Benchmark 750/1000 Boiler Installation, Operation & Maintenance Manual
BENCHMARK Series
USER MANUAL
Installation, Operation and Maintenance
Natural Gas & Propane
Modulating &
Condensing Hot Water Boiler
Models:
Gas-Fired Boilers
• BMK 750
• BMK 1000
Applicable to Serial Numbers :
• G-14-0752 and above
Latest Update: 05/21/2014
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Benchmark 750/1000 Boiler Installation, Operation & Maintenance Manual
Technical Support
(Mon-Fri, 8am-5pm EST)
1-800-526-0288
www.aerco.com
Disclaimer
The information contained in this manual is subject to change without notice from AERCO
International, Inc. AERCO makes no warranty of any kind with respect to t his mater ial, including
but not limited to implied warranties of merchantability and fitness for a particular application.
AERCO International is not liable for errors appearing in this manual. Nor for incidental or
consequential damages occurring in connection with the furnishing, performance, or use of this
material.
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TABLE OF CONTENTS
FOREWORD ................................................................................................................. 7
CHAPTER 1. SAFETY PRECAUTIONS ..................................................................... 11
1.1 WARNINGS & CAUTIONS ................................................................................................................... 11
1.2 EMERGENCY SHUTDOWN ................................................................................................................. 12
1.3 PROLONGED SHUTDOWN ................................................................................................................. 13
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 ............................................................................................................ 19
2.6 PRESSURE RELIEF VALVE INSTALLATION ........................................................................................... 19
2.7 CONDENSATE DRAIN & PIPING ......................................................................................................... 20
2.8 GAS SUPPLY PIPING ........................................................................................................................... 22
2.8.1 Gas Supply Specifications ........................................................................................................... 22
2.8.2 Manual Gas Shutoff Valve .......................................................................................................... 23
2.8.3 External Gas Supply Regulator .................................................................................................... 23
2.8.3.1 Massachusetts Installations Only ......................................................................................... 23
2.8.3.2 All Installations (Except Massachusetts) .............................................................................. 23
2.9 AC ELECTRICAL POWER WIRING ........................................................................................................ 24
2.9.1 Electrical Power Requirements ................................................................................................... 25
2.10 FIELD CONTROL WIRING .................................................................................................................. 26
2.10.1 OUTDOOR AIR IN Terminals...................................................................................................... 28
2.10.2 COMBUSTION AIR Terminal ...................................................................................................... 29
2.10.3 O
2.10.4 SPARK SIGNAL Terminals .......................................................................................................... 29
2.10.5 ANALOG IN Terminals ............................................................................................................... 29
2.10.6 B.M.S. (PWM) IN Terminals ...................................................................................................... 29
2.10.7 SHIELD Terminals ...................................................................................................................... 29
2.10.8 ANALOG OUT Terminals ........................................................................................................... 30
2.10.9 RS-485 Comm Terminals ........................................................................................................... 30
2.10.10 RS-232 Comm Terminals ......................................................................................................... 30
2.10.11 VFD/Blower (0-10 & AGND) .................................................................................................... 30
2.10.12 Interlocks ................................................................................................................................ 30
2.10.12.1 REMOTE INTL’K Terminals................................................................................................ 30
2.10.12.2 DELAYED INTL’K Terminals (OUT & IN) ............................................................................ 30
2.10.13 FAULT RELAY (NC, COM, & NO) Terminals ............................................................................. 31
2.10.14 AUX RELAY CONTACTS (NC, COM, & NO) Terminals .............................................................. 31
2.11 FLUE GAS VENT INSTALLATION ....................................................................................................... 31
2.12 COMBUSTION AIR ............................................................................................................................ 32
2.12.1 Combustion From Outside the Building ................................................................................... 32
SENSOR Terminals ................................................................................................................ 29
2
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2.12.2 Combustion Air from Inside the Building ................................................................................. 32
2.13 DUCTED COMBUSTION AIR ............................................................................................................. 33
2.14 BENCHMARK PUMP RELAY OPTION ................................................................................................ 33
2.15 SEQUENCING ISOLATION VALVE INSTALLATION ............................................................................. 34
CHAPTER 3. OPERATION ......................................................................................... 37
3.1 INTRODUCTION ................................................................................................................................. 37
3.2 CONTROL PANEL DESCRIPTION ......................................................................................................... 37
3.3 CONTROL PANEL MENUS .................................................................................................................. 41
3.3.1 Menu Processing Procedure ....................................................................................................... 41
3.4 OPERATING MENU ............................................................................................................................ 43
3.5 SETUP MENU ..................................................................................................................................... 43
3.6 CONFIGURATION MENU .................................................................................................................... 44
3.7 TUNING MENU .................................................................................................................................. 46
3.8 COMBUSTION CAL MENU .................................................................................................................. 47
3.9 BST (Boiler Sequencing Technology ) Menu ...................................................................................... 47
3.10 START SEQUENCE ............................................................................................................................ 50
3.11 START/STOP LEVELS ........................................................................................................................ 53
CHAPTER 4. INITIAL STAR T-UP ............................................................................... 55
4.1 INITIAL START-UP REQUIREMENTS ................................................................................................... 55
4.2 TOOLS AND INSTRUMENTATION FOR COMBUSTION CALIBRATION ................................................ 55
4.2.1 Required Tools & Instrumentation ............................................................................................. 56
4.2.2 Installing Gas Supply Manometer ............................................................................................... 56
4.2.3 Accessing the Analyzer Probe Port ............................................................................................. 57
4.3 NATURAL GAS COMBUSTION CALIBRATION ..................................................................................... 58
4.4 PROPANE COMBUSTION CALIBRATION............................................................................................. 61
4.5 REASSEMBLY AFTER COMBUSTION CALIBRATION ............................................................................ 64
4.6 OVER-TEMPERATURE LIMIT SWITCHES ............................................................................................. 65
4.6.1 Digital Alarm Switch Checks and Adjustments ........................................................................... 66
CHAPTER 5. MODE OF OPERATION ........................................................................ 69
5.1 INTRODUCTION ................................................................................................................................. 69
5.2 INDOOR/OUTDOOR RESET MODE ..................................................................................................... 69
5.2.1 Reset Ratio .................................................................................................................................. 69
5.2.2 Building Reference Temperature ................................................................................................ 69
5.2.3 Outdoor Air Temperature Sensor Installation ............................................................................ 69
5.2.4 Indoor/Outdoor Startup ............................................................................................................. 70
5.3 CONSTANT SETPOINT MODE ............................................................................................................. 70
5.3.1 Setting the Setpoint .................................................................................................................... 70
5.4 REMOTE SETPOINT MODES ............................................................................................................... 71
5.4.1 Remote Setpoint Field Wiring ..................................................................................................... 72
5.4.2 Remote Setpoint Startup ............................................................................................................ 72
5.5 DIRECT DRIVE MODES ....................................................................................................................... 72
5.5.1 Direct Drive Field Wiring ............................................................................................................. 73
5.5.2 Direct Drive Startup .................................................................................................................... 73
5.6 AERCO CONTROL SYSTEM (ACS) ........................................................................................................ 73
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5.6.1 ACS External Field Wiring ........................................................................................................... 74
5.6.2 ACS Setup and Startup ................................................................................................................ 74
5.7 COMBINATION CONTROL SYSTEM (CCS) ........................................................................................... 74
5.7.1 Combination Control System Field Wiring.................................................................................. 75
5.7.2 Combination Control System Setup and Startup ........................................................................ 75
CHAPTER 6. SAFETY DEVICE TESTING .................................................................. 77
6.1 TESTING OF SAFETY DEVICES ............................................................................................................. 77
6.2 LOW GAS PRESSURE FAULT TEST ...................................................................................................... 78
6.3 HIGH GAS PRESSURE TEST ................................................................................................................. 79
6.4 LOW WATER LEVEL FAULT TEST ........................................................................................................ 80
6.5 WATER TEMPERATURE FAULT TEST .................................................................................................. 81
6.6 INTERLOCK TESTS .............................................................................................................................. 82
6.6.1 Remote Interlock Test ................................................................................................................ 82
6.6.2 Delayed Interlock Test ................................................................................................................ 82
6.7 FLAME FAULT TESTs .......................................................................................................................... 83
6.8 AIR FLOW FAULT TESTS ..................................................................................................................... 84
6.8.1 Blower Proof Switch Test ............................................................................................................ 84
6.8.2 Blocked Inlet Switch Test ............................................................................................................ 84
6.9 SSOV PROOF OF CLOSURE SWITCH ................................................................................................... 86
6.10 PURGE SWITCH OPEN DURING PURGE ........................................................................................... 87
6.11 IGNITION SWITCH OPEN DURING IGNITION ................................................................................... 87
6.12 SAFETY PRESSURE RELIEF VALVE TEST ............................................................................................ 88
CHAPTER 7. MAINTENANCE .................................................................................... 89
7.1 MAINTENANCE SCHEDULE ................................................................................................................ 89
7.2 IGNITER-INJECTOR REPLACEMENT .................................................................................................... 90
7.3 FLAME DETECTOR REPLACEMENT ..................................................................................................... 92
7.4 O
SENSOR REPLACEMENT ................................................................................................................ 93
2
7.5 COMBUSTION CALIBRATION ............................................................................................................. 93
7.6 SAFETY DEVICE TESTING .................................................................................................................... 93
7.7 BURNER ASSEMBLY INSPECTION ....................................................................................................... 93
7.8 CONDENSATE DRAIN TRAP MAINTENANCE ...................................................................................... 96
7.9 AIR FILTER CLEANING & REPLACEMENT ............................................................................................ 98
7.10 SHUTTING THE BOILER DOWN FOR AN EXTENDED PERIOD OF TIME ............................................. 99
7.11 PLACING THE BOILER BACK IN SERVICE AFTER A PROLONGED SHUTDOWN .................................. 99
CHAPTER 8. TROUBLESHOOTING GUIDE ............................................................ 101
8.1 INTRODUCTION ............................................................................................................................... 101
8.2 ADDITIONAL FAULTS WITHOUT SPECIFIC FAULT MESSAGES .......................................................... 113
CHAPTER 9. RS-232 COMMUNICATION ................................................................ 117
9.1 INTRODUCTION ............................................................................................................................... 117
9.1.1 Aquiring the PuTTY Application ................................................................................................ 117
9.1.2 Logging on to a Remote Machine Using PuTTY ........................................................................ 117
9.1.3 Running a Command on a Remote Machine Using PuTTY ....................................................... 118
9.2 RS-232 COMMUNICATION SETUP ................................................................................................... 119
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9.3 MENU PROCESSING UTILIZING RS-232 COMMUNICATION ............................................................ 119
9.4 DATA LOGGING................................................................................................................................ 120
9.4.1 Fault Log .................................................................................................................................... 120
9.4.2 Operation Time Log .................................................................................................................. 121
9.4.3 Sensor Log ................................................................................................................................. 122
CHAPTER 10. BOILER SEQUENCING TECHNOLOGY ........................................ 123
10.1 INTRODUCTION ............................................................................................................................. 123
10.2 AERCO BST Quick Start Chart ........................................................................................................ 124
10.3 BST Implementation Instruction ................................................................................................... 125
10.3.1 Option 1 - Constant Setpoint with DIRECT Wired Header Sensor .......................................... 125
10.3.2 Option 2 - Constant Setpoint with MODBUS Wired Header Sensor ...................................... 126
10.3.3 Option 3 - Outdoor Reset with DIRECT WIRED Header Sensor AND DIRECT WIRED Outdoor
Sensor ................................................................................................................................................ 127
10.3.4 Option 4 - Outdoor Reset with MODBUS Header Sensor AND MODBUS Outdoor Sensor .... 129
10.3.5 Option 5 - Remote Setpoint with DIRECT WIRED Header Sensor AND 4-20ma Setpoint Drive
........................................................................................................................................................... 131
10.3.6 Option 6 - Remote Setpoint with DIRECT WIRED Header Sensor AND MODBUS Setpoint Drive
........................................................................................................................................................... 133
10.3.7 Option 7 - Remote Setpoint with MODBUS Header Sensor AND 4-20ma Setpoint Drive...... 134
10.3.8 Option 8 - Remote Setpoint with MODBUS Header Sensor AND MODBUS Setpoint Drive ... 136
APPENDIX A: BOILER MENU ITEM DESCRIPTIONS ...................................................................... 139
APPENDIX B: STARTUP, STATUS & DISPLAY MESSAGES ............................................................. 145
APPENDIX C: SENSOR RESISTANCE/VOLTAGE CHART ................................................................ 149
APPENDIX D – INDOOR/OUTDOOR RESET RATIO CHARTS ......................................................... 151
APPENDIX E – BOILER DEFAULT SETTINGS ................................................................................. 155
APPENDIX F – DIMENSIONAL DRAWINGS .................................................................................. 157
APPENDIX G – PART LIST DRAWINGS ......................................................................................... 161
APPENDIX H – PIPING DRAWINGS .............................................................................................. 171
APPENDIX I – C-MORE WIRING DIAGRAMS ................................................................................ 175
APPENDIX J – RECOMMENDED PERIODIC TESTING.................................................................... 179
APPENDIX K – C-MORE CONTROL PANEL VIEWS ........................................................................ 181
APPENDIX L: RECOMMENDED SPARES ...................................................................................... 183
APPENDIX M – ULTRA-LOW NOx CALIBRATION ......................................................................... 185
LIMITED WARRANTY ................................................................................................................... 189
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Input Range (BTU/hr.)
Output Range (BTU/hr.)
Benchmark Model
Minimum
Maximum
Minimum
Maximum
BMK 750
50,000
750,000
47750
716,250
BMK 1000
50,000
1,000,000
48300
968,000
FOREWORD
The AERCO Benchmark (BMK) 750 and 1000 MBH Boilers are modulating and condensing
units. They are a true industry advancement that meets the needs of today's energy and
environmental concerns. Designed for application in any closed loop hydronic system, the
Benchmark's modulating capability relates energy input directly to fluctuating system loads. The
maximum turn down ratios for the BMK 1000 and BMK 750 are 20:1 and 15:1, respectively.
Both BMK models provide extremely high efficiencies and make them ideally suited for modern
low temperature, as well as, conventional heating systems.
The Benchmark Models BMK 750 and BMK 1000 operate within the following input and output
ranges:
The output of each boiler model is a function of the unit’s firing rate (valve position) and return
water temperature.
When installed and operated in accordance with this Instruction Manual, the BMK 750 and BMK
1000 MBH Boilers comply with the NOx emission standards outlined in:
• South Coast Air Quality Management District (SCAQMD), Rule 1146.2
Whether used in singular or modular arrangements, the BMK 750 and BMK 1000 offer the
maximum venting flexibility with minimum installation space requirements. These Boilers are
Category II, II I and IV, positive pressure appliances. Single and/or multiple breeched units are
capable of operation in the following vent configurations:
• Conventional, Vertical
• Conventional, Sidewall
• Conventional, Direct Vent, Vertical
• Sealed, Direct Vent, Horizontal
These boilers are capable of being vented utilizing PVC, CPVC, Polypropylene and AL29-4C
vent systems.
The Benchmark's advanced electronics are available in several selectable modes of operation
offering the most efficient operating methods and energy management system integration.
IMPORTANT
Unless otherwise specified, all descriptions and procedures provided in this
Installation, Operation & Maintenance Manual apply to both Benchmark
750 MBH and Benchmark 1000 MBH boilers.
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Phrase, Abbreviation
or Acronym
A (Amp)
Ampere
ACS
AERCO Control System, AERCO’s boiler management systems
ADDR
Address
AGND
Analog Ground
ALRM
Alarm
ASME
American Society of Mechanical Engineers
AUX
Auxiliary
(see below)
Symbol rate, or simply the number of distinct symbol changes
second, unless each symbol is 1 bit long.
BMK
Benchmark series boilers
BLDG (Bldg)
Building
CCP
Combustion Control Panel
(or Control Box)
A control system developed by AERCO and currently used in all
Benchmark, Innovation and KC1000 Series product lines.
CO
Carbon Monoxide
COMM (Comm)
Communication
required to raise 1 pound of water 1° F.
Cal.
Calibration
CNTL
Control
DIP
Dual In-Line Package
EMS
Energy Management System; often used interchangeably with BAS
FM
Factory Mutual. Used to define boiler gas trains.
GND
Ground
HDR
Header
Hex
Hexadecimal Number (0 – 9, A – F)
HX
Heat Exchanger
Hz
Hertz (Cycles Per Second)
I.D.
Inside Diameter
IGN
Ignition
IGST Board
Ignition/Stepper Board contained in C-More Control Box
Phrases, Abbreviations and Acronyms
Meaning
BAS
Baud Rate
Building Automation System, often used interchangeably with EMS
(signaling events) transmitted per second. It is not equal to bits per
BMS or BMS II AERCO Boiler Management Systems
BST AERCO on-board Boiler Management Technology
BTU
British Thermal Unit. A unit of energy approximately equal to the heat
required to raise 1 pound of water 1° F.
C-More Controller
BTU
British Thermal Unit. A unit of energy approximately equal to the heat
Double Block and Bleed. Used to define boiler gas trains containing 2
DBB
Safety Shutoff Valves (SSOVs) and a solenoid operated vent valve.
Also known as IRI gas trains (see below)
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Phrase, Abbreviation
or Acronym
INTLK (INTL’K)
Interlock
I/O
Input/Output
KC1000 Series products
IP
Internet Protocol
trains containing two SSOVs and a solenoid operated vent valve.
ISO
Isolated
LED
Light Emitting Diode
LN
Low NOx
MA (mA)
Milliampere (1 thousandth of an ampere)
MAX (Max)
Maximum
MIN (Min)
Minimum
duplex data transmission protocol developed by AEG
Modicon
NC (N.C.)
Normally Closed
NO (N.O.)
Normally Open
NOx
Nitrogen Oxide
NPT
National Pipe Thread
O2
Oxygen
O.D.
Outside Diameter
Control Box used on all Benchmark units.
PPM
Parts Per Million
PTP
Point-to-Point (usually over RS-232 networks)
PWM
Pulse Width Modulation
REF (Ref)
Reference
RES.
Resistive
(or EIA-232)
the RS-232 Standard
(or EIA-422)
the RS-422 Standard
(or EIA-485)
the RS-485 Standard
RTN (Rtn)
Return
SETPT (Setpt)
Setpoint Temperature
SHLD (Shld)
Shield
SSOV
Safety Shut Off Valve
TEMP (Temp)
Temperature
Phrases, Abbreviations and Acronyms - Continued
Meaning
I/O Box
IRI
Modbus®
PMC Board
Input/Output (I/O) Box currently used on Benchmark, Innovation and
Industrial Risk Insurers. A now discontinued code used to define gas
A serial, half-
A Primary Micro-Controller (PMC) board is contained in the C-More
RS-232
RS-422
RS-485
A standard for serial, full-duplex (FDX) transmission of data based on
A standard for serial, full-duplex (FDX) transmission of data based on
A standard for serial, half-duplex (HDX) transmission of data based on
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Phrase,
Acronym
s that may cause invalid data in the
communication
VDC
Volts, Direct Current
VFD
Vacuum Fluorescent Display, or Variable Frequency Drive
W
Watt
W.C.
Water Column
Phrases, Abbreviations and Acronyms – Continued
Abbreviation or
Meaning
A resistor placed at each end of a daisy-chain or multi-drop network in
Terminating Resistor
order to prevent reflection
µA Micro amp (1 millionth of an ampere)
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WARNING
WARNING
WARNING
WARNING
CHAPTER 1 – 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)
for gas-fired boilers and ANSI/NFPASB for LP gas-fired boilers. Where applicable, the
equipment shall be installed in accordance with the current Installation Code for Gas Burning
Appliances and Equipment, CSA B149.1, and applicable Provincial regulations for the class;
which should be carefully followed in all cases. Authorities having jurisdiction should be
consulted before installations are made.
See pages 13 and 14 for important information regarding installation of units within the
Commonwealth of Massachusetts.
IMPORTANT
This Instruction Manual is an integral part of the product and must be
maintained in legible condition. It must be given to the user by the installer
and kept in a safe place for future reference.
DO NOT USE MATCHES, CANDLES, FLAMES, OR OTHER SOURCES
OF IGNITION TO CHECK FOR GAS LEAKS.
FLUIDS UNDER PRESSURE MAY CAUSE INJURY TO PERSONNEL OR
DAMAGE TO EQUIPMENT WHEN RELEASED. BE SURE TO SHUT OFF
ALL INCOMING AND OUTGOING WATER SHUTOFF VALVES.
CAREFULLY DECREASE ALL TRAPPED PRESSURES TO ZERO
BEFORE PERFORMING MAINTENANCE.
BEFORE ATTEMPTING TO PERFORM ANY MAINTENANCE ON THE
UNIT, SHUT OFF ALL GAS AND ELECTRICAL INPUTS TO THE UNIT.
THE EXHAUST VENT PIPE OF THE UNIT OPERATES UNDER A
POSITIVE PRESSURE AND THERE-FORE MUST BE COMPLETELY
SEALED TO PREVENT LEAKAGE OF COMBUSTION PRODUCT S INTO
LIVING SPACES.
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WARNING
WARNING
CAUTION
CAUTION
CHAPTER 1 – SAFETY PRECAUTIONS
ELECTRICAL VOLTAGES UP TO 120 VAC MAY BE USED IN THIS
EQUIPMENT. THEREFO RE THE COVER ON THE UNI T’S POWER BOX
(LOCATED BEHIND THE FRONT PANEL DOOR) MUST BE INSTALLED
AT ALL TIMES, EXCEPT DURING MAINTENANCE AND SERVICING.
A DOUBLE-POLE SWITCH MUST BE INSTAL LED ON T HE ELECTRICAL
SUPPLY LINE OF THE UNIT. T HE SWIT CH MUST BE INSTALLED IN AN
EASILY ACCESSIBLE POSITION TO QUICKLY AND SAFELY
DISCONNECT ELECTRICAL SERVICE. DO NOT AFFIX SWITCH TO
UNIT SHEET METAL ENCLOSURES.
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.
DO NOT use t his boiler if any part has been under water. Call a qualified
service technician to inspect and replace any part that has been under
water.
1.2 EMERGENCY SHUTDOWN
If overheating occurs or the gas supply fails to shut off, close the manual gas shutoff valve
(Figure 1-1) located external to the unit.
NOTE
The Installer must identify and indicate the location of the emergency
shutdown manual gas valve to operating personnel.
MANUAL GAS SHUT-OFF VALVE
Figure 1-1: Manual Gas Shutoff Valve
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VALVE CLOSED
Benchmark 750/1000 Boiler Installation, Operation & Maintenance Manual
CHAPTER 1 – SAFETY PRECAUTIONS
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 of the unit. The inst aller must
identify the emergency shut-off device.
IMPORTANT – FOR MASSACHUSETTS INSTALLATIONS
Boiler installations within the Commonwealth of Massachusetts must
conform to the following requirements:
• Boiler must be installed by a plumber or a gas fitter who is licensed
within the Commonwealth of Massachusetts.
• Prior to unit operation, the complete gas train and all connections must
be leak tested using a non-corrosive soap.
• The vent termination must be located a minimum of 4 f eet above grade
level. If side-wall venting is used, the installation must conform to the
following requirem ent s extract ed 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 installation of
the side wall horizontal vented gas fueled equipment, the installing plumber or gasfitter shall
observe that a hard wired carbon monoxide detector with an alarm and battery back-up is
installed on the floor level where the gas equipment is to be installed. In addition, the
installing plumber or gasfitter shall observe that a battery operated or hard wired carbon
monoxide detector with an alarm is installed on each additional level of the dwelling, building
or structure served by the side wall horizontal vented gas fueled equipment. It shall be the
responsibility of the property owner to secure the services of qualified licensed professionals
for the installation of hard wired carbon monoxide detectors.
a. In the event that the side wall horizontally vented gas fueled equipment is installed in a
crawl space or an attic, the hard wired carbon monoxide detector with alarm and batter y
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 com ply 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
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CHAPTER 1 – SAFETY PRECAUTIONS
the exhaust vent terminal for the horizontally vented gas fueled heating appliance or
equipment. The sign shall read, in print size no less than one-half (1/2) inch in size, "GAS
VENT DIRECTLY BELOW. KEEP CLEAR OF ALL OBSTRUC TIONS".
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 the manufacturer of a Product Approved side wall horizontally vented gas
fueled equipment does not provide the parts for venting the flue gases, but identifies "special
venting systems", the following requirements shall be satisfied by the manufacturer:
1. The referenced "special venting system" instructions shall be included with the appliance
or equipment installation instructions; and
2. The "special venting systems" shall be Product Approved by the Board, and the
instructions for that system shall include a parts list and detailed installation instructions.
(e) A copy of all installation instructions for all Product Approved side wall horizontally vented
gas fueled equipment, all venting instructions, all parts lists for venting instructions, and/or all
venting design instructions shall remain with the appliance or equipment at the completion of the
installation.
___________________________________________________________________________
[End of Extracted Information From 248 CMR 5.08 (2)]
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Benchmark 750/1000 Boiler Installation, Operation & Maintenance Manual
CHAPTER 2 – INSTALLATION
CHAPTER 2. INSTALLATION
2.1 INTRODUCTION
This Chapter provides the descriptions and procedures necessary to unpack, inspect and install
AERCO Benchmark Boiler Models BMK 750 and BMK 1000.
2.2 RECEIVING THE UNIT
Each Benchmark Boiler System is shipped as a single crated unit. T he shipping weights for the
BMK 750 and BMK 1000 Models are approximately 1100 and 1200 pounds , respectively. The
unit must be moved with the proper rigging equipment for safety and to avoid equipment
damage. The unit should be completely inspected for evidence of shipping damage and
shipment completeness at the time of receipt from the carrier and before the bill of lading is
signed.
NOTE
AERCO is not responsible for lost or damaged freight. Each unit has a TipN-Tell indicator on the outside of the crate. This indicates if the unit has
been turned on its side during shipment. If the Tip-N-Tell indicator is
tripped, do not sign for the shipment. Note the information on the carrier’s
paperwork and request a freight claim and inspection by a claims adjuster
before proceeding. Any other visual damage to the packaging materials
should also be made clear to the delivering carrier.
2.3 UNPACKING
Carefully unpack the unit taking care not to damage the unit enclosure when cutting away
packaging materials
After unpacking, closely inspect the unit to make sure there is no evidence of damage not
indicated by the Tip-N-Tell indicator. Notify the freight carrier immediately if any damage is
detected.
The following accessories come standard with each unit and are either packed separately within
the unit’s shipping container or are factory installed on the unit:
• Pressure/Temperature Gauge
• ASME Pressure Relief Valve
• Condensate Drain Trap (part no. 24060)
• 1” Gas Supply Shutoff Valve
• Lifting Bar (with attaching hardware)
When optional accessories are ordered, they may be packed within the unit’s shipping
container, factory installed on the unit, or packed and shipped in a separate container. Any
standard or optional accessories shipped loose should be identified and stored in a safe place
until ready for installation or use.
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Benchmark 750/1000 Boiler Installation, Operation & Maintenance Manual
Housekeeping pad should not extend under the condensate assembly
CHAPTER 2 – INSTALLATION
2.4 SITE PREPARATION
Ensure that the site selected for installation of the Benchmark Boiler includes:
• Access to AC Input Power at 1 20 VAC, S i ngle-Phase, 60 Hz @ 20 Amps.
• Access to one of the following with the unit operating at maximum capacity:
o For Benchmark 750 & 1000, a NATURAL GAS line at a minimum pressure of 4” W.C.
o For Benchmark 750, a PROPANE gas line at a minimum pressure of 7” W.C.
o For Benchmark 1000, a PROPANE gas line at a minimum pressure of 11” W.C.
2.4.1 Installation Clearances
Benchmark Models 750 and 1000 are packaged in enclosures having identical exterior
dimensions. The unit must be installed with the prescribed clearances for service as shown in
Figure 2-1a. The minimum clearance dimensions, required by AERCO, are listed below.
However, if Local Building Codes require additional clearances, these codes shall supersede
AERCO’s requirements. Minimum acceptable clearances required are as follows:
• Sides: 24 inches
• Front : 24 inches
• Rear: 24 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.
Figure 2-1a: BMK 750 & 1000 Clearances
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Benchmark 750/1000 Boiler Installation, Operation & Maintenance Manual
WARNING
CAUTION
CHAPTER 2 – INSTALLATION
Figure 2-1b: BMK 750 & 1000 Anchor Bolt Locations
KEEP THE UNIT AREA CLEAR AND FREE FR OM ALL COMBUSTIBLE
MATERIALS AND FLAMMABLE VAPORS OR LIQUIDS
.
While packaged in the shipping container, the unit must be moved by pallet
jack or forklift from the FRONT ONLY.
FOR MASSACHUSSETTS ONLY:
For Massachusetts installations, the unit must be installed by a plumber or
gas-fitter licensed within the Commonwealth of Massachusetts. In addition,
the installation must comply with all requirements specified in Chapter 1
(Safety Precautions), pages 11 and 12.
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 Figure 21b for anchor locations.
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.
After unpacking and inspecting the boiler, remove the four (4) lag screws securing the boiler to
the shipping pallet. The boiler can be lifted and moved by inserting forklift tines in the front slots
provided in the base of the unit, or it can be lifted by attaching a lifting bar to the unit’s heat
exchanger. A lifting bar (59174), with attaching hardware, is supplied with each unit. When
shipped, this bar is attached to the rear of the unit as shown in Figure 2-2, View A. One (1)
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Benchmark 750/1000 Boiler Installation, Operation & Maintenance Manual
VIEW B - LIFTING POSITION
CHAPTER 2 – INSTALLATION
lifting tab is provided at the top of the unit’s heat exchanger as shown. This tab is used to attach
the lifting bar to the unit as follows:
WARNING
WHEN LIFTING OR MOVING THE BOILER:
• DO NOT ATTEMPT TO MANIPULATE THE BOILER USING THE
GAS TRAIN OR BLOWER
• WHEN USING THE LIFTING TAB AND BAR, ENSURE THERE IS
NO LOAD PLACED ON THE GAS TRAIN OR BLOWER
Attachment of Lifting Bar
1. Remove the lifting bar from its shipping location at the r ear of the unit (Figure 2-2, Vi ew
A). Retain the attaching hardware consisting of two (2) hex head cap scr ews, hex nuts
and flat washers.
2. Remove the top shroud from the boiler by grasping the handle on the top of the unit and
lifting straight up. Locate the lifting tab at the top-rear of the heat exchanger.
3. Refer to Figure 2-2, View B and attach the lifting bar to the heat exchanger lifting tab
using the hardware removed in step 1. The upper end of the lifting bar containing the oval
cutout should be positioned over the top of the heat exchanger as shown.
4. Using proper rigging equipment, capable of supporting 1000 to 1200 lbs., lift the boiler
and position it on the housekeeping pad.
5. After the boiler is properly set on the pad, detach the lifting bar and replace the shroud on
the top of the unit.
6. Retain the lifting bar for possible reuse at the installation site.
LIFTING TAB
LIFTING
BAR IN
SHIPPING
POSITION
VIEW A - SHIPPING POSITION
LIFTING BAR IN
LIFTING
POSITION
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Figure 2-2: Boiler Lifting Provisions
Benchmark 750/1000 Boiler Installation, Operation & Maintenance Manual
PRIMARY INTLET
DRAIN VALVE
EXHAUST MANIFOLD
CHAPTER 2 – INSTALLATION
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 Boiler utilizes 3” 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-891 for additional
dimensional data.
BOILER HOT
WATER OUTLET
1” NATURAL GAS
OR PROPANE
INLET
SECONDARY INLET
AIR INLET
Figure2-3: Supply and Return Locations
2.6 PRESSURE RELIEF VALVE INSTALLATION
An ASME rated Pressure Relief Valve is supplied with each Benchmark Boiler. The pressure
rating for the relief valve must be specified on the sales order. Available pressure ratings range
from 30 psi to 160 psi. The relief valve is installed on the hot water outlet of the boiler as shown
in Figure 2-4. A suitable pipe joint compound should be used on the threaded connections. Any
excess should be wiped off to avoid getting any joint compound into the valve body. T he relief
valve must be piped to within 12 inches of the floor to prevent injury in the event of a discharge.
The relief piping must be full size, without reduct ion. No valves, restrictions, or other block ages
are allowed in the discharge line. In multiple unit installations t he discharge lines must not be
manifolded together. Each must be individually run to a suitable discharge location.
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PRIMARY INTLET
EXHAUST
MANIFOLD
PAR TI AL REAR VIE W
CHAPTER 2 – INSTALLATION
PRESSURE
RELIEF VALVE
3” HOT BOILER
WATER OUTLET
P&T GAUGE
COUPLING
Figure2-4: Pressure Relief Valve Location
2.7 CONDENSATE DRAIN & PIPING
The Benchmark Boiler is designed to condense water vapor from the flue products. Therefore,
the installation must have provisions for suitable condensate drainage or collection.
The condensate drain port located on the exhaust manifold (Figure 2-5) must be connected to
the condensate trap (part no. 24060) which is packed separately within the unit’s shipping
container. The condensate trap inlet and outlet connections contain tapped 3/4” NPT ports.
DRAIN VALVE
CONDENSATE DRAIN
ANALYZER
PROBE PORT
Figure2-5: Condensate Drain Connection Location
A sample condensate trap installation is shown in Figure 2-6. However, the actual installation
details for the trap will vary depending on the available clearances, housekeeping pad height/
dimensions and other prevailing conditions at the site. The following general guidelines must be
observed to ensure proper condensate drainage:
• The condensate trap inlet (Figure 2-6) must be level with, or lower than the exhaust
• The base of the condensate trap must be supported to ensure that it is level (horizontal).
• The trap must be removable for routine maintenance. AERCO recommends that a union
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manifold drain port.
be utilized between the exhaust manifold condensate drain port and the trap inlet port.
Benchmark 750/1000 Boiler Installation, Operation & Maintenance Manual
CAUTION
COMBUTION
PROBE PORT
EXHAUST
MANIFOLD
3/4” NPT
NIPPLE
HOSE
CLAMP
T O
DRAIN
(P/N 24060)
TRAP INLET
TOP COVER
(4 each)
1” DIAM.
HOSE
4” MINIMUM
(6” MAXIMUM)
4”
3/4” NPT
NIPPLES
UNION
CHAPTER 2 – INSTALLATION
While observing the above guidelines, install the condensate trap as follows:
Condensate Trap Installation
1. Connect the condensate trap inlet to the exhaust manifold drain connection using the
appropriate piping components (nipples, reducers, elb ows, etc.) for the boiler installation
site.
2. At the condensate trap outlet, install a 3/4” NPT nipple.
3. Connect a length of 1” I.D polypropylene hose to the trap outlet and secure with a hose
clamp.
4. Route the hose on the trap outlet to a nearby floor drain.
If a floor drain is not available, a condensate pump can be used to remove the condensate to an
appropriate drain. The maximum condensate flow rate is 10 GPH. The condensat e drain trap,
associated fittings and drain line must be removable for routine maintenance.
Use PVC, stainless steel, aluminum or polypropylene for condensate drain
piping (Figure 2-6). DO NOT use carbon or copper components.
ANALYZER
NOTE
HOUSKEEPING
PAD MUST NOT
EXTEND
UNDER THE
CONDENSATE
ASSEMBLY.
INTEGRAL ADAPTOR AND
THUMBSCREW
THUMB SREWS
CONDENSATE
TRAP
FLOOR
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Figure2-6: Sample Condensate Trap Installation
Benchmark 750/1000 Boiler Installation, Operation & Maintenance Manual
Natural Gas
Propane
Benchmark 750
Benchmark 1000
Natural Gas
Propane
Benchmark 750
728 CFH, maintaining 4” W.C.
300 CFH, maintaining 7” W.C.
Benchmark 1000
976 CFH, maintaining 4” W.C.
400 CFH, maintaining 11” W.C.
WARNING
CAUTION
CHAPTER 2 – INSTALLATION
2.8 GAS SUPPLY PIPING
The AERCO Benchmark Gas Components and Supply Design Guide, GF-2030 must be
consulted prior to designing or installing any gas supply piping.
NEVER USE MATCHES, CANDLES, FLAMES OR OTHER
SOURCES OF IGNITION TO CHECK FOR GAS LEAKS
Many soaps used for gas pipe leak testing are corros ive to met als.
Therefore, piping must be rinsed thoroughly with clean water after
soap 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 between the unit and walls, or another unit.
.
Benchmark 750 and 1000 MBH units contain either a 1 inch NATURAL GAS or a 1 inch
PROPANE gas inlet connection 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 g as 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.
2.8.1 Gas Supply Specifications
The gas supply input specifications to the unit are as follows:
• The maximum static pressure to the unit must not exceed the following:
14” W.C. 14” W.C.
14” W.C. 16” W.C.
• Supply piping and pressure to the unit must be sufficient to provide the volume of gas
while maintaining gas pressure listed below while operating at maximum capacity:
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CHAPTER 2 – INSTALLATION
2.8.2 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 2-7. Maximum allowable gas pressure to the boiler is 14” W.C.
2.8.3 External Gas Supply Regulator
An external gas pressure regulator is required on the gas inlet piping under most conditions
(see sections 2.8.3.1 and 2.8.3.2, below). Regulators must conform to the following
specifications:
• NATURAL GAS: The external natural gas regulator must be capable of regulating
49,000 – 1,020,000 BTU/HR while maintaining a minimum g as pr essu re of 4.0” W.C. to
the unit.
• PROPANE: The external natural gas regulator must be capable of regulating 49,000 –
1,020,000 BTU/HR while maintaining a minimum gas pressure of 11.0 ” W . C . to the unit.
• A lock-up style regulator MUST be used when gas supply pressure will exceed 14” W.C.
2.8.3.1
For Massachusetts installations, a mandatory external gas supply regulator must be
positioned as shown in Figure 2-7. 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.
2.8.3.2
For multi-unit installations (other than Massachusetts) that EXCEED 7” W.C. gas pressure, a
separate external g as supply regulator, as shown in Figure 2-7, is highly recomm ended. No
regulator is required for gas pressures below 7” W.C. of pressure. Consult the local gas
utility for detailed requirements concerning venting of the supply gas regulator.
Massachusetts Installations Only
All Installations (Except Massachusetts)
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POWER BOX
FRONT COVER
FRONT UPPER-RIGHT CORNER OF UNIT
1” MANUAL
VALVE
GAS PRESSURE
DIRT TRAP
It is the responsibility of the customer to
source and purchase the appropriate gas
e. However,
AERCO offers for sale an appropriate
of unit purchase or separately. Contact
CHAPTER 2 – INSTALLATION
SHUTOFF
GAS INLET
REGULATOR
NOTE
regulator as described abov
regulator, which may be ordered at the time
AERCO for more information.
Figure2-7: Manual Gas Shut-Off Valve and Gas Regulator Locations
2.9 AC ELECTRICAL POWER WIRING
The AERCO Benchmark Electrical Power Wiring Guide, GF-2060, 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. Remove the front panel to access the Power Box, which is mounted
in the upper right corner of the unit as shown in Figure 2-8. Open the hinged cover of the Power
Box to access the AC terminal block connections, and other internal components shown in
Error! Reference source not found. 2-9.
WITH HINGED
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Figure2-8: Power Box With Closed Cover
Benchmark 750/1000 Boiler Installation, Operation & Maintenance Manual
WARNING
12V POWER
FUSE BLOCKS
(2)
FUSIBLE
DISCONNECT
FLAME ROD SIGNAL
AMPLIFIER
TRANSFORMER
CHAPTER 2 – INSTALLATION
THE AC POWER OUTLETS SHOWN IN ERROR! REFERENCE
SOURCE NOT FOUND. 2-9 ARE LIMITED TO 600 WATTS (5
AMP) SERVICE. DO NOT OVER-LOAD THESE OUTLETS.
ALSO, THE FUSIBLE LINK SHOWN IN FIGURE 2-9 DOES NOT
REMOVE POWER FROM THE TERMINAL BLOCKS OR AC
OUTLETS.
AC POWER
OUTLETS (2)
TERMINAL BLOCKS
115V/24V
24 V POWER SUPPLY
(SEQUENCING VALVE)
Figure2-9: Power Box Internal Components
With the exception of the transformer shown in Err or! Reference source not found. 2-9, all of
the components in the Power Box are mounted on a DIN rail.
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.
2.9.1 Electrical Power Requirements
The Benchmark Boiler accepts 120 VAC, single-phase, 60 Hz @ 20A. The Power Box contains
terminal blocks as shown in Figure 2-10. In addition, a label showing the required AC power
connections is provided on the front cover of the Power Box as shown in Figure 2-8.
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CHAPTER 2 – INSTALLATION
Figure 2-10: Power Box Cover Label
Each unit 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 unit in service, the ignition safety shutoff device must be tested. If an external
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.
For electrical power wiring diagrams, see the AERCO Benchmark Electrical Power Guide, (GF-
2060).
2.10 FIELD CONTROL WIRING
Each unit is fully wired from the factory with an internal operating control system. No field control
wiring is required for normal operation. However, the C-More Control system used with all
Benchmark units does allow for some additional control and monitoring features. Wiring
connections for these features are made on the Input/Output (I/O) board located behind the
removable front panel assembly of the unit. The I/O board is located in the center-right portion
on the front of the unit directly below the C-More Control Panel as shown in Figure 2-11.
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Benchmark 750/1000 Boiler Installation, Operation & Maintenance Manual
ECU FOR O2
SENSOR
C-MORE CONTROL
BOX
TERMINAL
STRIPS
CHAPTER 2 – INSTALLATION
I/O BOARD
Figure2-11: Input/Output (I/O) Box Location
The I/O board terminal strip connections are shown in Figure 2-12. All field wir ing is installed
from the rear of the panel by routing the wires through one of the four bushings provided on the
sides of the I/O board.
NOTE
Use Figure 2-12 to determine the functions of the I/O PCB
connections. Do not use the silkscreened labels on the PCB itself,
as these may not match.
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CAUTION
CHAPTER 2 – INSTALLATION
DO NOT make any connections to the I/O Box terminals labeled
“NOT USED”. Attempting to do so may cause equipment
damage.
Figure2-12: I/O Box Terminal Strips
2.10.1 OUTDOOR AIR IN Terminals
The OUTDOOR AIR IN terminal is used for connecting an outdoor temperature sensor (AERCO
Part No. GM-123525), as required primarily for the Indoor/Outdoor r eset 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 DI SABLED. T o 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 AIR IN and AIR SENSOR COMMON terminals in the I/O Box (see Figure 2-12).
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 terminals
labeled SHIELD in the I/O Box. The sensor end of the shield must be left free and ungrounded.
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Benchmark 750/1000 Boiler Installation, Operation & Maintenance Manual
CHAPTER 2 – INSTALLATION
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 COMBUSTION AIR Terminal
The COMBUSTION AIR terminal is used to monitor the combustion air temperature sensor.
This input is always enabled and is a “to view only” input that can be seen in the operating
menu. The sensor is an AERCO BALCO wire sensor P/N 12449. A resistance chart for this
sensor is provided in APPENDIX C. This sensor is an active part of the combustion control
system and must be operational for accurate air/fuel mixing control.
2.10.3 O2 SENSOR Terminals
The O2 SENSOR (+) and O2 SENSOR (–) terminals are used to connect an external oxygen
sensor to the I/O Box. The O
Control system after a 60 second warm-up period.
2.10.4 SPAR K SIGNAL Terminals
The two SPARK SIGNAL terminals (+ & -) permit an external current sensor to be connected for
ignition spark monitoring purposes. If no spark is present during the ignition sequence, the
controller will shut down and display a fault message.
concentration is displayed in the operating menu of the C-More
2
2.10.5 ANALOG IN Terminals
The two ANALOG IN terminals (+ and –) are used when an external signal is used to 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 air/fuel 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 signal, a DIP switch must be set on the
PMC Board located inside the C-More Control Box. Contact the AERCO factory for information
on setting DIP switches.
All supplied signals must be floating (ungrounded) signals. Connections between the source
and the boiler’s I/O Box (see Figur e 2-12) must be made using twisted shielded pair of 18–22
AWG wire such as Belden 9841. Polarity must be maintained and the shield must be connected
only at the source end and must be left floating (not connected) at the Boiler’s I/O Box.
Whether using voltage or current for the drive signal, they are linearly mapped to a 40°F to
240°F setpoint or a 0% to 100% air/fuel valve position. No scaling for these signals is provided
2.10.6 B.M.S. (PWM) IN Terminals
These terminals are only used to connect TO the legacy AERCO Boiler Management System
(BMS), wh i ch utilize a 12 millisecond, ON/OFF duty cycle and 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. Note that thes e connections cannot be used with the AERCO Control System
(ACS).
2.10.7 SHIELD Terminals
The two SHIELD terminals are used to terminate any shields used on sensor wires connected to
the unit. Shields must only be connected to these terminals.
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CHAPTER 2 – INSTALLATION
2.10.8 ANALOG OUT Terminals
The ANALOG OUT terminals (+ & -) output from 0 to 20 mA and may be used to monitor
Setpoint, Outlet Temperature, Valve Pos ition 4-20 mA, Valve Position 0-10v or be set to OFF.
Default sett ing in th e C-More controller is Valve Position 0-10v and settings behave as follows:
• When 0-10VDC is selected, the voltage output is used by the c ontroller to modulate the
combustion blower via the I/O Box terminals labeled VFD/Blower (Section 2.10.11).
• If On Board Boiler Sequencing Technology (BST) is enabled, the Analog Output
terminals are used to drive the isolation valve, open and closed.
• When the 4-20mA is selected for the Analog Output, the 0-10VDC is disabled at the
VFD/Blower terminals, and the selected output is available at the terminals labeled
Analog Output +/-.
2.10.9 RS-485 Comm Terminals
The RS-485 communication terminals (+, GND, & -) are used when the boiler plant is being
controlled by an Energy Management System (EMS) or AERCO Control System (ACS) using
Modbus (RS-485) communication.
2.10.10 RS-232 Comm Terminals
The RS-232 communication terminals (TxD and RxD) permit a laptop computer or other suitable
terminal to be connected to the boiler. The RS-232 communication feature permits viewing or
changing of Control Panel menu options and also provides access to data logs showing fault
and sensor log displays.
2.10.11 VFD/Blower (0-10 & AGND)
These terminals (0-10 & AGND) send an analog signal to control the blower speed. When any
of the 4-20mA opt ions is selected for the Analog Outputs (Section 2.10.8), the output from the
VFD/Blower terminals is disabled.
2.10.12 Interlocks
The unit offers two interlock circuits for interfacing with Energy Management Systems and
auxiliary equipment such as pumps or louvers or other accessories. These interlocks are called
the Remote Interlock and Delayed Interlock (REMOTE INTL’K IN an d DELAYED INTL’K IN in
Figure 2-12). Both interlocks, described below, are fact ory wired in the closed position (using
jumpers).
NOTE
Both the Delayed Interlock and Remote Interlock must be in the
closed position for the unit to fire.
2.10.12.1
The remote interlock circuit is provided to remotely star t (enable) and stop (disable) t he unit
if desired. The is 24 VAC and comes factory pre-wired closed (jumped).
2.10.12.2
The unit offers two interlock circuits for interfacing with Energy Management Systems and
auxiliary equipment such as pumps or louvers or other accessories. These interlocks are
called the Remote Interlock and Delayed Interlock ((REMOTE INTL’K IN and DELAYED
INTL’K IN in Fig ure 2-12). Both interlocks, described below, are factory wired in the closed
position (using jumpers).
REMOTE INTL’K Terminals
DELAYED INTL’K Terminals (OUT & IN)
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CHAPTER 2 – INSTALLATION
2.10.12.2.1
NOTE
Both the Delayed Interl ock and Remote Interlock must be in t he closed
position for the unit to fire.
Remote Interlock In (OUT & IN)
The remote interlock circuit is provided to remotely start (enable) and stop (disable) the unit
if desired. The circuit is 24 VAC and comes factory pre-wired closed (jumped).
2.10.12.2.2 Delayed Interlock In (OUT & IN)
The Delayed Interlock terminals can be used in one of two ways:
• In conjunction with the optional external sequencing valve (see section 2.14 and
Chapter 10 – BST), a component of AERCO’s on-board Boiler Sequencing
Technology (BST) solution. By default a cable of the boiler’s wiring harness is
connected to these terminals. If BST is implemented, the other end of that cable is
connected to the sequencing valve.
• If BST is NOT implemented, the second use is typically in conjunction with the
AUXILIARY RELAY CONTACTS described in section 2.10.14. 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 equipment started by
the unit’s auxiliary relay. If the delayed interlock is connected to a proving device
that requires time to close (make), a time delay (AUX START ON DLY) that holds
the start sequence of the unit long enough for a proving switch to make (close) can
be programmed.
To use this option, you must disconnect the harness from the Delayed Interlock
terminals and connect the proving device in its place.
Should the proving switch not prove within the programmed time frame, the unit will
shut down. The AUX START ON DLY can be programmed from 0 to 120 seconds.
This option is located in the Configuration Menu (Chapter 3).
2.10.13 FAULT RELAY (NC, COM, & NO) Terminals
The fault relay is a single pole double throw (SPDT) relay having a normally open and normally
closed set of relay contacts that are rated for 5 amps at 120 VAC and 5 amps at 30 VDC. The
relay energizes when any fault condition occurs and remains energized until the fault is cleared
and the CLEAR button is depressed. The fault relay connections are shown in Figure 2-12.
2.10.14 AUX RELAY CONTACTS (NC, COM, & NO) Terminals
Each unit 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 satisfied. The relay is
provided for the control of auxiliary equipment, such as pumps and louvers, or can be used as a
unit status indictor (firing or not firing). Its cont acts are rated for 120 VAC @ 5 amps. Refer to
Figure 2-12 to lo cate the AUX RELAY t erminals for wiring connections.
2.11 FLUE GAS VENT INSTALLATION
AERCO Gas Fired Venting and Combustion Air Guide, GF-2050 must be consulted before any
flue or combustion air venting is designed or installed. Suitable, U/L approved, positive
pressure, watertight vent materials MUST be used for safety and UL certification. Because the
unit is capable of discharging low temperature exhaust gases, the flue must be pitched back
towards the unit a minimum of 1/4" per foot to avoid any condensate pooling and to allo w for
proper drainage.
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Selkirk Corporation - Heatfab Division
Watertown Supply
M. A. Peacard
www.mapeacard.com
Glover Sheet Meatal, Inc.
www.gloversheetmetal.com
CHAPTER 2 – INSTALLATION
While there is a positive flue pressure during operation, the combined pressure drop of vent and
combustion air systems must not exceed 140 equivalent feet or 1.9” W .C. Fittings as well as
pipe lengths must be calculated as part of the equivalent length. For a natural draft installation
the draft must not exceed - 0.25” 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 following companies provide vent systems that conform to
all applicable requirements for installations within the Commonwealth of Massachusetts.
Contact information is as follows:
130 Industrial Blvd.
Turners Falls, MA 01376
Phone: 1-800-772-0739
www.heat-fab.com
1250 Massachusetts Ave.
Boston MA 02125-1689
Phone: (617) 288-0629
33Grove St.
Watertown, MA 02472
Phone: (617) 924-2840
http://www.watertownsupply.com/
44 Riverdale Ave.
Newton, MA 02485
Phone: (617) 527-8178
2.12 COMBUSTION AIR
The AERCO Benchmark Boiler Venting and Combustion Air Guide, GF-2050 MUST be
consulted before any flue or inlet air venting is designed or installed. 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 and
warranty validation.
The more common methods of combustion air supply are outlined in the following sections. For
combustion air supply from ducting, consult the AERCO GF-2050, Gas Fired Venting and
Combustion Air Guide.
2.12.1 Combustion From Outside the Building
Air supplied from outside the building must be provided through two permanent openings. For
each unit these two openings must have a free area of not less than one square inch for each
4000 BTUs input of the equipment or 250 square inches of free area. The free area must take
into account restrictions such as louvers and bird screens. For Canada installations, refer to the
requirements specified in CSA B149.1-10, sections 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 BTUH of total input or 1000 square inches of free area. The f ree area
must take into account any restrictions, such as louvers.
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CHAPTER 2 – INSTALLATION
2.13 DUCTED COMBUSTION AIR
The AERCO Benchmark 750 & 1000 MBH Boilers ar e UL listed for 100%-ducted combustion.
For ducted combustion air installations, the screen inlet air ductwork must then be attached
directly to the unit’s air inlet.
In a ducted 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 heater in a ducted
combustion air configuration, each unit must have a minimum 6 inch diameter connection at the
unit.
2.14 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 Figures 2-13 and 2-14 for wiring details.
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 2-15.
Figure2-13: Schematic – System Pump Start using Boiler Pump Relay
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CHAPTER 2 – INSTALLATION
Figure2-14: Schematic – System Pump Start using a Separate Contact Relay
Figure 2-15: Identifying the Presence of BMK Pump Relay Option 69102
2.15 SEQUENCING ISOLATION VALVE INSTALLATION
All Benchmark units are shipped with a connection for an optional motorized external
sequencing isolation valve (p/n 92084-TAB) included in the shipping container. This valve is an
integral component of the AERCO’s on-board Boiler Sequencing Technology (BST) solution.
BST allows sites with multiple boilers to have one boiler, acting as a “master” to manage the
other boilers at the site in such a way that the efficiency of the entire boiler array is maximized.
When operated with the BST system, the Master controls its own isolation valve and sends
signals to the slave units to open or close their isolation valves. After the boiler load is satisfied,
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HOT WATER
SEQUENCING
ISOLATION VALVE
CHAPTER 2 – INSTALLATION
the isolation valve opens for a programmed interval (default = 1 minute) before closing. When
the system load is satisfied, the BST system will open the isolation valves for all of the boilers.
The implementation of BST, and the installation and use of this valve is optional.
The boiler is pre-wired to accept the sequencing isolation valve. Installation consists of installing
the sequencing isolation valve in the hot water outlet pipe, and then connecting it into the shell
harness, as described below.
NOTE
When the Sequencing Isolation Valve is used, the AUX START ON DLY in
the Configuration menu must be set to at least 120 seconds. The
Sequencing Isolation Valve control is only available when BST is enabled.
Refer to section 2.10.12.2 and Table 3-4 i n section 3-6 and Chapter 10.
Installing Sequencing Isolation Valve
1. Install the sequencing isolation valve in the boiler’s hot water outlet pipe.
OUTLET
Figure 2-13: Sequencing Isolation Valve Installed
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CHAPTER 2 – INSTALLATION
Installing Sequencing Isolation Valve – Continued
2. The boiler’s shell harness has one unused cable. One end of this cable is connected to
the DELAYED INTERLOCK IN terminals in the I/O board (see Figure 2-14) while the other
end contains a Molex connector with a jumper wire inserted in it (this jumper wire allows
units that do not have a sequencing isolation valve to operate normally). Find the free end
of this cable inside the unit’s enclosure.
Figure 2-14: Sequencing Isolation Valve Installed
3. Remove the jumper wire from the Molex connector and then plug it into the sequencing
isolation valve’s connector.
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WARNING
CAUTION
CHAPTER 3 – OPERATION
CHAPTER 3. OPERATION
3.1 INTRODUCTION
The information in this Chapter provides a guide to the operation of the Benchmark 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 may void the equipment warranty. In addition, the following WARNINGS and
CAUTIONS must be observed at all times.
WARNING
ELECTRICAL VOLTAGES IN THIS SYSTEM INCLUDE 120 AND 24
VOLTS AC. IT MUST BE SERVICED ONLY BY FACTORY CERTIFIED
SERVICE TECHNICIANS.
DO NOT ATTEMPT TO DRY FIRE THE UNIT. STARTING THE UNIT
WITHOUT A FULL WATER LEVEL CAN SERIOUSLY DAMAGE THE
UNIT AND MAY RESULT I N INJURY TO PERSONNEL OR PROPERTY
DAMAGE. THIS SITUATION WILL VOID ANY WARRANTY.
All of the installation procedures in Chapter 2 must be completed before
attempting to start the unit.
3.2 CONTROL PANEL DESCRIPTION
All Benchmark Series Boilers utilize the C-More Control Panel shown in Figure 3-1. This panel
contains all of the controls, indicators and displays necessary to operate, adjust and
troubleshoot the 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 and menu descriptions provided in this Chapter.
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3 1 8
9
10
11 7 6
5
*4
12
2
CHAPTER 3 – OPERATION
Figure 3-1: Control Panel Front View
*NOTE
If there is a requirement to use the RS232 port (Item 4) on the CMore controller front panel, contact AERCO to purchase the
RS232 Adaptor Cable (P/N 124675), which is designed for this
purpose. This cable features a DB9 connector for connection to
older computers with serial ports or can be used with a Serial-toUSB adaptor for use in modern computer USB ports.
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COMM
Lights when RS-232 communication is occurring
ts when the valve position (fire rate) is being controlled
using the front panel keypad. This mode of operation is for
service technician use only.
from an Energy Management System
DEMAND
Lights when there is a demand for heat.
On a BST Master, display flashes & shows header temperature.
Vacuum Fluorescent Display (VFD) consists of 2 lines each
o 16 alphanumeric characters. The
• BST Messages
Port permits a Laptop Computer or External Modem to be
anel. AERCO offers for
purchase the RS232 Adaptor Cable (P/N 124675), which is
designed to work with this port. This cable features a DB9
computer USB ports.
occurs. An alarm message will appear in the VFD.
Troubleshooting may be required to clear these types of alarms.
have been satisfied.
8
ON/OFF Switch
Enables and disables boiler operation.
Pressing the CLEAR key (item 6) resets the display.
CHAPTER 3 – OPERATION
Table 3-1: Operating Controls, Indicators and Displays
ITEM
1
2
3
FEATURE FUNCTION
Four (4) Status LEDs indicate the current operating status as follows:
MANUAL
REMOTE
OUTLET
TEMPERATURE
Display
VFD Display
LED Status Indicators
Ligh
Lights when the unit is being controlled by an external signal
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.
capable of displaying up t
information displayed includes:
• Startup Messages
• Fault Messages
• Operating Status Messages
• Menu Selection
connected to the unit’s Control P
RS-232 Port
4
connector for connection to older computers with serial ports or
can be used with a Serial-to-USB adaptor for use in modern
FAULT Indicator
5
Red FAULT LED indicator lights when a boiler alarm condition
Turns off the FAULT indicator and clears the alarm message if
CLEAR Key
6
READY Indicator
7
LOW WATER LEVEL
9
TEST/RESET
Switches
the alarm is no longer valid. Lockout type alarms will be latched
and cannot be cleared by simply pressing this key.
Lights ON/OFF switch is set to ON and all Pre-Purge conditions
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.
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2.
Allows you to go back to the previous menu level without
this key allows you to go back to the top of a main menu
key was pressed and the menu item is flashing,
this key will select the displayed menu category. If the
key was pressed and the menu item is flashing,
key is pressed, the displayed menu item will begin to flash.
between the Automatic and
Bargraph
CHAPTER 3 – OPERATION
Table 3-1: Operating Controls, Indicators and Displays – Continued
ITEM
10
FEATURE FUNCTION
MENU Keypad
Six (6) keys provide the following functions for the Control Panel Menus:
MENU
Steps through the main menu categories shown in Figure 3The Menu categories wrap around in the order shown.
changing any information. Continuously pressing this key will
BACK
bring you back to the default status display in the VFD. Also,
category.
When in one of the main menu categories (Figure 3-2), pr essing
▲ (UP) Arrow
the ▲ arrow k ey will select the displayed menu category. If the
CHANGE
pressing the ▲ arrow key will increment the selected setting.
When in one of the main menu categories (Figure 3-2), pr essing
▼ (DOWN) Arrow
CHANGE
pressing the ▼ arrow key will decrement the selected setting.
Permits a setting to be changed (edited). When the CHANGE
CHANGE
Pressing the ▲ or ▼ arrow key when the item is flashing will
increment or decrement the displayed setting.
ENTER
Saves the modified menu settings in memory. The display will
stop flashing.
This switch toggles the boiler
Manual modes of operation. When in the Manual (MAN) mode,
the front panel controls are enabled and the MANUAL status
11 AUTO/MAN Switch
LED lights. Manual operation is for service only.
When in the Automatic (AUTO) mode, the MANUAL status LED
will be off and the front panel controls disabled.
VALVE POSITION
12
20 segment red LED bargraph continuously shows the Air/Fuel
Valve position in 5% increments from 0 to 100%
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CHAPTER 3 – OPERATION
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 categories 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.
Once the valid level 1 password (159) is entered, the options list ed in the Setup. Configuration
and Tuning Menus can be viewed and changed, if desired. The Combustion Cal Menu is
protected by the level 2 password (6817) 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 familiar with the following basic
steps before attempting to perform specific menu procedures:
Menu Processing Procedure
1. The Control Panel will normally be in the Operating Menu and the VFD will displa y 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 ▼ arrow 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. The
displayed option will begin to flash. 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 3 – OPERATION
* Only if BST is enabled (see Chapter 10)
Figure 3-2: Menu Structure
NOTE
The following sections 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.
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Available Choices or Limits
Minimum
Maximum
Active Setpoint
40°F
240°F
Inlet Temp
40°F
140°F
Air Temp
-70°F
245°F
Outdoor Temp*
-70°F
130°F
Valve Position In
0%
100%
Valve Position Out*
0%
100%
Exhaust Temp
°F
°F
Flame Strength
0%
100%
Oxygen Level
0%
21%
Run Cycles
0
999,999,999
Run Hours
0
999,999,999
Fault Log
0
19
0
CHAPTER 3 – OPERATION
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).
Table 3-2: Operating Menu
Menu Item Display
Default
*NOTE
The Outdoor Temp and Valve Position Out display items 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).
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 time-out
after 1 hour. Therefore, the correct password must be reent ered 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 sof tware version display is also provided to indicate the
current Control Box software version.
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Available Choices or Limits
Minimum
Maximum
Password
0
9999
0
Language
English
English
Time
12:00 am
11:59 pm
Date
01/01/00
12/31/99
Unit of Temp
Fahrenheit or Celsius
Fahrenheit
Comm Address
0
127
0
Baud Rate
2400, 4800, 9600, 19.2K
9600
Upload Timer
0 0
Unit Alpha
A Z A
Unit Serial #
0000
9999
0000
Unit Year
0
99
00
C-More Year
0
99
11
C-More Serial #
0
9999
0000
C-More Alpha
A Z A
IP Address
Software
Ver 0.00
Ver 9.99
CHAPTER 3 – OPERATION
Table 3-3: Setup Menu
Menu Item Display
Default
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 FactorySet in accordance with the requirements specified for each
individual order. Therefore, under normal operating conditions, no
changes will be required.
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Available Choices or Limits
Minimum
Maximum
Reset)
CHAPTER 3 – OPERATION
Table 3-4: Configuration Menu
Menu Item Display
Internal Setpt Lo Temp Limit Hi Temp Limit 130°F
KC Boiler, KC Boiler LN,
BMK Blr Std, BMK Blr Std Dual,
Unit Type
Unit Size
(Only the unit sizes
available for the Unit
Type will be displayed)
Fuel Type Natural Gas, Propane Natural Gas
Boiler Mode
Remote Signal
(If Mode = Remote
Setpoint, Direct Drive
or Combination)
BMK Blr LN, BMK Blr LN Dual
KC Water Heater,
KC Water Heater LN,
Innovation WH
750 MBH, 1000 MBH,
1500 MBH, 2000 MBH,
2500 MBH, 3000 MBH,
6000 MBH
Constant Setpoint,
Remote Setpoint,
Direct Drive,
Combination,
Outdoor Reset
4 – 20 mA/1 – 5V
0 -20 mA/0 – 5V
PWM Input (Legacy BMS),
Network
Default
BMK Blr LN
750 MBH
or
1000 MBH
Constant Setpoint
4 – 20 mA,
1-5V
Outdoor Sensor Enabled or Disabled Disabled
*Bldg Ref Temp
(If Mode = Outdoor
*Reset Ratio
(If Mode = Outdoor
Reset)
*System Start Tmp
(If Outdoor Sensor =
Enabled)
Setpt Lo Limit
Setpt Hi Limit
Temp Hi Limit
40°F 230°F 70°F
0.1 9.9 1.2
30°F 100°F 60°F
40°F Setpt Hi Limit 60°F
Setpt Lo Limit 210°F 140°F
40°F 210°F 160°F
*NOTE
The Bldg Ref Temp and Reset Ratio Menu Items are only
displayed when the Outdoor Sensor is set to “Enabled”.
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Available Choices or Limits
Minimum
Maximum
Available Choices or Limits
Minimum
Maximum
CAUTION
CHAPTER 3 – OPERATION
Table 3-4: Configuration Menu - Continued
Menu Item Display
Max Valve Position
Pump Delay Timer
Aux Start On Dly
Failsafe Mode Shutdown or Constant Setpt Shutdown
Low Fire Timer 2 sec. 600 sec. 2 sec.
Setpt Limiting Enabled or Disabled Disabled
Setpt Limit Band 0°F 10°F 0
Network Timeout 5 Sec 999 Sec 30 Sec
HI DB Setpt EN 0% 100% 30%
Demand Offsert 0 25 0
Deadband High 0 25 0
Deadband Low 0 25 0
Spark Monitor Enabled or Disabled Disabled
Spark Current Display
40% 100% 100%
0 min. 30 min. 0 min.
0 sec. 120 sec. 0 sec.
Default
DO NOT CHANGE the Analog Output Menu Item from its Default
setting (Valve Position 0-10V).
3.7 TUNING MENU
The Tuning Menu items shown 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.
Table 3-5: Tuning Menu
Menu Item Display
Prop Band
Integral Gain
Derivative Time
Warmup Prop Band
Warmup Int Gain
Warmup PID timer
Reset Defaults?
1°F 120°F 8°F
0.00 2.00 1.6
0.0 min 2.00 min 0.10 min
0°F 120°F 95°F
0 2.00 0.50
0 sec. 240 sec. 20 sec.
Yes, No, Are You Sure? No
Default
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Benchmark 750/1000 Boiler Installation, Operation & Maintenance Manual
Available Choices or Limits
Minimum
Maximum
CAL Voltage 16%
1.70
2.20
1.80
CAL Voltage 30%
1.90
3.50
3.20
CAL Voltage 45%
2.60
4.40
3.70
CAL Voltage 60%
2.70
4.50
3.80
CAL Voltage 80%
3.60
4.40
4.60
CAL Voltage 100%
4.80
6.20
6.00
SET Valve Position
0%
100%
Variable
Blower Output
Monitor Blower Output Voltage
Set Stdby Volt
0
4.00 V
0/2.00 V
Oxygen Level
0%
25%
Variable
CHAPTER 3 – OPERATION
3.8 COMBUSTION CAL MENU
The Combustion Cal (Calibration) Menu is protected by the level 2 pass word (6817) which must
be entered to view or change the menu items shown in Table 3-6. These menu item s 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 the motor which adjusts the rotational speed of t he 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 dr ive voltages are
listed in Table 3-6.
Table 3-6: Combustion Cal Menu
Menu Item Display
Default
3.9 BST (BOILER SEQUENCING TECHNOLOGY ) MENU
The BST Menu must be Enabled in order to be displayed and accessed. The BST Enable item
is located at the end of the Configuration Menu.
The Boiler Sequencing Technology (BST) Menu contains all of the items required to Configure,
Operate and Monitor the functionality of the BST System. There are over 50 items in this menu,
and selecting any particular item from the list, for inspection or modification, could be time
consuming. As a result, the BST Menu has been segmented into FIVE logical groups based on
functionality.
The five Item groups are:
1. BST Monitor Items
2. BST SETUP MENU*
3. * OPERATE MENU *
4. *TEMP CTRL MENU*
5. *BST COMM MENU*
These displayed item groups are displayed in UPPER CASE letters, and are bounded by an
asterisk * in order to readily identify them within the item list.
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Available Choices or Limits
Minimum
Maximum
Off
BST Slave
BST Master
Off
BST Setpoint
BST Setpt Lo Limit
BST Setpt Hi Limit
130°F
Header Temp
Avg Fire Rate
Outdoor Temp
Units Available
0
8
Units Present
Units Ignited 0 8
Units firing
BST Valve State
0 (CLOSED)
1 (OPEN)
0
1 Comm Errors 8
0
9
0
1 BST Units 8
0 (see table)
0 (see table)
0
*BST SETUP MENU*
Disabled
Enabled
Disabled
Constant
Setpoint
Remote
Setpoint
Outdoor
Reset
Head Temp Source
Network
FFWD Temp
FFWD Temp
Header Temp Addr
0
255
240
Header Temp Point
0
255
14
BST Outdoor Sens
Disabled
Enabled
Disabled
Outdr Tmp Source
Outdoor Temp
Network
Outdoor Temp
Outdoor Tmp Addr
0
255
240
Outdoor Tmp Pnt
0
255
215
0-20 mA/0-5
Yes
BST Auto Timer
10 sec
120 sec
30 sec
System
CHAPTER 3 – OPERATION
The Items contained in group 1 (BST Monitor Items) are ALWAYS displayed within the menu,
as these items are c ritic al for pr oper sys tem operation. Therefore, the BST Monitor I tems
Header itself is NOT displayed.
The Items contained in groups 2-5 are NOT DISPLAYED unless that particular item group has
been enabled from the C-More keypad.
Table 3-7: BST Menu
Menu Item Display
Default
BST Mode
Header Temp NA
(°F)
BST Fire Rate 0 100% Fire rate %
BST Ave Fire Rate 0 100%
BST Outdoor Temp NA
BST Setpoint Mode
Constant Setpt
%
(°F)
BST Remote Signal 4-20 mA/1-5 Vdc;
BST Auto Mstr No
Remote Intlk Use Boiler Shutdown System Shutdown
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Vdc;
NOTE! A Modbus temperature
transmitter must be installed in
conjunction with this feature.
Network Network
No
Shutdown
Benchmark 750/1000 Boiler Installation, Operation & Maintenance Manual
Available Choices or Limits
Minimum
Maximum
On-Outlet
Temp
1 Blr Threshold
10
35
25
Setpoint Setback
Disable
Enable
Disable
Setback Setpoint
BST Setpt Lo Limit
BST Setpt HI Limit
130°F
Setback Start
12:00am
11:59pm
12.00am
Setback End
12:00am
11:59pm
12.00am
Rate Threshold
1°F
30°F
15°F
MENU*
BST Next On VP
16%
100%
50%
BST Max Boilers
1
8
8
BST On Delay
30 sec
300 sec
60 sec
BST On Timeout
15 sec
300 sec
60 Sec
Valve Override
Off
Closed
Open
Off
Valve Off Delay
0
15 min
1 min
BST Sequencing
Run Hours
Unit Size
Select Lead
Run Hours
Select Lead Unit
0
127
0
Select Lag Unit
0
127
0
Lead/Lag Hours
25 hours
225 hours
72 hours
BST Temp Hi Limit
40°F
210°F
210°F
BST Setpt Lo Limit
40°F
BST Setpt HI Limit
60°F
BST Setpt HI Limit
BST Setpt Lo Limit
220°F
195°F
BST Prop Band
1°F
120°F
100°F
BST Intgral Gain
0.00
2.00
0.50
BST Deriv Time
0.00 Min
2.00 Min
0.10 Min
BST Deadband Hi
0
25
1
BST Deadband Lo
0
25
1
Deadband En Time
0
120 Sec
30 Sec
BST FR Up Rate
1
120
20
BST Bldg Ref Tmp
40°F
230°F
70°F
BST Reset Ratio
0.1
9.9
1.2
System Start Tmp
30°F
120°F
60°F
*BST COMM MENU*
CHAPTER 3 – OPERATION
Menu Item Display
One Boiler Mode Off
*BST OPERATE
Disabled Enabled Disabled
Default
On-Avg Temp Off
*BST TEMP CTRL
MENU*
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Disabled Enabled Disabled
Benchmark 750/1000 Boiler Installation, Operation & Maintenance Manual
Available Choices or Limits
Minimum
Maximum
Comm Address
0
127
0
BST Min Addr
1
128
1
BST Max Addr
1
128
8
SSD Address
0
250
247
SSD Poll Control
0
1000
0
Err Threshold 1 9
5
SSD Temp Format
Degrees
Points
Degrees
BST Upld Timer
0
9999 sec
0
CHAPTER 3 – OPERATION
Menu Item Display
Default
3.10 START SEQUENCE
When t he Control Box ON/OFF switch is set to the ON position, it checks all pre-purge safety
switches to ensure they are closed. These switches include:
• Safety Shut-Off Valve (SSOV) Proof of Closure (POC) switch
• Low Water Level switch
• High Water Temperature switch
• High Gas Pressure switch
• Low Gas Pressure switch
• Blowe r Pro of switch
• Blocked Inlet switch
If all of the above switches are closed, the READY light above the ON/OFF switch will light 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
messages will be displayed throughout the start sequence, if the
required conditions are not observed.
1. The DEMAND LED st atus 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.
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Benchmark 750/1000 Boiler Installation, Operation & Maintenance Manual
SSOV
GAS INLET
BLOWER
AIR
100
CHAPTER 3 – OPERATION
TO AIR/FUEL
VALVE
MANUAL
SHUT-OFF VALVE
Figure 3-3: 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 the 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
full-open (100%).
c) The VALVE POSITION bargraph will show 100%.
STEPPER MOTOR
TO
Figure 3-4: Air/Fuel Valve In Purge Position
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TO
AIR
25
BLOWER PROOF
SWITCH
CHAPTER 3 – OPERATION
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.
BLOCKED
INLET SWITCH
Figure 3-5: Blower Proof Switch
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 the 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 igniter relay is activated and provides ignition spark. Current to t he spark igniter
is monitored for proper level. If no spark is present, the Controller will stop the ignition
process at 3 seconds and shut down the boiler. Refer to Chapter 8 – Troubleshooting
for guidance if this occurs.
(c) The gas Safety Shut-Off Valve (SSOV) is energized (opened) allowing gas to flow
into the Air/Fuel Valve.
STEPPER MOTOR
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Figure 3-6: Air/Fuel Valve In Ignition Position
Benchmark 750/1000 Boiler Installation, Operation & Maintenance Manual
750 MBH
1000 MBH
750 MBH
1000 MBH
0%
0 0 0 0 10%
0 0 0
0
18% (Stop Level)
50,000
50,000
6.7%
5%
20%
52,000
54,000
6.9%
5.4%
30%
108,000
140,000
14%
14%
40%
246,000
297,000
33%
30%
50%
369,000
443,000
49%
44%
60%
465,000
564,000
62%
56%
70%
554,000
660,000
74%
66%
80%
637,000
789,000
85%
79%
90%
733,000
933,000
98%
93%
100%
750,000
1,000,000
100%
100%
CHAPTER 3 – OPERATION
6. Up to 7 seconds will be allowed for ignition to be detected. The igniter relay will be turned
off one second after flame is detected.
7. After 2 seconds of continuous flame, Flame Proven will be displayed and the flame
strength will be indicated. After 5 seconds, the current date and time will be displayed in
place of the flame strength.
8. With the unit firing properly, it will be controlled by the temperature controller circuitry. The
boiler’s VALVE POSITION will be continuously displayed on the front panel bargraph.
Once the demand for heat has been satisfied, the Control Box will turn off the SSOV gas valve.
The blower relay will be deactivated and the Air/Fuel Valve will be closed. Standby will be
displayed.
3.11 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:
Start Level: 22%
Stop Level: 18%
Normally, these settings should not require adjustment.
Note that the energy input of the boiler is not linearly related to the Air/Fuel Valve position. Refer
to Table 3-8 for the relationship between the energy input and Air/Fuel Valve position f or a BMK
750 MBH or BMK 1000 MBH boiler running on natural gas.
Table 3-8: Relationship Between Air / Fuel Valve Position and Energy Input
For 750 MBH & 1000 MBH Units Running On NATURAL GAS
Air/Fuel Valve
Position (% Open)
Energy Input
(BTU/Hr)
Boiler Energy Input
(% of Full Capacity)
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Benchmark 750/1000 Boiler Installation, Operation & Maintenance Manual
750 MBH
1000 MBH
750 MBH
1000 MBH
0%
0 0 0
0
10%
0 0 0
0
18% (Stop Level)
50,000
50,000
6.7%
5.0%
20%
71,000
71,000
9.5%
7.1%
30%
128,000
181,000
17%
18%
40%
373,000
400,000
50%
40%
50%
508,000
562,000
68%
56%
60%
565,000
703,000
75%
70%
70%
621,000
791,000
83%
79%
80%
660,000
865,000
88%
87%
90%
723,000
963,000
96%
96%
100%
750,000
1,000,000
100%
100%
CHAPTER 3 – OPERATION
Table 3-9: Relationship Between Air/Fuel Valve Position and Energy Input
For 750 MBH & 1000 MBH Units Running On PROPANE
Air/Fuel Valve
Energy Input
(BTU/Hr)
Boiler Energy Input
(% of Full Capacity)
Position (% Open)
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WARNING
CHAPTER 4 – 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 750 or 1000 MBH boiler consists of
the following:
• Complete installation (Chapter 2)
• Set proper controls and limits (Chapter 3)
• Perform combustion calibration (Chapter 4)
• Test safety devices (Chapter 6)
All applicable installation procedures in Chapter 2 must be fully completed prior to performing
the initial start-up of the unit. 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 efficiency, with low
flue gas emissions.
Initial unit start-up must 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 Safety Device Testing procedures specified in Chapter 6 to complete all initial unit
start-up requir ements.
An AERCO Gas Fired Startup Sheet, included with each Benchmark, must be completed for
each unit for warranty validation and a copy must be returned promptly to AERCO at:
AERCO International, Inc.
100 Oritani Drive
Blauvelt, New York 10913
(FAX: 845-580-8090)
DO NOT ATTEMPT TO DRY FIRE THE UNI T. STARTING THE
UNIT WITHOUT A FULL WATER LEVEL CAN SERIOUSLY
DAMAGE THE UNIT AND MAY RESULT IN injury to
PERSONNEL OR PROPERT Y DAMAGE. THIS SITUATION WILL
VOID any warranty.
NOTE
ALL APPLICABLE INSTALLATION PROCEDURES I N 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 sections outline the necessary tools and
instrumentation as well as their installation.
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Benchmark 750/1000 Boiler Installation, Operation & Maintenance Manual
SSOV
GAS INLET
LEAK DETECTION
BALL VALVE
1/4” NTP PLUG
CHAPTER 4 – INITIAL START-UP
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 inch 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 m onitor the gas pressure on the downstream
side of the SSOV during the Combustion Calibration procedures described in section 4.3.
The gas supply manometer is installed at the upstream and/or downstream location shown in
Figure 4-1.
MANUAL
SHUT-OFF
VALVE
TO AIR/FUEL
VALVE
(Install manometer here
Figure 4-1: 1/4 Inch Gas Plug Location
Install the 16” W.C. manometer(s) as described in the following steps:
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Condensate Drain
ANALYZER PROBE
EXHAUST
CHAPTER 4 – INITIAL START-UP
Installing Gas Supply Manometer
1. Turn off the main gas supply upstream of the unit.
2. Remove the top panel and front panel from the boiler to access the gas train
components.
3. To monitor the gas pressure on the downstream side of the SSOV during Combustion
Calibration (section 4.3), 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.
4. Install a NPT-to-barbed fitting into the tapped plug port.
5. 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 a 1/4” NPT port on the side of the exhaust manifold as shown in Figure 4-2.
Prepare the port for the combustion analyzer probe as follows:
Accessing Analyzer Probe Port
1. Refer to Figure 4-2 and remove the 1/4” NPT plug from the exhaust manifold.
2. If necessary, adjust t he stop on the combustion analyzer probe so it will extend mid-way
into the flue gas flow. DO NOT install the probe at this time.
Figure 4-2: Analyzer Probe Port Location
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Benchmark 750/1000 Boiler Installation, Operation & Maintenance Manual
CHAPTER 4 – INITIAL START-UP
4.3 NATURAL GAS COMBUSTION CALIBRATION
Complete the instructions below if the unit will run on Natural Gas rather than PROPANE gas.
NOTE
When installed and operated in accordance with the requirements
specified in this section, this Benchmark boiler delivers low NOx
emissions of <20 ppm at all firing rates. Alternatively, these
boilers can be combustion calibrated to provide ultra-low NOx
emissions of <9 ppm.
To combustion calibrate the boiler to produce low NOx emissions
of <20 ppm, complete the instructions in this section. To
combustion calibrate the boiler to produce ultra-low NOx
emissions of <9 ppm, first complete the instructions in this section
and then, in addition, complete the instructions in Appendix M.
The Benchmark 750/1000 boiler is combustion calibrated at the factory prior to shipping.
However, recalibration is necessary as part of initial start-up due t o changes in the local alt it ude,
gas BTU content, gas supply piping and supply regulators. Combustion Calibration 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.
NATURAL GAS Combustion Calibration
1. Open the water supply and return valves to the unit and ensure that the system pumps
are running.
2. Open the natural gas supply valve 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 position in %. Also, the
MANUAL LED will light.
6. Adjust the air/fuel valve position to 0% by pressing the ▼ arrow key.
7. Ensure that the leak detection ball valve downstream of the SSOV is open.
8. Set the ON/OFF switch to the ON position.
9. Change the valve position to 30% 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 set t o 2.0 ± 0.4” W.C. If
gas pressure adjustment is required, remove the brass hex nut on the SS OV actuator to
access the gas pressure adjustment screw (Figure 4-3). Make gas pressure adjustments
using a flat-tip screwdriver to obtain a gas press ure of 2.0” W.C. ± 0.4” W.C.
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Benchmark 750/1000 Boiler Installation, Operation & Maintenance Manual
Nitrogen Oxide
(NOx)
Carbon Monoxide
(CO)
BRASS HEAD CAP
Adjustment Screw)
CHAPTER 4 – INITIAL START-UP
NATURAL GAS Combustion Calibration –
Continued
(Remove to access
Gas Pressure
Figure 4-3: Gas Pressure Adjustment Screw Location
11. Using the ▲ arrow key, increase the valve open position to 100%. Verify that the gas
pressure on the downstream side of the SSOV settles within the range of 2.0” W.C. ±
0.4” W.C. Readjust the gas 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 reading to stabilize.
13. Compare the oxygen readings on the combustion analyzer to the on-board O
sensor
2
value displayed in the Operating Menu of the C-More Control Panel. If the values differ by
more than ±1.5% and your combustion analyzer is correctly calibrated, the on-board O
sensor may be defective and need to be replaced.
14. Compare the measured oxygen level to the oxygen range shown below. Also, ensure that
the nitrogen oxide (NOx) and carbon monoxide (CO) readings do not exceed the values
shown. If you are not in a “NOx-limited” area and/or do not have a NOx measurement in
your analyzer, set the oxygen (O
) at 5.5% ± 0.5%.
2
Combustion Calibration Readings
Valve Position Oxygen (O2) %
100% 5% - 6%
15. If the oxygen level is not within the required tolerance, the gas pressure on the
downstream side of the SSOV must be adjusted using the gas pressure adjustment
screw on the SSOV (Figure 4-3). Slowly rotate the gas pressure adjustment
(approximately 1/4-turn increments). Allow the combustion analyzer to stabilize follo wing
each adjustment. Clockwise rotation reduces the oxygen level, while counterclockwise
rotation increases the oxygen level.
<20 ppm
<100 ppm
2
16. Once the oxygen level is within the specified range at 100%, record the O2, NOx and CO
readings on the Combustion Calibration Data Sheets provided with the unit.
17. Lower the valve position to 80% using the ▼arrow key.
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Nitrogen Oxide
(NOx)
Carbon Monoxide
(CO)
CHAPTER 4 – INITIAL START-UP
NATURAL GAS Combustion Calibration –
Continued
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 18% as described
in the following steps. These steps assume that the inlet air temperature is
within the range of 50°F to 100°F. If NOx readings exceed the target values
shown, increase the O
range. Record the increased O
sheet.
18. 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.
19. Press the MENU key until Combustion Cal Menu appears on the display.
20. Press the ▲ arrow key until SET Valve Position appears on the display.
21. Press the CHANGE key. SET Valve Position will beg i n to fla sh.
22. Press the ▲ arrow key until SET Valve Position reads 80%. Press the ENTER key.
23. Next, press the
down (▼) arrow key until CAL Voltage 80% is displayed.
level up to 1% higher than the listed calibration
2
value on the Combustion Calibration
2
24. Press the CHANGE key and observe that CAL Voltage 80% is flashing.
25. The oxygen level at the 80% valve position should be as shown below. Also, ensure that
the nitrogen oxide (NOx) and carbon monoxide (CO) readings do not exceed the
following values:
Natural Gas Combustion Calibration Readings
Valve Position Oxygen (O2) %
80% 5% - 6% <20 ppm <100 ppm
26. 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.
27. 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. Record all readings
on the Combustion Calibration Sheets provided.
28. Repeat steps 20 through 27 for valve positions of 60%, 45%, 30% and 18%* (see *NOTE
below). The oxygen (O
), nitrogen oxide (NOx) and carbon monoxide (CO) should remain
2
within the same limits for all valve positions as shown in the following table.
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Nitrogen Oxide
(NOx)
Carbon Monoxide
(CO)
CHAPTER 4 – INITIAL START-UP
NATURAL GAS Combustion Calibration –
Continued
*NOTE
Set the Valve Position at 18% but make adjustments to the Combustion
Calibration value designated as 16%.
NOTE
If NOx readings exceed the target values shown (<20 ppm), increase the
O
level up to 1% higher than the listed calibration range shown in the
2
table. Record the increased O
value on the Combustion Calibration sheet.
2
Natural Gas Combustion Calibration Readings
Valve Position Oxygen (O2) %
60% 5% - 6%
<20 ppm
<100 ppm
45% 5% - 6% <20 ppm <100 ppm
30% 5% - 6% <20 ppm <100 ppm
18% 5% - 6% <20 ppm <100 ppm
29. If the oxygen level at the 18% valve position is too high and the Blower voltage is at the
minimum value, you can adjust the idle screw (TAC valve) which is recessed in the top of
the Air/Fuel Valve (see Appendix G). Rotate the screw 1/2 turn clock wise (CW) to add f uel
and reduce the O
60% down to 18% after making a change to the idle screw (TAC valve).
to the specified level. Recalibration MUST be performed again from
2
30. This completes the NATU RAL GAS combustion calibration procedures.
4.4 PROPANE COMBUSTION CALIBRATION
Complete the instructions below if the unit will run on PROPANE gas rather than Natural Gas.
NOTE
When installed and operated in accordance with the requirements
specified in this section, this Benchmark boiler delivers low NOx
emissions of <30 ppm at all firing rates. Unlike units running on
Natural Gas, there is no ultra-low NOx emissions option.
The Benchmark 750/1000 boiler is combustion calibrated at the factory prior to shipping.
However, recalibration is necessary as part of initial start-up due to changes in the local alt it ude,
gas BTU content, gas supply piping and supply regulators. Combustion Calibration 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.
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Nitrogen Oxide
(NOx)
Carbon Monoxide
(CO)
CHAPTER 4 – INITIAL START-UP
PROPANE Combustion Calibr ation
1. Open the water supply and return valves to the unit and ensure that the system pumps
are running.
2. Open the natural gas supply valve 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 position in %. Also, the
MANUAL LED will light.
6. Adjust the air/fuel valve position to 0% by pressing the ▼ arrow key.
7. Ensure that the leak detection ball valve downstream of the SSOV is open.
8. Set the ON/OFF switch to the ON position.
9. Change the valve position to 30% 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 set to:
• Benchmark 750 units: 3.9” ± 0.2” W.C.
• Benchmark 1000 units: 7.4” ± 0.2” W.C .
If gas pressure adjustment is required, remove the brass hex nut on the SSOV actuator
to access the gas pressure adjustment screw (Figure 4-3, above). Make gas pressure
adjustments using a flat-tip screwdriver to obtain the gas pressure listed above.
11. Using the ▲ arrow key, increase the valve open position to 100%. Verify that the gas
pressure on the downstream side of the SSOV settles within the range listed in step 10
(3.9” ± 0.2”” or 7.4” ± 0.2”). Readjust the gas 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 reading to stabilize.
13. Compare the oxygen readings on the combustion analyzer to the on-board O
sensor
2
value displayed in the Operating Menu of the C-More Control Panel. If the values differ by
more than ±1.5% and your combustion analyzer is correctly calibrated, the on-board O
sensor may be defective and need to be replaced.
2
14. Compare the measured oxygen level to the oxygen range shown below. Also, ensure that
the nitrogen oxide (NOx) and carbon monoxide (CO) readings do not exceed the values
shown. If you are not in a “NOx-limited” area and/or do not have a NOx measurement in
your analyzer, set the oxygen (O
) at 5.5% ± 0.5%.
2
Propane Combustion Calibration Readings
Valve Position Oxygen (O2) %
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100% 5% - 6%
<30 ppm
<100 ppm
Benchmark 750/1000 Boiler Installation, Operation & Maintenance Manual
Nitrogen Oxide
(NOx)
Carbon Monoxide
(CO)
CHAPTER 4 – INITIAL START-UP
PROPANE Combustion Cali bration –
Continued
15. If the oxygen level is not within the required tolerance, the gas pressure on the
downstream side of the SSOV must be adjusted using the gas pressure adjustment
screw on the SSOV (Figure 4-3, above). Slowly rotate the gas pressure adjustment
(approximately 1/4-turn increments). Allow the combustion analyzer to stabili ze following
each adjustment. Clockwise rotation reduces the oxygen level, while counterclockwise
rotation increases the oxygen level.
16. Once the oxygen level is within the specified range at 100%, record the O2, NOx and CO
readings on the Combustion Calibration Data Sheets provided with the unit.
17. Lower the valve position to 80% using the ▼arrow key.
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 18% as described
in the following steps. These steps assume that the inlet air temperature is
within the range of 50°F to 100°F. If NOx readings exceed the target values
shown, increase the O
range. Record the increased O
sheet.
level up to 1% higher than the listed calibration
2
value on the Combustion Calibration
2
18. 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.
19. Press the MENU key until Combustion Cal Menu appears on the display.
20. Press the ▲ arrow key until SET Valve Position appears on the display.
21. Press the CHANGE key. SET Valve Position will begin to flash.
22. Press the ▲ arrow key until SET Valve Position reads 80%. Press the ENTER key.
23. Next, press the
down (▼) arrow key until CAL Voltage 80% is displayed.
24. Press the CHANGE key and observe that CAL Voltage 80% is flashing.
25. The oxygen level at the 80% valve position should be as shown below. Also, ensure that
the nitrogen oxide (NOx) and carbon monoxide (CO) readings do not exceed the
following values:
Propane Combustion Calibration Readings
Valve Position Oxygen (O2) %
80% 5% - 6% <30 ppm <100 ppm
26. 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.
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Nitrogen Oxide
(NOx)
Carbon Monoxide
(CO)
60%
5% - 6%
<30 ppm
<100 ppm
<30 ppm
<30 ppm
<30 ppm
CHAPTER 4 – INITIAL START-UP
PROPANE Combustion Cali bration –
Continued
27. 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. Record all readings
on the Combustion Calibration Sheets provided.
28. Repeat steps 20 through 27 for valve positions of 60%, 45%, 30% and 18%* (see *NOTE
below). The oxygen (O
within the same limits for all val ve positions as shown in the following table.
), nitrogen oxide (NOx) and carbon monoxide (CO) should remain
2
*NOTE
Set the Valve Position at 18% but make adjustments to the Combustion
Calibration value designated as 16%.
NOTE
If NOx readings exceed the target values shown (<30 ppm), increase the
O
level up to 1% higher than the listed calibration range shown in the
2
table. Record the increased O
value on the Combustion Calibration sheet.
2
Propane Combustion Calibration Readings
Valve Position Oxygen (O2) %
45% 5% - 6%
30% 5.8% - 6.8%
18% 5% - 6%
<100 ppm
<100 ppm
<100 ppm
29. If the oxygen level at the 18% valve position is too high and the Blower voltage is at the
minimum value, you can adjust the idle screw (TAC valve) which is recessed in the top of
the Air/Fuel Valve (see Appendix G). Rotate the screw 1/2 turn clock wise (CW) to add f uel
and reduce the O
60% down to 18% after making a change to the idle screw (TAC valve).
to the specified level. Recalibration MUST be performed again from
2
30. This completes the PROPANE combustion calibration procedures.
4.5 REASSEMBLY AFTER COMBUSTION CALIBRATION
Once the combustion calibration adjustments are properly set, the unit can be reassembled for
service operation.
Reassembly After Combustion Calibration
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.
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CHAPTER 4 – INITIAL START-UP
Reassembly After Combustion Calibration – Continued
5. Remove the combustion analyzer probe from the 1/4” vent hole in the exhaust m anifold.
Replace the 1/8” NPT plug in the manifold.
6. Replace all previously removed sheet metal enclosures on the unit.
4.6 OVER-TEMPERATURE LIMIT SWITCHES
The unit contains three (3) types of over-temperature limit switches. These switches consist of a
Manual Reset Switch, a Rotary Dial Adjustable Switch and a Digital Alarm Switch. These
switches are mounted on a plate as shown in Figure 4-4. The switches can be accessed by
removing the unit front panel from the unit.
The manual reset switch is not adjustable and is permanently fixed at 210°F. T his switch will
shut down and lock out the boiler if the water temperature exceeds 210°F. Following an overtemperature condition, it must be manually reset by pressing the manual reset button shown in
Figurer 4-4 before the boiler can be restarted.
The rotary dial temperature limit switch is manually adjustable from 32ºF - 212ºF (0ºC – 100ºC).
This switch allows the boiler to restart, once the temperature drops below the selected
temperature setting on the dial. Set the dial on this over-temperature switch to the desired
setting.
The digital alarm switch shown in Figures 4-5 and 4-6 is preset at the factory to 210ºF and
should not be changed. If an over-temperature condition is detected, this switch autom atically
shuts down the boiler and sounds an audible alarm. If desired, the over-temperature alarm
switch settings can be checked or adjusted using the procedure in section 4.5.1.
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F
Alarm
RST
SET
Limit Control
PARTIAL FRONT VIEW WITH PANEL REMO VED
Digital OverLimit Controller
Reset button for
Limit Switch
Manual
Adjustable
(auto-rest)
CHAPTER 4 – INITIAL START-UP
Temperature
Limit Switch
Figure 4-4: Over Temperature Limit Switch Locations
Manual Temperature
Temperature
Temperature
Limit Switch
4.6.1 Digital Alarm Switch Checks and Adju st ments
The digital alarm switch settings can be checked or adjusted using the controls and display on
the front panel of the switch illustrated and described in Figure 4-5.
Figure 4-5: Digital Alarm Switch Front Panel
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RST
RESET Button
Resets the unit after an alarm condition.
CHAPTER 4 – INITIAL START-UP
Table 4-1: Digital Over-Temperature Limit Controller Features
CONTROL OR
DISPLAY
LED Display
MEANING FUNCTION
TEMP status
Displays current water temperature or
setpoint.
UP Button Increases the displayed temperature.
DOWN Button Decreases the displayed temperature.
SET
SET Button
Used to access and store parameters in the
unit.
Perform the steps in the following procedure to check or adjust the digital alarm switch settings:
Switch Check or Adjustment
1. Set the ON/OFF to the ON position.
2. Press the SET button on the Digital Alarm Switch. SP will appear in the display.
3. Press the SET button again. The current over-temperature limit value stored in memory will
be displayed. (default = 210°F).
4. If the display does not show the required over-temperature alarm setting, press the ▲ or
▼ arrow button to change the display to the desired temperature setting.
5. Once the desired over-temperature alarm setting (210ºF) is displayed, press the SET
button to store the setting in memory.
6. To calibrate the offset (P1), press and hold the SET but ton for 8 seconds on the Digital
Alarm Switch. Access code value 0 should appear in the display. The switch comes from
the factory with the code set at 0. AERCO recommends that you do not change this code.
7. Press the SET button again to enter the code. The first parameter label (SP) will appear in
the display.
8. Using the ▲ and ▼ arrow keys, select parameter P1.
9. Press SET to view the value stored in memory.
10. If the desired value is not displayed, modify the setting using the ▲ and ▼ arrow keys.
The value can be changed from -10° to +10° offset. Press SET to enter the value and exit
to the text parameter.
11. To exit the programming mode, press the SET and ▼ buttons simultaneously, or simply
wait one minute and the display will automatically exit the programming mode.
12. Once the programming mode has been exited, the display will show the current outlet
water temperature of the boiler.
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CHAPTER 4 – INITIAL START-UP
(This Page Is Intentionally Blank)
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Benchmark 750/1000 Boiler Installation, Operation & Maintenance Manual
CHAPTER 5 – MODE OF OPERATION
CHAPTER 5. MODE OF OPER ATION
5.1 INTRODUCTION
The boiler is capable of being operated in any one of six different modes. The following sections
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 mode of operation is based on outside air temperatures. As the out side 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. T he 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 AIR IN and AIR SENSOR COM
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, section 2.9.1 for additional wiring
information.
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CHAPTER 5 – MODE OF OPERATION
5.2.4 Indoor/Outdoor Startup
Startup in the Indoor/Outdoor Reset Mode is accomplished as follows:
NOTE
A design engineer typically provides design outdoor air temperature and
supply header temperature data
Indoor/Outdoor Startup
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.
4. Once the design outdoor air temperature is chosen, go across the c hart 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). If necessary, refer to section 3. 3 f or d eta ile d
instructions on menu changing.
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.
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:
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CHAPTER 5 – MODE OF OPERATION
Table 5-1: Constant Setpoint Mode Settings
Menu Option Setting
Boiler Mode Constant Setpoint
Internal Setpt
Refer to section 3.3 for detailed instructions on changing menu options.
Select desired setpoint using ▲ and ▼
arrow keys (40°F to 240°F)
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. With 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 RS-485 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 PMC 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:
Table 5-2: Remote Setpoint Mode Settings
Menu Option Setting
Boiler Mode Remote Setpoint
Remote Signal
Refer to section 3.3 for detailed instructions on changing menu options.
If the Network setting is selected for RS-485 Modbus operation, a valid Comm Addr ess must be
entered in the Setup Menu. Refer to Modbus Communication Manual GF-114 for additional
information.
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4-20mA/1-5V,
0-20mA/0-5V, or Network
Benchmark 750/1000 Boiler Installation, Operation & Maintenance Manual
CHAPTER 5 – MODE OF OPERATION
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
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 t his mode, 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 go off.
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 t his 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 signal 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
be driven by a RS-485 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.
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Menu Option
Setting
CHAPTER 5 – MODE OF OPERATION
To enable the Direct Drive Mode, the following menu setting must be made in the Configuration
Menu:
Table 5-3: Direct Drive Mode Settings
Boiler Mode Direct Drive
Remote Signal
4-20mA/1-5V,
0-20mA/0-5V, or Network
Refer to section 3.3 for instructions on changing menu options.
If the Network setting is selected for RS-485 Modbus operation, a valid Comm 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 signal
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 switch. The REMOTE LED will go
off and the MANUAL LED will lig ht.
To change back to the Direct Drive mode, simply press the AUTO/MAN s witch. The REMOTE
LED will again light and the MANUAL LED will go off.
5.6 AERCO CONTROL SYSTEM (ACS)
NOTE
ACS is for installations with 9 or more boilers. It utilizes only RS-485
signaling to the boiler. Installations with 1 to 8 boilers can use BST (see
Chapter 10).
The ACS mode of operation is used in conjunction with the AERCO Control System. The ACS
mode is used when it is desired to operate multiple units in the most efficient manner possible.
For this mode of operation, an ACS Header Sensor must be installed between 2 and 10 feet
downstream of the LAST boiler in the boiler plant's supply water header. The ACS can control
up to 40 boilers; up to 32 via Modbus (RS-485) network communication. For ACS programming,
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CHAPTER 5 – MODE OF OPERATION
operation, and Header Sensor installation details, see ACS Operations Guide, GF-131. For
operation via an RS-485 Modbus network, refer to Modbus Communication Manual GF-114.
To enable the ACS Mode, the following menu settings must be made in the Configuration Menu:
Table 5-4: ACS Mode Settings
Menu Option Setting
Boiler Mode Direct Dr ive
Remote Signal Network (RS-485)
Refer to section 3.3 for instructions on changing menu options.
5.6.1 ACS External Field Wiring
Wiring connections for RS-485 Modbus control are made between the 485 A- and 485 B+
terminals on the ACS (boilers 9 through 40), and the RS-485 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 ACS RS-485 COMM wiring connections. Shields should be terminated only at
the ACS and the boiler end must be left floating. Each unit’s wiring must conform to the above.
5.6.2 ACS Setup and Startup
This mode of operation is factory preset and the 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 switch. The REMOTE LED will go
off and the MANUAL LED will lig ht
To change back to ACS m ode, simply press the AUTO/MAN s witch. The REMOTE LED will
again light and the MANUAL L ED will go off.
5.7 COMBINATION CONTROL SYSTEM (CCS)
NOTE
Only ACS can be utilized for the Combination Control System.
A Combination Control System (CCS) is one that uses multiple boilers to cover both spaceheating and domestic hot water needs. An AERCO Control System (ACS) and An optional ACS
Relay Box ar e neces sar y t o c onf igure 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. Therefore, boilers used for
domestic hot water are capable of switching between constant setpoint and ACS control.
For a typical CCS, 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 as well.
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.
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CHAPTER 5 – MODE OF OPERATION
Only the AERCO Control Syst em (ACS) is necessary to configure this system if only a single
valve is used to switch from space heating to domestic hot water. However, the ACS Relay
Panel is req uired in combination with the ACS when there are up to two isolation valves, boiler
interlocks, and/or a Domestic Hot Water (DHW) pump in a Combination heating plant where
AERCO boilers are being used for both Building Heat and Domestic Hot Water heating.
The following two options are available for using a combination system; one that uses only the
ACS, and one that requires the optional ACS Relay Box:
• OPTION 1 - This option is selected when the ACS controls a boiler plant cont aining up to
eight combination boilers that ar e Domestic Hot Water Priority (DHW PRIORITY) boilers,
along with building heat (BLDG HEAT) boilers, and one hydronic isolation valve in the main
header between the BLDG HEAT boilers and the DHW PRIORITY boilers.
• OPTION 2 – When this option is selected, the ACS Relay Panel must be used in
conjunction with the ACS. For this option, the ACS controls a boiler plant containing up to
eight combination boilers that are divided up into Building Priority (BLDG PRIORITY)
boilers and Domestic Hot Water Priority (DHW PRIORITY) boilers, along with building heat
(BLDG HEAT) boilers, and using two hydronic isolation valves in the main header, one
between the BLDG HEAT and BLDG PRIORITY boilers, and the other between the BLDG
PRIORITY and the DHW PRIORITY boilers.
In Option 2, when the space-heating load is such that when all the space-heating boilers are at
the 100% valve position, the ACS will then ask the ACS Relay Box for the domestic boilers to
become space-heating boilers. Provided the domestic hot water load is satisfied, the combo (hot
water) boilers will then become space-heating boilers. 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 ACS Relay Box switches
the combo units back to the domestic load. The ACS in combination with the ACS Relay Box
will ask the BLDG PRIORITY boilers to help with domestic hot water heating if the DHW
PRIORITY boilers are not able to satisfy the domestic hot water demand.
When the combo units are satisfying the domestic load, they are in the constant setpoint mode
of operation. When the combo units switch over to space heating, their mode of operation
changes to follow the ACS command. For more information concerning the operation of the
ACS, consult the ACS Operations Guide, GF-131. For more information on the ACS Relay Box,
see section 2.14 in the same manual.
5.7.1 Combination Control System Field Wiring
Wiring for this system is between the ACS, the ACS Relay Box and the terminals in the I/O Box.
Wire the units using a shielded twisted pair of 18 to 22 AWG wire. When wiring multiple units,
each unit’s wiring must conform to the above.
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 190°F.
Enter the following settings in the Configuration Menu:
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Internal Setpt
40°F to 190°F
CHAPTER 5 – MODE OF OPERATION
Table 5-5: Combination Mode Settings
Menu Option Setting
Boiler Mode Combination
Remote Signal Network
Refer to section 3.3 for instructions on changing menu options.
While it is possible to change other temperature-related functions for combination mode, these
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 s witch. The MANUAL LED will go
off and the REMOTE LED will light.
When the boiler is switched to ACS control, the ACS controls the valve position. There are no
setup requirements to the boiler(s) in this mode.
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CHAPTER 6 – SAFETY DEVICE TESTING
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, during 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 THAT CAN RESULT
IN ELECTRICAL SHOCK.
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SSOV
GAS INLET
TO AIR/FUEL
VALVE
LOW GAS PRESSURE
(shown closed)
LOW GAS PRESSURE SWITCH
MANUAL SHUT-OFF
VALVE
CHAPTER 6 – SAFETY DEVICE TESTING
6.2 LOW GAS PRESSURE FAULT TEST
Refer to Figure 6-1A and ensure that the leak detection ball valve located at the High Gas
Pressure switch is closed on both the Natural Gas and Propane gas trains.
Low Gas Pressure Fault Tes t
1. Remove the 1/4“ plug from the leak detection ball valve at the Low Gas Pressure switch,
shown in Figure 6-1A.
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 GAS PRESSURE fault message, and the
FAULT indicator should also start flashing at the following approximate pressures:
• BMK 750 & 1000 – NATURAL GAS gas trains: 2.6” W.C.
• BMK 750 – PROPANE gas train: 4.4” W.C.
• BMK 1000 – PROPANE gas train: 7.5” W.C.
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 , the FAULT indic ator should go off and 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.
HIGH GAS PRESSURE
SWITCH
HIGH GAS PRESSURE
LEAK DETECTION
BALL VALVE
1/4” NTP PLUG
(Install manometer
here for Low Gas
Pressure Test)
LEAK DETECTION BALL VALVE
Figure 6-1A: Low Gas Pressure Fault Test – Natural Gas gas train shown
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Benchmark 750/1000 Boiler Installation, Operation & Maintenance Manual
SSOV
GAS INLET
HIGH GAS PRESSURE LEAK
DETECTION BALL VALVE
CHAPTER 6 – SAFETY DEVICE TESTING
6.3 HIGH GAS PRESSURE TEST
The instructions below apply to both the Natural Gas and Propane gas trains.
To simulate a high gas pressure fault, refer to Figure 6-1B and perform the following steps:
High Gas Pressure Test
1. Remove the 1/4“ plug from the leak detection ball valve at the High Gas Pressure switch,
shown in Figure 6-1B.
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 near the High Gas Pressure switch.
4. Start the unit in Manual mode at a valve position (firing rate) between 25 and 30%.
5. With the unit running, monitor the gas pressure on the manometer installed in step 2 and
record the gas pressure reading.
6. Slowly increase the gas pressure using the adjustment screw on the SSOV (see Figure
4-3 in Chapter 4).
7. The unit should shut down and display a GAS PRESSURE fault message, and the
FAULT indicator should also start flashing at the following approximate pressures:
• BMK 750 & 1000 – NATURAL GAS gas trains: 4.7” W.C.
• BMK 750 – PROPANE gas train: 4.7” W.C.
• BMK 1000 – PROPANE gas train: 10.5” W.C.
8. Reduce the gas pressure back to the value recorded in step 5. This pressure should be
within the range of
• BMK 750 & 1000 – NATURAL GAS gas trains: 2.0” W.C. ± 0.4” W.C.
• BMK 750 – PROPANE gas train: 3.9” W.C. ± 0.2” W.C.
• BMK 1000 – PROPANE gas train: 7.4” W.C. ± 0.2” W.C.
9. Press the CLEAR button on the Control Box to clear the fault.
10. The fault message should clear and the FAULT indicator should go off. The unit should
restart.
11. Upon test completion, close the ball valve and remove the manometer. Replace the
1/4“plug removed in step 1.
MANUAL SHUT-OFF
Figure 6–1B: High Gas Pressure Test – Natural Gas gas train shown
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VALVE
TO AIR/FUEL
VALVE
HIGH GAS
PRESSURE SWITCH
LOW GAS
PRESSURE SWITCH
1/4” NTP PLUG
(Install manometer
here for High Gas
Pressure Test)
Benchmark 750/1000 Boiler Installation, Operation & Maintenance Manual
CHAPTER 6 – SAFETY DEVICE TESTING
6.4 LOW WATER LEVEL FAULT TEST
To simulate a low water level fault, proceed as follows:
Low Water Level Fault Test
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 t o 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.
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See Detail ‘A’
Front view with Panel removed
Digital Over-
Limit Controller
Reset button
Limit Switch
Manual
Adjustable
(auto-rest)
CHAPTER 6 – SAFETY DEVICE TESTING
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.
Water Temperature Fault Test
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.
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.
for Manual
Temperature
Temperature
Temperature
Limit Switch
Temperature
Limit Switch
Figure 6-2: Temperature Limit Switch Location and Setting
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CHAPTER 6 – SAFETY DEVICE TESTING
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) 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.
6.6.1 Remote Interlock Test
Remote Interlock Test
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 messag e should
automatically clear and the unit should restart.
6.6.2 Delayed Interlock Test
Delayed Interlock Test
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.
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SSOV
AIR FILTER
BLOCKED INLET VALVE
BLOWER PROOF SWITCH
AIR/FUEL VALVE
BLOWER
MANUAL SHUT-
OFF VALVE
CHAPTER 6 – SAFETY DEVICE TESTING
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:
Flame Fault Tests
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.
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 ignition 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.
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Figure 6-3: Bare Boiler – Partial View
Benchmark 750/1000 Boiler Installation, Operation & Maintenance Manual
CHAPTER 6 – SAFETY DEVICE TESTING
6.8 AIR FLOW FAULT TESTS
These tests check the operation of the Blower Proof Switch and Block ed Inlet Switch shown in
Figure 6-3.
6.8.1 Blower Proof Switch Test
Blower Proof Switch Test
1. Disable the blower output drive voltage as follows:
a) Press the MENU key until CONFIGURATION MENU is displayed.
b) Press the ▲ arrow key until the ANALOG OUTPUT function 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 lockout, showing AIRFLOW FAULT DURING PURGE in
the display.
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 CONFIGURATION MENU is displayed.
b) Press the ▲ arrow key until the ANALOG OUTPUT function is displayed, then
press the CHANGE key.
c) Press the ▲ arrow key until VALVE POSITIO N 0-10V is displayed, then press the
ENTER key.
d) Press the CLEAR but ton to clear the airflow fault.
6. Once the unit has proved flame, turn off the blower again 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.
6.8.2 Blocked Inlet Switch Test
This test will be run in simulated fire mode, with the Blocked Inlet Switch isolated from the rest
of the control circuitry.
Blocked Inlet Switch Test
1. Turn off the main ON/OFF switch on the front of the Control Panel.
2. For units that get combustion air from a Combustion Air Duct, remove that duct, located
on the rear panel of the boiler (see Figure 6.4, below). For units that have an air filter in
place of a Combustion Air Duct (not shown), remove the air filter.
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TO WIRE HARNESS
Flame Detector
Flame Signal Generator
CHAPTER 6 – SAFETY DEVICE TESTING
Blocked Inlet Switch Test – Continued
WARNING
THE BLOWER SUCTION IS VERY STRONG AND CAN PULL NEARBY
OBJECTS INTO THE BLOWER’S FAN BLADES. DO ALLOW ANYTHING
TO BE PULLED INTO THE BLOWER. DO NOT WEAR ANYTHING THAT
COULD GET CAUGHT AND PULL YOU INTO THE BLOWER.
3. Turn off the gas supply ball valve to the boiler and then complete the following steps:
a) Use jumper wires to jump out the Low Gas Pressure Switch and the Blower Proof
Switch.
b) Remove the black connector boot from the Flame Detector.
c) Connect the Flame Signal Generator to the black connector boot.
Connector Boot
Figure 6.3a: Connecting the Flame Signal Generator
(d) Keep the alligator clip away from bare metal parts until step 4c.
4. Complete the following with the boiler operating in Manual mode:
a) Ramp the boiler up to 100% fire rate and then turn on the main ON/OFF switch on
the front of the Control Panel.
b) Push the BACK button three (3) times to return to the upper level menu.
c) When the Controller gets into the ignition phase, the Control Panel will show
IGNITION TRIAL. At that point attach the alligator clip (see Figure 6.3a) to any bare
metal surface or ground. The C-More display should now show FLAM E PROVEN
and begin to ramp up to 100% fire rate. Note that no gas or flame is present in the
boiler at this time.
5. Wait for the boiler to ramp up to at least 90% before continuing.
6. Cover the combustion air inlet opening with a solid, flat object, such as a piece of thick
plywood or a thick metal plate.
7. The unit should shut down and display AIRFLOW FAULT DURING RUN. This step
confirms proper operation of the Blocked Inlet Switch.
8. Remove the cover from the air inlet opening and reinstall the Combustion Air Duct or air
filter.
9. Remove the jumper wires installed in step 2 and replace the black connector boot on the
Flame Detector.
10. Press the CLEAR button. The unit should restart.
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Benchmark 750/1000 Boiler Installation, Operation & Maintenance Manual
SSOV ACTUATOR
ACTUATOR
SECONDARY WATER
INLET/RETURN
PRIMARY WATER
EXHAUST MANIFOLD
CHAPTER 6 – SAFETY DEVICE TESTING
AIR INLET
(Combustion Air
Duct removed)
Figure 6-4: Boiler Rear View Showing Air Inlet Location
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:
SSOV Proof of Closure Swit ch
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 6-3 and locate the SSOV.
4. Remove the cover from the SSOV by loosening the screw shown in Figure 6-5. Lift off the
cover to access the terminal wiring connections.
5. Disconnect wire #148 from the SSOV to “open” the proof of closure switch ci rcuit.
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 the ON position 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.
COVER
COVER SCREW
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Figure 6-5: SSOV Actuator Cover Location
Benchmark 750/1000 Boiler Installation, Operation & Maintenance Manual
AIR/FUEL VALVE COVER
CHAPTER 6 – SAFETY DEVICE TESTING
6.10 PURGE SWITCH OPEN DURING PURGE
The Purge Switch (and Ignition Switch) is located on the Air/Fuel Valve. T o check the switch,
proceed as follows:
Purge Switch Open During Purge
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 (see
Figure 6-6).
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 its 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 6-6) 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 6-7).
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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(Rotate counter-clockwise
to remove)
Figure 6-6: Air/Fuel Valve Cover Location
Ignition Switch Open Duri ng Ignition
Benchmark 750/1000 Boiler Installation, Operation & Maintenance Manual
Ignition Position Switch
Purge Position Switch
AIR IN
TO BLOWER
CHAPTER 6 – SAFETY DEVICE TESTING
Ignition Switch Open During Ignition – Continued
Figure 6-7: 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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Benchmark 750/1000 Boiler Installation, Operation & Maintenance Manual
Labor
Time
Igniter-Injector Kit
(58023)
Flame Detector Kit
(24356-1)
Lean O2 Sensor
(61026)
Combustion
Calibration
Testi ng of Safety
Devices
See ASME
CSD-1 Chart
7.7
Burner
Inspect
2 hrs.
Inspect, Clean
Gaskets
Inspect, Clean
Gaskets
7.9
Air Filter (59139)
Clean
Replace
15 mins.
CHAPTER 7 – 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. For a complete inspection check list see ASME CSD1 chart.
In order to perform the maintenance tasks specified in Table 7-1, the following maintenance kits
are available through your local AERCO Sales Representative:
• Annual Maintenance Kit, Part No. 58025-01
• 24-Month Waterside/Fireside Inspection Kit, Part No. 58025-08 (See NOTE below)
NOTE
The 24-Month Waterside/Fireside Inspection Kit also includes the items
contained in the Annual Maintenance Kit (58025-01). Therefore, only Kit
Part No. 58025-08 is required when performing the waterside/fireside
inspections. Refer to Appendix L for recommended spare.
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 BRE AKER.
• SHUT OFF THE GAS SUPPLY AT T HE 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
Section Item 6 Mos. 12 Mos. 24 Mos.
7.2
7.3
7.4
7.5
*Inspect Inspect Replace 15 mins.
*Inspect Inspect Replace 15 mins.
*Inspect Inspect 15 mins.
*Check Check 1 hr.
7.6
7.8
* Only performed after initial 6 month period after initial startup.
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Condensate Drain
Trap
*Inspect
& Replace
45 mins.
& Replace
30 mins.
Benchmark 750/1000 Boiler Installation, Operation & Maintenance Manual
BLOWER PROOF
BLOCKED INLET
SWITCH
STAGED IGNITION
SOLENOID
STAGED IGNITION
ASSEMBLY
O2 SENSOR
BURNER PLATE
BURNER
AIR/FUEL VALVE
BLOWER
INJECTOR-IGNITOR
FLAME DETECTOR
GAS FLEX HOSE NIPPLE
CHAPTER 7 – MAINTENANCE
7.2 IGNITER-INJECTOR REPLACEMENT
The igniter-injector (P/N 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 t he igniter-inj ect or f la me
detector and other related components.
SWITCH
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. 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 top shroud from t he unit by grasping the top handle and lifting straight up.
This will disengage the shroud from the four (4) pins in the side panels.
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Figure 7-1: Benchmark Burner Assembly (Removed from Boiler)
Igniter-Injector Replacement
Benchmark 750/1000 Boiler Installation, Operation & Maintenance Manual
O2 SENSOR
& WASHERS
STAGED
SOLENOID
INJECTOR-IGNITOR
INDEXING WASHERS
FLAME
COMPRESSION FITTING AND ELBOW
BURNER
PLATE
CHAPTER 7 – MAINTENANCE
Igniter-Injector Replacement – Continued
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 assem bly from the
igniter-injector.
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 ig niter-injector should be replaced. If carbon
build-up is present, clean the component using f ine emery cloth. Repeated carbon buildup is an indication that the combustion settings of the unit should be checked. Refer to
Chapter 4 for combustion calibration procedures.
DETECTOR
& GASKET
IGNITION
(Quantity = 0-3 as
required)
Figure 7-2: Igniter-Injector & Flame Detector Mounting Details
7. Next, loosen and remove the igniter-injector from the burner plate using a 1" open-end
wrench.
8. Check the igniter-injector for evidence of erosion or carbon build-up. If there is evidence
of substantial erosion or carbon build-up, the ig niter-injector should be replaced. If carbon
build-up is present, clean the component using f ine emery cloth. Repeated carbon buildup is an indication that the combustion settings of the unit should be checked. Refer to
Chapter 4 for combustion calibration procedures.
9. Prior to reinstalling the igniter-injector, a high temperature, conductive, anti-seize compound must be applied to the threads.
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, 3 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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NOTE
Benchmark 750/1000 Boiler Installation, Operation & Maintenance Manual
INJECTOR TUBE
120°
INJECTER-IGNITOR
INJECTOR TUBE
ANGLE
BURNER PLATE
BLOWER
CHAPTER 7 – MAINTENANCE
Igniter-Injector Replacement – Continued
Figure 7-3: Igniter-Injector Orientation (Looking Down from Above)
10. Reinstall the igniter-injector in the burner plate. Torque to 170 - 180 in-lbs. DO NOT over
tighten.
11. 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.
12. Reconnect the igniter-injector cable.
13. Reinstall the shroud on the unit.
7.3 FLAME DETECTOR REPLACEMENT
The flame detector (P/N 24356-1) is located on the burner plate at the top of the unit (see Figure
7-1 and Figure 7-2). The flame detector may be hot. Allow the unit to cool sufficiently before
removing the flame detector. Inspect or replace the flame detector as follows:
Flame Detector Replacement
1. Set the control panel ON/OFF switch to the OFF position. Disconnect AC power from the
unit.
2. Remove the top shroud from the unit by grasping the top handle and lifting straight up.
This will disengage the shroud from the four (4) pins in the side panels.
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 page). The flame detector is secured to the burner plate with one #10-32 screw
and one #8-32 screw.
5. Remove the flame detector and gasket from the burner plate.
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 shroud on the unit.
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Benchmark 750/1000 Boiler Installation, Operation & Maintenance Manual
Part No.
Description
81143
Burner Gasket
81048
Flame Detector Gasket
81064
Blower Gasket
CHAPTER 7 – MAINTENANCE
7.4 O2 SENSOR REPLACEMENT
The Lean Oxygen Sensor (part no. 61026) is located on the burner plate at the top of the unit
(see Figure 7-1 and Figure 7-2). The sensor and burner plat e may be hot. Allow the unit t o cool
sufficiently before removing or replacing the O
O2 Sensor Replacement
1. Set the ON/OFF switch on the cont rol panel, to the OFF position. Disconnect AC power
from the unit.
2. Remove the top shroud from the unit by grasping the top handle and lifting straight up.
This will disengage the shroud from the four (4) pins in the side panels.
sensor.
2
3. Disconnect the O
sensor lead wire by pushing in on the release tab and pulling apart the
2
connector.
4. Next, loosen and remove the O
sensor and crush washer fr om the burner plate using a
2
15/16" open-end wrench.
5. Thoroughly inspect the O
sensor. If eroded, the sensor should be replaced. Otherwise
2
clean the sensor with a fine emery cloth.
6. Reinstall the O
sensor and crush washer on the burner plate.
2
7. Reconnect the sensor lead wire.
8. Reinstall the shroud on the unit.
7.5 COMBUSTION CALIBRATION
Combustion settings must be checked at the intervals shown in Table 7-1 as part of the
maintenance requirements. Refer to Chapter 4, section 4.3 for combustion calibration
instructions.
7.6 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 a s 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.
7.7 BURNER ASSEMBLY INSPECTION
The burner assembly (part no. 24276) is located at the top of the unit's heat exchanger. T he
burner assembly may be hot. Ther efore, a llow 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 assemblies for the unit.
The following parts will be required for reassembly after burner inspection:
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CHAPTER 7 – MAINTENANCE
To inspect or replace the burner assembly, proceed as follows:
Burner Assembly Inspection
1. Set the ON/OFF switch on the contr ol panel, to the OFF position. Disconnect AC power
from the unit and turn off the gas supply.
2. Remove the top shroud from the unit by grasping the top handle and lifting straight up.
This will disengage the shroud from the four (4) pins in the side panels.
3. Disconnect the lead wire from the flame detector installed on the burner plate. See Figure
7-2.
4. Remove the two (2) screws securing the flame detector to the plate. The 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.
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
(Figure 7-4 and Figure 7-5).
11. Disconnect the gas train from the air/fuel valve by removing the four (4) 1/2” bolts and
nuts (Figure 7-4).
12. Disconnect the flex hose from the air/fuel valve by loosening the hose clamp.
13. Remove the four 5/16-18 hex head screws securing the blower to the burner plate
(Figure 7-5).
14. Remove the blower and air/fuel valve from the burner plate by lifting straight up. Also,
remove the blower gasket.
15. Remove the eight (8) 3/8-16 nuts from the burner flange (Figure 7-4) using a 9/16”
wrench.
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Benchmark 750/1000 Boiler Installation, Operation & Maintenance Manual
AIR/FUEL VALVE
BLOCKED INLET
BURNER GASKET
FLAME DETECTOR
O2 SENSOR
STAGED IGNITION SOLENOID
BURNER
BLOWER
BLOWER PROOF SWITCH
BURNER PLATE
BURNER PLATE
3/16”–16 HEX NUTS (8)
IGNITOR-INJECTOR
STAGED IGNITION
BLOCKED INLET SWITCH
BLOWER PROOF SWITCH
AIR FILTER
BLOWER
FRONT
1/2" BOLTS & NUTS (4)
REAR
IGNITER/INJECTOR
CHAPTER 7 – MAINTENANCE
Burner Assembly Inspection – Continued
ASSEMBLY
(GAS TRAIN-to-A/F
VALVE)
Figure 7-4: Burner Assembly Mounting Details – Overhead View
SWITCH
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Figure 7-5: Burner Assembly Exploded View
Benchmark 750/1000 Boiler Installation, Operation & Maintenance Manual
CHAPTER 7 – MAINTENANCE
Burner Assembly Inspection – Continued
NOTE
The burner assembly is heavy, weighing approximately 25 pounds.
16. Remove the burner assembly from burner flange by pulling straight up.
17. Remove and replace the burner gasket.
NOTE
During reassembly, apply a light coating of high-temperature, antiseize 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 the igniter-injector to 170 - 180
in-lbs.
18. Beginning with the burner assembly removed in step 16, reinstall all the components in
the reverse order that they were removed. When reinstalling t he burner flange (removed
in step 15), tighten the 3/8-16 nuts using a typical torque pattern (for example, loosely
tighten one nut, then loosely tighten a second nut on the opposite side, a third at 90
degrees to the first two, and a fourth opposite the third, and then repeat this pattern with
the remaining four nuts. Repeat the entire pattern a second time to partially tighten all
eight nuts, and then repeat a third time until all eight nuts are fully torqued to 22 ft. lbs).
19. Ensure that the igniter-injector and flame detector cutouts in the burner plate are properly
aligned with the heat exchanger top flange.
7.8 CONDENSATE DRAIN TRAP MAINTENANCE
Benchmark boilers contain a condensate trap as shown in Chapter 2, Figure 2-6. The trap is
located external to the unit and attached to the drain pipe from the exhaust manifold. This trap
should be inspected and cleaned in accordance with the maintenance schedule shown in Table
7-1 to ensure proper operation. To inspect and clean the trap, proceed as follows:
Condensate Drain Trap Maintenance
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 7-6.
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 O-ring and orifice gaskets from the trap. AERCO recommends that these
items be replaced annually.
6. Thoroughly clean the trap and float. 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 O-ring
(84017) and orifice gasket (P/N 81092, if using older trap) with new parts.
8. Reassemble all piping and hose connections to the condensate trap inlet and outlet.
Reconnect trap to exhaust manifold drain.
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Benchmark 750/1000 Boiler Installation, Operation & Maintenance Manual
THUMB
SCREWS
COVER
GASKET
FLOAT
CONDENSATE
(P/N 24060)
OUTLET
Condensate
Float
Float Guide
O-Rings
3/4" NPT
Thumb Screws
(4)
INLET
Adapter
CHAPTER 7 – MAINTENANCE
Condensate Drain Trap Maintenance – Continued
NOTE
There are two slightly different types of condensate traps that may
be used in your configuration; an older style with a separate inlet
adapter, and a newer style with a built-in adapter (see Figure 7-6).
Maintenance is the same, except that the newer style does not
need an orifice gasket (Step 7).
Opening
(2)
Trap O-Ring
Figure 7-6: External Condensate Trap
FLOAT
GUIDE
TRAP
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Benchmark 750/1000 Boiler Installation, Operation & Maintenance Manual
MIRROR/VIEWPORT
HEAT
GAS TRAIN
ASSEMBLY
AIR FILTER
BLOWER
AIR FILTER
HOSE CLAMP
AIR/FUEL VALVE
CHAPTER 7 – MAINTENANCE
7.9 AIR FILTER CLEANING & REPLACEMENT
The Benchmark boiler is equipped with an air filter (P/N 59139) which should be cleaned and reoiled every 12 months and replaced every 24 months. The air filter is located at t he inlet of the
air fuel valve at the top of the boiler as shown in Figure 7-7.
To inspect/replace the air filter, proceed as follows:
Air Filter Cleaning & Replacement
1. Set the ON/OFF switch on the control panel, to the OFF position. Disconnect AC power
from the unit.
2. Remove the top shroud from the unit by grasping the top handle and lifting straight up.
This will disengage the shroud from the four (4) pins in the side panels.
3. Refer to Figure 7-7 and locate the air filter attached to the air/fuel valve inlet.
4. Using a flat -tip screwdriver or 5/16” nut driver, loosen the clamp securing the filter to the
inlet flange of the air/fuel valve. Remove the filter and clamp.
5. The filter may be cleaned in hot soapy water to r emove oil and dirt. The filter should be
thoroughly dried and then sprayed with a light coating of oil, such as WD-40, prior to
reinstallation.
6. Each replacement air filter is equipped with its own clamp. Ther efore, simply install the
replacement air filter on inlet flange of the air fuel valve and tighten the clamp with a flat tip screwdriver or 5/16” nut driver.
7. Replace the top shroud on the unit and return boiler to service use.
EXCHANGER
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Figure 7-7: Air Filter Replacement
Benchmark 750/1000 Boiler Installation, Operation & Maintenance Manual
CHAPTER 7 – MAINTENANCE
7.10 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.
Shutting the Boiler Down for an Extended Period
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.
7.11 PLACING THE BOILER BACK IN SERVICE AFTER A PROLONGED SHUTDOWN
After a prolonged shutdown (one year or more), the following procedures must be followed:
Placing Boiler Back In Serv ice After a Prolonged Shutdow n
1. Review installation requirements included in Chapter 2.
2. Inspect all piping and connections to the unit.
3. Inspect exhaust vent and air inlet duct work (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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Benchmark 750/1000 Boiler Installation, Operation & Maintenance Manual
CHAPTER 7 – MAINTENANCE
(This Page Is Intentionally Blank)
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