ensure that the device and or its end switch are
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GF-123 Benchmark 2.0LN Low NOx Boil e r Chapter 8
INDICATION
(voltage or current).
Configuration Menu.
8. Closed RSI Gas Valve in RSI line.
8. Check position of RSI Gas Valve (Figure 8-1).
OMM-0046_0E Installation, Operation and Maintenance Manual Troubleshooting
TABLE 8-1. BOILER TROUBLESHOOTING (Continued)
FAULT
PROBABLE CAUSES CORRECTIVE ACTION
DIRECT DRIVE
SIGNAL FAULT
FLAME LOSS
DURING IGN
1. Direct drive signal is not present:
Not yet installed.
Wrong polarity.
Signal defective at source.
Broken or loose wiring.
2. Signal is not isolated (floating).
3. Control Box signal type selection
switches not set for correct signal type
1. Burner Ground Screw not installed or
loose.
2. Worn flame detector
3. No spark from Spark Plug
4. Defective Ignition Transformer
5. Defective Ignition/Stepper (IGST) Board
6. Defective SSOV
7. RSI Regulator not properly adjusted.
1. Check I/O Box to ensure signal is hooked up.
Hook up if not installed.
If installed, check polarity.
Measure signal level.
Check continuity of wiring between source and boiler.
2. Check signal at source to ensure it is isolated.
3. Check DIP switch on PMC board to ensure it is set correctly for the
type of signal being sent. Check control signal type set in
1. Inspect and install/retighten Burner Ground Screw.
2. Remove and inspect the flame detector for signs of wear. Replace
if necessary.
3. Close the internal gas valve in the boiler. Install and arc a spark
igniter outside the unit.
4. If there is no spark, check for 120VAC at the primary side to the
ignition transformer during the ignition cycle.
5. If 120VAC is not present, the IGST Board in the Control Box may
be defective. Refer fault to qualified service personnel.
6. While externally arcing the spark igniter, observe the open/close
indicator in the Safety Shut-Off Valve to ensure it is opening. If the
valve does not open, check for 120VAC at the valves input
terminals. If 120VAC is not present, the IGST board in the Control
Box may be defective. Refer fault to qualified service personnel.
7. Refer to Chapter 7, paragraph 7.4 and check the RSI Regulator
calibration. The RSI regulator output should be between 3.0” W.C.
and 5.0” W.C.
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Chapter 8 Benchmark 2.0LN Low NOx Boil er GF-123
FAULT INDICATION
PROBABLE CAUSES
CORRECTIVE ACTION
4. Clogged staged ignition piece.
4. Remove and inspect staged ignition piece for blockage.
5. Remove blockage in condensate drain.
2. Relay is activated when not in Demand
installed at the high gas pressure switch.
Troubleshooting Installation, Operation and Maintenance Manual OMM-0046_0E
TABLE 8-1. BOILER TROUBLESHOOTING (Continued)
FLAME LOSS
DURING IGN
(continued)
FLAME LOSS
DURING RUN
HEAT DEMAND
FAILURE
HIGH GAS
PRESSURE
1. Unstable gas pressure.
2. Carbon or other debris on Burner.
3. Staged ignition solenoid valves don’t open.
1. Worn Flame Detector or cracked ceramic.
2. Defective Regulator.
3. Poor combustion calibration.
4. Debris on burner.
5. Blocked condensate drain.
1. The Heat Demand Relays on the Ignition/
Stepper board faile d to activat e when
commanded.
1. Incorrect supply gas pressure.
2. Defective gas pressure adjustment in SSOV
Actuator.
3. Defective High Gas Pressure Switch
4. Gas pressure snubber not installed.
1. Refer to “Gas Pressure Requirements” section of GF-2030:
BMK Gas Supply Design Guide.
2. Remove the burner and inspect for any carbon or debris.
Clean and reinstall.
3. When boiler goes to ignition, listen to the solenoid valves
for a clicking sound to ensure they are opening.
1. Remove and inspect the Flame Detector for signs of wear or
cracked ceramic. Replace if necessary.
2. Check gas pressure readings using a gauge or manometer
into and out of the Air/Fuel Valve to ensure that the gas
pressure into and out of the valve is correct.
3. Check combustion calibration. Adjust as necessary.
4. Remove the burner and inspect for any carbon or debris.
Clean and reinstall.
1. Press CLEAR button and restart the unit. If the fault
persists, replace Ignition/Stepper (IGST) Board.
2. Defective relay. Replace IGST Board.
1. Check to ensure gas pressure at inlet of SSOV is 14” w.c.
maximum.
2. If gas supply pressure downstream of SSOV Actuator cannot
be lowered, to 2.8” W.C. (or 2.3” W.C. for propane), using
the gas pressure adjustment screw (see para. 4.3, step 10),
the SSOV Actuator gas pressure adjustment mechanism
may be defective. See para. 4.3, Step 10 (nat. gas) or 4.4,
Step 10 (propane).
3. Remove the leads from the high gas pressure switch and
measure continuity across the common and normally closed
terminals with the unit not firing. Replace the switch if it does
not show continuity.
4. See Figure 8-1. Ensure that the gas pressure snubber is
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