Page 1
Benchmark 1.5LN Low NOx Boiler
Operation and Maintenance Manual
OMM-0041_0D
GF-120
AERCO International, Inc. • 100 Oritani Dr. • Blauvelt, NY 10913 • Ph: 800-526-0288
Revised: 05/09/2012
Benchmark 1.5LN Low NOx Boiler
Installation, Operation, and Maintenance
Benchmark 1.5LN
Low NOx Boiler
Modulating, Condensing,
Forced Draft, Hot Water Boiler
1,500,000 BTU/H Input
Applicable for Serial Numbers:
G-11-1938 and above.
USER MANUAL
PR2: 05/09/12 Page 1 of 152
Page 2
AERCO International, Inc. • 100 Oritani Dr. • Blauvelt, NY 10913 • Ph: 800-526-0288
Benchmark 1.5LN Low NOx Boiler
Operation and Maintenance Manual
OMM-0041_0D
GF-120
Technical Support:
1-800-526-0288
www.aerco.com
(Mon–Fri, 8am-5pm EST)
Disclaimer
The information contained in this manual is subject to change without notice from AERCO International,
Inc. AERCO makes no warranty of any kind with respect to this material, including but not limited to
implied warranties of merchantability and fitness for a particular application. AERCO International is not
liable for errors appearing in this manual. Nor for incidental or consequential damages occurring in
connection with the furnishing, performance, or use of this material.
Page 2 of 152 PR2: 05/09/12
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Benchmark 1.5LN Low NOx Boiler
Operation and Maintenance Manual
OMM-0041_0D
GF-120
AERCO International, Inc. • 100 Oritani Dr. • Blauvelt, NY 10913 • Ph: 800-526-0288
Table of Contents
CHAPTER 1 SAFETY PRECAUTIONS ............................................................................. 9
1.1 WARNINGS & CAUTIONS .................................................................................... 9
1.2 EMERGENCY SHUTDOWN ............................................................................... 10
1.3 PROLONGED SHUTDOWN ................................................................................ 10
CHAPTER 2 INSTALLATION ............................................................................................ 13
2.1 INTRODUCTION ................................................................................................. 13
2.2 RECEIVING THE UNIT ....................................................................................... 13
2.3 UNPACKING ....................................................................................................... 13
2.4 SITE PREPARATION. ......................................................................................... 14
Installation Clearances ............................................................................................. 14 2.4.1
Setting the Unit ........................................................................................................ 15
2.5 SUPPLY AND RETURN PIPING ......................................................................... 16
2.4.2
2.6 CONDENSATE DRAIN ........................................................................................ 16
Exhaust Manifold Condensate Drain ....................................................................... 16 2.6.1
2.7 GAS SUPPLY PIPING ......................................................................................... 17
Gas Supply Specifications. ...................................................................................... 18 2.7.1
Manual Gas Shutoff Valve ....................................................................................... 18 2.7.2
External Gas Supply Regulator ................................................................................ 18 2.7.3
IRI Gas Train Kit ..................................................................................................... 19 2.7.4
2.8 AC ELECTRICAL POWER WIRING .................................................................... 19
Electrical Power Requirements ................................................................................ 20 2.8.1
2.9 MODES OF OPERATION AND FIELD CONTROL WIRING ............................... 21
Constant Setpoint Mode ........................................................................................... 21 2.9.1
Indoor/Outdoor Reset Mode .................................................................................... 21 2.9.2
Boiler Management System Mode ........................................................................... 22 2.9.3
Remote Setpoint and Direct Drive Modes ............................................................... 22
Combination Mode .................................................................................................. 22
2.10 I/O BOX CONNECTIONS .................................................................................. 23
OUTDOOR SENSOR IN (1) ................................................................................ 23 2.10.1
AIR TEMP. SENSOR (2) ..................................................................................... 24 2.10.2
ANALOG IN (3) ................................................................................................... 24 2.10.3
B.M.S. (PWM) IN (4) ........................................................................................... 24 2.10.4
SHIELD (5) ........................................................................................................... 24 2.10.5
mA OUT (6) .......................................................................................................... 25 2.10.6
RS-485 COMM (7) ............................................................................................... 25 2.10.7
TxD, RxD (8) ........................................................................................................ 25 2.10.8
VFD/BLOWER (9) ............................................................................................... 25 2.10.9
EXHAUST SWITCH IN (11) ............................................................................. 25 2.10.10
INTERLOCKS (10, 12) ...................................................................................... 25 2.10.11
2.9.4
2.9.5
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AERCO International, Inc. • 100 Oritani Dr. • Blauvelt, NY 10913 • Ph: 800-526-0288
Benchmark 1.5LN Low NOx Boiler
Operation and Maintenance Manual
OMM-0041_0D
GF-120
FAULT RELAY (13) ........................................................................................... 26 2.10.12
2.11 AUXILIARY RELAY CONTACTS (14) ............................................................... 26
2.12 FLUE GAS VENT INSTALLATION .................................................................... 26
2.13 COMBUSTION AIR ........................................................................................... 26
Combustion Air From Outside the Building .......................................................... 27 2.13.1
Combustion Air From Inside The Building ........................................................... 27 2.13.2
Sealed Combustion ................................................................................................ 27 2.13.3
Temporary Combustion Air Filtering During Construction .................................. 27 2.13.4
2.14 BENCHMARK PUMP RELAY OPTION ............................................................. 27
CHAPTER 3 CONTROL PANEL OPERATION .............................................................. 29
3.1 INTRODUCTION ................................................................................................. 29
3.2 CONTROL PANEL DESCRIPTION ..................................................................... 29
3.3 CONTROL PANEL MENUS ................................................................................ 33
Menu Processing Procedure ..................................................................................... 33 3.3.1
3.4 OPERATING MENU ............................................................................................ 34
3.5 SETUP MENU ..................................................................................................... 35
3.6 CONFIGURATION MENU ................................................................................... 36
3.7 TUNING MENU ................................................................................................... 37
3.8 COMBUSTION CAL MENU ................................................................................. 37
1.1 START SEQUENCE ............................................................................................ 38
3.9 START/STOP LEVELS ........................................................................................ 41
CHAPTER 4 INITIAL START-UP ...................................................................................... 43
4.1 INITIAL START-UP REQUIREMENTS ................................................................ 43
4.2 TOOLS AND INSTRUMENTATION FOR COMBUSTION CALIBRATION .......... 43
4.2.1 Required Tools & Instrumentation ...................................................................... 44
4.2.2 Installing Gas Supply Manometer ....................................................................... 44
4.2.3 Accessing the Vent Probe Port ............................................................................ 45
4.3 RSI Regulator SAFE TEST .................................................................................. 45
4.4 NATURAL GAS COMBUSTION CALIBRATION ................................................. 47
4.5 UNIT REASSEMBLY ........................................................................................... 51
4.6 OVER-TEMPERATURE LIMIT SWITCHES ........................................................ 52
CHAPTER 5 MODE OF OPERATION .............................................................................. 53
5.1 INTRODUCTION ................................................................................................. 53
5.2 INDOOR/OUTDOOR RESET MODE .................................................................. 53
Reset Ratio ............................................................................................................... 53 5.2.1
Building Reference Temperature ............................................................................. 53 5.2.2
Outdoor Air Temperature Sensor Installation .......................................................... 53 5.2.3
Indoor/ Outdoor Startup ........................................................................................... 53 5.2.4
5.3 CONSTANT SETPOINT MODE .......................................................................... 54
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Benchmark 1.5LN Low NOx Boiler
Operation and Maintenance Manual
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AERCO International, Inc. • 100 Oritani Dr. • Blauvelt, NY 10913 • Ph: 800-526-0288
Setting the Setpoint .................................................................................................. 54 5.3.1
5.4 REMOTE SETPOINT MODES ............................................................................ 55
Remote Setpoint Field Wiring ................................................................................. 55 5.4.1
Remote Setpoint Startup .......................................................................................... 56 5.4.2
5.5 DIRECT DRIVE MODES ..................................................................................... 56
Direct Drive Field Wiring ........................................................................................ 56 5.5.1
Direct Drive Startup ................................................................................................. 57 5.5.2
5.6 BOILER MANAGEMENT SYSTEM (BMS) .......................................................... 57
BMS External Field Wiring ..................................................................................... 57 5.6.1
BMS Setup and Startup ............................................................................................ 58 5.6.2
5.7 COMBINATION CONTROL SYSTEM (CCS) ...................................................... 58
Combination Control System Field Wiring ............................................................. 58 5.7.1
Combination Control System Setup and Startup ..................................................... 59 5.7.2
CHAPTER 6 SAFETY DEVICE TESTING ....................................................................... 61
6.1 TESTING OF SAFETY DEVICES ....................................................................... 61
6.2 LOW GAS PRESSURE FAULT TEST ................................................................. 61
6.3 HIGH GAS PRESSURE TEST ............................................................................ 62
6.4 LOW WATER LEVEL FAULT TEST .................................................................... 63
6.5 WATER TEMPERATURE FAULT TEST ............................................................. 63
6.6 INTERLOCK TESTS ............................................................................................ 65
REMOTE INTERLOCK ......................................................................................... 65 6.6.1
DELAYED INTERLOCK ....................................................................................... 65 6.6.2
6.7 FLAME FAULT TESTs ........................................................................................ 65
6.8 AIR FLOW FAULT TESTS .................................................................................. 67
6.9 SSOV PROOF OF CLOSURE SWITCH .............................................................. 67
6.10 PURGE SWITCH OPEN DURING PURGE ....................................................... 68
6.11 IGNITION SWITCH OPEN DURING IGNITION ................................................ 69
6.12 SAFETY PRESSURE RELIEF VALVE TEST .................................................... 70
CHAPTER 7 MAINTENANCE ............................................................................................ 71
7.1 MAINTENANCE SCHEDULE .............................................................................. 71
7.2 IGNITER-INJECTOR ........................................................................................... 72
7.3 FLAME DETECTOR ............................................................................................ 74
7.4 COMBUSTION CALIBRATION & RSI REGULATOR ADJUSTMENT ................. 74
RSI Regulator Pressure ............................................................................................ 74 7.4.1
7.5 SAFETY DEVICE TESTING ................................................................................ 77
7.6 BURNER ASSEMBLY INSPECTION .................................................................. 77
7.7 CONDENSATE DRAIN TRAP ............................................................................. 80
7.8 SHUTTING THE BOILER DOWN FOR AN EXTENDED PERIOD OF TIME ....... 81
7.9 PLACING THE BOILER BACK IN SERVICE AFTER A PROLONGED SHUTDOWN . 81
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AERCO International, Inc. • 100 Oritani Dr. • Blauvelt, NY 10913 • Ph: 800-526-0288
Benchmark 1.5LN Low NOx Boiler
Operation and Maintenance Manual
OMM-0041_0D
GF-120
CHAPTER 8 TROUBLESHOOTING GUIDE ................................................................... 83
8.1 INTRODUCTION ................................................................................................. 83
8.2 ADDITIONAL FAULTS WITHOUT SPECIFIC FAULT MESSAGES .................... 93
CHAPTER 9 RS232 COMMUNICATION ......................................................................... 97
9.1 INTRODUCTION ................................................................................................. 97
9.2 RS232 COMMUNICATION SETUP ..................................................................... 97
9.3 MENU PROCESSING UTILIZING RS232 COMMUNICATION ........................... 97
9.4 DATA LOGGING ................................................................................................. 98
Fault Log .................................................................................................................. 98 9.4.1
Operation Time Log ................................................................................................. 99 9.4.2
Sensor Log ............................................................................................................... 99 9.4.3
APPENDIX A: MENU ITEM DESCRIPTIONS .............................................................. 101
APPENDIX B: STARTUP, STATUS AND FAULT MESSAGES ................................ 107
APPENDIX C: SENSOR TEMPERATURE RESISTANCE ......................................... 110
APPENDIX D: INDOOR/OUTDOOR RESET RATIO CHARTS................................. 111
APPENDIX E: BOILER DEFAULT SETTINGS ............................................................ 115
APPENDIX F: PART AND DIMENSIONAL DRAWINGS ........................................... 117
APPENDIX G: PIPING DRAWINGS ............................................................................... 133
APPENDIX H: WIRING SCHEMATICS .......................................................................... 139
APPENDIX I: RECOMMENDED PERIODIC TESTING CHECK LIST .................... 145
APPENDIX J: BENCHMARK CONTROL PANEL FEATURES ................................ 146
APPENDIX K: RECOMMENDED SPARE PARTS LISTS .......................................... 149
STANDARD WARRANTY: Benchmark Gas-Fired Hydronic Boiler .................... 150
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Benchmark 1.5LN Low NOx Boiler
Operation and Maintenance Manual
OMM-0041_0D
GF-120
AERCO International, Inc. • 100 Oritani Dr. • Blauvelt, NY 10913 • Ph: 800-526-0288
Foreword
The AERCO Benchmark 1.5LN Boiler is a modulating unit. It represents a true industry advance
that meets the needs of today's energy and environmental concerns. Designed for application in
any closed loop hydronic system, the Benchmark's modulating capability relates energy input
directly to fluctuating system loads. The Benchmark 1.5, with its 20:1 turn down ratio and
condensing capability, provides extremely high efficiencies and makes it ideally suited for
modern low temperature, as well as, conventional heating systems.
The Benchmark 1.5 operates at inputs ranging from 75,000 BTU/hr. to 1,500,000 BTU/hr. The
output of the boiler is a function of the unit’s firing rate and return water temperature. Output
ranges from 74,250 BTU/hr. to 1,450,000 BTU/hr., depending on operating conditions.
When installed and operated in accordance with this Instruction Manual, the Benchmark 1.5
Boiler complies with the NOx emission standards outlined in:
South Coast Air Quality Management District (SCAQMD), Rule 1146.2
Whether used in singular or modular arrangements, the Benchmark 1.5 offers the maximum
flexibility in venting with minimum installation space requirements. The Benchmark's advanced
electronics are available in several selectable modes of operation offering the most efficient
operating methods and energy management system integration.
For service or parts, contact your local sales representative or AERCO INTERNATIONAL.
NAME:
ORGANIZATION:
ADDRESS:
TELEPHONE:
INSTALLATION DATE: _____________________________________________
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AERCO International, Inc. • 100 Oritani Dr. • Blauvelt, NY 10913 • Ph: 800-526-0288
Benchmark 1.5LN Low NOx Boiler
Operation and Maintenance Manual
OMM-0041_0D
GF-120
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Benchmark 1.5LN Low NOx Boiler
Operation and Maintenance Manual
OMM-0041_0D
GF-120
AERCO International, Inc. • 100 Oritani Dr. • Blauvelt, NY 10913 • Ph: 800-526-0288
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).
Where ASME CSD-1 is required by local jurisdiction, the installation must conform to CSD-1.
Where applicable, the equipment shall be installed in accordance with the current Installation
Code for Gas Burning Appliances and Equipment, CSA B149.1, and applicable Provincial
regulations for the class; which should be carefully followed in all cases. Authorities having
jurisdiction should be consulted before installations are made.
IMPORTANT
This Instruction Manual is an integral part of the product and must
be maintained in legible condition. It must be given to the user by
the installer and kept in a safe place for future reference.
WARNING
MUST BE OBSERVED TO PREVENT SERIOUS INJURY.
WARNING
BEFORE ATTEMPTING TO PER-FORM ANY MAINTENANCE
ON THE UNIT, SHUT OFF ALL GAS AND ELECTRICAL INPUTS
TO THE UNIT.
WARNING
THE EXHAUST VENT PIPE OF THE UNIT OPERATES UNDER
A POSITIVE PRESSURE AND THERE-FORE MUST BE
COMPLETELY SEALED TO PREVENT LEAKAGE OF
COMBUSTION PRODUCTS INTO LIVING SPACES.
WARNING
A DOUBLE-POLE SWITCH MUST BE INSTALLED ON THE
ELECTRICAL SUPPLY LINE OF THE UNIT. THE SWITCH MUST
BE INSTALLED IN AN EASILY ACCESSIBLE POSITION TO
QUICKLY AND SAFELY DISCONNECT ELECTRICAL SERVICE.
DO NOT AFFIX SWITCH TO UNIT SHEET METAL
ENCLOSURES.
WARNING
DO NOT USE MATCHES, CANDLES, FLAMES, OR OTHER
SOURCES OF IGNITION TO CHECK FOR GAS LEAKS.
WARNING
FLUIDS UNDER PRESSURE MAY CAUSE INJURY TO
PERSONNEL OR DAMAGE TO EQUIPMENT WHEN
RELEASED. BE SURE TO SHUT OFF ALL INCOMING AND
OUTGOING WATER SHUTOFF VALVES. CAREFULLY
DECREASE ALL TRAPPED PRESSURES TO ZERO BEFORE
PERFORMING MAINTENANCE.
WARNING
electrical voltages up to 120 vac may be used in this equipment.
Therefore the cover on the unit’s power box (located behind the
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AERCO International, Inc. • 100 Oritani Dr. • Blauvelt, NY 10913 • Ph: 800-526-0288
MANUAL GAS SHUTOFF VALVE
VALVE OPEN
VALVE CLOSED
CHAPTER 1: SAFETY PRECAUTIONS
front panel door) must be installed at all times, except during
maintenance and servicing.
CAUTIONS
Must be observed to prevent equipment damage or loss of
operating effectiveness.
CAUTION
Many soaps used for gas pipe leak testing are corrosive to metals.
The piping must be rinsed thoroughly with clean water after leak
checks have been completed.
CAUTION!
DO NOT use this boiler if any part has been under water. Call a
qualified service technician to inspect and replace any part that
has been under water.
1.2 EMERGENCY SHUTDOWN
If overheating occurs or the gas supply fails to shut off, close the manual gas shutoff valve (Figure 1-1)
located external to the unit.
IMPORTANT
The Installer must identify and indicate the location of the
emergency shutdown manual gas valve to operating personnel.
1.3 PROLONGED SHUTDOWN
After prolonged shutdown, it is recommended that the startup procedures in Chapter 4 and the safety
device test procedures in Chapter 6 of this manual be performed, to verify all system-operating
parameters. If there is an emergency, turn off the electrical power supply to the AERCO boiler and close
the manual gas valve located upstream the unit. The installer must identify the emergency shut-off
device.
Figure 11: Manual Gas Shutoff Valve
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Benchmark 1.5LN Low NOx Boiler
Operation and Maintenance Manual
OMM-0041_0D
GF-120
AERCO International, Inc. • 100 Oritani Dr. • Blauvelt, NY 10913 • Ph: 800-526-0288
• Boiler must be installed by a plumber or a gas fitter who is licensed within the
• Prior to unit operation, the complete gas train and all connections must be leak tested
• If a glycol solution is used as anti-freeze protection, a backflow preventer must be installed
• The vent termination must be located a minimum of 4 feet above grade level.
• If side-wall venting is used, the installation must conform to the following requirements
(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:
CHAPTER 1: SAFETY PRECAUTIONS
IMPORTANT – FOR MASSACHUSETTS INSTALLATIONS ONLY
Boiler Installations within the Commonwealth of Massachusetts
must conform to the following requirements:
Commonwealth of Massachusetts.
using a non-corrosive soap.
upstream of the Fill/Makeup Valve.
extracted from 248 CMR 5.08 (2):
1. INSTALLATION OF CARBON MONOXIDE DETECTORS. At the time of installation
of the side wall horizontal vented gas fueled equipment, the installing plumber or
gasfitter shall observe that a hard wired carbon monoxide detector with an alarm and
battery back-up is installed on the floor level where the gas equipment is to be installed.
In addition, the installing plumber or gasfitter shall observe that a battery operated or
hard wired carbon monoxide detector with an alarm is installed on each additional level
of the dwelling, building or structure served by the side wall horizontal vented gas fueled
equipment. It shall be the responsibility of the property owner to secure the services of
qualified licensed professionals for the installation of hard wired carbon monoxide
detectors.
a. In the event that the side wall horizontally vented gas fueled equipment is
installed in a crawl space or an attic, the hard wired carbon monoxide detector
with alarm and battery back-up may be installed on the next adjacent floor level.
b. In the event that the requirements of this subdivision can not be met at the
time of completion of installation, the owner shall have a period of thirty (30) days
to comply with the above requirements; provided, however, that during said thirty
(30) day period, a battery operated carbon monoxide detector with an alarm shall
be installed.
2. APPROVED CARBON MONOXIDE DETECTORS. Each carbon monoxide detector
as required in accordance with the above provisions shall comply with NFPA 720 and be
ANSI/UL 2034 listed and IAS certified.
3. SIGNAGE. A metal or plastic identification plate shall be permanently mounted to the
exterior of the building at a minimum height of eight (8) feet above grade directly in line
with the exhaust vent terminal for the horizontally vented gas fueled heating appliance or
equipment. The sign shall read, in print size no less than one-half (1/2) inch in size,
"GAS VENT DIRECTLY BELOW. KEEP CLEAR OF ALL OBSTRUCTIONS".
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CHAPTER 1: SAFETY PRECAUTIONS
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 identification of each "special venting system" shall include the listing of either
the website, phone number or manufacturer’s address where the venting system
installation instructions can be obtained, 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 the Product Approved side wall horizontally vented
gas fueled equipment and all the venting instructions, parts lists and/or design instructions for
the venting system shall remain with the appliance or equipment at the completion of the
installation.
_______________ [End of Extracted Information From 248 CMR 5.08 (2)__________________
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AERCO International, Inc. • 100 Oritani Dr. • Blauvelt, NY 10913 • Ph: 800-526-0288
CHAPTER 2: INSTALLATION
CHAPTER 2: INSTALLATION
2.1 INTRODUCTION
This Chapter provides the descriptions and procedures necessary to unpack, inspect and install
the AERCO Benchmark 1.5 Boiler. Brief descriptions are also provided for each available mode
of operation. Detailed procedures for implementing these modes are provided in Chapter 5.
2.2 RECEIVING THE UNIT
Each Benchmark 1.5 System is shipped as a single crated unit. The shipping weight is
approximately 1551 pounds. The unit must be moved with the proper rigging equipment for
safety and to avoid equipment damage. The unit should be completely inspected for evidence of
shipping damage and shipment completeness at the time of receipt from the carrier and before
the bill of lading is signed.
NOTE
AERCO is not responsible for lost or damaged freight.
Each unit has a Tip-N-Tell indicator on the outside of the crate. This indicates if the unit has
been turned on its side during shipment. If the Tip-N-Tell indicator is tripped, do not sign for the
shipment. Note the information on the carrier’s paperwork and request a freight claim and
inspection by a claims adjuster before proceeding. Any other visual damage to the packaging
materials should also be made clear to the delivering carrier.
2.3 UNPACKING
Carefully unpack the unit taking care not to damage the unit enclosure when cutting away
packaging materials
A close inspection of the unit should be made to ensure that there is no evidence of damage not
indicated by the Tip-N-Tell indicator. The freight carrier should be notified immediately if any
damage is detected.
IMPORTANT
After unpacking, take off the unit top panel and remove the strap
and packing material at the top of the heat exchanger. The
packing material is located in the area of the ignitor-injector and
staged ignition solenoid on the burner assembly.
The following accessories come standard with each unit and are either packed separately within
the unit’s packing container or are factory installed on the boiler:
• Pressure/Temperature Gauge
• Spare Spark Ignitor-Injector
• Spare Flame Detector
• ASME Pressure Relief Valve
• Condensate Drain Trap
• 1-1/2” Gas Supply Shutoff Valve
When ordered, optional accessories may be packed separately, packed within the boiler
shipping container, or may be installed on the boiler. Any standard or optional accessories
shipped loose should be identified and stored in a safe place until ready for installation or use.
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CHAPTER 2: INSTALLATION
2.4 SITE PREPARATION.
Ensure that the site selected for installation of the Benchmark 1.5 Boiler includes:
• Access to AC Input Power at 120 VAC, 1-Phase, 60 Hz @ 20
• Access to Natural Gas line at a minimum pressure of 4 inches W.C.
Installation Clearances 2.4.1
The unit must be installed with the prescribed clearances for service as shown in Figure 2-1.
The minimum clearance dimensions, required by AERCO, are listed below. However, if Local
Building Codes require additional clearances, these codes shall supersede AERCO’s
requirements. Minimum acceptable clearances required are:
• Sides: 24 inches
• Front : 24 inches
• Rear: 30 inches
• Top: 18 inches
All gas piping, water piping and electrical conduit or cable must be arranged so that they do not
interfere with the removal of any panels, or inhibit service or maintenance of the unit.
Figure 2-1: Benchmark 1.5 Boiler Clearances
WARNING
KEEP THE UNIT AREA CLEAR AND FREE FROM ALL
COMBUSTIBLE MATERIALS AND FLAMMABLE VAPORS OR
LIQUIDS.
CAUTION
While packaged in the shipping container, the boiler must be
moved by pallet jack or forklift from the FRONT ONLY.
FOR MASSACHUSSETTS ONLY:
For Massachusetts installations, the boiler must be installed by a
plumber or gas fitter who is licensed within the Commonwealth of
Massachusetts. In addition, the installation must comply with all
requirements specified in Chapter 1 (Safety Precautions), pages
1-2 & 1-3.
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AERCO International, Inc. • 100 Oritani Dr. • Blauvelt, NY 10913 • Ph: 800-526-0288
CHAPTER 2: INSTALLATION
Setting the Unit 2.4.2
The unit must be installed on a 4 inch to 6 inch housekeeping pad to ensure proper condensate
drainage. If anchoring the unit, refer to the dimensional drawings in Appendix F for anchor
locations. Two lifting tabs are provided at the top of the heat exchanger. Figure 2-2 shows the
location of the tab on the top-left side. The second tab is located on the top-right side of the heat
exchanger. USE THESE TWO TABS TO LIFT AND MOVE THE UNIT. Remove the top panel
from the unit to provide access to the lifting tabs. Remove the four (4) lag screws securing the
unit to the shipping skid. Lift the unit off the shipping skid and position it on the 4 inch to 6 inch
housekeeping concrete pad (required) in the desired location.
WARNING
WHEN LIFTING OR MOVING THE BOILER:
• DO NOT MANIPULATE THE BOILER USING THE GAS TRAIN OR
BLOWER
• WHEN USING THE LIFTING TABS, ENSURE THERE IS NO LOAD
PLACED ON THE GAS TRAIN OR BLOWER
Figure 2-2: Partial Top View Showing Lifting Tab Location
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.
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AERCO International, Inc. • 100 Oritani Dr. • Blauvelt, NY 10913 • Ph: 800-526-0288
BOILER SUPPLY
3" – 150# FLANGED
CONNECTION
BOILER RETURN
3" – 150# FLANGED
CONNECTION
1-1/2”
GAS INLET
CONNECTION
SHELL DRAIN
VALVE
EXHAUST
MANIFOLD
REAR VIEW
EXHAUST
MANIFOLD
PARTIAL REAR VIEW
CONDENSATE DRAIN
CONNECTION
BOILER
RETURN
CHAPTER 2: INSTALLATION
2.5 SUPPLY AND RETURN PIPING
The Benchmark 1.5 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-832 for additional dimensional data.
Figure 2-3: Supply and Return Locations
2.6 CONDENSATE DRAIN
The Benchmark 1.5 Boiler is designed to condense water vapor from the flue products.
Therefore, the installation must have provisions for suitable condensate drainage or collection.
The condensate drain pipe located on the exhaust manifold (Figure 2-4) must be connected to a
condensate trap which is packed separately within the unit’s shipping container.
The procedure to install and connect the condensate drain is provided in paragraph 2.6.1.
Exhaust Manifold Condensate Drain 2.6.1
The exhaust manifold drain pipe connection shown in Figure 2-4, must be connected to a
condensate drain trap external to the unit.
Page 16 of 152 PR2: 05/09/12
Figure 2-4: Condensate Drain Connection Location
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GF-120
AERCO International, Inc. • 100 Oritani Dr. • Blauvelt, NY 10913 • Ph: 800-526-0288
Refer to Figure 2-5 and install the trap as follows:
CHAPTER 2: INSTALLATION
NOTE
There are two slightly different types of condensate traps that may
be used in your configuration; an older style without built-in
adapter, and a newer style with a built-in adapter (see Figure 2-5).
Installation is the same (1/4” threads are inside built-in adapter on
newer style).
1. Install 3/4” NPT nipples in the tapped inlet and outlet of the condensate trap (part no.
24060).
2. Install a third 3/4” NPT nipple in the tapped condensate outlet of the exhaust manifold.
3. Connect the exhaust manifold nipple to the condensate trap inlet using a female union.
4. install a suitable support under the condensate trap and ensure that the trap is level.
5. Connect a length of 1” I.D. polypropylene hose (part no. 91030) to the nipple on the
outlet side of the condensate trap and secure it with a hose clamp.
6. 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
drain. The maximum condensate flow rate is 20 GPH. The condensate drain trap, associated
fittings and drain lines must be removable for routine maintenance.
Figure 2-5: Condensate Trap Installation: Older (left) and Newer (right) Style
2.7 GAS SUPPLY PIPING
The AERCO Benchmark 1.5 Gas Components and Supply Design Guide, GF-4030 must be
consulted prior to designing or installing any gas supply piping.
WARNING
NEVER USE MATCHES, CANDLES, FLAMES OR OTHER
SOURCES OF IGNITION TO CHECK FOR GAS LEAKS.
Many soaps used for gas pipe leak testing are corrosive to metals.
There-fore, piping must be rinsed thoroughly with clean water after
leak checks have been completed.
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CHAPTER 2: INSTALLATION
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.
A 1-1/2 inch gas inlet connection is located on the rear of the unit as shown in Figure 2-3.
Prior to installation, all pipes should be de-burred and internally cleared of any scale, metal
chips or other foreign particles. Do Not install any flexible connectors or unapproved gas
fittings. Piping must be supported from the floor, ceiling or walls only and must not be supported
by the unit.
A suitable piping compound, approved for use with natural gas, should be used. Any excess
must be wiped off to prevent clogging of components.
To avoid unit damage when pressure testing gas piping, isolate the unit from the gas supply
piping. At no time should the gas pressure applied to the unit exceed 14” W.C. Leak test all
external piping thoroughly using a soap and water solution or suitable equivalent. The gas
piping used must meet all applicable codes.
Gas Supply Specifications. 2.7.1
The gas supply input specifications to the unit for Natural Gas are as follows:
The maximum static pressure to the unit must not exceed 14” W.C. The gas supply pressure to
the unit must be of sufficient capacity to provide 1500 cfh while maintaining the gas pressure at
4.0 inches W.C. for FM, or 4.2 inches W.C. for IRI gas trains.
Manual Gas Shutoff Valve 2.7.2
A manual shut-off valve must be installed in the gas supply line upstream of the Boiler as shown
in Figure 2-6. Maximum allowable gas pressure to the Boiler is 14” W.C.
NOTE
Paragraph 2.7.3 applies only to bolier installations within the
Commonwealth of Massachusetts.
External Gas Supply Regulator 2.7.3
For Massachusetts installations, a mandatory external gas supply regulator must be positioned
as shown in Figure 2-6. The gas supply regulator must be properly vented to outdoors. Consult
the local gas utility for detailed requirements concerning venting of the the supply gas regulator.
NOTE
The external regulator must be capable of regulating 1,500,000
BTU/HR of natural gas while maintaining a gas pressure of 4.0”
W.C. to the boiler.
CAUTION
A lock-up style regulator MUST be used when gas supply
pressure will exceed 14” W.C.
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GF-120
AERCO International, Inc. • 100 Oritani Dr. • Blauvelt, NY 10913 • Ph: 800-526-0288
NATURAL
GAS
SUPPLY
DIRT
TRAP
1-1/2” MANUAL
GAS SHUTOFF
VALVE
GAS PRESSURE
REGULATOR
(REQUIRED FOR
MASSACHUSETTS
INSTALALTIONS
ONLY)
CHAPTER 2: INSTALLATION
Figure 2-6: Manual Gas Shut-Off Valve Location
IRI Gas Train Kit 2.7.4
The IRI gas train is an optional gas train configuration which is required in some areas for code
compliance or for insurance purposes. The IRI gas train is factory pre-piped and wired. See
Appendix F, Drawing AP-A-830 for details.
2.8 AC ELECTRICAL POWER WIRING
The AERCO Benchmark 1.5 Electrical Power Wiring Guide, GF-4060, must be consulted prior
to connecting any AC power wiring to the unit. External AC power connections are made to the
unit inside the Power Box on the front panel of the unit. Remove the front door of the unit to
access the Power Box mounted directly above the Control Box. Loosen the four Power Box
cover screws and remove cover to access the AC terminal connections inside the Power Box
(Figure 2-7).
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.
NOTE
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UPPER RIGHT CORNER OF FRONT PANEL
TERMINAL BLOCK
GND
NEU
L1
120 VAC, 1 PHASE
CHAPTER 2: INSTALLATION
Figure 2-7: AC Input Terminal Block Location
Electrical Power Requirements 2.8.1
The AERCO Benchmark 1.5 Boiler accepts 120 VAC, single-phase, 60 Hz @ 20 A. The Power
Box contains a terminal block as shown in Figure 2-8. In addition, a wiring diagram showing the
required AC power connections is provided on the front cover of the Power Box.
Each Benchmark 1.5 Boiler must be connected to a dedicated electrical circuit. NO OTHER
DEVICES SHOULD BE ON THE SAME ELECTRICAL CIRCUIT AS THE BENCHMARK
BOILER.
A double-pole switch must be installed on the electrical supply line in an easily accessible
location to quickly and safely disconnect electrical service. DO NOT attach the switch to sheet
metal enclosures of the unit.
After placing the boiler in service, the ignition safety shutoff device must be 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 1.5 Electrical Power Wiring
Guide, (GF-4060).
Figure 2-8: AC Terminal Block Configurations
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GF-120
AERCO International, Inc. • 100 Oritani Dr. • Blauvelt, NY 10913 • Ph: 800-526-0288
CHAPTER 2: INSTALLATION
2.9 MODES OF OPERATION AND FIELD CONTROL WIRING
The Benchmark 1.5 Boiler is available in several different modes of operation. While each unit
is factory configured and wired for its intended mode, some additional field wiring may be
required to complete the installation. This wiring is typically connected to the Input/Output (I/O)
Box located on the lower portion of the unit front panel (Figure 2-9) behind the removable front
door.
To access the I/O Box terminal strips shown in Figure 2-10, loosen the four cover screws and
remove the cover. All field wiring is installed from the rear of the panel by routing the wires
through one of the four bushings provided.
Refer to the wiring diagram provided on the cover of the I/O Box (Figure 2-10) when making all
wiring connections.
Brief descriptions of each mode of operation, and their wiring requirements, are provided in the
following paragraphs. Additional information concerning field wiring is provided in paragraphs
2.9.1 through 2.9.9. Refer to Chapter 5 for detailed information on the available modes of
operation.
Figure 2-9: Input/Output (I/O) Box Location
Constant Setpoint Mode 2.9.1
The Constant Setpoint Mode is used when it is desired to have a fixed setpoint that does not
deviate. No wiring connections, other than AC electrical power connections, are required for
this mode. However, if desired, fault monitoring or enable/disable interlock wiring can be
utilized (see paragraphs 2.9.9.1 and 2.9.10).
Indoor/Outdoor Reset Mode 2.9.2
This mode of operation increases supply water temperature as outdoor temperatures decrease.
An outside air temperature sensor (AERCO Part No. 122790) is required. The sensor MUST
BE wired to the I/O Box wiring terminals (see Figure 2-10). Refer to paragraph 2.10.1 for
additional information on outside air temperature sensor installation.
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CHAPTER 2: INSTALLATION
Boiler Management System Mode 2.9.3
NOTE
BMS Model 168 can utilize either pulse width modulation (PWM)
or RS485 Modbus signaling to the Boiler. BMS II Model 5R5-384
can utilize only RS485 signaling to the Boiler.
When using an AERCO Boiler Management System (BMS), the field wiring is connected
between the BMS Panel and each Boiler’s I/O Box terminal strip (Figure 2-10). Twisted shielded
pair wire from 18 to 22 AWG must be utilized for the connections. The BMS Mode can utilize
either pulse width modulation (PWM) signaling, or RS485 Modbus signaling. For PWM
signaling, connections are made from the AERCO Boiler Management System to the B.M.S.
(PWM) IN terminals on the I/O Box terminal strip. For RS485 Modus signaling, connections are
made from the BMS to the RS485 COMM terminals on the I/O Box terminal strip. Polarity must
be maintained and the shield must be connected only at the AERCO BMS. The boiler end of the
shield must be left floating. For additional instructions, refer to Chapter 5, paragraph 5.6 in this
manual. Also, refer to GF-108M, BMS -Operations Guide.
Remote Setpoint and Direct Drive Modes 2.9.4
The Benchmark 1.5 Boiler can accept several types of signal formats from an Energy
Management System (EMS), Building Automation System (BAS) or other source, to control
either the setpoint (Remote Setpoint Mode) or air/fuel valve position (Direct Drive Mode) of the
Boiler. These formats are:
• 4 to 20 mA/1 to 5 VDC
• 0 to 20 mA/0 to 5 VDC
• PWM – (Pulse Width Modulated signal. See para. 2.10.4)
• Network (RS485 Modbus. See para. 2.10.7)
While it is possible to control a boiler or boilers using one of the previously described modes of
operation, it may not be the method best suited for the application. Prior to selecting one of
these modes of operation, it is recommended that you consult with your local AERCO
representative or the factory for the mode of operation that will work best with your application.
For more information on wiring the 4 to 20 mA / 1to 5VDC or the 0 to 20 mA / 0 to 5 VDC, see
paragraph 2.9.3.
Combination Mode 2.9.5
NOTE
Only BMS Model 168 can be utilized for the Combination Mode,
not the BMS II (Model 5R5-384).
With a Combination Mode unit, field wiring is between the unit’s I/O Box wiring terminals, the
CCP (Combination Control Panel), and the BMS (Boiler Management System). The wiring must
be accomplished using twisted-shielded pair wire from 18 to 22 AWG. Polarity must be
maintained. For further instructions and wiring diagrams, refer to the GF-108 Boiler
Management System Operations Guide and the CCP-1 data sheet.
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CHAPTER 2: INSTALLATION
Figure 2-10. I/O Box Terminal Locations and Functions
2.10 I/O BOX CONNECTIONS
The types of input and output signals and devices to be connected to the I/O Box terminals
shown in Figure 2-10 are described in the following paragraphs.
NOTE
Older I/O PCBs are wired the same as new ones, even if silkscreen designations may slightly differ.
DO NOT make any connections to the I/O Box terminals labeled
“NOT USED”. Attempting to do so may cause equipment
damage.
OUTDOOR SENSOR IN (1) 2.10.1
An outdoor air temperature sensor (AERCO Part No. 122790) will be required primarily for the
Indoor/Outdoor reset mode of operation. It can also be used with another mode if it is desired to
use the outdoor sensor enable/disable feature. This feature allows the boiler to be enabled or
disabled based on the outdoor air temperature.
The factory default for the outdoor sensor is DISABLED. To enable the sensor and/or select an
enable/disable outdoor temperature, see the Configuration menu in Chapter 3.
The outdoor sensor may be wired up to 200 feet from the boiler. It is connected to the
OUTDOOR SENSOR IN and SENSOR COMMON terminals in the I/O Box (see Figures 2-9 and
2-10). Wire the sensor using a twisted shielded pair wire from 18 to 22 AWG. There is no
polarity to observe when terminating these wires. The shield is to be connected only to the
terminals labeled SHIELD in the I/O Box. The sensor end of the shield must be left free and
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CHAPTER 2: INSTALLATION
ungrounded.
When mounting the sensor, it must be located on the North side of the building where an
average outside air temperature is expected. The sensor must be shielded from direct sunlight
as well as impingement by the elements. If a shield is used, it must allow for free air circulation.
AIR TEMP. SENSOR (2) 2.10.2
The Air Temperature Sensor is connected to the positive (+) and negative (-) terminals of the
AIR TEMP. SENSOR on the I/O board. This sensor measures the temperature of the air input to
the Air/Fuel Valve. This temperature reading is one of the components used to calculate the
rotational speed of the blower used in the combustion Calibration process (Chapter 4).
The AIR TEMP. SENSOR terminals can be used to add an additional temperature sensor for
monitoring purposes. This input is always enabled and is a view-only input that can be seen in
the Operating Menu. The sensor must be wired to the positive (+) and negative (-) terminals of
the AIR TEMP. SENSOR and must be similar to AERCO BALCO wire sensor Part No. 12449.
A resistance chart for this sensor is provided in Appendix C.
ANALOG IN (3) 2.10.3
The ANALOG IN + and – terminals are used when an external signal is used to drive the air/fuel
valve position (Direct Drive Mode) or change the setpoint (Remote Setpoint Mode) of the Boiler.
Either a 4 to 20 mA /1 to 5 VDC or a 0 to 20 mA / 0 to 5 VDC signal may be used to vary the
setpoint or valve position. The factory default setting is for 4 to 20 mA / 1 to 5 VDC, however this
may be changed to 0 to 20 mA / 0 to 5 VDC using the Configuration Menu described in Chapter
3. If voltage rather than current is selected as the drive signal, a DIP switch must be set on the
PMC Board located inside the Control Box. Contact the AERCO factory for information on
setting DIP switches.
All of the supplied signals must be floating (ungrounded) signals. Connections between the
signal source and the Boiler’s I/O Box must be made using twisted shielded pair wire from 18 to
22 AWG, such as Belden 9841 (see Figure 2-10). Polarity must be maintained. The shield
must be connected only at the source end and must be left floating (not connected) at the
Boiler’s I/O Box.
Regardless of whether voltage or current is used for the drive signal, they are linearly mapped
to a 40°F to 240°F setpoint or a 0% to 100% valve position. No scaling for these signals is
provided.
B.M.S. (PWM) IN (4) 2.10.4
NOTE
Only BMS Model 168 can utilize Pulse Width Modulation (PWM),
not the BMS II (Model 5R5-384).
These terminals are used to connect the AERCO Boiler Management System (BMS) to the unit.
The BMS utilizes a 12 millisecond, ON/OFF duty cycle. This duty cycle is Pulse Width
Modulated (PWM) to control valve position. A 0% valve position = a 5% ON pulse and a 100%
valve position = a 95% ON pulse.
SHIELD (5) 2.10.5
The SHIELD terminals are used to terminate any shields used on sensor wires connected to the
unit. Only shields must be connected to these terminals.
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Benchmark 1.5LN Low NOx Boiler
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GF-120
AERCO International, Inc. • 100 Oritani Dr. • Blauvelt, NY 10913 • Ph: 800-526-0288
CHAPTER 2: INSTALLATION
IMPORTANT
DO NOT USE the mA OUT output to remotely monitor Setpoint,
Outlet Temp or Fire Rate Out.
mA OUT (6) 2.10.6
These terminals provide a 4 to 20 mA output to the VFD (if so equipped) to control the rotational
speed of the blower. This function is enabled in the Configuration Menu (Chapter 3, Table 3-4).
RS-485 COMM (7) 2.10.7
These terminals are used for RS-485 MODBUS serial communication between the unit and an
external “Master” such as a Boiler Management System (BMS), Energy Management System
(EMS), Building Automation System (BAS) or other suitable device.
TxD, RxD (8) 2.10.8
These terminals provide a parallel connection to the connector on the C-More Controller front
panel, for connecting a computer or laptop.
VFD/BLOWER (9) 2.10.9
These terminals provide a 0 to 10 volt output to control the rotational speed of the blower. This
function is enabled in the Configuration Menu (Chapter 3, Table 3-4).
EXHAUST SWITCH IN (11) 2.10.10
These terminals permit an external exhaust switch to be connected to the exhaust manifold of
the boiler. The exhaust switch should be a normally open type switch (such as AERCO Part No.
123463) that closes (trips) at 500°F.
INTERLOCKS (10, 12) 2.10.11
The unit offers two interlock circuits for interfacing with Energy Management Systems and
auxiliary equipment such as pumps or louvers. These interlocks are called the Remote Interlock
and Delayed Interlock (Figure 2-10). The wiring terminals for these interlocks are located inside
the I/O Box on the unit front panel. The I/O Box cover contains a wiring diagram which shows
the terminal strip locations for these interlocks (REMOTE INTL’K IN and DELAYED INTL’K IN).
Both interlocks, described below, are factory wired in the closed position.
NOTE
Both the Delayed Interlock and Remote Interlock MUST be in the
closed position to allow the unit to fire.
REMOTE INTERLOCK IN (10) 2.10.11.1
The remote interlock circuit is provided to remotely start (enable) and stop (disable) the Boiler, if
desired. The circuit is labeled REMOTE INTL’K IN and is located inside the I/O Box on the front
panel. The circuit is 24 VAC and is factory pre-wired in the closed (jumpered) position.
DELAYED INTERLOCK IN (12) 2.10.11.2
The delayed interlock is typically used in conjunction with the auxiliary relay described in
paragraph 2.11. This interlock circuit is located in the purge section of the start string. It can be
connected to the proving device (end switch, flow switch etc.) of an auxiliary piece of equipment
started by the Boiler’s auxiliary relay. The delayed interlock must be closed for the boiler to fire.
If the delayed interlock is connected to a proving device that requires time to close (make), a
time delay (Aux Start On Dly) that holds the start sequence of the boiler long enough for a
proving switch to make can be programmed. Should the proving switch not prove within the
programmed time frame, the boiler will shut down. The Aux Start On Dly can be programmed
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CHAPTER 2: INSTALLATION
from 0 to 120 seconds. This option is locate in the Configuration Menu (Chapter 3, Table 3-4).
FAULT RELAY (13) 2.10.12
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 2-10.
2.11 AUXILIARY RELAY CONTACTS (14)
Each Boiler is equipped with a single pole double throw (SPDT) relay that is energized when
there is a demand for heat and de-energized after the demand for heat is satisfied. The relay is
provided for the control of auxiliary equipment, such as pumps and louvers, or can be used as a
Boiler status indictor (firing or not firing). Its contacts are rated for 120 VAC @ 5 amps. Refer to
Figure 2-10 to locate the AUX RELAY terminals for wiring connections.
2.12 FLUE GAS VENT INSTALLATION
The minimum allowable vent diameter for a single Benchmark 1.5 Boiler is 6 inches.
The AERCO Benchmark Venting and Combustion Air Guide, GF-2050, must be consulted
before any flue gas vent or inlet air venting is designed or installed. U/L listed, positive pressure,
watertight vent materials as specified in AERCO’s GF-2050, must be used for safety and code
compliance. Since the unit is capable of discharging low temperature exhaust gases, horizontal
sections of the flue vent system must be pitched back to the unit a minimum of 1/4 inch per foot
to avoid condensate pooling and allow for proper drainage.
The combined pressure drop of vent and combustion air systems must not exceed 140
equivalent feet of 6 inch ducting. 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 inch W.C. These factors must be
planned into the vent installation. If the maximum allowable equivalent lengths of piping are
exceeded, the unit will not operate properly or reliably.
For Massachusetts boiler installations, the Heatfab Division of the Selkirk Corporation provides
vent systems which conform to all applicable requirements within the Commonwealth of
Massachusetts. Contact information for this supplier is as follows:
Selkirk Corporation
Heatfab Division ( www.heat-fab.com
130 Industrial Blvd.
Turners Falls, MA 01376
Phone: 1-800-772-0739
)
2.13 COMBUSTION AIR
The AERCO Benchmark Venting and Combustion Air Guide, GF-2050 MUST be consulted
before any flue or combustion supply air venting is designed or implemented. Combustion 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.
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Benchmark 1.5LN Low NOx Boiler
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GF-120
AERCO International, Inc. • 100 Oritani Dr. • Blauvelt, NY 10913 • Ph: 800-526-0288
The AERCO Benchmark 1.5 Boiler is UL listed for 100% sealed combustion. It can also be
installed using room air, provided there is an adequate supply. (See paragraph 2.13.3 for more
information concerning sealed combustion air). If the sealed combustion air option is not being
used, an inlet screen will be attached at the air inlet on the top of the unit
The more common methods of supplying combustion air are outlined below. For more
information concerning combustion air, consult the AERCO Benchmark Venting and
Combustion Air Guide, GF-2050.
CHAPTER 2: INSTALLATION
Combustion Air From Outside the Building 2.13.1
Air supplied from outside the building must be provided through two permanent openings. Each
opening must have a free area of not less than one square inch for each 4000 BTU/H boiler
input. The free area must take into account restrictions such as louvers and bird screens. For
Canada installations, refer to the requirements specified in CSA B149.1-10, 8.4.1 and 8.4.3.
Combustion Air From Inside The Building 2.13.2
When combustion air is provided from within the building, it must be supplied through two
permanent openings in an interior wall. Each opening must have a free area of not less than
one square inch per 1000 BTU/H of total boiler input. The free area must take into account any
restrictions such as louvers.
Sealed Combustion 2.13.3
The AERCO Benchmark 1.5 Boiler is UL listed for 100%-sealed combustion. For sealed
combustion installations, the screen on the air inlet duct of the unit must be removed. The inlet
air ductwork must then be attached directly to the unit’s air inlet.
In a sealed combustion air application, the combustion air ducting pressure losses must be
taken into account when calculating the total maximum allowable venting run. See the AERCO
Benchmark Venting and Combustion Air Guide, GF-2050. When using the boiler in a sealed
combustion air configuration, each unit must have a minimum 6 inch diameter connection at the
unit.
Temporary Combustion Air Filtering During Construction 2.13.4
When the Benchmark 1.5 Boiler is used to provide heat temporarily during ongoing building
construction, accumulated drywall dust, sawdust and similar particles can accumulate in the
unit’s combustion air intake filter and block combustion air flow. In these situations, AERCO
recommends that a disposable air intake filter be installed, temporarily, above the boiler
combustion air inlet.
AERCO recommends that the temporary air filter be cut from a McMaster-Carr part no.
2122K315 Polyester Air Filter Roll Tackfield, ½” thick, 16” wide, or equivalent. Cover the
Benchmark 1.5 air inlet with the blue side of the filter material facing outward to hold the dust on
the outside surface. Maximize the surface area of the filter covering the 8" diameter opening by
creating a dome out of the filter material.
Cover the flared duct opening with the blue side facing outward. During construction check the
filter for dust accumulation and replace it when the accumulation becomes noticeable.
2.14 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:
PR2: 05/09/12 Page 27 of 152
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Benchmark 1.5LN Low NOx Boiler
Operation and Maintenance Manual
OMM-0041_0D
GF-120
AERCO International, Inc. • 100 Oritani Dr. • Blauvelt, NY 10913 • Ph: 800-526-0288
CHAPTER 2: INSTALLATION
• 10 A Resistive @ 277 VAC/28 VDC
• 1/3 HP N/O @ 120/240 VAC
• 1/6 HP N/C @ 120/240 VAC
• 480 VA Pilot Duty @ 240-277 VAC
If pump/valve load exceeds the above contact ratings, use a separate contact relay.
See Diagrams 2-1a and 2-1b.
To identify if the boiler is equipped with the BMK Pump Relay Option (part no. 69102), look for the label
and relay as shown in Figure 2-12.
Diagram 2-1a: Schematic – System Pump Start using Boiler Pump Relay
Diagram 2-1b: Schematic – System Pump Start using a Separate Contact Relay
Figure 2-11: Identifying the Presence of BMK Pump Relay Option 69102
Page 28 of 152 PR2: 05/09/12
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Benchmark 1.5LN Low NOx Boiler
Operation and Maintenance Manual
OMM-0041_0D
GF-120
AERCO International, Inc. • 100 Oritani Dr. • Blauvelt, NY 10913 • Ph: 800-526-0288
CHAPTER 3: CONTROL PANEL OPERATION
3.1 INTRODUCTION
The information in this Chapter provides a guide to the operation of the Benchmark 1.5 Boiler
using the Control Panel mounted on the front of the unit. It is imperative that the initial startup of
this unit be performed by factory trained personnel. Operation prior to initial startup by factory
trained personnel will void the equipment warranty. In addition, the following WARNINGS and
CAUTIONS must be observed at all times.
All of the installation procedures in Chapter 2 must be completed
before attempting to start the unit.
WARNING
ELECTRICAL VOLTAGES IN THIS SYSTEM MAY INCLUDE 460,
208 AND 24 VOLTS AC. IT MUST BE SERVICED ONLY BY
FACTORY CERTIFIED SERVICE TECHNICIANS
WARNING
DO NOT ATTEMPT TO DRY FIRE THE BOILER. STARTING
THE UNIT WITHOUT A FULL WATER LEVEL CAN SERIOUSLY
DAMAGE THE UNIT AND MAY RESULT IN INJURY TO
PERSONNEL OR PROPERTY DAMAGE. THIS SITUATION WILL
VOID ANY WARRANTY.
3.2 CONTROL PANEL DESCRIPTION
The Benchmark 1.5 Control Panel shown in Figure 3-1 contains all of the controls, indicators
and displays necessary to operate, adjust and troubleshoot the Benchmark 1.5 Boiler. These
operating controls, indicators and displays are listed and described in Table 3-1. Additional
information on these items are provided in the individual operating procedures provided in this
Chapter.
PR2: 05/01/11 Page 29 of 152
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Benchmark 1.5LN Low NOx Boiler
Operation and Maintenance Manual
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GF-120
AERCO International, Inc. • 100 Oritani Dr. • Blauvelt, NY 10913 • Ph: 800-526-0288
1
2
3
4
5
6
7
8
9
10
11
12
CHAPTER 3: CONTROL PANEL OPERATION
Figure 3-1: Control Panel Front View
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Benchmark 1.5LN Low NOx Boiler
Operation and Maintenance Manual
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GF-120
AERCO International, Inc. • 100 Oritani Dr. • Blauvelt, NY 10913 • Ph: 800-526-0288
DISPLAY
8
CHAPTER 3: CONTROL PANEL OPERATION
Table 3-1: Operating Controls, Indicators and Displays
ITEM
NO.
CONTROL,
INDICATOR OR
1 LED Status
Indicators
COMM
MANUAL
REMOTE
DEMAND
2
OUTLET
TEMPERATURE
Display
3 VFD Display
FUNCTION
Four Status LEDs indicate the current operating status as
follows:
Lights when RS-232 communication is occurring
Lights when the unit is being controlled using the front panel
keypad.
Lights when the unit is being controlled by an external signal
from an Energy Management System
Lights when there is a demand for heat.
3–Digit, 7–Segment LED display continuously displays the
outlet water temperature. The °F or °C LED next to the
display lights to indicate whether the displayed temperature is
in degrees Fahrenheit or degrees Celsius. The °F or °C blinks
when operating in the Deadband Mode.
Vacuum Fluorescent Display (VFD) consists of 2 lines each
capable of displaying up to 16 alphanumeric characters. The
information displayed includes:
Startup Messages
Fault Messages
Operating Status Messages
Menu Selection
4 RS-232 Port
5 FAULT Indicator
6 CLEAR Key
READY Indicator
7
ON/OFF Switch
9
LOW WATER
LEVEL
TEST/RESET
Switches
PR2: 05/09/12 Page 31 of 152
Port permits a Laptop Computer or External Modem to be
connected to the unit’s Control Panel.
Red FAULT LED indicator lights when a boiler alarm
condition occurs. An alarm message will appear in the VFD.
Turns off the FAULT indicator and clears the alarm message
if the alarm is no longer valid. Lockout type alarms will be
latched and cannot be cleared by simply pressing this key.
Troubleshooting may be required to clear these types of
alarms.
Lights ON/OFF switch is set to ON and all Pre-Purge
conditions have been satisfied.
Enables and disables boiler operation.
Allows operator to test operation of the water level monitor.
Pressing TEST opens the water level probe circuit and
simulates a Low Water Level alarm.
Pressing RESET resets the water level monitor circuit.
Pressing the CLEAR key (item 6) resets the display.
Page 32
Benchmark 1.5LN Low NOx Boiler
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GF-120
AERCO International, Inc. • 100 Oritani Dr. • Blauvelt, NY 10913 • Ph: 800-526-0288
DISPLAY
Bargraph
CHAPTER 3: CONTROL PANEL OPERATION
Table 3-1: Operating Controls, Indicators and Displays (Continued)
ITEM
NO.
CONTROL,
INDICATOR OR
10 MENU Keypad
MENU
BACK
▲ (UP) Arrow
▼ (DOWN) Arrow
FUNCTION
Consists of 6 keys which provide the following functions for
the Control Panel Menus:
Steps through the main menu categories shown in Figure 3-
2. The Menu categories wrap around in the order shown.
Allows you to go back to the previous menu level without
changing any information. Continuously pressing this key
will bring you back to the default status display in the VFD.
Also, this key allows you to go back to the top of a main
menu category.
When in one of the main menu categories (Figure 3-2),
pressing the ▲ arrow key will select the displayed menu
category. If the CHANGE key was pressed and the menu
item is flashing, pressing the ▲ arrow key will increment the
selected setting.
When in one of the main menu categories (Figure 3-2),
pressing this key will select the displayed menu category. If
the CHANGE key was pressed and the menu item is
flashing, pressing the ▼ arrow key will decrement the
selected setting.
CHANGE
ENTER
11 AUTO/MAN Switch
12
VALVE POSITION
Permits a setting to be changed (edited). When the
CHANGE key is pressed, the displayed menu item will begin
to flash. Pressing the ▲ or ▼ arrow key when the item is
flashing will increment or decrement the displayed setting.
Saves the modified menu settings in memory. The display
will stop flashing.
This switch toggles the boiler between the Automatic and
Manual modes of operation. When in the Manual (MAN)
mode, the front panel controls are enabled and the
MANUAL status LED lights.
When in the Automatic (AUTO) mode, the MANUAL status
LED will be off and the front panel controls disabled.
20 segment red LED bargraph continuously shows the
Air/Fuel Valve position in 5% increments from 0 to 100%
Page 32 of 152 PR2: 05/09/12
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Benchmark 1.5LN Low NOx Boiler
Operation and Maintenance Manual
OMM-0041_0D
GF-120
AERCO International, Inc. • 100 Oritani Dr. • Blauvelt, NY 10913 • Ph: 800-526-0288
CHAPTER 3: CONTROL PANEL 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 listed 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 which is used in Chapter 4 to perform combustion calibration
prior to service use.
Menu Processing Procedure 3.3.1
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.
1. The Control Panel will normally be in the Operating Menu and the VFD will display the
current unit status. Pressing the ▲ or ▼ arrow key will display the other available data items
in the Operating Menu.
2. Press the MENU key. The display will show the Setup Menu, which is the next menu
category shown in Figure 3-2. This menu contains the Password option which must be
entered if other menu options will be changed.
3. Continue pressing the MENU key until the desired menu is displayed.
4. With the desired menu displayed, press the ▲ or ▼ 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.
PR2: 05/09/12 Page 33 of 152
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Benchmark 1.5LN Low NOx Boiler
Operation and Maintenance Manual
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GF-120
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OPERATING
SETUP
CONFIGURATION
TUNING
COMBUSTION CAL
CALIBRATION
(NOT USED IN THIS O & M)
LEVEL 2 PWD
LEVEL 1 PWD
DIAGNOSTICS
(NOT USED IN THIS O & M)
CHAPTER 3: CONTROL PANEL OPERATION
Figure 3-2: Control Panel Menu Structure
The following paragraphs provide brief descriptions of the
NOTE
options contained in each menu. Refer to Appendix A for
detailed descriptions of each menu option. Refer to
Appendix B for listings and descriptions of displayed
startup, status and error messages.
3.4 OPERATING MENU
The Operating Menu displays a number of key operating parameters for the unit as listed in
Table 3-2. This menu is “Read-Only” and does not allow personnel to change or adjust any
displayed items. Since this menu is “Read-Only”, it can be viewed at any time without entering a
password. Pressing the ▲ arrow key to display the menu items in the order listed (Top-Down).
Pressing the ▼ arrow key will display the menu items in reverse order (Bottom-Up).
Page 34 of 152 PR2: 05/09/12
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Benchmark 1.5LN Low NOx Boiler
Operation and Maintenance Manual
OMM-0041_0D
GF-120
AERCO International, Inc. • 100 Oritani Dr. • Blauvelt, NY 10913 • Ph: 800-526-0288
Available Choices or Limits
Available Choices or Limits
Menu Item Display
Minimum
Maximum
Default
CHAPTER 3: CONTROL PANEL OPERATION
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 reentered when required. In addition to
permitting password entries, the Setup Menu is also used to enter date and time, units of
temperature measurements and entries required for external communication and control
of the unit via the RS-232 port. A view-only software version display is also provided to indicate
the current Control Box software version.
NOTE
The Outdoor Temp display item shown with an asterisk in
Table 3-2 will not be displayed unless the Outdoor Sensor
function has been enabled in the Configuration Menu
(Table 3-4).
Table 3-2: Operating Menu
Menu Item Display Minimum Maximum Default
Status Message
Active Setpoint 40°F 240°F
AIR Temp -70°F 245°F
Outdoor Temp* -70°F 130°F
Valve Position In 0% 100% Valve Position
Flame Strength 0% 100%
Run Cycles 0 999,999,999
Run Hours 0 999,999,999
Fault Log 0 19 0
Table 3-3. Setup Menu
Passsword 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
Software Ver 0.00 Ver 9.99
PR2: 05/09/12 Page 35 of 152
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Benchmark 1.5LN Low NOx Boiler
Operation and Maintenance Manual
OMM-0041_0D
GF-120
AERCO International, Inc. • 100 Oritani Dr. • Blauvelt, NY 10913 • Ph: 800-526-0288
Available Choices or Limits
Menu Item Display
Minimum
Maximum
Default
Available Choices or Limits
Menu Item Display
Minimum
Maximum
Default
CHAPTER 3: CONTROL PANEL OPERATION
3.6 CONFIGURATION MENU
The Configuration Menu shown in Table 3-4 permits adjustment of the Internal Setpoint (Setpt)
temperature regardless of whether the valid password has been entered. Setpt is required for
operation in the Constant Setpoint mode. The remaining options in this menu require the valid
password to be entered, prior to changing existing entries. This menu contains a number of
other configuration settings which may or may not be displayed, depending on the current
operating mode setting.
NOTE
The Configuration Menu settings shown in Table 3-4 are
Factory-Set in accordance with the requirements
specified for each individual order. Therefore, under
normal operating conditions, no changes will be required.
Table 3-4: Configuration Menu
Internal Setpt Lo Temp Limit Hi Temp Limit 130°F
Unit Type
BMK Blr Std Dual, BMK Blr LN KC Water
Unit Size
Fuel Type Natural Gas, Propane Natural Gas
Boiler Mode
Remote Signal
(If Mode = Remote Setpoint, Direct
Drive or Combination)
Bldg Ref Temp (If Mode = Outdoor Reset) 40°F 230°F 70°F
Reset Ratio(If Mode = Outdoor Reset) 0.1 9.9 1.2
Outdoor Sensor Enabled or Disabled Disabled
System Start Tmp (If Outdoor SensorEnabled)
Setpt Lo Limit 40°F Setpt Hi Limit 60°F
Setpt Hi Limit Setpt Lo Limit 195°F 195°F
Temp Hi Limit 40°F 210°F 195°F
Max Valve Position 40% 100% 100%
600 MBH, 750 MBH, 800 MBH 1000 MBH,
KC Boiler, KC Boiler LN,
BMK Boiler Std, BMK Boiler LN,
Heater,
KC Wtr Heater LN,
Innovation WH
1060 MBH,
1500 MBH, 2000 MBH,
3000 MBH
Constant Setpoint, Remote Setpoint,
Direct Drive, Combination
Outdoor Reset
4 – 20 mA/1 – 5V
0 -20 mA/0 – 5V
PWM Input (BMS)
Network
30°F 100°F 60°F
BMK Boiler LN
1500 MBH
Constant Setpoint
4 – 20 mA,
1-5V
Page 36 of 152 PR2: 05/09/12
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Benchmark 1.5LN Low NOx Boiler
Operation and Maintenance Manual
OMM-0041_0D
GF-120
AERCO International, Inc. • 100 Oritani Dr. • Blauvelt, NY 10913 • Ph: 800-526-0288
Available Choices or Limits
Menu Item Display
Minimum
Maximum
Default
CHAPTER 3: CONTROL PANEL OPERATION
Table 3-4: Configuration Menu (Continued)
Aux Start On Dly 0 sec. 120 sec. 0 sec.
Failsafe Mode Shutdown or Constant Setpt Shutdown
*Analog Output
(See CAUTION at end of Table
3-4 )
Low Fire Timer 2 sec. 600 sec. 2 sec.
Setpt Limiting Enabled or Disabled Disabled
Setpt Limit Band 0°F 10°F 5°F
Network Timeout 5 Sec 999 Sec 30 Sec
HI DB Setpt EN 0% 100% 30%
Demand Offsert 0 25 10
Deadband High 0 25 2
Deadband Low 0 25 2
Off, Setpoint, Outlet Temp,
Valve Position 4-20 mA,
Valve Position 0-10V
*Valve Position
0-10V
*CAUTION
DO NOT CHANGE the Analog Output Menu Item from its
Default setting (Valve Position 0-10V).
3.7 TUNING MENU
The Tuning Menu items in Table 3-5 are Factory set for each individual unit. Do not change
these menu entries unless specifically requested to do so by Factory-Trained personnel.
3.8 COMBUSTION CAL MENU
The Combustion Cal (Calibration) Menu items in Table 3-6 are used to vary the speed of the
unit’s blower motor based on air temperature and air density at prescribed Air/Fuel Valve
positions (% open). This is accomplished by providing a DC drive voltage to the motor which
adjusts the rotational speed of the blower to maximize combustion efficiency and ensure the unit
conforms to the Nitrogen Oxide (NOx) and Carbon Monoxide (CO) emissions specified in
Chapter 4. The valve positions (%) and default drive voltages are listed in Table 3-6.
Table 3-5: Tuning Menu
Prop Band 1°F 120°F 70°F
Integral Gain 0.00 2.00 1.00
Derivative Time 0.0 min 2.00 min 0.00 min
Reset Defaults? Yes, No, Are You Sure? No
PR2: 05/09/12 Page 37 of 152
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Benchmark 1.5LN Low NOx Boiler
Operation and Maintenance Manual
OMM-0041_0D
GF-120
AERCO International, Inc. • 100 Oritani Dr. • Blauvelt, NY 10913 • Ph: 800-526-0288
Available Choices or Limits
Menu Item Display
Minimum
Maximum
Default
CHAPTER 3: CONTROL PANEL OPERATION
Table 3-6: Combustion Cal Menu
CAL Voltage 16% .25 8.20 1.80v
CAL Voltage 30% .25 8.20 3.20v
CAL Voltage 45% .25 8.20 3.70v
CAL Voltage 60% .25 8.20 3.80
CAL Voltage 80% .25 8.20 4.60
CAL Voltage 100% .25 8.20 6.00
SET Valve Position 0% 100% 0%
Blower Output Monitor Blower Output Voltage .00
2.9 START SEQUENCE
When the 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 Proof of Closure (POC) switch
• Low Water Level switch
• High Water Temperature switch
• High Gas Pressure switch
• Low Gas Pressure switch
• Blower Proof 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 fault messages will be displayed throughout
the start sequence, if the required conditions are not
observed.
1. The DEMAND LED status indicator will light.
2. The unit checks to ensure that the Proof of Closure (POC) switch in the downstream Safety
Shut-Off Valve (SSOV) is closed. See Figure 3-3 for SSOV location.
3. With all required safety device switches closed, a purge cycle will be initiated and the
following events will occur:
a) The Blower relay energizes and turns on blower.
b) The Air/Fuel Valve rotates to the full-open purge position and closes purge position
switch. The dial on the Air/Fuel Valve (Figure 3-4) will read 100 to indicate that it is fullopen (100%).
c) The VALVE POSITION bargraph will show 100%.
Page 38 of 152 PR2: 05/09/12
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Benchmark 1.5LN Low NOx Boiler
Operation and Maintenance Manual
OMM-0041_0D
GF-120
AERCO International, Inc. • 100 Oritani Dr. • Blauvelt, NY 10913 • Ph: 800-526-0288
SSO
MANUAL GAS
VALVE
CHAPTER 3: CONTROL PANEL OPERATION
SHUT-OFF
TO
AIR/FUEL
VALVE
GAS INLET
Figure 3-3: SSOV Location
4. Next, the blower proof switch on the Air/Fuel Valve (Figure 3-5) closes. The display will
show Purging and indicate the elapsed time of the purge cycle in seconds.
5. Upon completion of the purge cycle, the Control Box initiates an ignition cycle and the
following events occur:
a) The Air/Fuel Valve rotates to the low-fire ignition position and closes 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.
c) The gas Safety Shut-Off Valve (SSOV) is energized (opened) allowing gas to flow
into the Air/Fuel Valve.
PR2: 05/09/12 Page 39 of 152
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Operation and Maintenance Manual
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GF-120
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100
DETAIL “A”
TO BLOWER
AIR IN
DIAL
(DETAIL “A”)
STEPPER
MOTOR
AIR/FUEL
VALVE OUTLET
TO BLOWER
BLOWER
PROOF
SWITCH
CHAPTER 3: CONTROL PANEL OPERATION
Figure 3-4: Air/Fuel Valve In Purge Position
Figure 3-5: Blower Proof Switch
Page 40 of 152 PR2: 05/09/12
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Benchmark 1.5LN Low NOx Boiler
Operation and Maintenance Manual
OMM-0041_0D
GF-120
AERCO International, Inc. • 100 Oritani Dr. • Blauvelt, NY 10913 • Ph: 800-526-0288
25
TO BLOWER
AIR IN
DIAL
(DETAIL “A”)
STEPPER
MOTOR
DETAIL “A”
CHAPTER 3: CONTROL PANEL OPERATION
6. Up to 7 seconds will be allowed for ignition to be detected. The igniter relay will be turned
7. After 2 seconds of continuous flame, Flame Proven will be displayed and the flame strength
8. With the unit firing properly, it will be controlled by the temperature controller circuitry. The
Once the demand for heat has been satisfied, the Control Box will turn off the dual SSOV gas
valves. The blower relay will be deactivated and the Air/Fuel Valve will be closed. Standby will
be displayed.
3.10 START/STOP LEVELS
The start and stop levels are the Air/Fuel Valve positions (% open) that start and stop the unit,
based on load. These levels are Factory preset as follows:
Start Level: 20%
Stop Level: 16%
Normally, these settings should not require adjustment.
Figure 3-6: Air/Fuel Valve In Ignition Position
off one second after flame is detected.
will be indicated. After 5 seconds, the current date and time will be displayed in place of the
flame strength.
boiler’s VALVE POSITION will be continuously displayed on the front panel bargraph.
Note that the energy input of the boiler is not linearly related to the Air/Fuel Valve position. Refer
to Table 3-7 for the relationship between the energy input and Air/Fuel Valve position for a unit
running on natural gas.
PR2: 05/09/12 Page 41 of 152
Page 42
Benchmark 1.5LN Low NOx Boiler
Operation and Maintenance Manual
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GF-120
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Air/Fuel Valve
Energy Input
Boiler Energy Input
0% 0 0
10% 0 0
16%
(Stop Level)
75,000
5.0%
20%
157,000
10%
30%
310,000
21%
40%
534,000
36%
50%
783,000
52%
60%
970,000
65%
70%
1,140,000
76%
80%
1,240,000
83%
90%
1,370,000
91%
100%
1,500,000
100%
CHAPTER 3: CONTROL PANEL OPERATION
Relationship Between Air/Fuel Valve Position and Energy Input For Unit
Table 3-7:
Running On Natural Gas
Position (% Open)
(BTU/Hr)
(% of Full Capacity)
Page 42 of 152 PR2: 05/09/12
Page 43
Benchmark 1.5LN Low NOx Boiler
Operation and Maintenance Manual
OMM-0041_0D
GF-120
AERCO International, Inc. • 100 Oritani Dr. • Blauvelt, NY 10913 • Ph: 800-526-0288
CHAPTER 4: INITIAL START-UP
4.1 INITIAL START-UP REQUIREMENTS
The requirements for the initial start-up of the Benchmark 1.5 Boiler consists of the following:
• Complete installation (Chapter 2)
• Set proper controls and limits (Chapter 3)
• Perform combustion calibration (Chapter 4)
• Set up mode of operation (Chapter 5)
• Test safety devices (see Chapter 6)
All applicable Installation procedures in Chapter 2 must be fully completed before performing
initial start-up. The initial start-up must be successfully completed prior to putting the unit into
service. Starting a unit without the proper piping, venting, or electrical systems can be
dangerous and may void the product warranty. The following start-up instructions should be
followed precisely in order to operate the unit safely and at a high thermal efficiency, with low
flue gas emissions.
Initial unit start-up is to be performed ONLY by AERCO factory trained start-up and service
personnel. After performing the start-up procedures in this Chapter, it will be necessary to
perform the Mode of Operation settings in Chapter 5, and the Safety Device Testing procedures
in Chapter 6 to complete all initial start-up requirements.
AERCO Gas Fired Startup Sheets, included with each Benchmark Boiler, must be completed for
each unit for warranty validation. A copy of these sheets must be returned promptly to AERCO
at:
AERCO International, Inc.
159 Paris Ave.
Northvale, NJ 07647
WARNING
DO NOT ATTEMPT TO DRY FIRE THE BOILER.
STARTING THE UNIT WITHOUT A FULL WATER LEVEL
CAN SERIOUSLY DAMAGE THE UNIT AND MAY RESULT
IN INJURY TO PERSONNEL OR PROPERTY DAMAGE.
THIS SITUATION WILL VOID ANY WARRANTY.
All applicable installation procedures in Chapter 2 must be
completed before attempting to start the unit.
4.2 TOOLS AND INSTRUMENTATION FOR COMBUSTION
CALIBRATION
To properly perform combustion calibration, the proper instruments and tools must be used and
correctly attached to the unit. The following paragraphs outline the necessary tools and
instrumentation as well as their installation.
PR2: 05/01/11 Page 43 of 152
Page 44
Benchmark 1.5LN Low NOx Boiler
Operation and Maintenance Manual
OMM-0041_0D
GF-120
AERCO International, Inc. • 100 Oritani Dr. • Blauvelt, NY 10913 • Ph: 800-526-0288
VALVE
SSO
RSI BLEED-
1/4” NPT PLUG
TEST/CALIBRATION)
REGULATOR
1/4” NPT 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" NPT-to-barbed fittings for use with gas supply manometer or gauge.
• Small and large flat blade screwdrivers.
• Tube of silicone adhesive
4.2.2 Installing Gas Supply Manometer
The gas supply manometer (or gauge) is used to calibrate the gas pressure to be monitored on
the downstream side of the SSOV during the Combustion Calibration procedures described in
paragraph 4.4.
The gas supply manometer is installed at the downstream location on the 1/4” NPT port shown
in Figure 4-1. Note that a 1/4” plug must be removed from the port in order to install the
manometer.
MANUAL SHUTOFF VALVE
(INSTALL
MONOMETER HERE
FOR COMBUSTION
CALIBRATION)
RSI
SOLENOID
VALVE
OFF VALVE
TO
AIR/FUEL
(INSTALL
MONOMETER HERE
FOR RSI PRESSURE
RSI
PRESSURE
RSI GAS
VALVE
Figure 4-1: Combustion Calibration & RSI Manometer Installation Locations
Page 44 of 152 PR2: 05/09/12
GAS INLET
Page 45
Benchmark 1.5LN Low NOx Boiler
Operation and Maintenance Manual
OMM-0041_0D
GF-120
AERCO International, Inc. • 100 Oritani Dr. • Blauvelt, NY 10913 • Ph: 800-526-0288
EXHAUST
MANIFOLD
CONDENSATE DRAIN
CONNECTION
VENT PROBE
PORT
UNIT
FRAME
PARTIAL TOP VIEW
Install the 16” W.C. manometer(s) as described in the following steps:
4.2.3 Accessing the Vent Probe Port
The unit contains a NPT plug on the exhaust manifold at the rear of the unit as shown in Figure
4-2. Prepare the port for the combustion analyzer probe as follows:
CHAPTER 4: INITIAL START-UP
1. Turn off the main gas supply upstream of the unit.
2. Remove the top panel and left or right side panel from the boiler to access the gas train
components.
3. Perform the RSI regulator Safe Test as described in paragraph 4.3. If test shows a
successful RSI ignition, proceed to the next step. If RSI ignition is not successful, follow
instructions in paragraph 4.3 before attempting Combustion Calibration.
4. To monitor the gas pressure on the downstream side of the SSOV during Combustion
Calibration (paragraph 4.4), remove the 1/4” NPT plug from the leak detection ball valve
on the downstream side of the SSOV as shown in Figure 4-1.
5. Install a NPT-to-barbed fitting into the tapped plug port.
6. Attach one end of the plastic tubing to the barbed fitting and the other end to the 16”
W.C. manometer.
1. Remove the plug from the probe port on the top of the exhaust manifold.
2. If necessary, adjust the stop on the combustion analyzer probe so that it will extend midway into the flue gas flow. DO NOT install the probe at this time.
Figure 4.2: Analyzer Probe Hole Location
4.3 RSI REGULATOR SAFE TEST
The Benchmark 1.5LN contains a RSI regulator in the Regulated Staged Ignition (RSI) line of
the unit. The RSI regulator is calibrated prior to shipment, however the RSI system should be
safe tested prior to performing the Combustion Calibration Procedure to ensure it is working
properly. RSI regulator safe testing is performed as follows:
PR2: 05/09/12 Page 45 of 152
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Benchmark 1.5LN Low NOx Boiler
Operation and Maintenance Manual
OMM-0041_0D
GF-120
AERCO International, Inc. • 100 Oritani Dr. • Blauvelt, NY 10913 • Ph: 800-526-0288
CHAPTER 4: INITIAL START-UP
1. Close the main gas supply shut-off valve upstream of the unit.
2. Refer to Figure 4.1 and CLOSE the following valves in the unit’s gas train:
• RSI gas valve
• RSI Bleed-off Valve
• Manual shut-off valve to Air/Fuel Valve.
3. OPEN the main gas supply upstream of the unit.
4. Turn ON electrical power to the system.
5. Slowly OPEN the RSI Gas Valve.
6. Turn on the external gas supply to the unit.
7. Slowly open the RSI gas supply valve.
8. Start the boiler in MANUAL Mode.
9. Look into the observation port in the top head (see Figure 4-3) and ensure that you
observe the orange glow of the RSI flame during the ignition trial period.
10. Conduct at least three safe RSI ignitions while looking into the observation port in the top
head. Assure the igniter lights immediately with a strong orange flame after the Staged
Ignition Solenoid Valve opens, and then proceed with the Combustion Calibration
procedure described in Section 4.4.
NOTE
Clear any Flame Loss During Ignition messages during the tests
by pressing The CLEAR key on control panel.
IMPORTANT!
If you do NOT see the orange glow from the RSI ignition in the
observation port, refer to Paragraph 7.4.1.2 to calibrate the RSI
regulator. Do NOT proceed with Combustion Calibration until the
RSI is igniting properly.
Figure 4-3: Observation Port Location
Page 46 of 152 PR2: 05/09/12
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Benchmark 1.5LN Low NOx Boiler
Operation and Maintenance Manual
OMM-0041_0D
GF-120
AERCO International, Inc. • 100 Oritani Dr. • Blauvelt, NY 10913 • Ph: 800-526-0288
BRASS HEX
HEAD CAP
(REMOVE TO
ACCESS GAS
PRESSURE
ADJUSTMENT
SCREW)
SSOV ACTUATOR
CHAPTER 4: INITIAL START-UP
4.4 NATURAL GAS COMBUSTION CALIBRATION
The Benchmark 1.5LN Boiler is combustion calibrated at the factory prior to shipping. However,
recalibration as part of initial start-up is necessary due to changes in the local altitude, gas BTU
content, gas supply piping and supply regulators. Factory Test Data sheets are shipped with
each unit. These sheets must be filled out and returned to AERCO for proper Warranty
Validation.
It is important to perform the following procedure as outlined. This will keep readjustments to a
minimum and provide optimum performance.
1. Open the water supply and return valves to the unit and ensure that the system pumps
are running.
2. Open the natural gas supply valve(s) to the unit.
3. Set the control panel ON/OFF switch to the OFF position.
4. Turn on external AC power to the unit. The display will show LOSS OF POWER and the
time and date.
5. Set the unit to the Manual Mode by pressing the AUTO/MAN key. A flashing Manual
Valve Position message will be displayed with the present rate 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 down-stream of the SSOV is open.
8. Set the ON/OFF switch to the ON position.
9. Change the valve position to 29% using the ▲ arrow key. The unit should begin its start
sequence and fire.
10. Next, verify that the gas pressure downstream of the SSOV is 3” W.C. for both FM and
IRI gas trains. If gas pressure adjustment is required, remove the brass hex nut on the
downstream SSOV actuator (IRI gas train) to access the gas pressure adjustment screw
(Figure 4-4). Make gas pressure adjustments using a flat-tip screwdriver to obtain 3”
W.C.
Figure 4-4: Gas Pressure Adjustment Screw Location
PR2: 05/09/12 Page 47 of 152
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Benchmark 1.5LN Low NOx Boiler
Operation and Maintenance Manual
OMM-0041_0D
GF-120
AERCO International, Inc. • 100 Oritani Dr. • Blauvelt, NY 10913 • Ph: 800-526-0288
Inlet Air
Oxygen
± 0.2
Carbon
e
>100°F
4.8 %
<100 ppm
<30 ppm
90°F
5.0 %
<100 ppm
<30 ppm
80°F
5.2 %
<100 ppm
<30 ppm
<70°F
5.3 %
<100 ppm
<30 ppm
USE 1/2"
WRENCH TO
INCREASE (CW)
OR DECREASE
(CCW) INLET AIR
IRIS
ADJUSTMENT
VIEW A - A
AIR INLET
IRIS AIR
DAMPER
FRONT
A
A
AIR/FUEL
VALVE
CHAPTER 4: INITIAL START-UP
11. Increase the valve open position to 100% and verify that the gas pressure downstream
of the SSOV remains at 3” W.C. Readjust pressure if necessary.
12. With the valve position at 100%, insert the combustion analyzer probe into the flue probe
opening and allow enough time for the combustion analyzer to settle.
13. Compare the measured oxygen level to the oxygen range for the inlet air temperature
shown in Table 4-1. Also, ensure that the carbon monoxide (CO) and nitrogen oxide
(NOx) readings do not exceed the values shown.
Table 4-1: Combustion Oxygen Levels for a 100% Air/Fuel Valve Position
Temp
14. If necessary, adjust the iris air damper shown in Figure 4-5 until the oxygen level is
within the range specified in Table 4-1.
15. Once the oxygen level is within the specified range at 100%, lower the valve position to
80%.
%
Monoxid
NOx
Page 48 of 152 PR2: 05/09/12
Figure 4-5: Iris Air Damper Location/Adjustment
Page 49
Benchmark 1.5LN Low NOx Boiler
Operation and Maintenance Manual
OMM-0041_0D
GF-120
AERCO International, Inc. • 100 Oritani Dr. • Blauvelt, NY 10913 • Ph: 800-526-0288
Oxygen
± 0.2
Carbon
6.0 %
<100 ppm
<30 ppm
CHAPTER 4: INITIAL START-UP
NOTE
The remaining combustion calibration steps are performed using
the Combustion Cal Menu included in the C-More Control System.
The combustion calibration control functions will be used to adjust
the oxygen level (%) at air/fuel valve positions of 80%, 60%, 45%,
30% and 16% as described in the following steps. These steps
assume that the inlet air temperature is within the range of 50°F to
100°F.
16. Press the MENU key on the front panel of the C-MORE and access the Setup menu.
Enter password 6817 and then press the ENTER key.
17. Press the MENU key on the front panel of the C-MORE until Combustion Cal Menu
appears on the C-More display.
18. Press the ▲ arrow key until SET Valve Position appears on the C-MORE display.
19. Press the CHANGE key. SET Valve Position will begin to flash.
20. Press the ▲ arrow key until the SET Valve Position reads 80%. Press the ENTER key.
21. Next, press the down (▼) arrow key until CAL Voltage 80% is displayed.
22. Press the CHANGE key and observe that CAL Voltage 80% is flashing.
23. The oxygen level at the 80% valve position should be as shown below. Also, ensure that
the carbon monoxide (CO) and nitrogen oxide (NOx) readings do not exceed the values
shown.
Table 4-2: Combustion Oxygen Levels for a 80% Air/Fuel Valve Position
%
24. If the oxygen level is not within the specified range, adjust the level using the ▲ and ▼
arrow keys. This will adjust the output voltage to the blower motor as indicated on the
display. Pressing the ▲ arrow key increases the oxygen level and pressing the down ▼
arrow key decreases the oxygen level.
25. Once the oxygen level is within the specified range at 80%, press the ENTER key to
store the selected blower output voltage for the 80% valve position.
The remaining steps basically repeat the procedures in steps 18
through 25 for valve positions of 60%, 45%, 30% and 16%.
However, since oxygen levels vary, these steps are repeated in
their entirety. When performing these steps, also ensure that the
carbon monoxide (CO) and nitrogen oxide (NOx) readings do not
exceed the values shown for each valve position.
26. Press the ▲ arrow key until SET Valve Position appears on the C-MORE display.
Monoxide NOx
NOTE
27. Press the CHANGE key. SET Valve Position will begin to flash.
28. Press the ▼ arrow key until the SET Valve Position reads 60% and press the ENTER
key.
PR2: 05/09/12 Page 49 of 152
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Benchmark 1.5LN Low NOx Boiler
Operation and Maintenance Manual
OMM-0041_0D
GF-120
AERCO International, Inc. • 100 Oritani Dr. • Blauvelt, NY 10913 • Ph: 800-526-0288
Oxygen
± 0.2
Carbon
6.3 %
<50 ppm
<30 ppm
Oxyge
Carbo
ide
7.0 %
<50 ppm
<30 ppm
CHAPTER 4: INITIAL START-UP
29. Press the down ▼ arrow key until CAL Voltage 60% is displayed.
30. Press the CHANGE key. CAL Voltage 60% will begin to flash.
31. The oxygen level at the 60% valve position should be as shown below. Also, ensure that
the carbon monoxide (CO) and nitrogen oxide (NOx) readings do not exceed the values
shown.
Table 4-3: Combustion Oxygen Levels for a 60% Air/Fuel Valve Position
%
32. If the oxygen level is not within the specified range, adjust the level using the ▲ and ▼
arrow keys. This will adjust the output voltage to the blower motor as indicated on the
display. Pressing the ▲ arrow key increases the oxygen level and pressing the ▼ arrow
key decreases the oxygen level.
33. Once the oxygen level is within the specified range at 60%, press the ENTER key to
store the selected blower output voltage for the 60% valve position.
34. Press the ▲ arrow key until SET Valve Position appears on the C-MORE display.
35. Press the CHANGE key. SET Valve Position will begin to flash.
36. Press the ▼ arrow key until the SET Valve Position reads 45%, then press the ENTER
key.
37. Press the ▼ arrow key until CAL Voltage 45% is displayed.
38. Press the CHANGE key. CAL Voltage 45% will begin to flash.
39. The oxygen level at the 45% valve position should be as shown below. Also, ensure that
the carbon monoxide (CO) and nitrogen oxide (NOx) readings do not exceed the values
shown.
Monoxide NOx
Table 4-4: Combustion Oxygen Levels for a 45% Air/Fuel Valve Position
n %
± 0.2
Monox
40. If the oxygen level is not within the specified range, adjust the level using the ▲ and ▼
arrow keys. This will adjust the output voltage to the blower motor as indicated on the
display. Pressing the ▲ arrow key increases the oxygen level and pressing the ▼ arrow
key decreases the oxygen level.
41. Once the oxygen level is within the specified range at 45%, press the ENTER key to
store the selected blower output voltage for the 45% valve position.
42. Press the ▲ arrow key until SET Valve Position appears on the C-MORE display.
43. Press the CHANGE key. SET Valve Position will begin to flash.
44. Press the ▼ arrow key until the SET Valve Position reads 30%, then press the ENTER
key.
Page 50 of 152 PR2: 05/09/12
n
NOx
Page 51
Benchmark 1.5LN Low NOx Boiler
Operation and Maintenance Manual
OMM-0041_0D
GF-120
AERCO International, Inc. • 100 Oritani Dr. • Blauvelt, NY 10913 • Ph: 800-526-0288
Oxygen
± 0.2
Carbon
7.0 %
<50 ppm
<30 ppm
Oxygen
± 0.2
Carbon
8.0 %
<50 ppm
<30 ppm
CHAPTER 4: INITIAL START-UP
45. Press the ▼ arrow key until CAL Voltage 30% is displayed.
46. Press the CHANGE key. CAL Voltage 30% will begin to flash.
47. The oxygen level at the 30% valve position should be as shown below. Also, ensure that
the carbon monoxide (CO) and nitrogen oxide (NOx) readings do not exceed the values
shown.
Table 4-5: Combustion Oxygen Levels for a 30% Air/Fuel Valve Position
%
48. If the oxygen level is not within the specified range, adjust the level using the ▲ and ▼
arrow keys. This will adjust the output voltage to the blower motor as indicated on the
display. Pressing the ▲ arrow key increases the oxygen level and pressing the ▼ arrow
key decreases the oxygen level.
49. Once the oxygen level is within the specified range at 30%, press the ENTER key to
store the selected blower output voltage for the 30% valve position.
50. Press the ▲ arrow key until SET Valve Position appears on the C-MORE display.
51. Press the CHANGE key. SET Valve Position will begin to flash.
52. Press the ▼ arrow key until the SET Valve Position reads 16%, then press the ENTER
key.
53. Press the ▼ arrow key until CAL Voltage 16% is displayed.
54. Press the CHANGE key. CAL Voltage 16% will begin to flash.
55. The oxygen level at the 16% valve position should be as shown below. Also, ensure that
the carbon monoxide (CO) and nitrogen oxide (NOx) readings do not exceed the values
shown.
Monoxide NOx
Table 4-1: Combustion Oxygen Levels for a 16% Air/Fuel Valve Position
%
Monoxide NOx
56. If the oxygen level is not within the specified range, adjust the level using the ▲ and ▼
arrow keys. This will adjust the output voltage to the blower motor as indicated on the
display. Pressing the ▲ arrow key increases the oxygen level and pressing the ▼ arrow
key decreases the oxygen level.
57. Once the oxygen level is within the specified range at 16%, press the ENTER key to
store the selected blower output voltage for the 16% valve position.
58. This completes the natural gas combustion calibration procedure.
4.5 UNIT REASSEMBLY
Once the combustion calibration adjustments are properly set, the unit can be reassembled for
service operation.
1. Set the ON/OFF switch in the OFF position.
PR2: 05/09/12 Page 51 of 152
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Benchmark 1.5LN Low NOx Boiler
Operation and Maintenance Manual
OMM-0041_0D
GF-120
AERCO International, Inc. • 100 Oritani Dr. • Blauvelt, NY 10913 • Ph: 800-526-0288
FRONT VIEW
ADJUSTABLE
TEMPERATURE
LIMIT SWITCH
RESET BUTTON
FOR MANUAL
TEMPERATURE
LIMIT SWITCH
SEE
DETAIL “A”
DETAIL “A”
CHAPTER 4: INITIAL START-UP
2. Disconnect AC power from the unit.
3. Shut off the gas supply to the unit.
4. Remove the manometer and barbed fittings and reinstall the NPT plug using a suitable
pipe thread compound.
5. Remove the combustion analyzer probe from the vent hole. Replace the NPT plug in
the vent hole using a suitable pipe joint compound.
6. Replace the unit’s side panels and front door.
4.6 OVER-TEMPERATURE LIMIT SWITCHES
The unit contains both automatic and manual reset over-temperature limit switches. These
switches are mounted on a plate as shown in Figure 4-6. The switches can be accessed by
opening the front panel door of the unit. The manual reset switch is not adjustable and is
permanently fixed at 200°F. This switch will shut down and lock out the boiler if the water
temperature exceeds 200°F. Following an over-temperature condition, it must be manually reset
by pressing the RESET button before the boiler can be restarted. The automatic reset overtemperature switch is adjustable and allows the boiler to restart, once the temperature drops
below its temperature setting. Set the automatic over-temperature switch to the desired setting.
Figure 4-6 Over-Temperature Limit Switch Locations
Page 52 of 152 PR2: 05/09/12
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Benchmark 1.5LN Low NOx Boiler
Operation and Maintenance Manual
OMM-0041_0D
GF-120
AERCO International, Inc. • 100 Oritani Dr. • Blauvelt, NY 10913 • Ph: 800-526-0288
CHAPTER 5: MODE OF OPERATION
5.1 INTRODUCTION
The boiler is capable of being operated in any one of six different modes. The following
paragraphs in this Chapter provide descriptions of each of these operating modes. Each boiler
is shipped from the factory tested and configured for the ordered mode of operation. All
temperature related parameters are at their factory default values which work well in most
applications. However, it may be necessary to change certain parameters to customize the unit
to the system environment. A complete listing and descriptions of the temperature related
parameters are included in Appendix A. Factory defaults are listed in Appendix E. After reading
this chapter, parameters can be customized to suit the needs of the specific application.
5.2 INDOOR/OUTDOOR RESET MODE
This mode of operation is based on outside air temperatures. As the outside air temperature
decreases, the supply header temperature will increase and vice versa. For this mode, it is
necessary to install an outside air sensor as well as select a building reference temperature and
a reset ratio.
Reset Ratio 5.2.1
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.
Building Reference Temperature 5.2.2
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.
Outdoor Air Temperature Sensor Installation 5.2.3
The outdoor air temperature sensor must be mounted on the North side of the building in an
area where the average outside air temperature is expected. The sensor must be shielded from
the sun's direct rays, as well as direct impingement by the elements. If a cover or shield is used,
it must allow free air circulation. The sensor may be mounted up to two hundred feet from the
unit. Sensor connections are made at the Input/Output (I/O) Box on the front of the boiler.
Connections are made at the terminals labeled OUTDOOR SENSOR IN and SENSOR
COMMON inside the I/O Box. Use shielded 18 to 22 AWG wire for connections. A wiring
diagram is provided on the cover of the I/O Box. Refer to Chapter 2, paragraph 2.9.1 for
additional wiring information.
Indoor/ Outdoor Startup 5.2.4
Startup in the Indoor/Outdoor Reset Mode is accomplished as follows:
1. Refer to the Indoor/Outdoor reset ratio charts in Appendix D.
2. Choose the chart corresponding to the desired Building Reference Temperature.
3. Go down the left column of the chart to the coldest design outdoor air temperature expected
in your area.
PR2: 05/01/11 Page 53 of 152
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Benchmark 1.5LN Low NOx Boiler
Operation and Maintenance Manual
OMM-0041_0D
GF-120
AERCO International, Inc. • 100 Oritani Dr. • Blauvelt, NY 10913 • Ph: 800-526-0288
MENU OPTION
SETTING
CHAPTER 5: MODE OF OPERATION
NOTE
A design engineer typically provides design outdoor air
temperature and supply header temperature data.
4. Once the design outdoor air temperature is chosen, go across the chart to the desired
supply header temperature for the design temperature chosen in step 3.
5. Next, go up that column to the Reset Ratio row to find the corresponding reset ratio.
6. Access the Configuration Menu and scroll through it until the display shows Bldg Ref Temp.
(Building Reference Temperature).
7. Press the CHANGE key. The display will begin to flash.
8. Use the ▲ and ▼ arrow keys to select the desired Building Reference Temperature.
9. Press ENTER to save any changes.
10. Next, scroll through the Configuration Menu until the display shows Reset Ratio.
11. Press the CHANGE key. The display will begin to flash.
12. Use the ▲ and ▼ arrow keys to select the Reset Ratio determined in step 5.
13. Press ENTER to save the change.
Refer to paragraph 3.3 for detailed instructions on menu changing.
5.3 CONSTANT SETPOINT MODE
The Constant Setpoint mode is used when a fixed header temperature is desired. Common
uses of this mode of operation include water source heat pump loops, and indirect heat
exchangers for potable hot water systems or processes.
No external sensors are required to operate in this mode. While it is necessary to set the
desired setpoint temperature, it is not necessary to change any other temperature-related
functions. The unit is factory preset with settings that work well in most applications. Prior to
changing any temperature-related parameters, other than the setpoint, it is suggested that an
AERCO representative be contacted. For descriptions of temperature-related functions and their
factory defaults, see Appendices A and E.
Setting the Setpoint 5.3.1
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:
Boiler Mode Constant Setpoint
Internal Setpt Select desired setpoint
using ▲ and ▼ arrow
keys (40°F to 240°F)
Refer to paragraph 3.3 for detailed instructions on changing menu options.
Page 54 of 152 PR2: 05/09/12
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Benchmark 1.5LN Low NOx Boiler
Operation and Maintenance Manual
OMM-0041_0D
GF-120
AERCO International, Inc. • 100 Oritani Dr. • Blauvelt, NY 10913 • Ph: 800-526-0288
MENU OPTION
SETTING
CHAPTER 5: MODE OF OPERATION
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 change the unit's
setpoint. The 4 mA/1V signal is equal to a 40°F setpoint while a 20 mA /5V signal is equal to a
240°F setpoint. When a 0 to 20 mA/0 to 5 Vdc signal is used, 0 mA is equal to a 40°F setpoint.
In addition to the current and voltage signals described above, the Remote Setpoint mode can
also driven by a RS485 Modbus Network signal from an EMS or BAS.
The Remote Setpoint modes of operation can be used to drive single as well as multiple units.
NOTE
If a voltage, rather than current signal is used to control the
remote setpoint, a DIP switch adjustment must be made on the
CPU Board located in the Control Panel Assembly. Contact your
local AERCO representative for details.
In order to enable the Remote Setpoint Mode, the following menu setting must be made in the
Configuration Menu:
Boiler Mode Remote Setpoint
Remote Signal 4-20mA/1-5V,
0-20mA/0-5V, or
Network
Refer to paragraph 3.3 for detailed instructions on changing menu options.
If the Network setting is selected for RS485 Modbus operation, a valid Comm Address must be
entered in the Setup Menu. Refer to Modbus Communication Manual GF-114 for additional
information.
While it is possible to change the settings of temperature related functions, the unit is factory
preset with settings that work well in most applications. It is suggested that an AERCO
representative be contacted, prior to changing any temperature related function settings. For
descriptions of temperature-related functions and their factory defaults, refer to Appendices A
and E.
Remote Setpoint Field Wiring 5.4.1
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 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
PR2: 05/09/12 Page 55 of 152
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Benchmark 1.5LN Low NOx Boiler
Operation and Maintenance Manual
OMM-0041_0D
GF-120
AERCO International, Inc. • 100 Oritani Dr. • Blauvelt, NY 10913 • Ph: 800-526-0288
CHAPTER 5: MODE OF OPERATION
multiple units, each unit’s wiring must conform to the above.
Remote Setpoint Startup 5.4.2
Since this mode of operation is factory preset and the setpoint is being externally controlled, no
startup instructions are necessary. In this 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 this setting, a 4
to 20 mA signal, sent by an EMS or BAS is used to change the unit’s valve position from 0% to
100%. A 4 mA/1V signal is equal to a 0% valve position, while a 20 mA /5V 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
driven by a RS485 Modbus Network signal from an EMS or BAS.
When in a Direct Drive mode, the unit is a slave to the EMS or BAS and does not have a role in
temperature control. Direct Drive can be used to drive single, or multiple units.
NOTE
If a voltage, rather than current signal is used to control the
remote setpoint, a DIP switch adjustment must be made on the
CPU Board located in the Control Box Assembly. Contact your
local AERCO representative for details.
To enable the Direct Drive Mode, the following menu setting must be made in the Configuration
Menu:
MENU OPTION SETTING
Boiler Mode Direct Drive
Remote Signal 4-20mA/1-5V,
0-20mA/0-5V, or
Network
Refer to paragraph 3.3 for instructions on changing menu options.
If the Network setting is selected for RS485 Modbus operation, a valid Comm Address must be
entered in the Setup Menu. Refer to Modbus Communication Manual GF-114 for additional
information.
Direct Drive Field Wiring 5.5.1
The only wiring connections necessary for Direct Drive mode are connection of the remote
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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.
CHAPTER 5: MODE OF OPERATION
Direct Drive Startup 5.5.2
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 light.
To change back to the Direct Drive mode, simply press the AUTO/MAN switch. The REMOTE
LED will again light and the MANUAL LED will go off.
5.6 BOILER MANAGEMENT SYSTEM (BMS)
NOTE
BMS Model 168 can utilize either pulse width modulation (PWM)
or RS485 Modbus signaling to the Boiler. BMS II Model 5R5-384
can utilize only RS485 signaling to the Boiler.
The BMS mode of operation is used in conjunction with an AERCO Boiler Management System.
The BMS mode is used when it is desired to operate multiple units in the most efficient manner
possible. For this mode of operation, a BMS Header Sensor must be installed between 2 and 10
feet downstream of the LAST boiler in the boiler plant's supply water header. The BMS can
control up to 40 boilers; 8 via pulse width modulation (PWM) and up to 32 via Modbus (RS485)
network communication. For BMS programming, operation, and Header Sensor installation
details, see GF-108M (BMS Model 168) and GF-124 (BMS II Model 5R5-384), BMS Operations
Guides. For operation via an RS485 Modbus network, refer to Modbus Communication Manual
GF-114.
To enable the BMS Mode, the following menu settings must be made in the Configuration
Menu:
MENU OPTION SETTING
Boiler Mode Direct Drive
Remote Signal BMS (PWM Input)
or
Network (RS485)
Refer to paragraph 3.3 for instructions on changing menu options.
BMS External Field Wiring 5.6.1
Wiring connections for BMS control using PWM signaling are made between connector JP2 on
the BMS panel (boilers 1 through 8), and the B.M.S. (PWM) IN terminals in the I/O Box on the
front of the boilers. Refer to the wiring diagram provided on the cover of the I/O Box.
Wiring connections for RS485 Modbus control are made between connector JP11 on the BMS
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CHAPTER 5: MODE OF OPERATION
(boilers 9 through 40) and the RS485 COMM terminals in the I/O Box on the front of the boilers.
Wire the units using shielded twisted pair wire between 18 and 22 AWG. Observe the proper
polarity for the B.M.S. (PWM) IN and/or RS485 COMM wiring connections. Shields should be
terminated only at the BMS and the boiler end must be left floating. Each unit’s wiring must
conform to the above.
BMS Setup and Startup 5.6.2
This mode of operation is factory preset and the AERCO BMS 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 light
To change back to the BMS mode, simply press the AUTO/MAN switch. The REMOTE LED
will again light and the MANUAL LED will go off.
5.7 COMBINATION CONTROL SYSTEM (CCS)
NOTE
Only BMS Model 168 can be utilized for the Combination Mode,
not the BMS II (Model 5R5-384).
A Combination Control System (CCS) is one that uses multiple boilers to cover both spaceheating and domestic hot water needs. An AERCO Boiler Management System (BMS) Model
168 and a Combination Control Panel (CCP) are necessary to configure this system. Typically,
an adequate number of boilers are installed to cover the space-heating load on the design day,
however one or more units are used for the domestic hot water load.
The theory behind this type of system is that the maximum space-heating load and the
maximum domestic hot water load do not occur simultaneously.+ Therefore, boilers used for the
domestic hot water are capable of switching between constant setpoint and BMS modes of
operation. These boilers are the combination units and are referred to as the combo boilers. The
combo boilers heat water to a constant setpoint temperature. That water is then circulated
through a heat exchanger in a domestic hot water storage tank.
When the space-heating load is such that all the space-heating boilers are at the 100% valve
position, the BMS will then ask the Combination Control Panel 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 CCP switches the
combo units back to the domestic load.
When the combo units are satisfying the domestic load they are in constant setpoint mode of
operation. When the combo units switch over to space heating, their mode of operation changes
to the BMS mode. For more information concerning the operation of the Combination Control
Panel see the AERCO CCP-1 literature.
Combination Control System Field Wiring 5.7.1
Wiring for this system is between the BMS Model 168 panel, the CCP and the B.M.S. (PWM) IN
terminals in the I/O Box. 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. For a complete CCP
system-wiring diagram see the AERCO CCP-1 literature.
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AERCO International, Inc. • 100 Oritani Dr. • Blauvelt, NY 10913 • Ph: 800-526-0288
CHAPTER 5: MODE OF OPERATION
Combination Control System Setup and Startup 5.7.2
Setup for the Combination Mode requires entries to be made in the Configuration Menu for
boiler mode, remote signal type and setpoint. The setpoint is adjustable from 40°F to 240°F.
Enter the following settings in the Configuration Menu:
MENU OPTION SETTING
Boiler Mode Combination
Remote Signal BMS (PWM Input)
Internal Setpt 40°F to 240°F
Refer to paragraph 3.3 for instructions on changing menu options.
While it is possible to change other temperature-related functions for combination mode, thes
functions are preset to their factory default values. These default settings work well in most
applications. It is suggested that AERCO be contacted prior to changing settings other 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, press the AUTO/MAN switch. The MANUAL LED will go
off and the REMOTE LED will light.
When the boiler is switched to BMS mode, the AERCO BMS controls the valve position. There
are no setup requirements to the boiler(s) in this mode.
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CHAPTER 5: MODE OF OPERATION
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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 THIS SYSTEM MAY INCLUDE 120
AND 24 VOLTS AC. POWER MUST BE REMOVED PRIOR TO
PERFORMING WIRE REMOVAL OR OTHER TEST
PROCEDURES THAT CAN RESULT IN ELECTRICAL SHOCK.
6.2 LOW GAS PRESSURE FAULT TEST
Refer to Figure 6-1 and ensure that the leak detection ball valve located at the high gas
pressure switch is closed.
1. Remove the 1/4“ plug from the ball valve at the low gas pressure switch shown in the lower
portion of Figure 6-1.
2. Install a 0 – 16 “ W.C. manometer or a W.C. gauge where the 1/4" plug was removed.
3. Slowly open the ball valve near the low gas pressure switch.
4. Place the unit in Manual Mode and adjust the air/fuel valve position (% open) between 25
and 30%.
5. While the unit is firing, slowly close the external manual gas shut-off valve.
6. The unit should shut down and display a LOW GAS PRESSURE fault message at
approximately 2.6” W.C. The FAULT indicator should also start flashing.
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VALVE
SSO
RSI BLEED-
1/4” NPT PLUG
TEST/CALIBRATION)
REGULATOR
HIGH GAS
SWITCH
1/4” NPT PLUG
PRESSURE TEST)
1/4” NPT PLUG
PRESSURE TEST)
CHAPTER 6: SAFETY DEVICE TESTING
PRESSURE
HIGH GAS BALL
VALVE
MANUAL SHUTOFF VALVE
(INSTALL
MONOMETER HERE
FOR HIGH GAS
RSI
SOLENOID
VALVE
(INSTALL
MONOMETER HERE
FOR RSI PRESSURE
RSI
PRESSURE
RSI GAS
VALVE
OFF VALVE
TO
AIR/FUEL
LOW GAS
PRESSURE
SWITCH
(INSTALL
MONOMETER HERE
FOR LOW GAS
GAS INLET
Figure 6-1: Low & High Gas Pressure Testing
7. Fully open the external manual gas shut-off valve and press the CLEAR button on the
Control Box.
8. The fault message should clear and the FAULT indicator should go off. The unit should
restart.
9. Upon test completion, close the ball valve and remove the manometer. Replace the 1/4“
plug removed in step 1.
6.3 HIGH GAS PRESSURE TEST
To simulate a high gas pressure fault, refer to Figure 6-1 and proceed as follows:
1. Remove the 1/4“ plug from the leak detection ball valve shown in Figure 6-1.
2. Install a 0 – 16” W.C. manometer (or W.C. gauge) where the 1/4” plug was removed.
3. Slowly open the leak detection ball valve
4. Start the unit in Manual mode at a valve position (firing rate) between 25 and 30%.
5. Slowly increase the gas pressure using the adjustment screw on the SSOV.
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6. The unit should shut down and display a HIGH GAS PRESSURE fault message when the
7. Reduce the gas pressure back to 3.0” W.C.
8. Press the CLEAR button on the Control Box to clear the fault.
9. The fault message should clear and the FAULT indicator should go off. The unit should
10.
CHAPTER 6: SAFETY DEVICE TESTING
gas pressure exceeds 4.7” W.C. The FAULT indicator should also start flashing.
restart.
Upon test completion, close the ball valve and remove the manometer. Replace the
1/4“ plug removed in step 1.
6.4 LOW WATER LEVEL FAULT TEST
To simulate a low water level fault:
1. Set the ON/OFF switch to the OFF position
2. Close the water shut-off valves in the supply and return piping to the unit.
3. Slowly open the drain valve on the rear of the unit. If necessary the unit’s relief valve may
be opened to aid in draining.
4. Continue draining the unit until a LOW WATER LEVEL fault message is displayed and the
FAULT indicator flashes.
5. Place the unit in the Manual Mode and raise the valve position above 30%.
6. Set the ON/OFF switch to the ON position. The READY light should remain off and the unit
should not start. If the unit does start, shut the unit off immediately and refer fault to
qualified service personnel.
7. Close the drain and pressure relief valve used in draining the unit.
8. Open the water shut-off valve in the return piping to the unit.
9. Open the water supply shut-off valve to the unit to refill.
10. After the shell is full, press the LOW WATER LEVEL RESET button to reset the low water
cutoff.
11. Press the CLEAR button to reset the FAULT LED and clear the displayed error message.
12. Set the ON/OFF switch to the ON position. The unit is now ready for operation.
6.5 WATER TEMPERATURE FAULT TEST
A high water temperature fault is simulated by adjusting the automatic over-temperature switch.
This switch is accessible from the front of the unit as shown in Figure 6-2.
1. Start the unit in the normal operating mode. Allow the unit to stabilize at its setpoint.
2. Lower the adjustable over-temperature switch setting to match the displayed OUTLET
TEMPERATURE.
3. Once the adjustable over-temperature switch setting is approximately at, or just below, the
actual outlet water temperature, the unit should shut down. The FAULT indicator should
start flashing and a HIGH WATER TEMP SWITCH OPEN fault message should be
displayed. It should not be possible to restart the unit.
4. Reset the adjustable over-temperature switch to its original setting.
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FRONT VIEW
ADJUSTABLE
TEMPERATURE
LIMIT SWITCH
RESET BUTTON
FOR MANUAL
TEMPERATURE
LIMIT SWITCH
SEE
DETAIL “A”
DETAIL “A”
CHAPTER 6: SAFETY DEVICE TESTING
5. The unit should start once the adjustable temperature limit switch setting is above the actual
outlet water temperature.
Figure 6-2: Temperature Limit Switch Setting
6. Once the adjustable over-temperature switch setting is approximately at, or just below, the
actual outlet water temperature, the unit should shut down. The FAULT indicator should
start flashing and a HIGH WATER TEMP SWITCH OPEN fault message should be
displayed. It should not be possible to restart the unit.
7. Reset the adjustable over-temperature switch to its original setting.
8. The unit should start once the adjustable temperature limit switch setting is above the actual
outlet water temperature.
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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 2-9) and are
labeled REMOTE INTL’K IN and DELAYED INTL’K IN. These circuits can shut down the unit in
the event that an interlock is opened. These interlocks are shipped from the factory jumpered
(closed). However, each of these interlocks may be utilized in the field as a remote stop and
start, an emergency cut-off, or to prove that a device such as a pump, gas booster, or louver is
operational.
REMOTE INTERLOCK 6.6.1
1. Remove the cover from the I/O Box and locate the REMOTE INTL’K IN terminals.
2. Start the unit in the Manual Mode and set the valve position between 25% and 30%.
3. If there is a jumper across the REMOTE INTL’K IN terminals, remove one side of the
jumper. If the interlock is being controlled by an external device, either open the interlock
via the external device or disconnect one of the wires leading to the external device.
4. The unit should shut down and display INTERLOCK OPEN.
5. Once the interlock connection is reconnected, the INTERLOCK OPEN message should
automatically clear and the unit should restart.
DELAYED INTERLOCK 6.6.2
1. Remove the cover from the I/O Box and locate the DELAYED INTL’K IN terminals.
2. Start the unit in the Manual Mode at a valve position between 25% and 30%.
3. If there is a jumper across the DELAYED INTL’K IN terminals, remove one side of the
jumper. If the interlock is connected to a proving switch of an external device, disconnect
one of the wires leading to the proving switch.
4. The unit should shut down and display a DELAYED INTERLOCK OPEN fault message.
The FAULT LED should be flashing.
5. Reconnect the wire or jumper removed in step 3 to restore the interlock.
6. Press the CLEAR button to reset the fault
7. The unit should start.
6.7 FLAME FAULT TESTS
Flame faults can occur during ignition or while the unit is already running. To simulate each of
these fault conditions, proceed as follows:
1. Set the ON/OFF switch to the OFF position.
2. Place the unit in the Manual Mode and set the valve position between 25% and 30%.
3. Close the manual gas shutoff valve located between the Safety Shut-Off Valve (SSOV) and
the Air/Fuel Valve (see Figure 6-3).
4. Set the ON/OFF switch to the ON position to start the unit.
5. The unit should shut down after reaching the Ignition cycle and display FLAME LOSS
DURING IGN.
6. Open the valve previously closed in step 3 and press the CLEAR button.
7. Restart the unit and allow it to prove flame.
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PARTIAL LEFT SIDE VIEW
BLOWER
PROOF
SWITCH
BLOCKED
INLET
SWITCH
AIR
INLET
AIR/FUEL
VALVE
SSOV
MANUAL
GAS
SHUTOFF
VALVE
CHAPTER 6: SAFETY DEVICE TESTING
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.
Figure 6-3: Manual Gas Shut-Off Valve Location
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CHAPTER 6: SAFETY DEVICE TESTING
6.8 AIR FLOW FAULT TESTS
These tests check the operation of the Blower Proof Switch and Blocked Inlet Switch shown in
Figure 6-3.
1. Disable the blower output drive voltage as follows:
(a)
Press the MENU key until CONFIGUR-ATION MENU is displayed.
(b) Press the ▲ arrow key until the ANA-LOG OUTPUT 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 execute an IGNITION RETRY cycle by performing the
following steps:
(a)
The unit will execute a 30 second re-ignition delay and display WAIT RETRY PAUSE.
(b) The unit will then execute a standard ignition sequence and display WAIT IGNITION RETRY.
4. The unit should perform one IGNITION RETRY cycle and then shut down, since the blower
is disabled. The unit will then display AIRFLOW FAULT DURING PURGE.
5. Re-enable the blower output drive voltage by performing the following steps:
(a)
Press the MENU key until CONFIGUR-ATION MENU is displayed.
(b) Press the ▲ arrow key until the ANA-LOG OUTPUT function is displayed, then press the
CHANGE key.
(c) Press the ▲ arrow key until VALVE POSITION 0-10V is displayed, then press the ENTER key.
6. Once the unit has proved flame, turn off the blower by going to the Configuration Menu,
Analog Output menu item and select OFF.
7. The Blower Proof Switch will open and the blower should stop. The unit should shut down
and display AIRFLOW FAULT DURING RUN.
8. Go to the Configuration Menu, Analog Output item and select VALVE POSITION 0-10v.
9. Press the CLEAR button. The unit should restart.
10. Next, check the Blocked Inlet Switch by first noting the current position of the Iris Air
Damper and then closing the Damper to position 8.
11. .The unit should shut down and again display AIRFLOW FAULT DURING RUN.
12. Return the Iris Air Damper to its previous setting.
13. Press the CLEAR button. The unit should restart.
6.9 SSOV PROOF OF CLOSURE SWITCH
The SSOV shown in Figure 6-1 contains the proof of closure switch. The proof of closure switch
circuit is checked as follows:
1. Set the unit’s ON/OFF switch to the OFF position.
2. Place the unit in Manual Mode and set the valve position between 25% and 30%
3. Refer to Figure 6-1 and locate the SSOV.
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ACTUATOR
COVER
SCREW
SSOV
ACTUATOR
COVER
CHAPTER 6: SAFETY DEVICE TESTING
4. Remove the cover from the SSOV by loosening the screw shown in Figure 6-4. Lift off the
cover to access the terminal wiring connections.
5. Disconnect wire #148 from the SSOV to “open” the proof of closure switch circuit.
6. The unit should fault and display SSOV SWITCH OPEN.
7. Replace wire #148 and press the CLEAR button.
8. Set the ON/OFF switch to ON to start the unit.
9. Remove the wire again when the unit reaches the purge cycle and PURGING is displayed.
10. The unit should shut down and display SSOV FAULT DURING PURGE.
11. Replace the wire on the SSOV and press the CLEAR button. The unit should restart.
Figure 6-4: SSOV Actuator Cover Location
6.10 PURGE SWITCH OPEN DURING PURGE
The Purge Switch (and Ignition Switch) is located on the Air/Fuel Valve. To check the switch,
proceed as follows:
1. Set the unit’s ON/OFF switch to the OFF position. Place the unit in manual mode and set the
valve position between 25% and 30%.
2. Remove the Air/Fuel Valve cover by rotating the cover counterclockwise to unlock it and
then lift up (see Figure 6-5).
3. Remove one of the two wires (#171 or #172) from the Purge Switch (Figure 6-6).
4. Initiate a unit start sequence.
5. The unit should begin it’s start sequence, then shut down and display PRG SWITCH OPEN
DURING PURGE.
6. Replace the wire on the Purge Switch and depress the CLEAR button. The unit should
restart.
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AIR/FUEL VALVE COVER
(ROTATE CCW TO REMOVE)
CHAPTER 6: SAFETY DEVICE TESTING
6.11 IGNITION SWITCH OPEN DURING IGNITION
The Ignition Switch (and the Purge Switch) is located on the Air/Fuel Valve. To check the
switch, proceed as follows:
1. Set the unit’s ON/OFF switch to the OFF position.
2. Place the unit in Manual Mode and set the valve position between 25% and 30%.
3. Remove the Air/Fuel Valve cover (Figure 6-5) by rotating the cover counterclockwise to
unlock and lift up to remove.
4. Remove one of the two wires (#169 or #170) from the Ignition Switch (Figure 6-6).
5. Initiate a unit start sequence.
6. The unit should begin its start sequence and then shut down and display IGN SWITCH
OPEN DURING IGNITION.
7. Replace the wire on the Ignition Switch and press the CLEAR button. The unit should
restart.
Figure 6-5: Air/Fuel Valve Cover Location
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AERCO International, Inc. • 100 Oritani Dr. • Blauvelt, NY 10913 • Ph: 800-526-0288
STEPPER
MOTOR
DIAL
172
171
169
170
IGNITION
POSITION
SWITCH
PURGE
POSITION
SWITCH
AIR
IN
TO
BLOWER
CHAPTER 6: SAFETY DEVICE TESTING
Figure 6-6: Air/Fuel Valve Purge and Ignition Switch Locations
6.12 SAFETY PRESSURE RELIEF VALVE TEST
Test the safety Pressure Relief Valve in accordance with ASME Boiler and Pressure Vessel
Code, Section VI.
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OMM-0041_0D
GF-120
AERCO International, Inc. • 100 Oritani Dr. • Blauvelt, NY 10913 • Ph: 800-526-0288
Labor
Time
7.2
Igniter-Injector (58023)
*Inspect
Inspect
Replace
15 mins.
7.3
Flame Detector (66006)
*Inspect
Inspect
Replace
15 mins.
Combustion Calibration
Adjustment
See CSD-1
Appendix I
7.6
Burner
Inspect
2 hrs.
Inspect &
Clean
CHAPTER 7: MAINTENANCE
7.1 MAINTENANCE SCHEDULE
The unit requires regular routine maintenance to keep up efficiency and reliability. For best
operation and life of the unit, the following routine maintenance procedures should be performed
in the time periods specified in Table 7-1. See Appendix I for a complete CSD-1 inspection
check list.
In order to perform the maintenance tasks specified in Table 7-1, the following maintenance kits
are available through your local AERCO Sales Representative:
• Annual Maintenance Kit, Part No. 58025-01
• 24-Month Waterside/Fireside Inspection Kit, Part No. 58025-05 (See NOTE below)
NOTE
The 24-Month Waterside/Fireside Inspection Kit also
includes the items contained in the Annual Maintenance
Kit. Therefore, only Kit Part No. 58025-05 is required
when performing the waterside/fireside inspections.
Appendix K contains recommended spare parts lists for maintenance of the boiler.
WARNING
TO AVOID PERSONAL INJURY, PRIOR TO SERVICING
ENSURE THAT THE FOLLOWING GUIDELINES ARE STRICTLY
OBSERVED:
• DISCONNECT THE AC SUPPLY BY TURNING OFF THE
SERVICE SWITCH AND AC SUPPLY CIRCUIT BREAKER.
• SHUT OFF THE GAS SUPPLY AT THE MANUAL SHUT-
OFF VALVE PROVIDED WITH THE UNIT
• ALLOW THE UNIT TO COOL TO A SAFE WATER
TEMPERATURE TO PREVENT BURNING OR SCALDING
Table 7-1: Maintenance Schedule
Paragraph Item 6 Mos. 12 Mos. 24 Mos.
7.4
& RSI Regulator
*Check Check 1 hr.
7.5
Testing of Safety
Devices
7.7 Condensate Drain Trap *Inspect
*Only performed after initial 6 month period after initial startup.
PR2: 05/01/11 Page 71 of 152
Chart in
20 mins.
30 mins.
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Benchmark 1.5LN Low NOx Boiler
Operation and Maintenance Manual
OMM-0041_0D
GF-120
AERCO International, Inc. • 100 Oritani Dr. • Blauvelt, NY 10913 • Ph: 800-526-0288
AIR/FUEL
VALVE
STAGED
IGNITION
ASSEMBLY
FLAME
DETECTOR
IGNITOR-
INJECTOR
BLOWER
BURNER
PLATE
BURNER
CHAPTER 7: MAINTENANCE
7.2 IGNITER-INJECTOR
The igniter-injector (part no. 58023) is located on the burner plate at the top of the boiler. In
addition to providing the ignition spark required to light the burner, the igniter-injector also
contains a gas injector tube which connects to the staged ignition assembly. Figure 7-1 shows
the complete burner assembly removed from the boiler and indicates the location of the igniterinjector flame detector and other related components.
The igniter-injector may be hot, therefore, care should be exercised to avoid burns. It is easier to
remove the igniter-injector from the unit after the unit has cooled to room temperature.
Figure 7-1: Benchmark 1.5LN Burner Assembly (Shown Removed from Boiler)
To inspect/replace the Igniter:
1. Set the ON/OFF switch on the control panel, to the OFF position. Disconnect AC power
from the unit
2. Remove the side and top panels from the unit.
3. Disconnect the cable from the igniter-injector (Figure 7-1).
4. Refer to the partial exploded view in Figure 7-2. Using a 7/16” open-end wrench, disconnect
Page 72 of 152 PR2: 05/09/12
the compression nut securing the gas injector tube of the igniter-injector to the elbow of the
staged ignition assembly. Disconnect the staged ignition assembly from the igniter-injector.
Page 73
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Operation and Maintenance Manual
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STAGED
IGNITION
ASSEMBLY
FLAME
DETECTOR
IGNITOR-
INJECTOR
BURNER
PLATE
COMPRESSION
FITTING & ELBOW
FLAME
DETECTOR
GASKET
INDEXING
WASHERS
(QTY = 0-3
AS REQ’D)
120
IGNITOR-
INJECTOR
GAS
INJECTOR
TUBE
BLOWER
BURNER
PLATE
CHAPTER 7: MAINTENANCE
Figure 7-2
Igniter-Injector & Flame Detector Mounting Details
5. Next, loosen and remove the igniter-injector from the burner plate using a 1" open-end
wrench.
6. Check the igniter-injector for evidence of erosion or carbon build-up. If there is evidence of
substantial erosion or carbon build-up, the igniter-injector should be replaced. If carbon
build-up is present, clean the component using fine emery cloth. Repeated carbon build-up
is an indication that the combustion settings of the unit should be checked. Refer to Chapter
4 for combustion calibration procedures.
7. Prior to reinstalling the igniter-injector, a high temperature, conductive, anti-seize compound
must be applied to the threads.
NOTE
If a replacement igniter-injector (part no. 58023) is being
installed, a compression nut containing a built-in ferrule
will be included with the replacement part. If needed, 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.
Figure 7-3: Igniter-Injector Orientation
PR2: 05/09/12 Page 73 of 152
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Benchmark 1.5LN Low NOx Boiler
Operation and Maintenance Manual
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AERCO International, Inc. • 100 Oritani Dr. • Blauvelt, NY 10913 • Ph: 800-526-0288
CHAPTER 7: MAINTENANCE
8. Reinstall the igniter-injector in the burner plate. Torque to 15 ft-lbs. Do not over tighten.
9. Connect the staged ignition assembly to the gas injector tube of the igniter-injector by
securing the compression nut to the elbow of the staged ignition assembly.
10. Reconnect the igniter-injector cable.
11. Reinstall the side and top panels on the unit.
7.3 FLAME DETECTOR
The flame detector (part no. 66006) is located on the burner plate at the top of the unit (see
Figures 7-1 and 7-2). The flame detector may be hot. Allow the unit to cool sufficiently before
removing the flame detector.
To inspect or replace the flame detector:
1. Set the ON/OFF switch on the control panel, to the OFF position. Disconnect AC power from
the unit.
2. Remove the side and top panels from the unit.
3. Disconnect the flame detector lead wire.
4. Remove the two (2) screws securing the flame detector to the plate (Figure 7-2 on previous
page). 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. Thoroughly inspect the flame detector. If eroded, the detector should be replaced.
Otherwise clean the detector with a fine emery cloth.
7. Reinstall the flame detector and flame detector gasket.
8. Reconnect the flame detector lead wire.
9. Reinstall the side and top panels on the unit.
7.4 COMBUSTION CALIBRATION & RSI REGULATOR ADJUSTMENT
The Combustion Calibration settings and RSI Regulator adjustment must be checked at the
intervals shown in Table 7-1 as part of the maintenance requirements. Refer to Chapter 4 for
combustion calibration instructions. Refer to paragraph 7.4.1, below, for RSI regulator test and
calibration instructions.
RSI Regulator Pressure 7.4.1
The BMK1.5LN unit has a RSI (Regulated Staged Ignition) system in the gas train that should
be pressure tested annually. If the pressure is above 5.0” w.c. or below 3.0” w.c., then the RSI
pressure regulator must be recalibrated per paragraph 7.4.1.2.
RSI Regulator Pressure Test 7.4.1.1
The RSI regulator test is performed as follows:
1. Ensure that gas supply shut-off valve upstream of the unit is still turned OFF.
2. Turn OFF electrical power to the system.
3. CLOSE the following valves in the unit’s gas train (refer to Figure 7-4):
• RSI Gas Supply Valve
• RSI Bleed-off Valve
• Manual Shut-off Valve (between the Air/Fuel Valve and the SSOV).
Page 74 of 152 PR2: 05/09/12
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Benchmark 1.5LN Low NOx Boiler
Operation and Maintenance Manual
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4. Remove the pipe plug from the 1/4” NPT port on the outlet side of the RSI regulator and
5. Attach one end of the plastic tubing to the barbed fitting and the other end to the 16” W.C.
6. Remove the cap from the RSI Pressure Regulator and rotate the regulator adjustment
7. OPEN the main gas supply upstream of the unit.
8. Turn ON electrical power to the system.
9. Slowly OPEN the RSI Gas Supply Valve and observe the reading on the manometer. It
10. Start the boiler in MANUAL Mode. Observe the manometer pressure when the RSI solenoid
CHAPTER 7: MAINTENANCE
insert a NPT-to-barbed adapter fitting (see Figure 7-4).
manometer.
(beneath cap) counterclockwise (CCW) to its lowest possible pressure setting that will allow
the cap to be installed.
should have a reading of less than 8.0” w.c.
“clicks” open after purge. It should now provide a reading of less than 5.0” w.c., but not less
than 3.0” w.c..
11. Look into the observation port in the top head and ensure that you observe the orange glow
of the RSI flame during the ignition trial period.
12. If the pressure is within specifications, return the unit to service. Make sure that the unit is
operating in AUTO Mode. The “MAN” light in the upper left of the control box should NOT
be lit when in AUTO Mode.
13. If the RSI regulator is NOT within specifications, proceed to paragraph 7.4.1.2, RSI
Regulator Calibration, and initiate the pressure calibration procedures
RSI Regulator Calibration 7.4.1.2
RSI regulator calibration is performed as follows:
1. Ensure that gas supply shut-off valve upstream of the unit is still turned OFF.
2. Turn OFF electrical power to the system.
3. CLOSE the following valves in the unit’s gas train (refer to Figure 7-4):
• RSI Gas Supply Valve
• RSI Bleed-off Valve
• Manual Shut-off Valve (between the Air/Fuel Valve and the SSOV).
4. Remove the pipe plug from the 1/4” NPT port on the outlet side of the RSI regulator, insert
NPT-to-barbed adapter fitting, and insert tube from the 16” w.c. manometer.
5. Remove the cap from the RSI Pressure Regulator and rotate the regulator adjustment
(beneath cap) counter-clockwise (CCW) to its lowest possible pressure setting that will
allow the cap to be installed.
6. OPEN the main gas supply upstream of the unit.
7. Turn ON electrical power to the system.
8. Slowly OPEN the RSI Gas Supply Valve and observe the reading on the manometer. It
should have a reading of less than 8.0” w.c.
9. Start the boiler in MANUAL Mode. Observe the manometer pressure when the RSI solenoid
“clicks” open after purge. The manometer should now provide a reading of less than 5.0”
w.c.
PR2: 05/09/12 Page 75 of 152
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Benchmark 1.5LN Low NOx Boiler
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CHAPTER 7: MAINTENANCE
10. Look into the observation port in the top head and ensure that you observe the orange glow
of the RSI flame during the ignition trial period.
NOTE
If you don’t see the orange glow, contact AERCO technical
support to ascertain the problem. If you DO see it, proceed to
the next step.
11. If the manometer reading is less than 3.0” w.c., increase the regulator setting by rotating the
adjustment screw clockwise (CW).
12. Repeat steps 8 through 11 until the gas pressure at the outlet of the RSI regulator reads
between 3.0” w.c. and 4.0” w.c. on the monometer.
13. Once the pressure reading is between 3.0” w.c. and 4.0” w.c., conduct at least three safe
RSI ignitions while observing the observation port. Assure the igniter lights immediately with
a strong orange flame after the Staged Ignition Solenoid Valve opens.
NOTE
Clear any Flame Loss During Ignition messages during the
tests by pressing The CLEAR key on control panel.
14. Close the external gas supply and RSI Staged Ignition Gas Valves. Disconnect the
manometer, tubing and barbed fitting from the 1/4” NPT port hole.
15. Bleed off any remaining pressure using the RSI bleed-off valve, then ensure this valve is
closed.
16. Replace the 1/4” plug in place of the barbed fitting.
17. OPEN the gas supply upstream of the unit.
18. Ensure power is restored and Boiler turned on in MANUAL Mode.
19. Open the Manual Shut-off Gas Valve (to the Air/Fuel Valve) and assure a smooth light off.
Perform this test three times.
20. Leak test the RSI line after the first solenoid valve.
21. Refer to paragraph 4.4 in Initial Start-up to perform the Combustion Calibration.
22. Return the unit to service. Make sure that the unit is operating in AUTO Mode. The “MAN”
light in the upper left of the control box should NOT be lit in AUTO Mode.
Page 76 of 152 PR2: 05/09/12
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Benchmark 1.5LN Low NOx Boiler
Operation and Maintenance Manual
OMM-0041_0D
GF-120
AERCO International, Inc. • 100 Oritani Dr. • Blauvelt, NY 10913 • Ph: 800-526-0288
Part No.
Description
81063
Burner Gaskets (Qty=2)
81048
Flame Detector Gasket
81064
Blower Gasket
CHAPTER 7: MAINTENANCE
Figure 7-4: RSI Manometer Installation Location
7.5 SAFETY DEVICE TESTING
Systematic and thorough tests of the operating and safety devices should be performed to
ensure that they are operating as designed. Certain code requirements, such as ASME CSD-1,
require that these tests be performed on a scheduled basis. Test schedules must conform to
local jurisdictions. The results of the tests should be recorded in a log book. See Chapter 6Safety Device Testing Procedures.
7.6 BURNER ASSEMBLY INSPECTION
The burner assembly (part no. 24012) is located at the top of the unit's heat exchanger. The
burner assembly may be hot. Therefore, allow the unit to cool sufficiently before removing the
burner assembly. It should be noted that the complete burner assembly also includes the blower
and air/fuel valve assemblies for the unit.
The following parts will be required for reassembly after burner inspection:
To inspect or replace the burner assembly:
1. Set the ON/OFF switch on the control panel, to the OFF position. Disconnect AC power from
the unit and turn off the gas supply.
PR2: 05/09/12 Page 77 of 152
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Benchmark 1.5LN Low NOx Boiler
Operation and Maintenance Manual
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BLOWER
PROOF
SWITCH
BURNER
PLATE
BLOWER
IGNITER-
INJECTOR
HOSE
CLAMP
FLAME
DETECTOR
STAGED
IGNITION
ASSEMBLY
3/8-16
HEX NUTS
(8)
1/2" BOLTS
& NUTS (4)
AIR/FUEL
VALVE
BLOCKED
INLET
SWITCH
10-32 x 1 /2" LG
GROUNDING
SCREW
CHAPTER 7: MAINTENANCE
2. Remove the side and top panels from the unit.
3. Disconnect the lead wire from the flame detector installed on the burner plate. See Figure
7-4.
Figure 7-4: Burner Assembly Mounting Details
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
(Figures 7-4 & 7-5).
11. Remove the 10-32 x 1/2" long. grounding screw from the burner plate (Figures 7-4 and 7-
5).
12. Disconnect the gas train from the air/fuel valve by removing the four (4) 1/2” bolts and nuts
(Figure 7-4).
13. Disconnect the flex hose from the air/fuel valve by loosening the hose clamp.
Page 78 of 152 PR2: 05/09/12
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Benchmark 1.5LN Low NOx Boiler
Operation and Maintenance Manual
OMM-0041_0D
GF-120
AERCO International, Inc. • 100 Oritani Dr. • Blauvelt, NY 10913 • Ph: 800-526-0288
AIR/FUEL
VALVE
BLOWER
IGNITOR-
INJECTOR
FLAME
DETECTOR
STAGED IGNITION
ASSEMBLY
BURNER GASKET
BURNER GASKET
BURNER
HEX HEAD SCREWS (4)
BLOWER
GASKET
BURNER
PLATE
BLOWER
PROOF
SWITCH
BLOCKED
INLET
SWITCH
GROUNDING
SCREW
14. Remove the four (4) 5/16-18 hex head screws securing the blower to the burner plate
15. Remove the blower and air/fuel valve from the burner plate by lifting straight up. Also,
16. Remove the eight (8) 3/8-16 nuts from the burner flange (Figure 7-4) using a 9/16” wrench.
17. Remove the burner assembly from burner flange by pulling straight up.
18. Remove and replace the two (2) burner gaskets.
CHAPTER 7: MAINTENANCE
(Figure 7-5).
remove the blower gasket.
NOTE
The burner assembly is heavy, weighing approximately
25 pounds.
NOTE
During reassembly, apply high-temperature, anti-seize
lubricant to the threads of the igniter-injector and
grounding screw. Also, ensure that the igniter-injector is
properly positioned as indicated in Figure 7-3. Torque the
igniter-injector to 15 ft-lbs.
19. Beginning with the burner assembly removed in step 17, reinstall all the components in the
reverse order that they were removed.
20. Ensure that the igniter-injector and flame detector cutouts in the burner plate are properly
aligned with the heat exchanger top flange.
PR2: 05/09/12 Page 79 of 152
Figure 7-4: Burner Assembly Exploded View
Page 80
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Operation and Maintenance Manual
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CHAPTER 7: MAINTENANCE
7.7 CONDENSATE DRAIN TRAP
The Benchmark 1.5 Boiler contains a condensate trap as shown in Chapter 2, Figure 2-5. The
trap is located external to the unit and attached to the drain pipe from the exhaust manifold. This
trap should be inspected and, if necessary, cleaned to ensure proper operation.
NOTE
There are two slightly different types of condensate traps that may
be used in your configuration; an older style without an inlet
adapter, and a newer style with a built-in adapter (see Figure 7.5).
Maintenance is the same, except that the newer style does not
need an orifice gasket (Step 6).
To inspect and clean the trap, proceed as follows:
1. Disconnect the external condensate trap by loosening the union pipe connection between
the trap and the exhaust manifold drain pipe.
2. Remove the connections on the inlet and outlet sides of the condensate trap shown in
Figure 7-5.
3. Loosen the four (4) thumbscrews securing the cover on the condensate trap. Remove the
cover.
4. Remove the float from the condensate trap.
5. Remove the orifice gasket from the trap.
6. Thoroughly clean the trap, float and gasket. Also inspect the drain piping for blockage. If the
trap cannot be thoroughly cleaned, replace the trap.
7. After the above items have been inspected and thoroughly cleaned, replace the orifice
gasket and float in the condensate trap and replace the trap cover.
8. Reassemble all piping and hose connections to the condensate trap inlet and outlet.
Reconnect trap to exhaust manifold drain.
Figure 7-5: External Condensate Trap
Page 80 of 152 PR2: 05/09/12
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Benchmark 1.5LN Low NOx Boiler
Operation and Maintenance Manual
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AERCO International, Inc. • 100 Oritani Dr. • Blauvelt, NY 10913 • Ph: 800-526-0288
CHAPTER 7: MAINTENANCE
7.8 SHUTTING THE BOILER DOWN FOR AN EXTENDED PERIOD OF
TIME
If the boiler is to be taken out of service for an extended period of time (one year or more), the
following instructions must be followed.
1. Set ON/OFF switch on the front panel to the OFF position to shut down the boiler’s
operating controls.
2. Disconnect AC power from the unit.
3. Close the water supply and return valves to isolate boiler.
4. Close external gas supply valve.
5. Open relief valve to vent water pressure.
7.9 PLACING THE BOILER BACK IN SERVICE AFTER A PROLONGED
SHUTDOWN
After a prolonged shutdown (one year or more), the following procedures must be followed:
1. Review installation requirements included in Chapter 2.
2. Inspect all piping and connections to the unit.
3. Inspect exhaust vent, air duct (if applicable).
4. Perform initial startup per Chapter 4.
5. Perform safety device testing and scheduled maintenance procedures per Chapters 6 and 7
of this manual.
PR2: 05/09/12 Page 81 of 152
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CHAPTER 7: MAINTENANCE
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Benchmark 1.5LN Low NOx Boiler
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AERCO International, Inc. • 100 Oritani Dr. • Blauvelt, NY 10913 • Ph: 800-526-0288
CHAPTER 8: TROUBLESHOOTING GUIDE
8.1 INTRODUCTION
This troubleshooting guide is intended to aid service/maintenance personnel in isolating the
cause of a fault in a Benchmark 1.5 Boiler. The troubleshooting procedures contained herein
are presented in tabular form on the following pages. These tables are comprised of three
columns labeled: Fault Indication, Probable Cause and Corrective Action. The numbered items
in the Probable Cause and Corrective Action columns correspond to each other. For example,
Probable Cause No. 1 corresponds to Corrective Action No. 1, etc.
NOTE
The front panel of the C-More Control Box contains an RS232 port
which can be interfaced to a laptop computer or other suitable
device. This RS232 communication feature permits service
personnel to view menu items and data logs which can be useful
in isolating faults. Refer to Chapter 9 of this manual for detailed
RS232 communication set-up and procedures.
When a fault occurs in the Benchmark Boiler, proceed as follows to isolate and correct the fault:
1. Observe the fault messages displayed in the Control Box display.
2. Refer to the Fault Indication column in Troubleshooting Table 8-1 which follows and locate
the Fault that best describes the existing conditions.
3. Proceed to the Probable Cause column and start with the first item (1) listed for the Fault
Indication.
4. Perform the checks and procedures listed in the Corrective Action column for the first
Probable Cause candidate.
5. Continue checking each additional Probable Cause for the existing fault until the fault is
corrected.
6. Paragraph 8.2 and Table 8-2 contain additional troubleshooting information which may apply
when no fault message is displayed.
7. If the fault cannot be corrected using the information provided in the Troubleshooting
Tables, contact your local AERCO Representative.
PR2: 05/01/11 Page 83 of 152
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Benchmark 1.5LN Low NOx Boiler
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AERCO International, Inc. • 100 Oritani Dr. • Blauvelt, NY 10913 • Ph: 800-526-0288
INDICATION
1. Blower stopped running due to thermal or
1. Check combustion blower for signs of excessive heat or high
FAULT
TABLE 8-1. BOILER TROUBLESHOOTING
PROBABLE CAUSES CORRECTIVE ACTION
current overload
2. Blocked Blower inlet or inlet ductwork
3. Blocked Blower proof switch
4. Blocked blocked-air inlet switch
AIRFLOW FAULT
DURING IGNITION
5. Defective Blower proof switch
6. Defective blocked-air inlet switch
7. Loose temperature to AUX connection in I/O
Box
8. Defective temperature sensor
9. Loose wire connection between the 0-10V
signal from I/O box to the Blower Motor
input.
10. Defective I/O box
11. Wrong 0-10V output selection on the
control box
12. Defective Air-Fuel Valve potentiometer
current drain that may trip thermal or current overload devices.
2. Inspect the inlet to the combustion blower including any ductwork
leading up to the combustion blower for signs of blockage.
3. Remove the Blower proof switch and inspect for signs of blockage,
clean or replace as necessary.
4. Remove the blocked-air inlet switch and inspect for signs of
blockage, clean or replace as necessary.
5. Measure the Blower proof switch for continuity with the
combustion blower running. If there is an erratic resistance reading
or the resistance reading is greater than zero ohms, replace the
switch.
6. Measure the blocked-air inlet switch for continuity with the
combustion blower running. If there is an erratic resistance reading
or the resistance reading is greater than zero ohms, replace the
switch.
7. Check the actual inlet air temperature and measure voltage at
AUX input in the I/O Box. Verify that the voltage conforms to the
values shown in the tabular listing provided in Appendix C.
8. Refer to CORRECTIVE ACTION 7 and verify that the voltage
conforms to the values shown in Appendix C.
9. Check wire connection from I/O Box 0-10V signal to the Blower
Motor.
10. Measure voltage at the I/O box 0-10V output. A voltage of 8.2V
equates to a 100% open valve position.
11. Check the Analog Out option on the C-More Configuration Menu.
Valve Position 0-10V should be selected.
12. Check Air/Fuel Valve position at 0%, 50% and 100% open
positions. The positions on the VALVE POSITION bargraph
should match the dial readings on the Air/Fuel Valve dial.
PR2: 05/01/11 Page 84 of 152
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Benchmark 1.5LN Low NOx Boiler
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FAULT INDICATION
PROBABLE CAUSES
CORRECTIVE ACTION
state relay for input and output voltage. If the relay is okay,
Start the unit. If the blower runs, check the airflow switch for
ow switch and inspect for signs of blockage,
Inspect the inlet to the combustion blower including any
ductwork leading up to the combustion blower for signs of
switch to ground. If 24VAC is not present refer to qualified
Check combustion blower for signs of excessive heat or high
Inspect the inlet to the combustion blower including any
ductwork leading up to the combustion blower for signs of
Remove the airflow switch and inspect for signs of blockage,
Measure the airflow switch for continuity with the combustion
blower running. If there is an erratic resistance reading or the
bles or runs rough, perform
CHAPTER 7: MAINTENANCE
TABLE 8-1. BOILER TROUBLESHOOTING (Continued)
1. Blower not running or running too slow
2. Defective Air Flow Switch
3. Blocked Air flow Switch
AIRFLOW FAULT
DURING PURGE
AIRFLOW FAULT
DURING RUN
4. Blocked Blower inlet or inlet ductwork.
5. No voltage to switch from control box.
6. PROBABLE CAUSES from 3 to 16 for
AIRFLOW FAULT DURING IGNITION
applies for this fault
1. Blower stopped running due to thermal
or current overload
2. Blocked Blower inlet or inlet ductwork
3. Blocked airflow switch
4. Defective airflow switch
5. Combustion oscillations
6. PROBABLE CAUSES from 3 to 16 for
AIRFLOW FAULT DURING IGNITION
applies for this fault
1. Start the unit. If the blower does not run check the blower solid
check the blower.
2.
continuity. Replace the switch if there is no continuity.
3. Remove the air fl
clean or replace as necessary.
4.
blockage.
5. Measure for 24 VAC during start sequence from each side of the
service personnel.
6. See CORRECTIVE ACTIONS from 3 to 16 for AIRFLOW
FAULT DURING IGNITION.
1.
current draw that may trip thermal or current overload devices.
2.
blockage.
3.
clean or replace as necessary.
4.
resistance reading is greater than zero ohms, replace the switch.
5. Run unit to full fire. If the unit rum
combustion calibration.
6. See CORRECTIVE ACTIONS from 3 to 16 for AIRFLOW
FAULT DURING IGNITION.
PR2: 05/09/12 Page 85 of 152
Page 86
Benchmark 1.5LN Low NOx Boiler
Operation and Maintenance Manual
OMM-0041_0D
GF-120
AERCO International, Inc. • 100 Oritani Dr. • Blauvelt, NY 10913 • Ph: 800-526-0288
INDICATION
1. Check for a jumper properly installed across the delayed interlock
functional. (jumper may be temporarily installed to test interlock)
(voltage or current).
Configuration Menu.
CHAPTER 7: MAINTENANCE
FAULT
TABLE 8-1. BOILER TROUBLESHOOTING (Continued)
PROBABLE CAUSES CORRECTIVE ACTION
1. Delayed Interlock Jumper not installed or
removed.
DELAYED
INTERLOCK OPEN
DIRECT DRIVE
SIGNAL FAULT
FLAME LOSS
DURING IGN
2. Device proving switch hooked to
interlocks is not closed
1. Direct drive signal is not present:
Not yet installed.
Wrong polarity.
Signal defective at source.
Broken or loose wiring.
2. Signal is not isolated (floating).
3. Control Box signal type selection
switches not set for correct signal type
1. Burner Ground Screw not installed or
loose.
2. Worn flame detector
3. No spark from Spark Plug
4. Defective Ignition Transformer
5. Defective Ignition/Stepper (IGST) Board
6. Defective SSOV
7. RSI Regulator not properly adjusted.
8. Closed RSI Gas Valve in RSI line.
terminals in the I/O box.
2. If there are 2 external wires on these terminals, check to see if an
end switch for a device such as a pump, louver, etc. is tied these
interlocks. Ensure that the device and or its end switch are
1. Check I/O Box to ensure signal is hooked up.
Hook up if not installed.
If installed, check polarity.
Measure signal level.
Check continuity of wiring between source and boiler.
2. Check signal at source to ensure it is isolated.
3. Check DIP switch on PMC board to ensure it is set correctly for the
type of signal being sent. Check control signal type set in
1. Inspect and install/retighten Burner Ground Screw.
2. Remove and inspect the flame detector for signs of wear. Replace
if necessary.
3. Close the internal gas valve in the boiler. Install and arc a spark
ignitor outside the unit.
4. If there is no spark, check for 120VAC at the primary side to the
ignition transformer during the ignition cycle.
5. If 120VAC is not present, the IGST Board in the Control Box may
be defective. Refer fault to qualified service personnel.
6. While externally arcing the spark ignitor, observe the open/close
indicator in the Safety Shut-Off Valve to ensure it is opening. If the
valve does not open, check for 120VAC at the valves input
terminals. If 120VAC is not present, the IGST board in the Control
Box may be defective. Refer fault to qualified service personnel.
7. Refer to Chapter 7, paragraph 7.4 and check the RSI Regulator
calibration. The RSI regulator output should be between 3.0” W.C.
and 5.0” W.C.
8. Check position of RSI Gas Valve (Figure 8-1).
Page 86 of 152 PR2: 05/09/12
Page 87
Benchmark 1.5LN Low NOx Boiler
Operation and Maintenance Manual
OMM-0041_0D
GF-120
AERCO International, Inc. • 100 Oritani Dr. • Blauvelt, NY 10913 • Ph: 800-526-0288
FAULT INDICATION
PROBABLE CAUSES
CORRECTIVE ACTION
2030:
any carbon or debris.
1. Measure the actual exhaust temperature and continuity of the
CHAPTER 7: MAINTENANCE
TABLE 8-1. BOILER TROUBLESHOOTING (Continued)
FLAME LOSS
DURING IGN
(continued)
FLAME LOSS
DURING RUN
HEAT DEMAND
FAILURE
9. Unstable gas pressure.
10. Carbon or other debris on Burner.
11. Staged ignition solenoid valves
don’t open.
12. Clogged staged ignition piece.
1. Worn Flame Detector or cracked
ceramic.
2. Defective Regulator.
3. Poor combustion calibration.
4. Debris on burner.
5. Blocked condensate drain.
1. The Heat Demand Relays on the
Ignition/Stepper board failed to
activate when commanded.
2. Relay is activated when not in
Demand
9. Refer to “Gas Pressure Requirements” section of GFBMK Gas Supply Design Guide.
10. Remove the burner and inspect for
Clean and reinstall.
11. When boiler goes to ignition, listen to the solenoid valves for
a clicking sound to ensure they are opening.
12. Remove and inspect staged ignition piece for blockage.
1. Remove and inspect the Flame Detector for signs of wear or
cracked ceramic. Replace if necessary.
2. Check gas pressure readings using a gauge or manometer into
and out of the Air/Fuel Valve to ensure that the gas pressure
into and out of the valve is correct.
3. Check combustion calibration. Adjust as necessary.
4. Remove the burner and inspect for any carbon or debris. Clean
and reinstall.
5. Remove blockage in condensate drain.
1. Press CLEAR button and restart the unit. If the fault persists,
replace Ignition/Stepper (IGST) Board.
2. Defective relay. Replace IGST Board.
1. Defective exhaust sensor.
HIGH EXHAUST
TEMPERATURE
PR2: 05/09/12 Page 87 of 152
2. Carboned heat exchanger due to
incorrect combustion calibration
exhaust sensor. If the exhaust temperature is less than 475
F and the exhaust sensor shows continuity replace the
sensor.
2. If exhaust temperature is greater than 500o F, check
combustion calibration. Calibrate or repair as necessary.
o
Page 88
Benchmark 1.5LN Low NOx Boiler
Operation and Maintenance Manual
OMM-0041_0D
GF-120
AERCO International, Inc. • 100 Oritani Dr. • Blauvelt, NY 10913 • Ph: 800-526-0288
INDICATION
CHAPTER 7: MAINTENANCE
FAULT
TABLE 8-1. BOILER TROUBLESHOOTING (Continued)
PROBABLE CAUSES CORRECTIVE ACTION
HIGH GAS
PRESSURE
HIGH WATER
TEMP
SWITCH OPEN
1. Incorrect supply gas pressure.
2. Defective SSOV Actuator.
3. Defective High Gas Pressure Switch
4. Gas pressure snubber not installed.
1. Faulty Water temperature switch.
2. Incorrect PID settings.
3. Faulty shell temperature sensor.
4. Unit in Manual mode
5. Unit setpoint is greater than Over Temperature
Switch setpoint.
6. Boiler Management System PID or other
settings not correctly setup.
7. No interlock to boiler or BMS to disable
boiler(s) in event that system pumps have
failed.
8. System flow rate changes are occurring faster
than boilers can respond.
1. Check to ensure gas pressure at inlet of SSOV is 2 psig maximum.
2. If gas supply pressure downstream of SSOV Actuator cannot be
lowered, to 1.5” W.C. using the gas pressure adjustment screw
(see para. 4.3, step 10), the SSOV Actuator may be defective.
3. Remove the leads from the high gas pressure switch and measure
continuity across the common and normally closed terminals with
the unit not firing. Replace the switch if it does not show continuity.
4. See Figure 8-1. Ensure that the gas pressure snubber is installed
at the high gas pressure switch.
1. Test the temperature switch to insure it trips at its actual water
temperature setting.
2. Check PID settings against Menu Default settings in the Appendix.
If the settings have been changed, record the current readings then
reset them to the default values.
3. Using the resistance charts in the Appendix C, Measure the
resistance of Shell sensor and BTU sensor at a known water
temperature.
4. If unit is in Manual Mode switch to Auto Mode.
5. Check setpoint of unit and setpoint of Temperature Switch; Ensure
that the temperature switch is set higher than the unit’s setpoint.
6. Check the BMS for changes to PID default values, correct as
necessary.
7. If system pump is controlled by Energy Management System other
than BMS or pumps are individually controlled by boiler, check to
see if there are flow switches interlocked to the BMS or boiler.
8. If the system is a variable flow system, monitor system flow
changes to ensure that the rate of flow change is not faster than
what the boilers can respond to.
HIGH WATER
TEMPERATURE
Page 88 of 152 PR2: 05/09/12
1. See HIGH WATER TEMPERATURE SWITCH OPEN.
2. Temp HI Limit setting is too low.
1. See HIGH WATER TEMPERATURE SWITCH OPEN.
2. Check Temp HI Limit setting.
Page 89
Benchmark 1.5LN Low NOx Boiler
Operation and Maintenance Manual
OMM-0041_0D
GF-120
AERCO International, Inc. • 100 Oritani Dr. • Blauvelt, NY 10913 • Ph: 800-526-0288
FAULT INDICATION
PROBABLE CAUSES
CORRECTIVE ACTION
Air/Fuel Valve should rotate to the purge
(open) position, then back to ignition position (towards closed)
during the ignition cycle. If the valve does not rotate back to the
ignition position, check the Air/Fuel Valve calibration. If
the problem may be in the Air/Fuel Valve or
CHAPTER 7: MAINTENANCE
TABLE 8-1. BOILER TROUBLESHOOTING (Continued)
IGN BOARD
COMM FAULT
IGN SWTCH CLOSED
DURING PURGE
IGN SWTCH OPEN
DURING IGNITION
1. Communication fault has occurred
between the PMC board and
Ignition/Stepper (IGST) board
1. Air/Fuel Valve not rotating
2. Defective or shorted switch
3. Switch wired incorrectly
4. Defective Power Supply Board or
fuse
5. Defective IGST Board
1. Air/Fuel Valve not rotating to
ignition position.
2. Defective ignition switch
3. Defective Power Supply Board or
fuse
4. Defective IGST Board
1. Press CLEAR button and restart unit. If fault persists, contact
qualified Service Personnel.
1. Start the unit. The Air/Fuel Valve should rotate to the purge
(open) position. If the valve does not rotate at all or does not
rotate fully open, check the Air/Fuel Valve calibration. If
calibration is okay, the problem may be in the Air-Fuel Valve or
the Control Box. Refer to qualified service personnel
2. . If the Air/Fuel Valve does rotate to purge, check the ignition
switch for continuity between the N.O. and COM terminals. If the
switch shows continuity when not in contact with the cam replace
the switch.
3. Check to ensure that the switch is wired correctly (correct wire
numbers on the normally open terminals). If the switch is wired
correctly, replace the switch
4. Check DS1 & DS2 LEDs on Power Supply Board. If they are not
steady ON, replace Power Supply Board.
5. Check “Heartbeat” LED DS1 and verify it is blinking ON & OFF
every second. If not, replace IGST Board.
1. Start the unit. The
calibration is okay,
the Control Box. Refer fault to qualified service personnel.
2. If the Air/Fuel Valve does rotate to the ignition position, check the
ignition position switch for continuity between the N.O. and COM
terminals when in contact with the cam.
3. Check DS1 & DS2 LEDs on Power Supply Board. If they are not
steady ON, replace Power Supply Board.
4. Check “Heartbeat” LED DS1 and verify it is blinking ON & OFF
every second. If not, replace IGST Board.
PR2: 05/09/12 Page 89 of 152
Page 90
Benchmark 1.5LN Low NOx Boiler
Operation and Maintenance Manual
OMM-0041_0D
GF-120
AERCO International, Inc. • 100 Oritani Dr. • Blauvelt, NY 10913 • Ph: 800-526-0288
INDICATION
1. Interlock jumper not installed or
wiring.
continuity.
FAULT
Boiler not seeing information from
Start the unit. The Air/Fuel Valve should rotate to the purge (open)
cycle. If the valve does not rotate back to the ignition position, check the
ation. If calibration is okay, the problem may be in
the Air/Fuel Valve or the Control Box. Refer fault to qualified service
personnel.
CHAPTER 7: MAINTENANCE
FAULT
TABLE 8-1. BOILER TROUBLESHOOTING (Continued)
PROBABLE CAUSES CORRECTIVE ACTION
INTERLOCK
OPEN
LINE
VOLTAGE
OUT OF
PHASE
LOW GAS
PRESSURE
LOW WATER
LEVEL
removed
2. Energy Management System does not
have boiler enabled.
3. Device proving switch hooked to
interlocks is not closed.
1. Line and Neutral switched in AC
Power Box.
2. Incorrect power supply transformer
1. Incorrect supply gas pressure.
2. Defective Low Pressure Gas Switch
1. Insufficient water level in system
2. Defective water level circuitry.
3. Defective water level probe.
1. Check for a jumper properly installed across the interlock terminals in the
I/O box
2. If there are two external wires on these terminals check any Energy
Management system to see if they have the units disabled (a jumper may
be temporarily installed to see if the interlock circuit is functioning).
3. Check that proving switch for any device hooked to the interlock circuit is
closing and that the device is operational.
1. Check hot and neutral in AC Power Box to ensure they are not reversed
2. Check transformer wiring, in AC Power Box, against the power box
transformer wiring diagram to ensure it is wired correctly
1. Measure gas pressure upstream of the SSOV Actuator(s) with the unit
firing. For FM gas trains, ensure it is between 4.0” W.C. and 2 psig. For
IRI gas trains, ensure it is between 4.2" W.C. and 2 psig (see para.
2.7.1).
2. Measure gas pressure at the low gas pressure switch. If it is greater than
2.6” W.C., measure continuity across the switch and replace if necessary.
1. Check system for sufficient water level.
2. Test water level circuitry using the Control Box front panel LOW WATER
TEST and RESET buttons. Replace water level circuitry if it does not
respond.
3. Check continuity of probe end to the shell, change probe if there is no
MODBUS
COMM
PRG SWTCH
CLOSED
DURING
IGNITION
Page 90 of 152 PR2: 05/09/12
1.
Modbus network
1. A/F Valve rotated open to purge and
did not rotate to ignition position.
1. Check network connections. If fault persists, contact qualified Service
Personnel.
1.
position, then back to ignition position (towards closed) during the ignition
Air/Fuel Valve calibr
Page 91
Benchmark 1.5LN Low NOx Boiler
Operation and Maintenance Manual
OMM-0041_0D
GF-120
AERCO International, Inc. • 100 Oritani Dr. • Blauvelt, NY 10913 • Ph: 800-526-0288
FAULT INDICATION
PROBABLE CAUSES
CORRECTIVE ACTION
If the Air/Fuel Valve does rotate to the ignition position, check
the purge switch for continuity between the N.O. and COM
terminals. If the switch shows continuity when not in contact
with the cam, check to ensure that the switch is wired correctly
every second. If not, replace IGST Board.
rotate, check the purge switch for
continuity when closing. Replace switch if continuity does not
Measure for 24 VAC from each side of the switch to ground. If
e switch is wired correctly (correct wire
Check “Heartbeat” LED DS1 and verify it is blinking ON & OFF
every second. If not, replace IGST Board.
3. Incorrect Sensor.
3. Ensure that the correct sensor is installed.
current).
Configuration Menu.
CHAPTER 7: MAINTENANCE
TABLE 8-1. BOILER TROUBLESHOOTING (Continued)
PRG SWTCH
CLOSED
DURING IGNITION
(continued)
PRG SWTCH OPEN
DURING PURGE
OUTDOOR TEMP
SENSOR FAULT
2. Defective or shorted switch.
3. Switch wired incorrectly.
4. Defective Power Supply Board or fuse
5. Defective IGST Board
1. Defective purge switch.
2. No voltage present at switch.
3. Switch wired incorrectly.
4. Defective Power Supply Board or fuse
5. Defective IGST Board
1. Loose or broken wiring.
2. Defective Sensor.
2.
(correct wire numbers on the normally open terminals).
3. If the switch is wired correctly, replace the switch.
4. Check DS1 & DS2 LEDs on Power Supply Board. If they are not
steady ON, replace Power Supply Board.
5. Check “Heartbeat” LED DS1 and verify it is blinking ON & OFF
1. If the air-fuel valve does
exist.
2.
24VAC is not present, refer fault to qualified service personnel.
3. Check to ensure that th
numbers on the normally open terminals).
4. Check DS1 & DS2 LEDs on Power Supply Board. If they are not
steady ON, replace Power Supply Board.
5.
1. Inspect Outdoor Temperature sensor for loose or broken wiring.
2. Check resistance of sensor to determine if it is within
specification.
1. Remote setpoint signal not present:
Not yet installed.
Wrong polarity.
REMOTE SETPT
SIGNAL FAULT
PR2: 05/09/12 Page 91 of 152
Signal defective at source.
Broken or loose wiring.
2. Signal is not isolated (floating) if 4 to 20 mA.
3. Control Box signal type selection switches
not set for correct signal type (voltage or
1. Check I/O Box to ensure signal is hooked up.
Hook up if not installed.
If installed, check polarity.
Measure signal level.
Check continuity of wiring between source and boiler.
2. Check signal at source to ensure it is isolated.
3. Check DIP switch on PMC board to ensure it is set correctly for
the type of signal being sent. Check control signal type set in
Page 92
Benchmark 1.5LN Low NOx Boiler
Operation and Maintenance Manual
OMM-0041_0D
GF-120
AERCO International, Inc. • 100 Oritani Dr. • Blauvelt, NY 10913 • Ph: 800-526-0288
INDICATION
1. SSOV not fully closed.
2. Replace Flame Detector.
PURGE
DURING RUN
SSOV switch closed for 15
3. Hot and Neutral reversed at SSOV.
4. Incorrectly wired switch.
Stepper Feedback Calibration (GF-112, para. 6.2.1).
CHAPTER 7: MAINTENANCE
FAULT
RESIDUAL
FLAME
PROBABLE CAUSES CORRECTIVE ACTION
2. Defective Flame Detector
TABLE 8-1. BOILER TROUBLESHOOTING (Continued)
1. Check open/close indicator window of Safety Shut-Off Valve (SSOV) and ensure
that the SSOV is fully closed. If not fully closed, replace the valve and or actuator.
Close gas shut-off valve downstream of SSOV. Install a manometer or gauge in a
gas test port between the SSOV and the gas shut off valve. If a gas pressure
reading is observed replace the SSOV valve and or actuator.2.
SSOV FAULT
DURING
SSOV FAULT
SSOV RELAY
FAILURE
SSOV
SWITCH
OPEN
STEPPER
MOTOR
FAILURE
See SSOV SWITCH OPEN
1.
seconds during run.
1. SSOV relay failed on board.
2. Floating Neutral.
1. Actuator not allowing for full closure
of gas valve
2. SSOV powered when it should not
be
3. Defective Switch or Actuator
1. Air/Fuel Valve out of calibration.
1. Replace or adjust microswitch in SSOV actuator. If fault persists, replace
actuator.
1. Press CLEAR button and restart unit. If fault persists, replace Ignition/Stepper
(IGST) Board.
2. The Neutral and Earth Ground are not connected at the source and therefore
there is a voltage measured between the two. Normally this measurement should
be near zero or no more than a few millivolts.
3. Check SSOV power wiring.
1. Observe operation of the Safety Shut-Off Valve (SSOV) through indicator on the
Valve actuator and ensure that the valve is fully and not partially closing.
2. If the SSOV never closes, it may be powered continuously. Close the gas supply
and remove power from the unit. Refer fault to qualified service personnel.
3. Remove the electrical cover from the SSOV and check switch continuity. If the
switch does not show continuity with the gas valve closed, either adjust or replace
the switch or actuator.
4. Ensure that the SSOV Proof of Closure switch is correctly wired.
1. Refer to GF-112 and perform Stepper Test (para. 6.3.5) to ensure stepper motor
rotates properly between the 0% (fully closed) and 100% (fully open) positions.
Verify that the VALVE POSITION bargraph and the dial on the Air/Fuel Valve track
each other to indicate proper operation. If operation is not correct, perform the
Page 92 of 152 PR2: 05/09/12
Page 93
Benchmark 1.5LN Low NOx Boiler
Operation and Maintenance Manual
OMM-0041_0D
GF-120
AERCO International, Inc. • 100 Oritani Dr. • Blauvelt, NY 10913 • Ph: 800-526-0288
FAULT INDICATION
PROBABLE CAUSES
CORRECTIVE ACTION
connection to the
Defective Air/Fuel Valve stepper
every second. If not, replace IGST Board.
OBSERVED INCIDENT
PROBABLE CAUSES
CORRECTIVE ACTION
4. RSI regulator out of adjustment.
1. Open the 1/4” Ball Valve downstream of the SSOV (Fig. 8-1).
adjusted.
procedure.
CHAPTER 7: MAINTENANCE
TABLE 8-1. BOILER TROUBLESHOOTING (Continued)
2. Check that the Air/Fuel Valve is connected to the Control Box.
3. .Inspect for loose connections between the Air/Fuel Valve motor
and the wiring harness.
4. Replace stepper motor.
5. Check DS1 & DS2 LEDs on Power Supply Board. If they are not
steady ON, replace Power Supply Board.
6. Check “Heartbeat” LED DS1 and verify it is blinking ON & OFF
STEPPER MOTOR
FAILURE
(continued)
2. Air/Fuel Valve unplugged.
3. Loose wiring
stepper motor.
4.
motor.
5. Defective Power Supply Board or
fuse
6. Defective IGST Board
8.2 ADDITIONAL FAULTS WITHOUT SPECIFIC FAULT MESSAGES
Refer to Table 8-2 to troubleshoot faults which may occur without a specific fault message being displayed.
TABLE 8-2. BOILER TROUBLESHOOTING WITH NO FAULT MESSAGE DISPLAYED
Hard Light-Off
1. Staged Ignition Ball Valve closed.
2. Clogged/damaged Gas Injector
(Figure 8-2).
3. Defective Staged Ignition Solenoid
(Figure 8-2).
2. Remove and inspect Gas Injector to ensure it is not clogged or
damaged.
3. Close the 2” and the 1/4” Ball Valve downstream of the SSOV (Fig. 8-
1). Start the unit and listen for a “clicking” sound that the Staged
Ignition Solenoid makes during Ignition Trial. If “clicking” sound is not
heard after 2 or 3 attempts, replace the Staged Ignition Solenoid.
4. See Chapter 7, Section 7.4.
1. Gas pressure going into unit is
fluctuating.
2. Damping Orifice not installed.
Fluctuating Gas Pressure
Air/Fuel Valve “hunting” at
the 80% Valve Position
PR2: 05/09/12 Page 93 of 152
3. RSI Regulator not properly
1. IGST and Power Supply Boards in
Control Box are outdated.
1. Stabilize gas pressure going into unit. If necessary, troubleshoot
Building Supply Regulator.
2. Check to ensure that the Damping Orifice is installed in the SSOV
Actuator shown in Figure 8-3. (For IRI Gas Trains, the Damping Orifice
is installed in the downstream SSOV Actuator).
3. Refer to Chapter 4, paragraph 4.3 for RSI Regulator Calibration
1. Check to ensure that the IGST and Power Supply Boards are Rev. E
or higher.
Page 94
Benchmark 1.5LN Low NOx Boiler
Operation and Maintenance Manual
OMM-0041_0D
GF-120
AERCO International, Inc. • 100 Oritani Dr. • Blauvelt, NY 10913 • Ph: 800-526-0288
AIR/FUEL
VALVE
STAGED
IGNITION
SOLENOID #1
FLAME
DETECTOR
IGNITOR-
INJECTOR
BLOWER
BURNER
PLATE
BURNER
Figure 8-1: High Gas Pressure Switch & Snubber Locations
PR2: 05/01/11 Page 94 of 152
Figure 8-2: Staged Ignition Solenoid Location
Page 95
Benchmark 1.5LN Low NOx Boiler
Operation and Maintenance Manual
OMM-0041_0D
GF-120
AERCO International, Inc. • 100 Oritani Dr. • Blauvelt, NY 10913 • Ph: 800-526-0288
SSOV ACTUATOR WITH GAS
PRESSURE ADJUSTMENT
DAMPING
ORIFICE
CHAPTER 7: MAINTENANCE
Figure 8-3: Damping Orifice Location
PR2: 05/09/12 Page 95 of 152
Page 96
Benchmark 1.5LN Low NOx Boiler
Operation and Maintenance Manual
OMM-0041_0D
GF-120
AERCO International, Inc. • 100 Oritani Dr. • Blauvelt, NY 10913 • Ph: 800-526-0288
CHAPTER 7: MAINTENANCE
(This page intentionally blank)
Page 96 of 152 PR2: 05/09/12
Page 97
Benchmark 1.5LN Low NOx Boiler
Operation and Maintenance Manual
OMM-0041_0D
GF-120
AERCO International, Inc. • 100 Oritani Dr. • Blauvelt, NY 10913 • Ph: 800-526-0288
CHAPTER 9: RS232 COMMUNICATION
9.1 INTRODUCTION
The RS232 port on the front panel of the C-More Control Box (Figure 3-1) can be interfaced to a
laptop computer or other suitable terminal using a RS232 adapter cable. RS232 communication can
be accomplished using any “Dumb Terminal” emulation, such as “Hyper Terminal” which is included
with Microsoft Windows. The RS232 communication feature permits viewing or changing of Control
Panel menu options and also provides access to data logs showing Event Time Line, Fault and
Sensor log displays.
9.2 RS232 COMMUNICATION SETUP
Regardless of the terminal emulation utilized, the following guidelines must be adhered to when
setting up the RS232 communication link:
o Baud Rate – The baud rates which can be used with the C-More Control Panel are:
• 2400
• 4800
• 9600 (Default)
• 19.2K
o Data Format – The program must be set for: 8 data bits, 1 stop bit, no parity and either
Xon/Xoff or No flow control.
9.3 MENU PROCESSING UTILIZING RS232 COMMUNICATION
Viewing data logs and viewing or changing Control Panel menu options using RS232
communication is accomplished as follows:
1. Start the emulator software program and ensure that the specified baud rate and data formats
have been entered.
2. Press the Enter key on the laptop. An asterisk (*) prompt should appear.
3. At the prompt, enter the valid RS232 password (jaguar) in lower case letters and press Enter.
4. “Welcome to Aerco” will appear in the laptop or “dumb terminal” display with a listing of the
following available entry choices:
M = Display next Menu
D = Display menu items
N = Display next menu items
Cxx = Change item xx
F = Fault log display
S = Sensor log display
T = Time line display
L = Log off
NOTE
The Level 1 password (159) must be entered to change
options in the Setup, Configuration and Tuning Menus. The
Level 2 password (6817) must be entered to view or change
options in the Calibration and Diagnostics Menus. With the
exception of the password entry, all other keyboard entries
can be made using either upper or lower case.
PR2: 05/01/11 Page 97 of 152
Page 98
Benchmark 1.5LN Low NOx Boiler
Operation and Maintenance Manual
OMM-0041_0D
GF-120
AERCO International, Inc. • 100 Oritani Dr. • Blauvelt, NY 10913 • Ph: 800-526-0288
CHAPTER 9: RS232 COMMUNICATION
5. To view the available menus in the top-down sequence shown in Figure 3-2, enter M <Rtn>.
The Menu title and first 10 options will be displayed.
6. When viewing menus containing more than 10 options, enter N <Rtn> to display the remaining
options.
7. Shortcut keys are also available to go directly to a specific menu. These shortcut keys are:
m0 = Default (Operating) Menu
m1 = Setup Menu
m2 = Configuration Menu
m3 = Tuning Menu
m4 = Calibration Menu
m5 = Diagnostic Menu
8. To change a value or setting for a displayed menu option, proceed as follows:
a) Enter C, followed by the number to the right of the displayed option to be changed, and then
press <Rtn>.
b) Enter the desired value or setting for the option and press <Rtn>. Refer to Chapter 3, Tables
3-2 through 3-5 for allowable entry ranges and settings for the Operating, Setup,
Configuration and Tuning Menus. (The Calibration and Diagnostic Menus should only be
used by Factory-Trained service personnel).
c) Menu changes will be stored in non-volatile memory.
9. To redisplay the menu and view the option which was just changed in step 5, enter D and press
<Rtn>.
10. To display the Fault (F) Log, Sensor (S) Log or Time (T) Line Log, press F, S or T followed by
<Rtn>. Refer to paragraph 9.4 for descriptions and samples of these data logs.
11. To log off and terminate the RS232 com-munication link, press L followed by <Rtn>.
9.4 DATA LOGGING
During operation, the C-More Control Panel continuously monitors and logs data associated with
operational events, faults and sensor readings associated with the boiler or water heater system.
Descriptions of these data logs are provided in the following paragraphs. The basic procedure for
accessing each data log is described in paragraph 9.3, step 7.
Fault Log 9.4.1
The C-More Control Panel logs the last 20 faults (0 – 19) starting with the most recent (#0). They
can be viewed in the front panel display or via the RS232 port. The Fault Log cannot be cleared. If
the Fault Log already contains 10 faults, the earliest fault is overwritten when a new fault occurs. A
sample Fault Log display is shown in Table 9-1.
NOTE
The Operation Time (T) Log can store thousands of records.
Therefore, to view the most recently logged record, enter “T”
followed by 0 (zero) and press Enter (i.e. T0 <Enter>). To
view earlier records in reverse chronological order, enter T
and press Enter. To go back 200 or 1000 records, enter T200
or T1000, etc. and press Enter.
Page 98 of 152 PR2: 05/09/12
Page 99
Benchmark 1.5LN Low NOx Boiler
Operation and Maintenance Manual
OMM-0041_0D
GF-120
AERCO International, Inc. • 100 Oritani Dr. • Blauvelt, NY 10913 • Ph: 800-526-0288
No.
Fault Message
Cycle
Date
Time
0
Direct Drive Signal Fault
609
1/10/02
8:42am
1
Low Gas Pressure
366
7/04/01
5:29pm
2
Loss of Power
0
1/01/01
11:50am
Status
Fire Rate
Flame
Run Length
Date
Time
Off, Direct Drive
0 0 8
1/15/02
2:35pm
Run, Direct Drive
38
100
34
1/15/02
2:27pm
Run, Direct Drive
31
100
30
1/15/02
1:53am
Run, Direct Drive
35
100
2
1/15/02
1:23pm
Run, Direct Drive
29
100
0
1/15/02
1:21pm
Ignition
0 0 0
1/15/02
1:20pm
Off, Switch
0 0 35
1/15/02
12:30pm
Run, Manual
40
100
0
1/15/02
11:55am
Ignition
0 0 0
1/15/02
11:55am
Power-up
0 0 0
1/15/02
11:50am
CHAPTER 9: RS232 COMMUNICATION
Operation Time Log 9.4.2
The Operation Time Log consists of a string of ASCII records stored in non-volatile memory within
the C-More Control Panel. Events such as power-up, ignition and turn-off are time stamped. Data
logged while the unit is running are run-length encoded. Data is logged or the run-length
incremented every 30 seconds. For a new run record to be logged, the fire rate or flame strength
must change by more than 5%, or the run mode must change. At steady-state, the run-length is
allowed to reach a maximum of 30 minutes before the record is logged. This means that no more
than 30 minutes of data can be lost if the unit loses power. Table 9-2 shows a sample Operation
Time Log for a boiler:
The Operation Time Log can only be accessed through the RS232 interface using a laptop or other
terminal device. Ten operation time records are displayed for each T command entry. The operation
time log can be cleared ONLY by factory authorized personnel using the Clear Log option in the
Factory menu.
NOTE:
The Sensor (S) Log can store up to 1200 records. Therefore,
to view the most recently logged record, enter “S” followed by
0 (zero) and then press Enter (i.e. S0 <Enter>). To view
earlier records in reverse chronological order, enter S and
press Enter. To go back 200 or 700 records, enter S200 or
S700, etc. and press Enter.
Sensor Log 9.4.3
The sensor values can be logged at a different rate if needed by setting the Sensor Log Interval in
the Diagnostics Menu. The log interval can vary from once every minute to once every day. Table 93 shows a sample Sensor Log every 5 minutes for a boiler running in Constant Setpoint mode.
Table 9-1. Sample Fault Log Display
Table 9-2. Sample Operation Time Log Display
PR2: 05/09/12 Page 99 of 152
Page 100
Benchmark 1.5LN Low NOx Boiler
Operation and Maintenance Manual
OMM-0041_0D
GF-120
AERCO International, Inc. • 100 Oritani Dr. • Blauvelt, NY 10913 • Ph: 800-526-0288
Setpt
Outlet
Outdr
FFWD
Aux
Inlet
Exhst
CO
O2
Flow
Date
Time
130
181
OPEN
OPEN
OPEN
OPEN
OPEN
0
.0 0 1/15/02
5:51pm
130
180
OPEN
OPEN
OPEN
OPEN
OPEN
0
.0 0 1/15/02
5:46pm
130
180
OPEN
OPEN
OPEN
OPEN
OPEN
0
.0 0 1/15/02
5:41pm
130
179
OPEN
OPEN
OPEN
OPEN
OPEN
0
.0 0 1/15/02
5:36pm
130
180
OPEN
OPEN
OPEN
OPEN
OPEN
0
.0 0 1/15/02
5:31pm
130
180
OPEN
OPEN
OPEN
OPEN
OPEN
0
.0 0 1/15/02
5:26pm
130
180
OPEN
OPEN
OPEN
OPEN
OPEN
0
.0 0 1/15/02
5:21pm
130
180
OPEN
OPEN
OPEN
OPEN
OPEN
0
.0 0 1/15/02
5:16pm
130
179
OPEN
OPEN
OPEN
OPEN
OPEN
0
.0 0 1/15/02
5:11pm
130
180
OPEN
OPEN
OPEN
OPEN
OPEN
0
.0 0 1/15/02
5:06pm
CHAPTER 9: RS232 COMMUNICATION
Table 9-3. Sample Sensor Log Display
Page 100 of 152 PR2: 05/09/12
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