The information cont ained in this manual is s ubject to change without notic e from AERCO Internationa l,
Inc. AERCO makes no warranty of any kind with respect to this material, including but not limited to implied
warranties of m erchantability and f itness for a particul ar application. AERC O Internationa l is not liable for
errors appearing in this manua l. Nor for i ncidental or consequentia l damages oc curring in con nection wit h
the furnishing, performance, or use of this material.
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2.2 RECEIVING THE UNIT ........................................................................................................................................... 15
2.3 MOVING & UNPACKING THE UNIT ...................................................................................................................... 15
2.4 SITE PREPARATION .............................................................................................................................................. 16
2.4.2 Setting the Unit ............................................................................................................................................ 18
2.5 SUPPLY AND RETURN PIPING .............................................................................................................................. 20
2.8 GAS SUPPLY PIPING ............................................................................................................................................. 23
2.8.1 Gas Supply Specifications ............................................................................................................................. 24
2.8.2 Manual Gas Shutoff Valve ............................................................................................................................ 24
2.8.3 External Gas Supply Regulator ..................................................................................................................... 24
2.8.3.1 Massachusetts Installations Only .......................................................................................................... 24
2.8.3.2 All Installations (Except Massachusetts) ............................................................................................... 25
2.9 AC ELECTRICAL POWER WIRING .......................................................................................................................... 25
2.9.1 Electrical Power Requirements .................................................................................................................... 27
2.10 FIELD CONTROL WIRING .................................................................................................................................... 27
2.10.1 OUTDOOR AIR IN Terminal ......................................................................................................................... 29
2.10.2 COMBUSTION AIR Terminal ....................................................................................................................... 30
2.10.4 SPARK SIGNAL Terminals ............................................................................................................................ 30
2.10.5 ANALOG IN Terminals ................................................................................................................................. 30
2.10.6 B.M.S. (PWM) IN Terminals ........................................................................................................................ 30
2.10.8 ANALOG OUT Terminals ............................................................................................................................. 30
2.10.9 RS485 Comm Terminals .............................................................................................................................. 31
2.10.10 RS232 Comm Terminals ............................................................................................................................ 31
2.11 FLUE GAS VENT INSTALLATION ......................................................................................................................... 32
2.12 COMBUSTION AIR .............................................................................................................................................. 33
2.12.1 Combustion From Outside the Building ..................................................................................................... 33
2.12.2 Combustion Air from Inside the Building ................................................................................................... 33
2.13 DUCTED COMBUSTION AIR ............................................................................................................................... 34
3.2 CONTROL PANEL DESCRIPTION ........................................................................................................................... 37
3.3 CONTROL PANEL MENUS ..................................................................................................................................... 41
3.3.1 Menu Processing Procedure ......................................................................................................................... 41
3.4 OPERATING MENU .............................................................................................................................................. 43
3.5 SETUP MENU ....................................................................................................................................................... 43
3.6 CONFIGURATION MENU ...................................................................................................................................... 44
3.7 TUNING MENU .................................................................................................................................................... 46
3.8 COMBUSTION CAL MENU .................................................................................................................................... 47
3.9 BST (Boiler Sequencing Technology ) Menu ........................................................................................................ 47
4.2.2 Installing Gas Supply Manometer................................................................................................................. 60
4.2.3 Accessing the Analyzer Probe Port ............................................................................................................... 61
4.3 PILOT IGNITION ................................................................................................................................................... 62
4.4 NATURAL GAS COMBUSTION CALIBRATION ....................................................................................................... 62
4.5 PROPANE GAS COMBUSTION CALIBRATION ....................................................................................................... 67
5.2.1 Reset Ratio .................................................................................................................................................... 73
5.2.2 Building Reference Temperature ................................................................................................................. 73
5.2.3 Outdoor Air Temperature Sensor Installation .............................................................................................. 73
5.5 DIRECT DRIVE MODES ......................................................................................................................................... 76
5.5.1 Direct Drive Field Wiring............................................................................................................................... 77
5.5.2 Direct Drive Startup ...................................................................................................................................... 77
5.6 AERCO CONTROL SYSTEM (ACS) .......................................................................................................................... 77
5.6.1 ACS External Field Wiring ............................................................................................................................. 78
5.6.2 ACS Setup and Startup .................................................................................................................................. 78
5.7 COMBINATION CONTROL SYSTEM (CCS) ............................................................................................................. 78
5.7.1 Combination Control System Field Wiring ................................................................................................... 79
5.7.2 Combination Control System Setup and Startup .......................................................................................... 79
6.1 TESTING OF SAFETY DEVICES ............................................................................................................................... 81
6.2 LOW GAS PRESSURE FAULT TESTs ....................................................................................................................... 81
6.3 HIGH GAS PRESSURE FAULT TEST ........................................................................................................................ 83
6.4 LOW WATER LEVEL FAULT TEST .......................................................................................................................... 84
6.5 WATER TEMPERATURE FAULT TEST .................................................................................................................... 85
7.2 PILOT BURNER ..................................................................................................................................................... 98
7.3 MAIN FLAME DETECTOR ...................................................................................................................................... 99
9.1.1 Aquiring the PuTTY Application .................................................................................................................. 135
9.1.2 Logging on to a Remote Machine Using PuTTY .......................................................................................... 135
9.1.3 Running a Command on a Remote Machine Using PuTTY ......................................................................... 136
9.2 RS-232 COMMUNICATION SETUP ..................................................................................................................... 137
9.3 MENU PROCESSING UTILIZING RS-232 COMMUNICATION ............................................................................... 137
9.4 DATA LOGGING .................................................................................................................................................. 138
APPENDIX C – SENSOR RESISTANCE/VOLTAGE CHART ............................................................................................ 165
APPENDIX D – INDOOR/OUTDOOR RESET RATIO CHARTS ...................................................................................... 167
APPENDIX E – BOILER DEFAULT SETTINGS .............................................................................................................. 171
APPENDIX F – DIMENSIONAL & CLEARANCE DRAWINGS ........................................................................................ 173
APPENDIX G – PART LIST DRAWINGS ...................................................................................................................... 175
APPENDIX H – PIPING DRAWINGS ........................................................................................................................... 193
APPENDIX I – C-MORE WIRING DIAGRAMS ............................................................................................................. 197
The AERCO Benchmark 6000 Dual Fuel (BMK 6000) MBH boiler is a modulating and
condensing unit. It represents a true industry advancement that meets the needs of today's
energy and environmental concerns. Designed for application in any closed loop hydronic
system, the Benchmark's modulating capability relates energy input directly to fluctuating system
loads. The maximum turn down ratio for this model is 15:1. This model provides extremely high
efficiency and makes it ideally suited for modern low temperature, as well as, conventional
heating systems.
The Benchmark 6000 operates within the following input and output ranges:
Input Range (BTU/hr.) Output Range (BTU/hr.)
400,000 6,000,000 372,000 5,670,000
The output of the boiler is a function of the unit’s firing rate (valve position) and return water
temperature.
When installed and operated in accordance with this Instruction Manual, the Benchmark 6000
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 6000 offers the maximum
venting flexibility with minimum installation space requirements. These boilers are Category II, III
and IV, positive pressure appliances. Single and/or multiple breeched units are capable of
operation in the following vent configurations:
• Conventional, Vertical
• Conventional, Sidewall
• Conventional, Direct Vent, Vertical
• Sealed, Direct Vent, Horizontal
These boilers are capable of being vented utilizing Polypropylene and AL29-4C vent systems.
The Benchmark's advanced electronics are available in several selectable modes of operation
offering the most efficient operating methods and energy management system integration.
IMPORTANT
Unless otherwise specified, all descriptions and procedures provided in this
Installation, Operation & Maintenance Manual apply to the Benchmark 6000
MBH boiler.
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Building Automation System, often used interchangeably with EMS
(see below)
Symbol rate, or simply the number of distinct symbol changes
currently used in all
EMS
Energy Management System; often used interchangeably with BAS
IGN
Ignition
FORWARD
Phrases, Abbreviations and Acronyms
Phrase, Abbreviation
or Acronym
A (Amp) Ampere
ACS AERCO Control System, AERCO’s boiler management system
ADDR Address
AGND Anal og Ground
ALRM Alarm
ASME American Society of Mechanical Engineers
AUX Auxiliary
BAS
Baud Rate
BMK Benchmark series boilers
Meaning
(signaling events) transmitted per second. It is not equal to bits per
second, unless each symbol is 1 bit long.
BLDG (Bldg) Building
BST AERCO on-board Boiler Management Technology
BTU
British Thermal Unit. A unit of energy approximately equal to the heat
required to raise 1 pound of water 1° F.
CCP Combustion Control Panel
C-More Controller
(or Control Box)
A control system developed by AERCO and
Benchmark, Innovation and KC1000 Series product lines.
CO Carbon Monoxide
COMM (Comm) Communication
Cal. Calibration
CNTL Control
DBB
Double Block and Bleed. Used to define boiler gas trains containing 2
Safety Shutoff Valves (SSOVs) and a solenoid operated vent valve.
Also known as IRI gas trains(see below)
DIP Dual In-Line Package
FM Factor y Mutual. Used to define boiler gas trains.
GND Ground
HDR Header
HX Heat Exchanger
Hz Hertz (Cycles Per Second)
I.D. Inside Diameter
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order to prevent reflections that may cause invalid data in the
FORWARD
Phrases, Abbreviations and Acronyms - Continued
RTN (Rtn) Return
SETPT (Setpt) Setpoint Temperature
SHLD (Shld) Shield
SSOV Saf ety Shut Off Valve
TEMP (Temp) Temperature
Terminating Resistor
A resistor placed at each end of a daisy-chain or multi-drop network in
communication
VAC Volts, Alternating Current
VDC Volts, Direct Current
VFD Vacuum Fluor escent Display, or Variable Frequency Drive
W Watt
W.C. Water Co lumn
µA Micro amp (1 millionth of an ampere)
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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 conf orm with local building codes, or,
in the absence of local codes, ANSI Z223.1 (National Fuel Gas Code Publication No. NFPA-54)
for gas-fired boilers and ANSI/NFPASB for LP gas-fired boilers. Where applicable, the equipment
shall be installed in accordance with the current Installation Code for Gas Burning Appliances
and Equipment, CSA B149.1, and applicable Provincial regulations for the class; which should
be carefully followed in all cases. Authorities having jurisdiction should be consulted before
installations are made.
See pages 14 and 15 for important information regarding installation of units within the
Commonwealth of Massachusetts.
IMPORTANT
This Instruction Manual is an integral part of the product and must be
maintained in legible condition. It must be given to the user by the installer
and kept in a safe place for future reference.
DO NOT USE MATCHES, CANDLES, FLAMES, OR OTHER SOURCES
OF IGNITION TO CHECK FOR GAS LEAKS.
FLUIDS UNDER PRESSURE MAY CAUS E INJURY TO PERSONNEL OR
DAMAGE TO EQUIPMENT WHEN RELEASED. BE SURE TO SHUT OFF
ALL INCOMING AND OUTGOING WATER SHUTOFF VALVES.
CAREFULLY DECREASE ALL TRAPPED PRESSURES TO ZERO
BEFORE PERFORMING MAINTENANCE.
BEFORE ATTEMPTING TO PERFORM ANY MAINTENANCE ON THE
UNIT, SHUT OFF ALL GAS AND ELECTRICAL INPUTS TO THE UNIT.
THE EXHAUST VENT PIPE OF THE UNIT OPERATES UNDER A
POSITIVE PRESSURE AND THEREFORE MUST BE COMPLETELY
SEALED TO PREVENT LEAKAGE OF COMBUSTION PRODUCTS INTO
LIVING SPACES.
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ELECTRICAL VOLTAGES UP TO 480 VAC MAY BE USED IN THIS
EQUIPMENT. THEREFORE THE COVER ON THE UNIT ’S POWER BOX
(LOCATED BEHIND T HE FRONT PANEL DOOR) MUST BE INSTALLED
AT ALL TIMES, EXCEPT DURING MAINTENANCE AND SERVICING.
A THREE-POLE SWITCH MUST BE INSTALLED ON THE ELECTRICAL
SUPPLY LINE OF THE UNI T. THE SWITCH MUST BE INST ALLED IN AN
EASILY ACCESSIBLE POSITION TO QUICKLY AND SAFELY
DISCONNECT ELECTRICAL SERVICE. DO NOT AFFIX SWITCH TO UNIT
SHEET METAL ENCLOSURES.
Many soaps used for gas pipe leak testing are corrosive to metals. The
piping must be rinsed thoroughly with clean water after leak checks have
been completed.
DO NOT use this boiler if any part has been under water. Call a qualified
service technician to inspect and replace any part that has been under
water.
1.2 EMERGENCY SHUTDOWN
If overheating occurs or the gas supply fails to shut off, close the manual gas shutoff valve
(Figure 1-1) located external to the unit.
NOTE
The Installer must identify and indicate the location of the emergency
shutdown manual gas valve to operating personnel.
MANUAL GAS SHUT-OFF VALVE
Figure 1-1: Manual Gas Shutoff Valve
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If the boiler will be shut down for an extended period of time (one year or more), it is
recommended that the steps in Chapter 7, section 7.11 be performed to prepare the boiler.
After a prolonged shutdown, it is recommended that the steps in Chapter 7, section 7.12 be
performed. In addition, the startup procedures in Chapter 4 and the safety device test procedures
in Chapter 6 of this manual should be performed to verify that all s ystem-operating parameters
are correct. If there is an emergency, turn off the electrical power supply to the AERCO boiler
and close the manual gas valve located upstream of the unit. The installer must identify the
emergency shut-off device.
1.4 MASSACHUSETTS INSTALLATIONS
Boiler installations within the Commonwealth of Massachusetts must conform to the following
requirements:
• Boiler must be installed by a plumber or a gas fitter who is licensed within
the Commonwealth of Massachusetts.
• Prior to unit operation, the complete gas train and all connections must be
leak tested using a non-corrosive soap.
• AERCO provides an optional external CO Detector, part number 58092. It
can be installed and configured to simply sound an alarm or to shut down
the boiler(s) if CO concentrations rise above a configurable threshold.
Contact your AERCO representative for details.
• 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 requirem ent s extract ed from 248 CMR 5.08 (2):
(a) For all side wall horizontally vented gas fueled equipment installed in every dwelling, building
or structure used in whole or in part for residential purposes, including those owned or operated
by the Commonwealth and where the side wall exhaust vent termination is less than seven (7)
feet above finished grade in the area of the venting, including but not limited to decks and
porches, the following requirements shall be satisfied:
•INSTALLATION OF CARBON MONOXIDE DET ECTORS. 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 t he services of q ualified 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 thir ty (30) day period, a battery
operated carbon monoxide detector with an alarm shall be installed.
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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 dir ectly in line with the exhaust
vent terminal for the horizontally vented gas fueled heating appliance or equipment. The sign
shall read, in print size no less than one-half (1/2) inch in size, "GAS VENT DIRECTLY BELOW.
KEEP CLEAR OF ALL OBSTRUCTIONS".
4. INSPECTION. The state or local gas inspector of the side wall horizontally vented gas fueled
equipment shall not approve the installation unless, upon inspection, the inspector observes
carbon monoxide detectors and signage installed in accordance with the provisions of 248 CMR
5.08(2)(a)1 through 4.
(b) EXEMPTIONS: The following equipment is exempt from 248 CMR 5.08(2)(a)1 through 4:
1. The equipment listed in Chapter 10 entitled "Equipment Not Required To Be Vented" in
the most current edition of NFPA 54 as adopted by the Board; and
2. Product Approved side wall horizontally vented gas fueled equipment installed in a room
or structure separate from the dwelling, building or structure used in whole or in part for
residential purposes.
(c) MANUFACTURER REQUIREMENTS - GAS EQUIPMENT VENTING SYSTEM PROVIDED.
When the manufacturer of Product Approved side wall horizontally vented gas equipment
provides a venting system design or venting system components with the equipment, the
instructions provided by the manufacturer for installation of the equipment and the venting
system shall include:
1. Detailed instructions for the installation of the venting system design or the venting system
components; and
2. A complete parts list for the venting system design or venting system.
(d) MANUFACTURER REQUIREMENTS - GAS EQUIPMENT VENTING SYSTEM NOT
PROVIDED. When the manufacturer of a Product Approved side wall horizontally vented gas
fueled equipment does not provide the parts for venting the flue gases, but identifies "special
venting systems", the following requirements shall be satisfied by the manufacturer:
1. The referenced "special venting system" instructions shall be included with the appliance
or equipment installation instructions; and
2. The "special venting systems" shall be Product Approved by the Board, and the
instructions for that system shall include a parts list and detailed installation instructions.
(e) A copy of all installation instructions for all Product Approved side wall horizontally vented
gas fueled equipment, all venting instructions, all parts lists for venting instructions, and/or all
venting design instructions shall remain with the appliance or equipment at the completion of the
installation.
[End of Extracted Information From 248 CMR 5.08 (2)]
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This Chapter provides the descriptions and procedures necessary to unpack, inspect and install
the Benchmark 6000 boiler.
2.2 RECEIVING THE UNIT
Each Benchmark boiler system is shipped as a single crated unit. The shipping weight for the
Benchmark 6000 is approximately3500 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 TipN-Tell indicator on t he outside of the shipping container. 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 MOVING & UNPACKING THE UNIT
While packaged in the shipping container, the unit can be moved using a forklift.
Carefully unpack the unit taking care not to damage the unit enclosure when cutting away
packaging materials
After unpacking, closely inspect the unit to make sure there is no evidence of damage not
indicated by the Tip-N-Tell indicator. Notify the freight carrier immediately if any damage is
detected.
The following accessories come standard with each unit and are either factory installed on the
unit or packed separately with the unit:
• Pressure/Temperature Gauge
• ASME Pressure Relief Valve
• Condensate Drain Trap (part no. 24060)
• 2” Gas Supply Shutoff Valve
When optional accessories are ordered, they may be packed with the unit, factory installed on
the unit, or packed and shipped in a separate container. Any standard or optional accessories
shipped loose should be identified and stored in a safe place until ready for installation or use.
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Figure 2-1. Benchmark 6000 Mounted on Shipping Skid
2.4 SITE PREPARATION
Ensure that the site selected for installation of the Benchmark boiler includes:
• Access to AC Input Power at 208 VAC, Three-Phase, 60 Hz @ 30 Amps
OR 460 VAC, Three-Phase, 60 Hz @ 20 Amps
• Access to both a NATURAL GAS and a PROPANE line at a minimum pressure of 14
inches W.C. with the unit in operation (approximately 20” W.C. static).
2.4.1 Installation Clearances
The Benchmark Model 6000 boiler dimensions and minimum acceptable clearances are shown
in Figure 2-2. The minimum clearance dimensions, required by AERCO, are listed below.
However, if Local Building Codes require additional clearances, these codes shall supersede
AERCO’s requirements. Minimum acceptable clearances required are as follows:
• Front : 36 inches (914 mm)
• Sides: 24 inches (610 mm)
• Rear: 24 inches (610 mm)
• Top: 18 inches (457 mm)
All gas piping, water piping and electrical conduit or cable must be arranged so that t hey do not
interfere with the removal of any panels, or inhibit service or maintenance of the unit.
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Ensure that adequate clearance exists at the rear of the unit to permit
installation and service maintenance of the AERCO Condensate Trap. Refer
to section 2.7 for Condensate Trap installation details.
When using the AERCO Condensate Neutralizer Tank for condensate
drainage, the tank must be installed in a pit, OR the boiler and AERCO
Condensate Trap must be elevated higher than 4” above the floor. See
Condensate Neutralizer Tank Instructions TID-0074 for details.
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4” MINIMUM
Figure 2-2a. Benchmark Boiler Model 6000 Clearances
KEEP THE UNIT AREA CLEAR AND FREE FROM ALL COMBUSTIBLE
MATERIALS AND FLAMMABLE VAPORS OR LIQUIDS
FOR MASSACHUSSETTS ONLY
For Massachusetts installations, the unit must be installed by a plumber or
gas-fitter who is licensed within the Commonwealth of Massachusetts. In
addition, the installation must comply with all requirements specified in
Chapter 1 – Safety Precautions.
2.4.2 Setting the Unit
The unit must be installed on a concrete housekeeping pad, a m i nimum of 4 inches and a
maximum of 8 inches thick, to ensure proper condensate drainage (see NOTE below).
NOTE
When using the AERCO Condensate Neutralizer Tank for proper
condensate drainage, the Neutralizer Tank must be stored in a pit , OR the
boiler and AERCO Condensate Trap must be elevated higher than 4” above
the floor. Ensure that t he condensate assembly is not positioned above the
housekeeping pad during installation so as not to interference with
condensate piping. See Condensate Tank Instructions TID-0074 for details.
If anchoring the unit, refer to Figure 2-2b for anchor bolt locations.
.
• All holes are flush with the bottom surface of the frame.
• All dimensions shown are in inches [millimeters]
Figure 2-2b. Benchmark 6000 Anchor Bolt Locations
Two (2) lifting lugs are provided at the top of the primary heat exchang er as shown in Figure 2-3.
Cut the cardboard at marked locations to provide access to the lifting tabs.
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Remove the four (4) lag screws securing the unit to the shipping skid, and, if still in place,
remove the front and r ear Top Panels. Lift the unit off the shipping skid and position it on the
concrete Housekeeping Pad (required) in the desired location.
WHEN LIFTING OR MOVING THE BOILER: DO NOT ATTEMPT
TO MANIPULATE THE BOILER USING THE GAS TRAIN OR
BLOWER. A SPREADER BAR IS REQUIRED FOR ALL
VERTICAL LIFTS.
Remove the two top panels
to access the lifting tabs.
CHAPTER 2 – INSTALLATION
Figure 2-3. Boiler Lifting Provisions
In multiple unit installations, it is important to plan the position of each unit in advance. Sufficient
space for piping connections and future service/maintenance requirements m ust 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 t hem in the proper physical location. Refer to Chapter 5 for
information on Combination Mode Boilers.
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The Benchmark boiler utilizes 6” flanged fittings for the water system supply and return piping
connections. The physical location of the supply and return piping connections are shown in
Figure 2-4. For dimensional data, refer to Drawing AP-A-901 in Appendix F.
Depending on the pressure required, the Benchmark 6000 is supplied with either a single 2” or
two (2) 1¼“ ASME rated Pressure Relief Valves. The pressure rating for the relief valve must be
specified on the sales order. Available press ure ratings range from 30 psi to 160 psi, depending
on pressure vessel maximum rated pressure. Each pressure relief valve is furnished as a kit
(92102-Tab) which consists of the relief valve for the pressure rating specified on the Sales
Order. The appropriate size reducing bushing and nipple are also included in the kit. The
pressure relief valves, nipples and bushings are connected to 45º street elbows already installed
on the heat exchanger of the boiler. The relief valves are installed on the top of the boiler as
shown in Figure 2-5A. A suitable pipe joint compound should be used on all threaded
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connections. Any excess should be wiped off to avoid getting any joint compound into the valve
body. Each relief valve must be piped to within 12 inches of the floor to prevent injury in the
event of a discharge. The discharge piping m ust be full size, without reduction. No valve or size
reductions are allowed in the discharge line. In multiple unit installations the discharge lines must
not be manifolded together. Each must be individually run to a suitable discharge location.
A manual Pressure/Temperature Gauge is included in the loose parts kit for installation for
installation in the boiler outlet piping. It must be installed so that the sensing bulb is inserted into
the hot water outlet flow from the boiler. Refer to Figure 2-5B for sample installations.
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The Benchmark boiler is designed to condense water vapor from the flue products. Therefore,
the installation must have provisions for suitable condensate drainage or collection.
The condensate drain port is located on the exhaust manifold (Figure 2-6) at the rear of the unit.
This drain port must be connected to the condensate trap (part no. 24060), which is packed
separately within the unit’s shipping container. The condensate trap outlet connection features a
tapped 3/4” NPT drain port.
A sample condensate trap installation is shown in Figure 2-7. However, the actual installation
details for the trap will vary depending on the available clearances, housekeeping pad height/
dimensions and other prevailing conditions at the site. The following general guidelines must be
observed to ensure proper condensate drainage:
• The condensate trap inlet (Figure 2-7) must be level with, or lower than the exhaust
manifold drain port.
• The base of the condensate trap must be supported to ensure that it is level (horizontal).
• The trap must be removable for routine maintenance. AERCO recommends that a union
be utilized between the exhaust manifold condensate drain port and the trap inlet port.
While observing the above guidelines, install the condensate trap as follows:
Condensate Trap Installat ion
1. Connect the condensate trap inlet to the exhaust manifold drain connection by sliding the
trap inlet onto the drain port. Tighten the thumbscrew on the trap inlet.
2. At the condensate trap outlet, install a stainless steel or PVC 3/4” NPT nipple.
3. Connect a length of 1” I.D. polypropylene hose to the trap outlet and secure with a hose
4. Route the hose on the trap outlet to a nearby floor drain.
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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 40 GPH. The condensate drain trap, associated
fittings and drain line must be removable for routine maintenance.
Use PVC, stainless steel, aluminum or polypropylene for condensate drain
piping (Figure 2-6). DO NOT use carbon or copper components.
ANALYZER
INT E G RAL ADAPT OR
AND THUMBSCREW
COVER
THUMB
SREWS
CONDENSATE
NOTE
HOUSKEEPING
PAD MUST NOT
EXTEND
UNDER THE
CONDENSATE
2.8 GAS SUPPLY PIPING
The AERCO Benchmark Gas Supply Design Guide, GF-2030 must be consulted prior to
designing or installing any gas supply piping.
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MANIFOLD
DRAIN PORT
Tilt down 2° for
T O
FLOOR
Figure 2-7. Sample Condensate Trap Installation – Side View
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.
Therefore, piping must be rinsed thoroughly with clean water after leak
checks have been completed.
All gas piping must be arranged so that it does not interfere with removal of
any covers, inhibit service/maintenance, or restrict access between the unit
and walls, or another unit.
Benchmark 6000 DF units contain a 2 inch natural gas inlet and a 2 inch propane gas inlet on the
back of the unit, as shown in Figure 2-4.
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 and propane, 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 56” W.C. (2 psig). Leak
test all external piping thoroughly using a soap and water solution or suitable equivalent. The gas
piping used must meet all applicable codes.
2.8.1 Gas Supply Specifications
The gas supply input specifications to the unit for both NATURAL GAS and PROPANE gas are
as follows:
• The maximum static pressure to the unit must not exceed 56 inches W.C. (2 psi).
• The gas supply pressure to the unit must be sufficient to provide 6000 cfh while
maintaining a gas pr essure of 14 inches W.C. for FM gas trains while in operation.
2.8.2 Manual Gas Shutoff Valve
A manual shut-off valve must be installed in the gas supply lines upstream of the boiler as shown
in Figure 2-8. Maximum allowable gas pressure to the boiler is 56” W.C. (2 psi).
2.8.3 External Gas Supply Regulator
An external gas pressure regulator is required on the gas inlet piping under most conditions (see
sections 2.8.3.1 and 2.8.3.2, below). Regulators must conform to the following specifications:
• The external natural gas regulator must be capable of regulating 300,000 – 6,000,000
BTU/HR of natural gas while maintaining a gas pressure of 14” W.C. minimum to the unit.
• A lock-up style regulator MUST be used on all Benchmark 6000 DF units.
NOTE
The external regulator must be capable of regulating 300,000 – 6,360,000
BTU/HR of natural ga s while maintaining a gas pressure of 14” W.C. to the
unit while in operation.
2.8.3.1
For Massachusetts installations, a mandatory external gas supply regulator must be positioned
as shown in Figure 2-8. The gas supply regulator must be properly vented to outdoors. Consult
the local gas utility for detailed requirements concerning venting of the supply gas regulator.
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For all installations (other than Massachusetts) that EXCEED 1 PSI gas pressure, a mandatory
external gas supply regulator must be positioned as shown in Figure 2-8. No regulator is required
for gas pressures below 1 PSI of pressure. Consult the local gas utility for detailed requirements
concerning venting of the supply gas regulator.
GAS
SUPPLY
GAS
SUPPLY
SHUT-OFF
VALVES
2.9 AC ELECTRICAL POWER WIRING
The AERCO Benchmark Electrical Power Wiring Guide, GF-2060, must be consulted prior to
connecting any AC power wiring to the unit. External AC power connections are made to the unit
inside the Power Box on the front of the unit. Rem ove the unit’s front panel to access the Power
Box, which is mounted in the upper right corner of t he unit as shown in Figure 2-9. Loosen the
four Power Box cover screws and remove the cover to access the AC terminal block
connections, and other internal components shown in Figure 2-10.
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With the exception of the transformer shown in Figur e 2-10, all of the components in the Power
Box are mounted on a DIN rail.
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Figure 2-10. Power Box Internal Components (Cover Removed)
NOTE
All electrical conduit and hardware must be installed so that it does not
interfere with the removal of any unit covers, inhibit service/maintenance, or
prevent access between the unit and walls or another unit.
The Benchmark boiler is available in two voltage configurations:
• 208 VAC, three-phase, 60 Hz @ 30A
• 460 VAC, three-phase, 60 Hz @ 15A.
The Power Box contains terminal blocks as shown in Figure 2-10. In addition, a label showing
the required AC power connections is provided on the front cover of the Power Box, as shown in
Figure 2-11.
Figure 2-11 Power Box Cover Labels – 208VAC (Left) and 460VAC (Right)
Each unit must be connected to a dedicated electrical circuit. NO OTHER DEVICES SHOULD
BE ON THE SAME ELECTRICAL CIRCUIT AS THE BOILER.
A double-pole switch must be installed on the electrical supply line in an easily accessible
location to quickly and safely disconnect electrical service. DO NOT attach the switch to sheet
metal enclosures of the unit.
After placing the unit in service, the ignition safety shutoff device must be tested. If an external
electrical power source is used, the installed boiler must be electrically bonded to ground in
accordance with the requirements of the authority having jurisdiction. In the absence of such
requirements, the installation shall conform to National Electrical Code (NEC), ANSI/NFPA 70
and/or the Canadian Electrical Code (CEC) Part I, CSA C22.1 Electrical Code.
For electrical power wiring diagrams, see the AERCO Benchmark Electrical Power Guide, (GF-
2060).
2.10 FIELD CONTROL WIRING
Each unit is fully wired from the factory with an internal operating control system. No field control
wiring is required for normal operation. However, the C-More Control system used with all
Benchmark units does allow for some additional control and monitoring features. Wiring
connections for these features are made on the Input/Output (I/O) board located behind the
removable front panel assembly of the unit. The I/O board is located in the I/O Box. The I/O
board terminal strip connections are shown in Figure 2-13. All f ield wiring is installed fr om the
rear of the panel by routing the wires through one of the four bushings provided on the sides of
the I/O board.
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Refer to the wiring diagram provided below the I/O Box (Figure 2-13) when making all wiring
connections.
I/O PCB
BOARD
FRONT VIEW
Figure 2-12. Input/Output (I/O) Box Location
NOTE
Use Figure 2-13 to determine the functions of the I/O PCB connections. Do
not use the silkscreened labels on the PCB itself, as these may not match
the function names. T here is a diagram of the connection functions on the
cover of the I/O Box as well.
DO NOT make any connections to the I/O Box terminals labeled “NOT
USED”. Attempting to do so may cause equipment damage.
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An OUTDOOR AIR IN terminal is used f or connecting an outdoor temperature sensor (AERCO
Part No. GM-123525) as 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 AIR IN and AIR SENSOR COMMON terminals of the I/O Box (see Figure 2-13).
Wire the sensor using a twisted shielded pair wire between 18 and 22 AWG. There is no polarity
to observe when terminating these wires. The shield is to be connected only to the terminals
labeled SHIELD in the I/O Box. The sensor end of the shield must be left free and ungrounded.
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 f rom direct sunlight
as well as impingement by the elements. If a shield cover is used, it must allow for free air
circulation.
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The COMBUSTION AIR terminal is used to m onitor the combustion air temperature sensor . T h is
input is always enabled and is a “to view only” input that can be seen in the operating menu. The
sensor is an AERCO BALCO wire sensor Part No. 12449. A resistance chart for this sensor is
provided in APPENDIX C. This sensor is an active part of the combustion control system and
must be operational for accurate air/fuel mixing control.
2.10.3 O2 SENSOR Terminals
The O2 SENSOR (–) and O2 SENSOR (+) terminals are used to connect an external oxygen
sensor to the I/O box. The O
Control system after a 60 second warm-up period.
2.10.4 SPARK SIGNAL Terminals
The SPARK SIGNAL terminals are not in use on the Benchmark 6000.
2.10.5 ANALOG IN Terminals
The ANALOG IN terminals (+ and –) are used when an external signal is used to change the
setpoint (Remote Setpoint Mode) of the boiler.
concentration is displayed in the operating menu of the C-More
2
Either a 4 to 20 mA /1 to 5 VDC or a 0 to 20 mA/ 0 to 5 VDC signal may be used to vary the setpoint or air/fuel valve position. The factory default setting is for 4 to 20 mA / 1 to 5 VDC, however
this may be changed to 0 to 20 mA / 0 to 5 VDC using the Configuration Menu described in
Chapter 3.
If voltage rather than current is selected as the drive signal, a DIP switch must be set on the
PMC Board located inside the Control Box. Refer to Appendix D of the C-More Control Panel
OMM, GF-112, for information on setting DIP switches.
All supplied signals must be floating (ungrounded) signals. Connections between the source and
the boiler’s I/O Box must be made using twisted shielded pair of 18–22 AWG wire such as
Belden 9841. Polarity must be maintained and the shield must be connected only at the source
end and must be left floating (not connected) at the boiler’s I/O Box.
Whether using voltage or current for the drive signal, they are linearly mapped to a 40°F to 240°F
setpoint or a 0% to 100% air/fuel valve position. No scaling for these signals is provided
2.10.6 B.M.S. (PWM) IN Terminals
The two B.M.S. (PWM) IN terminals are only used to connect the legacy AERCO Boiler
Management Systems (BMS), which utilize a 12 millisecond, ON/OFF duty cycle and is Pulse
Width Modulated (PWM) to control valve position. A 0% valve position = a 5% ON pulse and a
100% valve position = a 95% ON pulse. Note that these connections cannot be used with the
ARECO Control System (ACS).
2.10.7 SHIELD Terminals
The two SHIELD terminals are used to terminate any shields used on sensor wires connected t o
the unit. Shields must only be connected to these terminals.
2.10.8 ANALOG OUT Terminals
The ANALOG OUT terminals (+ & -) output from 0 to 20 mA and may be used to monitor
Setpoint, Outlet Temperature, Valve Position 4-20 mA, Valve Position 0-10v or be set to OFF.
Default sett ing in th e C -More controller is Valve Position 0-10v and settings behave as follows:
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• When 0-10VDC is selected, the voltage output is used by the controller to modulate the
combustion blower via the I/O Box terminals labeled VFD/Blower (Section 2.10.11).
• If On Board Boiler Sequencing Technology (BST) is enabled, the Analog Output terminals
are used to drive the isolation valve, open and closed.
• When the 4-20mA is selected for the Analog Output, the 0-10VDC is disabled at the
VFD/Blower terminals, and the selected output is available at the terminals labeled
Analog Output +/-.
2.10.9 RS485 Comm Terminals
The RS-485 communication terminals (+, GND, & -) are used when the boiler plant is being
controlled by an Energy Management System (EMS) or AERCO ACS (formerly BMS/BMS-II)
using Modbus (RS-485) communication.
2.10.10 RS232 Comm Terminals
The RS-232 communication terminals (TxD, RxD) permit a laptop computer or other suitable
terminal to be connected to the boiler. The RS-232 communication feature permits viewing or
changing of Control Panel menu options and also provides access to data logs showing fault and
sensor log displays.
2.10.11 VFD/BLOWER Terminals
These terminals (0-10 & AGND) send an analog sig nal to control the blower speed. When any of
the 4-20mA options is selected for the Analog Outputs (Section 2.10.8), the output from the
VFD/Blower terminals is disabled.
2.10.12 Interlock Terminals
The unit offers two interlock circuits for interfacing with Energy Management Systems and
auxiliary equipment such as pumps or louvers or other accessories. These interlocks are called
the Remote Interlock and Delayed Interlock ((REMOT E INTL’K IN and DELAYED INTL’K IN in
Figure 2-12). Both interlocks, described below, are factory wired in the closed position (using
jumpers).
NOTE
Both the Delayed Interlock and Remote Interlock must be in the
closed position for the unit to fire.
2.10.12.1
The remote interlock circuit is provided to remotely start (enable) and stop (disable) the unit if
desired. The circuit is 24 VAC and comes factory pre-wired closed (jumped).
2.10.12.2
The Delayed Interlock terminals can be used in one of two ways:
Remote Interlock In (OUT & IN)
Delayed Interlock In (OUT & IN)
• In conjunction with the optional external sequencing valve (see section 2.14 and Chapter
10 – BST), a component of AERCO’s on-board Boiler Sequencing Technology (BST)
solution. By default a cable of the boiler’s wiring harness is connected t o these terminals.
If BST is implemented, the other end of that cable is connected to the sequencing valve.
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• If BST is NOT implemented, the second use is typically in conjunction with the
AUXILIARY RELAY CONTACTS described in section 2.10.14. This interlock circuit is
located in the purge section of the start string. It can be connected to the proving device
(end switch, flow switch etc.) of an auxiliary piece of equipment started by the unit’s
auxiliary relay. If the delayed interlock is connected to a proving device that r equires time
to close (make), a time delay (AUX START ON DLY) that holds the start sequence of the
unit long enough for a proving switch to make (close) can be programmed.
To use this option, you must disconnect the harness from the Delayed Interlock terminals
and connect the proving device in its place.
Should the proving switch not prove within the programmed time frame, the unit will shut
down. The AUX START ON DLY can be programmed from 0 to 120 seconds. This
option is located in the Configuration Menu (Chapter 3).
2.10.13 FAULT RELAY Terminals
The fault relay is a single pole double throw (SPDT ) relay having a normally open and normally
closed set of relay contacts that are rated for 5 amps at 120 VAC and 5 amps at 30 VDC. The
relay energizes when any fault condition occurs and remains energized until the fault is cleared
and the CLEAR button is depressed. The fault relay connections are shown in Figure 2-13.
2.10.14 AUX.RELAY Terminals
Each unit is equipped with a single pole double throw (SPDT) auxiliary relay that is energized
when there is a demand for heat and de-energized after the demand for heat is satisfied. The
relay is provided for the control of auxiliary equipment, such as pumps and louvers, or can be
used as a unit status indictor (firing or not firing). Its contacts are rated for 120 VAC @ 5 amps.
Refer to Figure 2-13 to locate the AUX.RELAY terminals (N.C., COM, & N.O.) for wiring
connections.
2.11 FLUE GAS VENT INSTALLATION
The AERCO Gas Fired Venting and Combustion Air Guide, GF-2050 must be consulted before
any flue or combustion air venting is designed or installed. Suitable, U/L approved, positive
pressure, watertight vent materials MUST be used for safety and UL certification. Because the
unit is capable of discharging low temperature exhaust gases, the flue must be pitched back
towards the unit a minimum of 1/4" per foot to avoid any condensate pooling and to allow for
proper drainage.
While there is a positive flue pressure during operation, the combined pressure drop of vent and
combustion air systems must not exceed 140 equivalent feet or 1.9” W.C. Fittings as well as
pipe lengths must be calculated as part of the equivalent length. For a natural draft installation
the draft must not exceed - 0.25” W.C. These factors must be planned into the vent installation. If
the maximum allowable equivalent lengths of piping are exceeded, the unit will not operate
properly or reliably.
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For Massachusetts installations, the following companies provide vent systems which conform to
all applicable requirements for installations within the Commonwealth of Massachusetts. Contact
information is as follows:
130 Industrial Blvd.
Turners Falls, MA 01376
Phone: 1-800-772-0739
www.heat-fab.com
1250 Massachusetts Ave.
Boston MA 02125-1689
Phone: (617) 288-0629
www.mapeacard.com
33Grove St.
Watertown, MA 02472
Phone: (617) 924-2840
http://www.watertownsupply.com/
44 Riverdale Ave.
Newton, MA 02485
Phone: (617) 527-8178
www.gloversheetmetal.com
2.12 COMBUSTION AIR
The AERCO Benchmark Boiler Venting and Combustion Air Guide, GF-2050 MUST be
consulted before any flue or inlet air venting is designed or installed. Air supply is a direct
requirement of ANSI 223.1, NFPA-54, CSA B149.1 and local codes. These codes should be
consulted before a permanent design is determined.
The combustion air must be free of chlorine, halogenated hydrocarbons or other chemicals that
can become hazardous when used in gas-fired equipment. Common sources of these
compounds are swimming pools, degreasing compounds, plastic processing, and refrigerants.
Whenever the environment contains these types of chemicals, combustion air MUST be supplied
from a clean area outdoors for the protection and longevity of the equipment and warranty
validation.
The more common methods of combustion air supply are outlined in the following sections. For
combustion air supply from ducting, consult the AERCO GF-2050, Gas Fired Venting and
Combustion Air Guide.
2.12.1 Combustion From Outside the Building
Air supplied from outside the building must be provided through two permanent openings. For
each unit these two openings must have a free area of not less than one square inch for each
4000 BTUs input of the equipment or 1,500 square inches of free area. The free area must take
into account restrictions such as louvers and bird screens. For Canada installations, refer to the
requirements specified in CSA B149.1-10, sections 8.4.1 and 8.4.3.
2.12.2 Combustion Air from Inside the Building
When combustion air is provided from within the building, it must be supplied through two
permanent openings in an interior wall. Each opening m ust have a free area of not less than one
square inch per 1000 BTUH of total input or 6000 square inches of free area. The free area must
take into account any restrictions, such as louvers.
The source of internal combustion air must be positive or neutral in
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pressure. Negative pressure inside a boiler room may have an adverse
effect on combustion equipment.
For ducted combustion air installations, the air ductwork must then be at tached directly to the air
inlet connection on the sheet metal enclosure.
In a ducted combustion air application, the combustion air ducting pressure losses must be taken
into account when calculating the total maximum allowable venting run. See the AERCO
Benchmark Venting and Combustion Air Guide, GF-2050. When using the unit in a ducted
combustion air configuration, each unit must have a minimum 8 inch d iameter connection at the
unit.
2.14 SEQUENCING VALVE INSTALLATION
All Benchmark units are shipped with a connection for an optional motorized external sequencing
valve (p/n 92084-TAB) included in the shipping container. This valve is an integral component of
the AERCO’s on-board Boiler Sequencing Technology (BST) solution. BST allows sites with
multiple boilers to have one boiler, acting as a “master” to manage the other boilers at the site in
such a way that the efficiency of the entire boiler array is maximized.
The implementation of BST, and the installation and use of this valve is optional.
The boiler IS pre-wired to accept the sequencing valve. Installation consists of installing the
sequencing valve in the hot water outlet pipe, and then connecting it into the shell harness, as
described below.
1. Install the sequencing valve in the boiler’s hot water outlet pipe.
VALVE
OUTLET
Figure 2-13: Sequencing Valve Installed
2. The boiler’s shell harness has one unused cable. One end of this cable is connected to the
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DELAYED INTERLOCK IN terminals in the I/O board (see Figure 2-14) while the other end
contains a Molex connector with a jumper wire inserted in it (this jumper wire allows units
that do not have a sequencing valve to operate normally). Find the free end of this cable
inside the unit’s enclosure.
The information in this Chapter provides a guide to the operation of the Benchmark boiler using
the Control Panel mounted on the front of the unit. It is imperative that the initial startup of this
unit be performed by factory trained personnel. Operation prior to initial startup by factory trained
personnel may void the equipment warranty. In addition, the following WARNINGS and
CAUTIONS must be observed at all times.
ELECTRICAL VOLTAGES IN THIS SYSTEM INCLUDE 460 OR 208, 120
AND 24 VOLTS AC. IT MUST BE SERVICED ONLY BY FACTORY
CERTIFIED SERVICE TECHNICIANS.
DO NOT ATTEMPT TO DRY FIRE THE UNIT. STARTING THE UNIT
WITHOUT A FULL WATER LEVEL CAN SERIO USLY DAMAG E THE UNIT
AND MAY RESULT IN INJURY TO PERSONNEL OR PROPERTY
DAMAGE. THIS SITUATION WILL VOID ANY WARRANTY.
All of the installation procedures in Chapter 2 must be completed before
attempting to start the unit.
3.2 CONTROL PANEL DESCRIPTION
All Benchmark series boilers utilize the C-More Control Panel shown in Fig ure 3-1. This panel
contains all of the controls, indicators and displays necessary to operate, adjust and troubleshoot
the boiler. These operating controls, indicators and displays are listed and described in Table 3-
1. Additional information on these items is provided in the individual operating procedures and
menu descriptions provided in this Chapter.
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If there is a requ irement to use the RS232 port (Item 4) on the C -More
controller front panel, contact AERCO to purchase the RS232 Adaptor
Cable (P/N 124675), which is designed for this purpose. This cable
features a DB9 connector for connection to older computers with serial
ports or can be used with a Serial-to-USB adaptor for use in modern
computer USB ports.
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Lights when the valve position (fire rate) is being controlled
service technician use only.
Lights when the unit is being controlled by an external signal
from an Energy Management System.
DEMAND
Lights when there is a demand for heat.
3–Digit, 7–Segment LED display continuously displays the
LED next to the
On a BST Master, display flashes & shows header
temperature.
Vacuum Fluorescent Display (VFD) consists of 2 lines each
• BST Messages
Port permits a Laptop Computer or External Modem to be
USB adaptor for use in modern computer USB ports.
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
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.
8
ON/OFF Switch
Enables and disables boiler operation.
Allows operator to test operation of the water level monitor.
opens the water level probe circuit and
Pressing the CLEAR key (item 6) resets the display.
CHAPTER 3 – OPERATION
Table 3-1: Operating Controls, Indicators and Displays
ITEM
NO.
CONTROL,
INDICATOR OR
Four Status LEDs indicate the current operating status as follows:
FUNCTION
LED Status Indicators
1
2
3
4
MANUAL
REMOTE
OUTLET
TEMPERATURE
Display
VFD Display
RS-232 Port
using the front panel keypad. This mode of operation is for
outlet water temperature. The °F or °C
display lights to indicate whether the displayed temper ature is
in degrees Fahrenheit or degrees Celsius. The °F or °C blinks
when operating in the Deadband Mode.
capable of displaying up to 16 alphanumeric characters. The
information displayed includes:
• Startup Messages
• Fault Messages
• Operating Status Messages
• Menu Selection
connected to the unit’s Co ntrol Panel. AERCO offers for purchas e
the RS232 Adaptor Cable ( P/N 124675), which is desi gned to work
with this port. This c able features a DB9 c onnect or for connecti on to
older computers with serial ports or can be used with a Serial-to-
5
FAULT Indicator
6
if the alarm is no longer valid. Lockout type alarms will be
CLEAR Key
7
9
READY Indicator
LOW WATER LEVEL
TEST/RESET
Switches
Pressing TEST
simulates a Low Water Level alarm.
Pressing RESET resets the water level monitor circuit.
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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 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 (6817), which is used in Chapter 4 to perform combustion
calibration prior to service use.
3.3.1 Menu Processing Procedure
Accessing and initiating each menu and option is accomplished using the Menu Keys shown in
Figure 3-1. Therefore, it is imperative that you be thoroughly familiar with the following basic
steps before attempting to perform specific menu procedures:
Menu Processing Procedure
1. The Control Panel will normally be in the Operating Menu and the VFD will 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. T he
displayed option will begin to flash. Press the ▲ or ▼ arrow key to scroll through the
available menu option choices for the option to be changed. The menu option choices do
not wrap around.
7. To select and store a changed menu item, press the ENTER key.
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The following sections provide brief descriptions of the options cont ained in
each menu. Refer to Appendix A for detailed descriptions of each menu
option. Refer to Appendix B for listings and descriptions of displayed
startup, status and error messages.
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The Operating Menu displays a number of key operating parameters for the unit as listed in
Table 3-2. This menu is “Read-Only” and does not allow personnel to change or adjust any
displayed items. Since this menu is “Read-Only”, it can be viewed at any time without entering a
password. Pressing the ▲ arrow key to display the menu items in the order listed (Top-Down).
Pressing the ▼ arrow key will display the menu items in reverse order (Bottom-Up).
Table 3-2: Operating Menu
Menu Item Display
Default
*NOTE
The Outdoor Temp and Valve Position Out display items shown with an
asterisk in Table 3-2 will not be displayed unless the Outdoor Sensor
function has been enabled in the Configuration Menu (Table 3-4).
3.5 SETUP MENU
The Setup Menu (Table 3-3) permits the operator to enter the unit password (159) which is
required t o 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.
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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 m enu 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.
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Max Valve Position
Pump Delay Timer
Aux Start On Dly
Failsafe Mode Shutdown or Constant Setpt Shutdown
Low Fire Timer 2 sec. 600 sec. 2 sec.
Setpt Limiting Enabled or Disabled Disabled
Setpt Limit Band 0°F 10°F 0
Network Timeout 5 Sec 999 Sec 30 Sec
HI DB Setpt EN 0% 100% 30%
Demand Offsert 0 25 0
Deadband High 0 25 0
Deadband Low 0 25 0
* Spark Monitor Enabled or Disabled Disabled
* Spark Current Display
40% 100% 100%
0 min. 30 min. 0 min.
0 sec. 120 sec. 0 sec.
Default
NOTE
Spark Monitor and Spark Current are not used on the Benchmark 6000.
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.
Table 3-5: Tuning Menu
Menu Item Display
Prop Band
Integral Gain 0.00 2.00 1.6
Derivative Time 0.0 min 2.00 min 0.10 min
Warmup Prop Band 0 °F 120 °F 95 °F
Warmup Int Gain 0 2.0 0.50
1°F 120°F 8°F
Default
Warmup PID timer 0 sec. 240 sec. 20 sec.
Reset Defaults? Yes, No, Are You Sure? No
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The Combustion Cal (Calibration) Menu is protected by the level 2 password (6817) which must
be entered to view or change the menu items shown in Table 3-6. These menu items are used to
vary the speed of the unit’s blower motor based on air temperature and air density at pres cribed
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 3-6: Combustion Cal Menu
Menu Item Display
Default
3.9 BST (BOILER SEQUENCING TECHNOLOGY ) MENU
The BST Menu must be Enabled in order to be displayed and accessed. The BST Enable item is
located at the end of the Configuration Menu.
The Boiler Sequencing Technology (BST) Menu contains all of the items required to Configure,
Operate and Monitor the functionality of the BST System. There are over 50 items in this menu,
and selecting any particular item from the list, for inspection or modification, could be time
consuming. As a result, the BST Menu has been segmented into FIVE logical groups based on
functionality.
The five Item groups are:
1. BST Monitor Items
2. BST SETUP MENU*
3. * OPERATE MENU *
4. *TEMP CTRL MENU*
5. *BST COMM MENU*
These displayed item groups are displayed in UPPER CASE letters, and are bounded by an
asterisk * in order to readily identify them within the item list.
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The Items contained in group 1 (BST Monitor Items) are ALWAYS displayed within the menu, as
these items are critical for proper system operation. Therefore, the BST Monitor Items Header
itself is NOT displayed.
The Items contained in groups 2-5 are NOT DISPLAYED unless that particular item group has
been enabled from the C-More keypad.
Table 3-7: BST Menu
Menu Item Display
BST Setpoint BST Setpt Lo Limit BST Setpt Hi Limit 130°F
Header Temp NA
BST Fire Rate 0 100% Fire rate %
BST Ave Fire Rate 0 100% Avg Fire Rate %
BST Outdoor Temp NA
Units Available 0 8 Units Present
Units Ignited 0 8 Units firing
BST Valve State 0 (CLOSED) 1 (OPEN) 0
1 Comm Errors 8 0 9 0
1 BST Units 8 0 (see table) 0 (see table) 0
Setback Setpoint BST Setpt Lo Limit BST Setpt HI Limit 130°F
Setback Start 12:00am 11:59pm 12.00am
Setback End 12:00am 11:59pm 12.00am
Rate Threshold 1°F 30°F 15°F
*BST OPERATE
BST Next On VP 16% 100% 50%
BST Max Boilers 1 8 8
BST On Delay 30 sec 300 sec 60 sec
BST On Timeout 15 sec 300 sec 60 Sec
Valve Override Off Closed Open Off
Valve Off Delay 0 15 min 1 min
BST Sequencing Run Hours U ni t Si ze Select Lead Run Hours
Select Lead Unit 0 127 0
Select Lag Unit 0 127 0
Lead/Lag Hours 25 hours 225 hours 72 hours
Minimum Maximum
Disabled Enabled Disabled
Default
*BST TEMP CTRL
BST Temp Hi Limit 40°F 210°F 210°F
BST Setpt Lo Limit 40°F BST Setpt HI Limit 60°F
BST Setpt HI Limit BST Setpt Lo Limit 220°F 195°F
BST Prop Band 1°F 120°F 100°F
BST Intgral Gain 0.00 2.00 0.50
BST Deriv Time 0.00 Min 2.00 Min 0.10 Min
BST Deadband Hi 0 25 1
BST Deadband Lo 0 25 1
Deadband En Time 0 120 Sec 30 Sec
BST FR Up Rate 1 120 20
BST Bldg Ref Tmp 40°F 230°F 70°F
BST Reset Ratio 0.1 9.9 1.2
System Start Tmp 30°F 120°F 60°F
Comm Address 0 127 0
BST Min Addr 1 128 1
BST Max Addr 1 128 8
SSD Address 0 250 247
SSD Poll Control 0 1000 0
Disabled Enabled Disabled
Disabled Enabled Disabled
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When the Benchmark DF unit is set to natural gas, it checks only the natural gas side, and when
it is set to propane, it checks the propane side.
When the Control Box ON/OFF switch is set to the ON position, it checks all pre-purge s afety
switches to ensure they are closed. These switches include:
• Downstream Safet y Shut-Off Valve (SSOV) Proof of Closure (POC) switch
• Low Water Level switch
• High Water Temperature switch
• High Gas Pressure switch
• Low Gas Pressure switch
• Blowe r Proo f swit ch
• 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, if the required conditions are not
observed at any point during the start sequence, appropriate messages will
be displayed and the unit will go into fault mode.
1. The DEMAND LED status indicator will light.
2. The unit checks to ensure that the Proof of Closure (POC) switch in the downstr eam Safety
Shut-Off Valve (SSOV) is closed. See Figure 3-3 for the downstream SSOV location.
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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.
INLET
SWITCH
VALVE TO
BLOWER
PROOF
SWITCH
Figure 3-5: Blower Proof Switch
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NOTE
A Function Timing Chart for the Benchmark 6000 Proved Pilot Control
System is provided in Figure 3-7, below.
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) position and closes the
ignition switch. The Dial on the Air/Fuel Valve will read bet ween 45 and 50 (Figure 3-6)
to indicate that the valve is in the low-fire position.
b) Power is supplied to the Spark Igniter.
c) Power is supplied to the Pilot Gas Solenoid.
d) The Optical Pilot Flame Sensor proves the Pilot Flame and the red LED stops blinking
and changes to steady ON.
e) Ignition relay 1 (R1) closes allowing the main Burner ignition sequence to start.
MOTOR
Figure 3-6: Air/Fuel Valve In Ignition Position
6. When ignition relay 1 (R1) closes, power is supplied to the SSOVs and the following events
occur:
a) The SSOVs open allowing gas to flow into the Air/Fuel Valve.
b) The Main Burner ignites.
c) Main Burner flame is sensed by the C-More Controller.
d) The Control Box turns off power to the ignition transformer and Pilot solenoid valve.
e) Relay 2 (R2) remains energized via the POC Normally Open (N.O.) contact of the
upstream SSOV actuator.
7. A maximum of 7 seconds are allowed for the entire ignition sequence, from applying power
to the ignition transformer through actual Burner flame establishment. The igniter relay wil l
be turned off one second after flame is detected.
8. After 2 seconds of continuous flame, Flame Proven will be displayed and the flame
strength will be indicated. After 5 seconds, the current date and time will be displayed in
place of the flame strength.
9. With the unit firing properly, it will be controlled by the temperature controller circuitry. The
boiler’s VALVE POSITION will be continuously displayed on the front panel bargraph.
Once the demand for heat has been satisfied, the C-More Controller will turn off the SSOV gas
valves. The blower relay will be deactivated and the Air/Fuel Valve will be closed. Standby will
be displayed.
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The start and stop levels are the Air/Fuel Valve posit ions (% open) that start and stop the unit,
based on load. These levels are Factory preset. They are as follows:
Natural Gas Start Level: 22%
Natural Gas Stop Level: 18%
Normally, these settings should not require adjustment.
Note that the energy input of the boiler is not linearly related to the Air/Fuel Valve position. Refer
to Tables 3-8 & 3-9 and the chart in Figure 3-8 for the relationship between the energy input and
Air/Fuel Valve position for a Benchmark 6000 boiler running on natural gas.
Propane Gas Start Level: 22%
Propane Gas Stop Level: 18%
Table 3-8: Relationship Between Air / Fuel Valve Position and Energy Input
For 6000 MBH Units Running Natural Gas or Propane
Air Fuel Valve Position
(% Full Open)
Turndown
Ratio
Note, there is no de-rating for Propane.
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Table 3-9: Gas Pressure De-Rating Char for Natural Gas
The requirements for the initial start-up of the Benchmark 6000 MBH boiler consists of the
following:
• Complete installation (Chapter 2)
• Set proper controls and limits (Chapter 3)
• Perform combustion calibration (Chapter 4)
• Test safety devices (Chapter 6)
All applicable installation procedures in Chapter 2 must be fully completed prior to performing the
initial start-up of the unit. The initial start-up must be successfully completed prior to putting t he
unit into service. Starting a unit without the proper piping, venting, or electrical systems can be
dangerous and may void the product warranty. The following start-up instructions should be
followed precisely in order to operate the unit safely and at a high thermal efficiency, with low flue
gas emissions.
Initial unit start-up must be performed ONLY by AERCO factory trained start-up and service
personnel. After performing the start-up procedures in this Chapter, it will be necessary to
perform the Safety Device Testing procedures specified in Chapter 6 to complete all initial unit
start-up requir ements.
An AERCO Gas Fired Startup Sheet, included with each Benchmark, must be completed for
each unit for warranty validation and a copy must be returned promptly to AERCO at:
AERCO International, Inc.
100 Oritani Drive
Blauvelt, New York 10913
(FAX: 845-580-8090)
DO NOT ATTEMPT TO DRY FIRE THE UNIT. STARTING THE
UNIT WITHOUT A FULL WATER LEVEL CAN SERIOUSLY
DAMAGE THE UNIT AND MAY RESULT IN INJURY TO
PERSONNEL OR PROPERTY DAMAGE. THIS SITUATIO N WILL
VOID ANY WARRANTY.
NOTE
All applicable installation procedures in Chapter 2 must be completed before
attempting to start the unit.
4.2 TOOLS AND INSTRUMENTATION FOR COMBUSTION CALIBRATION
To properly perform combustion calibration, the proper instruments and tools must be used and
correctly attached to the unit. The following sections outline the necessary tools and
instrumentation as well as their installation.
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The following tools and instrumentation are necessary to perform combustion calibration of the
unit:
• Digital Combustion Analyzer: Oxygen accuracy to ± 0.4%; Carbon Monoxide (CO) and
Nitrogen Oxide (NOx) resolution to 1PPM.
• 16 inch W.C. manometer or equivalent gauge and plastic tubing.
• 1/4 inch NPT-to-barbed fittings for use with gas supply manometer or gauge.
• Small and large flat blade screwdrivers.
• Tube of silicone adhesive
4.2.2 Installing Gas Supply Manometer
The gas supply manometer (or gauge) is used to monitor the gas pressure on the downstr eam
side of the SSOV during the Combustion Calibration procedures described in sections 4.4 & 4-5.
The gas supply manometer is installed at the downstream location shown in Figure 4-1.
VALVE
(Install Manometer
here for NATURAL
GAS Combustion
Calibration)
HIGH GAS
PRESSURE
SWITCH
(10.5” W.C.)
OFF VALVE
SSOV with POC
SWITCH
INLETS
LOW GAS
PRESSURE
SWITCH
(8.5” W.C.)
LOW GAS PRESSURE
SWITCH (8.5” W.C.)
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HIGH GAS PRESSURE
SWITCH (6.3” W.C.)
(Install Manometer here for PROPANE Combustion Calibration)
Figure 4-1: 1/4 Inch Gas Plug Location for Combustion Calibration
The Benchmark 6000 is equipped with an interrupted pilot ignition system. The pilot is ignited by
a spark discharge within the Pilot Burner inside the combustion chamber. The input of the Pilot
flame is approximately 18,000 BTU/hr. The Pilot Burner flame will stay ignited until the main
Burner flame has stabilized and “Flame Proven” appears in the C-More Controller display.
A Pilot gas supply regulator reduces the supply pressure from line pressure to 4.9” W.C. An
orifice (0.073” dia.) further restricts the gas flow to the Pilot in accordance with UL safety test
requirements.
The Pilot Burner should be inspected at the beginning of each heating season, or every 6
months for continuous operation units. It is constructed of high quality, heat resistant stainless
steel materials, however some darkening of the metal is to be expected. No adjustment of the
Pilot should be required, however the gas pressure downstream of the regulator should be
checked if an ignition issue is encountered. Refer to Figure 4-1 for test port location.
The Pilot flame is proven by the AERCO BST Sensors located above and below the Pilot. Th e
boiler has two Pilot Flame Detectors. The AERCO BST is an optical sensor inserted in a
viewport. The sensor has a red LED which changes from flashing to steady- ON when the sensor
encounters the flicker of a flame that meets or exceeds the internal sensing threshold. The
sensor is inserted into a tube with a quartz window and observes the Pilot through a hole in the
refractory. The hole in the refractory should be check ed annually to ensure that the optical path
to the Pilot Burner is clear.
NOTE
The AERCO BST sensor switches the signal to neutral when the flame is
proven.
NOTE
When installed and operated in accordance with the r equirements specified
in this manual, the Benchmark 6000 delivers low NOx emis s io ns of <20 ppm
at all firing rates; or if required <9ppm.
The procedures provided in section 4.4 and 4.5 are used to combustion
calibrate the Benchmark 6000 boiler.
4.4 NATURAL GAS COMBUSTION CALIBRATION
Refer to section 4.6 for instructions on how to switch the BMK 6000 boiler fuel source from
Natural Gas to Propane Gas.
NOTE
When installed and operated in accordance with t he requirements specified
in this section, the Benchmark 6000 boiler delivers low NOx emissions of
<20 ppm at all firing rates. Alternatively, these boilers can be combustion
calibrated to provide ultra-low NOx em is s ion s of <9 ppm.
To combustion calibrate the boiler to produce low NOx emissions of <20ppm, complete the instructions in this section. To combustion calibrate the
boiler to produce ultra-low NOx emissions of <9 ppm (Natural Gas only)
first complete the instructions in this section and then, in addition, complet e
the instructions in Appendix N.
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The Benchmark 6000 boiler is combustion calibrated at the factory prior to shipping. The gas
pressure, measured at 100% fire rate ( Air/Fuel Valve % open position) on the downstream side
of the SSOV, must be within the range of 7.9” W.C. ±0.4” W.C. Recalibration as part of initial
start-up is necessary due to changes in t he local altitude, gas BTU content, gas supply piping
and supply regulators. Combustion Calibration Test Data sheets are shipped with each unit.
These sheets must be filled out and returned to AERCO for proper Warranty Validation.
It is important to perform the following procedure as outlined. This will keep readjustments to a
minimum and provide optimum performance.
Natural Gas Combustion Calibration
1. Open the water supply and return valves to the unit and ensure that the system pumps
are running.
2. Open the natural gas supply valve to the unit and then slowly open the Pilot gas valve.
3. Set the control panel ON/OFF switch to the OFF position
4. Turn on external AC power to the unit. The display will show loss of power and the time
and date.
5. Set the unit to the manual mode by pressing the AUTO/MAN key. A f l as hin g manual valve
position message will be displayed with the present position in %. Also, the MANUAL LED
will light.
6. Adjust the air/fuel valve position to 0% by pressing the ▼ arrow key.
7. Ensure that the leak detection ball valve downstream of the SSOV is open and the
manometer is attached and functioning properly.
8. Setthe ON/OFF switch to the ON position.
9. Change the valve position to 50% using the ▲ arrow key. The unit should begin its start
sequence and fire.
10. Next, verify that the gas pressure downstream of the SSOV is set to 7.5” to 8.3” W.C. If
gas pressure adjustment is required, remove the brass hex nut on the SSOV actuator to
access the gas pressure adjustment screw (Figure 4-3). Make gas pressure adjustments
using a flat-tip screwdriver to obtain a gas pressure between 7.5” and 8.3” W.C.
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BRASS HEX HEAD
(Remove to access the Gas
Pressure Adjustment Screw)
Figure 4-3: Gas Pressure Adjustment Screw Location
11. Using the ▲ arrow key, increase the valve open position to 100%. Verify that the gas
pressure on the downstream side of the SSOV settles within the required range of 7.9 ±
0.4” W.C. Readjust the gas pressure if necessary.
NOTE
Record this value as it will be used in the lo w & high pressure gas tests, in
sections 6.3 and 6.4.
12. With the valve position at 100%, insert the combustion analyzer probe into the flue probe
opening and allow enough time for the combustion analyzer reading to stabilize.
13. Compare the oxygen readings on the combustion analyzer to the on-board O
sensor value
2
displayed in the Operating Menu of the C-More Control Panel. If the values differ by more
than ±1.5% and your combustion analyzer is correctly calibrated, the on-board O2 sens or
may be defective and need to be replaced.
14. Compare the measured oxygen level to the oxygen range shown below. Also, ensure that
the nitrogen oxide (NOx) and carbon monoxide (CO) readings do not exceed the values
shown. If you are not in a “NOx-limited” area and/or do not have a NOx measurement in
your analyzer, set the oxygen (O
15. If the oxygen level is not within the required tolerance, the gas pressure on the
downstream side of the SSOV must be adjusted using the gas pressure adjustment screw
on the SSOV (see Figure 4-3). Slowly rotate the gas pressure adjustment (approximately
1/4-turn increments). Allow the combustion analyzer to stabilize following each adjustment.
Clockwise rotation reduces the oxygen level, while counterclockwise rotation increases the
oxygen level.
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16. Once the oxygen level is within the specified range at 100%, record the O2, NOx and CO
readings on the Combustion Calibration Data Sheets provided with the unit.
17. Lower the valve position to 80%using the ▼arrow key.
NOTE
The remaining combustion calibration steps are performed using the
Combustion Cal Menu included in the C-More Control System. The
combustion calibration control functions will be used to adjust the oxygen
level (%) at valve positions of 80%, 60%, 45%, 30% and 18% as described
in the following steps. These steps assume that the inlet air temperature is
within the range of 50°F to 100°F. If NOx readings exceed the target values
shown, increase the O
range. Record the increased O
18. Press the MENU key on the front panel of the C-MORE and access the Setup menu. Enter
password 6817 and then press the ENTER key.
level up to 1% higher than the listed calibration
2
value on the Combustion Calibration sheet.
2
19. Press the MENU key on the front panel of the C-MORE until Combustion Cal Menu
appears on the display.
20. Press the ▲ arrow key until SET Valve Position appears on the display.
21. Press the CHANGE key. SET Valve Position will begin to flash.
22. Press the ▲ arrow key until the SET Valve Position reads 80%. Press the ENTER key.
23. Next, press the down (▼) arrow key until CAL Voltage 70% is displayed.
24. Press the CHANGE key and observe that CAL Voltage 70% is flashing.
25. The oxygen level at the 70% valve position should be as shown below. Also, ensure t hat
the nitrogen oxide (NOx) and carbon monoxide (CO) readings do not exceed the following
values:
Combustion Calibration Readings
Valve Position Oxygen (O2) % Nitrogen Oxid e (NOx) Carbon Monoxide (CO)
70% 6.0% - 6.5% <20 ppm <100 ppm
26. If the oxygen level is not within the specified range, adjust the level using the ▲ and ▼
arrow keys. This will adjust the output voltage to the blower motor as indicated on the
display. Pressing the ▲ arrow key increases the oxygen level and pressing the down ▼
arrow key decreases the oxygen level.
27. Once the oxygen level is within the specified range at 70%, press the ENTER k ey to st ore
the selected blower output voltage for the 80% valve position. Record all readings on the
Combustion Calibration Sheets provided.
28. Repeat steps 20 through 27 f or valve pos itions of 50%, 40%, 30% and 18%* (see *NOTE
below). The oxygen (O
), nitrogen oxide (NOx) and carbon monoxide (CO) should remain
2
within the same limits for all valve positions as shown in the following table.
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Set the Valve Position at 18% but make adjustments to the Combustion
Calibration value designated as 16%.
NOTE
If NOx readings exceed the target values shown (<20 ppm), increase the O2
level up to 1% higher than the listed calibration range shown in the table.
Record the increased O
Valve Position Oxygen (O2) % Nitrogen Oxid e (NOx) Carbon Monoxide (CO)
29. If the oxygen level at the 18% valve position is too high and the Blower voltage is at the
minimum value, you can adjust the idle screw (TAC valve) which is recessed in the top of
the Air/Fuel Valve (see Figure 4-4). Rotate the screw 1/2 turn clockwise ( CW) to add fuel
and reduce the O
to the specified level. Recalibration MUST be performed again from
2
50% down to 14% after making a change to the idle screw (TAC valve).
30. This completes the Natural Gas combustion calibration procedures.
TAC VALVE
IDLE SCREW
Figure 4-4: TAC Valve Adjust (Idle Screw)
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Refer to section 4.6 for instructions on how to switch the BMK 6000 boiler fuel source from
Natural Gas to Propane Gas.
The Benchmark boiler is combustion calibrated and set for Natural Gas fuel at the factory prior to
shipping. The gas pressure must be within the range of 3.8” W.C. ±0.4” W.C.
Recalibration as part of initial start-up is necessary due to changes in the local altitude, gas BTU
content, gas supply type (Natural or Propane), gas supply piping and supply regulators.
Combustion Calibration Test Data sheets are shipped with each unit. These sheets must be filled
out and returned to AERCO for proper Warranty Validation.
It is important to perform the following procedure as outlined. This will keep readjustments to a
minimum and provide optimum performance.
PROPANE Gas Combustion Calibration
1. Open the water supply and return valves to the unit and ensure that the system pumps are
running.
2. Set the control panel ON/OFF switch to the OFF position
3. Turn on external ac power to the unit. The display will show loss of power and the time
and date.
4. Set the unit to the manual mode by pressing the AUTO/MAN key. A f l as hin g manual valve
position message will be displayed with the present position in % and the MANUAL LED
will light.
5. Adjust the air/fuel valve position to 0% by pressing the ▼ arrow key.
6. Ensure that the leak detection ball valve downstream of the SSOV is open.
7. Set the ON/OFF switch to the ON position.
8. Change the valve position to 50%using the ▲ arrow key. The unit should begin its start
sequence and fire.
9. Next, verify that the gas pressure downstream of the SSOV is set to 3.8” W.C. ± 0.4” W.C.
If gas pressure adjustment is required, remove the brass hex nut on the SSOV actuator t o
access the gas pressure adjustment screw (Figure 4-5). Make gas pressure adjustments
using a flat-tip screwdriver to obtain a gas pressure range of 3.8 ” W.C. ± 0.4” W.C .
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BRASS HEX HEAD
(Remove to access the Gas
Pressure Adjustment Screw)
10. Using the ▲ arrow key, increase the valve open position to 100%. Verify that the gas
pressure on the downstream side of the SSOV settles within the required range of 3.8”
W.C. ± 0.4” W.C. Readjust the gas pressure if necessary.
NOTE
Record this value as it will be used in the lo w & high pressure gas tests, in
sections 6.3 and 6.4.
11. With the valve position at 100%, insert the combustion analyzer probe into the flue probe
opening and allow enough time for the combustion analyzer reading to stabilize.
Figure 4-5: Gas Pressure Adjustment Screw Location
12. Compare the oxygen readings on the combustion analyzer to the on-board O
displayed in the Operating Menu of the C-More Control Panel. If the values differ by more
than ±0.5%, have your combustion analyzer calibration checked as soon as possible. If the
readings differ by more than ±1.5%, use the on-board O
sensor to calibrate the unit. Have
2
your combustion analyzer serviced.
13. Compare the measured oxygen level to the oxygen range shown below. Also, ensure that
the nitrogen oxide (NOx) and carbon monoxide (CO) readings do not exceed the values
shown. If you are not in a “NOx-limited” area and/or do not have a NOx measurement in
your analyzer, set the oxygen (O
Combustion Calibration Readings
) at 4.3% ± 0.3%.
2
sensor value
2
Valve Position Oxygen (O2) % Nitrogen Oxid e (NOx) Carbon Monoxide (CO)
100%
4.3% ± 0.3%
<200 ppm <200 ppm
14. If the oxygen level is not within the required tolerance, the gas pressure on the
downstream side of the SSOV must be adjusted using the gas pressure adjustment screw
on the SSOV (Figure 4-5). Slowly rotate the gas pressure adjustment (approximately 1/4turn increments). Allow the combustion analyzer to stabilize following each adjustment.
Clockwise rotation reduces the oxygen level, while counterclockwise rotation increases the
oxygen level.
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15. Once the oxygen level is within the specified range at 100%, record the O2, NOx and
naivety CO readings on the Combustion Calibration Data Sheets provided with the unit.
16. Lower the valve position to 85 %using the ▼arrow key.
NOTE
The remaining combustion calibration steps are performed using
the Combustion Cal Menu included in the C-More Control System.
The combustion calibration control functions will be used to adjust
the oxygen level (%) at valve positions of 85%, 65%, 45%, 30%
and 18% as described in the following steps. These steps assume
that the inlet air temperature is within the range of 50°F to 100°F. If
NOx readings exceed the target values shown, increase the O
level up to 1% higher than the listed calibration range. Record the
increased O
value on the Combustion Calibration sheet.
2
17. 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.
2
18. Press the MENU key on the front panel of the C-MORE until Combustion Cal Menu
appears on the display.
19. Press the ▲ arrow key until SET Valve Position appears on the display.
20. Press the CHANGE key. SET Valve Position will begin to flash.
21. Press the ▲ arrow key until the SET Valve Position reads 85%. Press the ENTER key.
22. Next, press the down (▼) arrow key until CAL Voltage 85% is displayed.
23. Press the CHANGE key and observe that CAL Voltage 85% is flashing.
24. The oxygen level at the 85% valve position should be as shown below. Also, ensure t hat
the nitrogen oxide (NOx) and carbon monoxide (CO) readings do not exceed the following
values:
Combustion Calibration Readings
Valve Position Oxygen (O2) % Nitrogen Oxid e (NOx) Carbon Monoxide (CO)
85% 5.5% - ± 0.5% <200 ppm <200 ppm
25. 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.
26. Once the oxygen level is within the specified range at 85%, press the ENTER key to store
the selected blower output voltage for the 85% valve position. Record all readings on the
Combustion Calibration Sheets provided.
27. Repeat steps 20 through 26 for valve positions of 65%, 45%, 30% and 18%. The oxygen
(O
), nitrogen oxide (NOx) and carbon monoxide (CO) should remain within the same limits
2
for all valve positions as shown in the following table.
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If NOx readings exceed the target values shown (<20 ppm),
increase the O
range shown in the table. Record the increased O
Combustion Calibration sheet.
28. If the oxygen level at the 18% valve position is too high and the Blower voltage is at t he
minimum value, you can adjust the idle screw (TAC valve) which is recessed in the top of
the Air/Fuel Valve (see Figure 4-4, above). Rotate the screw 1/2 turn clockwise (CW) to
add fuel and reduce the O
to the specified level. Recalibration MUST be performed again
2
from 45% down to 18% after making a change to the idle screw (TAC valve).
29. This completes the Propane gas combustion calibration procedures.
4.6 DUAL-FUEL SWITCHOVER INST RUCTIONS
4.6.1 Switchover from NATURAL GAS to PROPANE
To switch from Natural Gas to Propane Gas operation, proceed as follows:
Switchover from NATURAL GAS to PROPANE
1. Set the ON/OFF switch on the C-More Controller to the OFF position.
2. Close the external Natural Gas supply valves.
3. Open the external Propane Gas supply valves.
4. Refer to Figure 4-6 and locate the Fuel Selector Switch on the unit, behind the front door.
5. Set the Fuel Selector Switch to the PROPANE position. A Gas pressure Fault message will
be displayed on the Control Box.
6. Clear the Gas Pressure Fault by pressing the CLEAR key.
7. Set the ON/OFF switch on the C-More /control Box to the ON position.
8. Press the MENU key once. Setup Menu will be displayed.
9. Press the ▲ arrow key once. Password will be displayed.
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The boiler is capable of being operated in any one of six different modes. The sections in this
Chapter provide descriptions of each of these operating modes. Each boiler is shipped from the
factory tested and configured for the ordered mode of operation. All temperature related
parameters are at their factory default values which work well in most applications. However, it
may be necessary to change certain parameters to customize the unit to the system
environment. A complete listing and descriptions of the temperature related parameters are
included in Appendix A. Factory defaults are listed in Appendix E. After reading this chapter,
parameters can be customized to suit the needs of the specific application.
5.2 INDOOR/OUTDOOR RESET MODE
This mode of operation is based on outside air temperatures. As the 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 bui lding reference tem perature and
a reset ratio.
5.2.1 Reset Ratio
Reset ratio is an adjustable number from 0.1 to 9.9. Once adjusted, the supply header
temperature will increase by that number for each degree that the outside air temperature
decreases. For instance, if a reset ratio of 1.6 is used, for each degree that outside air
temperature decreases the supply header temperature will increase by 1.6 degrees.
5.2.2 Building Reference Temperature
This is a temperature from 40°F to 230°F. Once selected, it is the temperature that the system
references to begin increasing its temperature. For instance, if a reset ratio of 1.6 is used, and
we select a building reference temperature of 70°F, then at an outside temperature of 69°F, the
supply header temperature will increase by 1.6° to 71.6°F.
5.2.3 Outdoor Air Temperature Sensor Installation
The outdoor air temperature sensor must be mounted on the North side of the building in an area
where the average outside air temperature is expected. The sensor must be shielded from the
sun's direct rays, as well as direct impingement by the elements. If a cover or shield is used, it
must allow free air circulation. The sensor may be mounted up to two hundred feet from the unit.
Sensor connections are made at the Input/Output (I/O) Box on the front of the boiler.
Connections are made at the terminals labeled OUTDOOR AIR IN and AIR SENSOR COM
inside the I/O Box. Use shielded 18 to 22 AWG wire for connections. A wiring diagram is
provided on the cover of the I/O Box. Refer to Chapter 2, section 2.9.1 for additional wiring
information.
5.2.4 Indoor/Outdoor Reset Mode Startup
Startup in the Indoor/Outdoor Reset Mode is accomplished as follows:
NOTE
A design engineer typically provides design outdoor air temperature and
supply header temperature data
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1. Refer to the Indoor/Outdoor reset ratio charts in Appendix D.
2. Choose the chart corresponding to the desired Building Reference Temperature.
3. Go down the left column of the chart to the coldest design outdoor air temperature
expected in your area.
4. Once the design outdoor air temperature is chosen, go across the 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). If necessary, refer to section 3.3 for detailed
instructions on menu changing.
7. Press the CHANGE key. The display will begin to flash.
8. Use the ▲ and ▼ arrow keys to select the desired Building Reference Temperature.
9. Press ENTER to save any changes.
10. Next, scroll through the Configuration Menu until the display shows Reset Ratio.
11. Press the CHANGE key. The display will begin to flash.
12. Use the ▲ and ▼ arrow keys to select the Reset Ratio determined in step 5.
13. Press ENTER to save the change.
5.3 CONSTANT SETPOINT MODE
The Constant Setpoint mode is used when a fixed header temperature is desired. Common uses
of this mode of operation include water source heat pump loops, and indirect heat exchangers
for potable hot water systems or processes.
No external sensors are required to operate in this mode. While it is necessary to set t he desired
setpoint temperature, it is not necessary to change any other temperature-r elated 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 Appendix A and E.
5.3.1 Setting the Setpoint
The setpoint temperature of the unit is adjustable from 40°F to 240°F. To set the unit for
operation in the Constant Setpoint Mode, the following menu settings must be made in the
Configuration Menu:
Menu Option Setting
Boiler Mode Constant Setpoint
Internal Setpt Select desired setpoint using ▲ and ▼
Refer to section 3.3 for detailed instructions on changing menu options.
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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 Remot e Setpoint mode can
also driven by a RS-485 Modbus Network signal from an EMS or BAS.
The Remote Setpoint modes of operation can be used to drive single as well as multiple units.
NOTE
If a voltage, rather than current signal is used to control t he remote setpoint,
a DIP switch adjustment must be made on the PMC Board located in the
Control Panel Assembly. Refer to Appendix D of the C-More Control Panel
OMM, GF-112, for DIP switch settings, or contact your local AERCO
representative for details.
In order to enable the Remote Setpoint Mode, the following menu setting must be made in the
Configuration Menu:
Menu Option Setting
Boiler Mode Remote Setpoint
Remote Signal 4-20mA/1-5V, 0-20mA/0-5V,
or Network
Refer to section 3.3 for detailed instructions on changing menu options.
If the Network setting is selected f or RS-485 Modbus operation, a valid Comm Address must be
entered in the Setup Menu. Refer to Modbus Communication Manual GF-114 for additional
information.
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 f unctions and their factory defaults, refer to Appendix A and
E.
5.4.1 Remote Setpoint Field Wiring
The only wiring connections necessary for the Remote Setpoint mode are connection of the
remote signal leads from the source to the unit’s I/O Box. The I/O Box is located on the front
panel of the boiler. For either a 4-20mA/0-5V or a 0-20mA/0-5V setting, the connections are
made at the ANALOG IN terminals in the I/O Box. For a Network setting, the connections are
made at the RS485 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
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must be observed. The source end of the shield must be connected at the source. W hen driving
multiple units, each unit’s wiring must conform to the above.
5.4.2 Remote Setpoint Startup
Since this mode of operation is factory preset and t he 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 RS-485 Modbus Network signal from an EMS or BAS.
When in a Direct Drive mode, the unit is a slave to the EMS or BAS and does not have a role in
temperature control. Direct Drive can be used to drive single, or multiple units.
NOTE
If a voltage, rather than current signal is used to contr ol the remote setpoint,
a DIP switch adjustment must be made on the PMC Board located in the
Control Box Assembly. Refer to Appendix D of the C-More Control Panel
OMM, GF-112, for DIP switch settings, or contact your local AERCO
representative for details.
To enable the Direct Drive Mode, the following menu setting must be made in the Configuration
Menu:
Refer to section 3.3 for instructions on changing menu options.
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Menu Option Setting
Boiler Mode Direct Drive
Remote Signal 4-20mA/1-5V, 0-20mA/0-
If the Network setting is selected f or RS-485 Modbus operation, a valid Comm Address must be
entered in the Setup Menu. Refer to Modbus Communication Manual GF-114 for additional
information.
5.5.1 Direct Drive Field Wiring
The only wiring connections necessary for Direct Drive mode are connect ion of the remote signal
leads from the source to the unit’s I/O Box. For either a 4-20mA/0-5V or a 0-20mA/0-5V setting,
the connections are made at the ANALOG IN terminals in the I/O Box. For a Network setting, the
connections are made at the RS-485 COMM terminals in the I/O Box. The signal must be
floating, (ungrounded) at the I/O Box and the wire used must be a two wire shielded pair f rom 18
to 22 AWG. Polarity must be observed. The source end of the shield must be connected at the
source. When driving multiple units, each unit’s wiring must conform to the above.
5.5.2 Direct Drive Startup
Since this mode of operation is factory preset and the valve position is being externally
controlled, no startup instructions are necessary. In this mode, the REMOTE LED will light when
the signal is present.
To operate the unit in manual mode, press the AUTO/MAN s witch. The REMOTE LED wi ll 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 AERCO CONTROL SYSTEM (ACS)
NOTE
ACS utilizes RS-485 signaling to the boiler.
The ACS mode of operation is used in conjunction with an AERCO Control System. The ACS
mode is used when it is desired to operate multiple units in the most efficient manner possible.
For this mode of operation, an ACS Header Sensor must be installed between 2 and 10 feet
downstream of the LAST boiler in the boiler plant's supply water header. The ACS can control up
to 40 boilers; 8 via pulse width modulation (PWM) and up to 32 via Modbus (RS-485) network
communication. The ACS can control up to 32 b oilers via RS-485 network communication. For
programming, operation, and Header Sensor installation details, see GF-131 (ACS) Operations
Guide. For operation via an RS-485 Modbus network, refer to Modbus Communication Manual
GF-114.
To enable the ACS Mode, the following menu settings must be made in the Configuration Menu:
Menu Option Setting
Boiler Mode Direct Drive
Remote Signal Network (RS-485)
Refer to section 3.3 for instructions on changing menu options.
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Wiring connections for RS-485 Modbus control are made between the 485 A- and 485 B+
terminals on the ACS (boilers 9 through 40), and the 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 ACS RS485 COMM wiring connections. Shields should be terminated only at the
ACS and the boiler end must be left floating. Each unit’s wiring must conform to the above.
5.6.2 ACS Setup and Startup
This mode of operation is factory preset and the ACS controls the firing rate (air/fuel valve %
open position). There are no setup instructions for each individual unit.
To operate the unit in manual mode, press the AUTO/MAN s witch. The REMOTE LED wi ll go
off and the MANUAL LED will light
To change back to the ACS mode, simply press the AUTO/MAN switch. T he REMOTE LED will
again light and the MANUAL LED will go off.
5.7 COMBINATION CONTROL SYSTEM (CCS)
NOTE
Only ACS can be utilized for the Combination Control System.
A Combination Control System (CCS) is one that uses multiple boilers to cover both spaceheating and domestic hot water needs. The theory behind this type of system is that the
maximum space-heating load and the maximum domestic hot water load do not occur
simultaneously. Therefore, boilers used for domestic hot water are capable of switching between
constant setpoint and ACS control.
For a typical CCS, an adequate number of boilers are installed to cover the space-heating load
on the design-day. However, one or more units are used for the domestic hot water load as well.
These boilers are the combination units and are referred to as the combo boilers. The combo
boilers heat water to a constant setpoint temperature. That water is then circulated through a
heat exchanger in a domestic hot water storage tank.
Only the AERCO Control System (ACS) is necessary to configure this system if only a single
valve is used to switch from space heating to domestic hot water. However, the ACS Relay
Panel is required in combination with the ACS when there are up to two isolation valves, boiler
interlocks, and/or a Domestic Hot Water (DHW) pump in a Combination heating plant where
AERCO boilers are being used for both Building Heat and Domestic Hot Water heating.
The following two options are available for using a combination system; one that uses only the
ACS, and one that requires the optional ACS Relay Box:
•OPTION 1 - T his option is selected when the ACS controls a boiler plant containing up to
eight combination boilers that are Domestic Hot Water Priority (DHW PRIORITY) boilers,
along with building heat (BLDG HEAT) boilers, and one hydronic isolat ion valve in the main
header between the BLDG HEAT boilers and the DHW PRIORITY boilers.
•OPTION 2 – When this option is selected, the ACS Relay Panel must be used in
conjunction with the ACS. For this option, the ACS controls a boiler plant containing up to
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eight combination boilers that are divided up into Building Priority (BLDG PRIORITY) boilers
and Domestic Hot Water Priority (DHW PRIORITY) boilers, along with building heat (BLDG
HEAT) boilers, and using two hydronic isolation valves in the main header, one between the
BLDG HEAT and BLDG PRIORITY boilers, and the other between the BLDG PRIORITY
and the DHW PRIORITY boilers.
In Option 2, when the space-heating load is such that when all the space-heating boilers are at
the 100% valve position, the ACS will then ask the ACS Relay Box for the domestic boilers to
become space-heating boilers. Provided the domestic hot water load is satisfied, the combo (hot
water) boilers will then become space-heating boilers. If the domestic hot water load is not
satisfied, the combo boiler(s) remain on the domestic hot water load. If the combo boilers switch
over to space heating, but there is a call for domestic hot water, the ACS Relay Box switches the
combo units back to the domestic load. The ACS in combination with the ACS Relay Box will ask
the BLDG PRIORITY boilers to help with domestic hot water heating if the DHW PRIORITY
boilers are not able to satisfy the domestic hot water demand.
When the combo units are satisfying the domestic load, they are in the constant setpoint mode of
operation. When the combo units switch over to space heating, their mode of operation changes
to follow the ACS command. For more information concerning the operation of the ACS, consult
the ACS Operations Guide, GF-131. For more information on the ACS Relay Box, see section
2.14 in the same manual.
5.7.1 Combination Control System Field Wiring
Wiring for this system is between the ACS, the ACS Relay Box, and the terminals in the I/O Box.
Wire the units using a shielded twisted pair of 18 to 22 AWG wire. When wiring multiple units,
each unit’s wiring must conform to the above.
5.7.2 Combination Control System Setup and Startup
Setup for the Combination Mode requires entries to be made in the Configuration Menu for boiler
mode, remote signal type and setpoint. The setpoint is adjustable from 40°F to 190°F.
Enter the following settings in the Configuration Menu:
Menu Option Setting
Boiler Mode Combination
Remote Signal Network
Internal Setpt 40°F to 190°F
Refer to section 3.3 for instructions on changing menu options.
While it is possible to change other temperature-related functions for combination mode, these
functions are preset to their factory default values. These default settings work well in most
applications. It is suggested that AERCO be contacted prior to changing settings 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 L ED will go
off and the REMOTE LED will light.
When the boiler is switched to ACS control, the ACS controls the valve position. There are no
setup requirements to the boiler(s) in this mode.
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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 t o
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.
Also, it will be necessary to remove the front door and side panels from the
unit to perform the following tests.
ELECTRICAL VOLTAGES IN THIS SYSTEM MAY INCLUDE 208-230 OR
460, 120 AND 24 VOLTS AC. POW ER MUST BE REMOVED PRIOR TO
PERFORMING W IRE REMOVAL OR OT HER TEST PROCEDURES THAT
CAN RESULT IN ELECTRICAL SHOCK.
6.2 LOW GAS PRESSURE FAULT TESTS
Refer to Figure 6-1A to locate both Low Gas Pressure switches and the proper locations to
connect the water column manometer when performing the tests in this section.
The Low Gas Pressure Switch is adjustable; the instructions below set it to the correct position.
The instructions below apply to both the Natural Gas and Propane gas trains.
Low Gas Pressure Fault Test
1. Sh u t o ff th e external gas supply by closing the external gas supply ball valve.
2. Remove the 1/4“ plug from the Tee at the NATURAL GAS Low Gas Pressure Switch
shown in the top-half of Figure 6-1A.
3. Install a NPT-to-barbed fitting and connect a 14“ W.C. to 2 psi manometer where the 1/4"
plug was removed.
4. Apply the readings of the manifold pressure taken in Step 11 of section 4.4 (for Natural
Gas) and Step 10 of section 4.5 (for Propane), and plug them into the following formulas,
which calculate the minimum allowable gas pressure:
• Natural Gas Pressure ____ x 0.5 + 6.0 = ______ min gas pressure
• Propane Gas Pressure ____ x 0.5 + 3.7 = ______ min gas pressure
OMM-0096_0B AERCO International, Inc. • 100 Oritani Dr. • Blauvelt, NY 10913 Page 81 of 219
GF-141 Ph.: 800-526-0288 03/21/2014
To simulate a high gas pressure fault, refer to Figure 6-1B and perform the following steps. T he
instructions below apply to both the Natural Gas and Propane gas trains.
SSOV with POC
SWITCH
VALVE
TEE with 1/4" PLUG
(Install manometer
here for HIGH GAS
PRESSURE test)
INLET
HIGH GAS PRESSURE
SWITCH
(10.5” W.C.)
TEE with 1/4" PLUG
(Install manometer
here for HIGH GAS
PRESSURE test)
1. Remove the 1/4“ plug from the Tee next to the NATURAL G AS High G as Pressur e Switch,
shown in the upper half of Figure 6-1B.
2. Install a NPT-to-barbed fitting and a 0 – 16” W.C. manometer where the 1/4” plug was
removed. Open the ball valve at the High Gas Pressure switch.
3. Apply the readings of the manifold pressure taken in Step 11 of section 4.4 (for Natural
Gas) and Step 10 of section 4.5 (f or Propane), and plug them into the following formulas,
which calculate the maximum allowable gas pressure:
• Natural Gas Pressure ______ x 1.5 = ______ max gas pressure
• Propane Gas Pressure ______ x 1.5 = ______ max gas pressure
(6.3” W.C.)
Figure 6-1B. High Gas Pressure Test
High Gas Pressure Fault Test
4. Remove the cover from the High Gas Pressure switch and set the dial indicator to 20 (the
maximum).
OMM-0096_0B AERCO International, Inc. • 100 Oritani Dr. • Blauvelt, NY 10913 Page 83 of 219
GF-141 Ph.: 800-526-0288 03/21/2014
5. Open the external gas supply ball valve upstream of the unit.
6. Start the unit in Manual Mode and adjust the Air/Fuel Valve position to bring the unit up to
100%,
7. Slowly increase the manifold gas supply pressure by turning the Gas Pressure Adjustment
Screw in the Downstream SSOV (Figure 6-2) while reading the CO level on the
combustion analyzer. Adjust the manifold pr essure until the CO reading is 300 ppm. Note
the number of turns you make, as you will turn it back to its original position in step 10,
below.
(Remove to access
the Gas Pressure
Adjustment Screw).
Figure 6-2: Gas Pressure Adjustment Screw Location
8. Take a reading of the manifold gas pressure. If the manifold pressure is greater than the
maximum calculated in step 3, then use the Gas Pressure Adjustment Screw to decrease
the manifold pressure until it is at the maximum allowed.
9. Slowly turn the indicator dial on the High Gas Pressure Switch until the unit shuts down
due to a gas pressure fault. This is the setpoint.
10. Readjust the manifold gas supply pressure to what it was before it was increased in step 7.
11. Press the CLEAR button on the Control Panel to clear the fault.
12. Upon test completion, close the ball valve and remove the manometer, and then replace
the 1/4“ plug removed in step 1.
13. Repeat this procedure on t he PROPANE gas train, starting with the 1/4“ plug next to the
PROPANE High Gas Pressure switch, shown in the bottom-half of Figure 6-1B.
6.4 LOW WATER LEVEL FAULT TEST
To simulate a low water level fault, proceed as follows:
Low Water Level Fault Test
1. Set the ON/OFF switch to the OFF position
2. Close the water shut-off valves in the supply and return piping to the unit.
3. Slowly open the drain valve on the rear of the unit. If necessary the unit’s relief valve may
Page 84 of 219AERCO International, Inc. • 100 Oritani Dr. • Blauvelt, NY 10913 OMM-0096_0B
03/21/2014 Ph.: 800-526-0288 GF-141
4. Continue draining the unit until a LOW WATER LEVEL f ault 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 t o 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 6-3.
Water Temperature Fault Tes t
1. Start the unit in the normal operating mode. Allow the unit to stabilize at its setpoint.
2. Lower the adjustable over-temperature switch setting to match the displayed OUTLET
TEMPERATURE.
3. Once the adjustable over-temperature switch setting is approximately at, or just below, the
actual outlet water temperature, the unit should shut down. The FAULT indicator should
start flashing and a HIGH WATER TEMP SWITCH OPEN fault message should be
displayed. It should not be possible to restart the unit.
4. Reset the adjustable over-temperature switch to its original setting.
5. The unit should start once the adjustable temperature limit switch setting is above the
actual outlet water temperature.
OMM-0096_0B AERCO International, Inc. • 100 Oritani Dr. • Blauvelt, NY 10913 Page 85 of 219
GF-141 Ph.: 800-526-0288 03/21/2014
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 2-13) and ar e labeled
REMOTE INTL’K IN and DELAYED INTL’K IN. These circuits can shut down the unit in the
event that an interlock is opened. These interlocks are shipped from the factory jumpered
(closed). However, each of these interlocks may be utilized in the field as a remote stop and
start, an emergency cut-off, or to prove that a device such as a pump, gas booster, or louver is
operational.
6.6.1 Remote Interlock Test
Remote Interlock Test
1. Remove the cover from the I/O Box and locate the REMOTE INTL’K IN terminals.
2. Start the unit in the Manual Mode and set the valve position between 25% and 30%.
3. If there is a jumper across the REMOTE INTL’K IN terminals, remove one side of the
jumper. If the interlock is being controlled by an external device, either open the interlock
via the external device or disconnect one of the wires leading to the external device.
4. The unit should shut down and display INTERLOCK OPEN.
5. Once the interlock connection is reconnected, the INTERLOCK OPEN message should
automatically clear and the unit should restart.
6.6.2 Delayed Interlock Test
Delayed Interlock Test
1. Remove the cover from the I/O Box and locate the DELAYED INTL’K IN terminals.
2. Start the unit in the Manual Mode at a valve position between 25% and 30%.
3. If there is a jumper across the DELAYED INTL’K IN terminals, remove one side of the
jumper. If the interlock is connected to a proving switch of an external device, disconnect
one of the wires leading to the proving switch.
4. The unit should shut down and display a DELAYED INTERLOCK OPEN fault message.
The FAULT LED should be flashing.
5. Reconnect the wire or jumper removed in step 3 to restore the interlock.
6. Press the CLEAR button to reset the fault
7. The unit should start.
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:
OMM-0096_0B AERCO International, Inc. • 100 Oritani Dr. • Blauvelt, NY 10913 Page 87 of 219
GF-141 Ph.: 800-526-0288 03/21/2014
8. Go to the Configuration Menu, Analog Output item and select VALVE POSITION 0-10v.
6.8.2 Blocked Inlet Switch Test
This test will be run in simulated fire mode, with the Blocked Inlet Switch isolated from the rest of
the control circuitry.
Blocked Inlet Switch Test
1. Turn off the main ON/OFF switch on the front of the Control Panel.
2. For units that get combustion air from a Combustion Air Duct, remove that duct, located
directly above the boiler (see Figure 6.6, below). For units that have an air filter in place of
a Combustion Air Duct (not shown), Remove the three (3) hex head screws securing the YDuct and air filters to the Air/Fuel valve and carefully remove the Y-Duct and air filter
assembly.
WARNING
THE BLOWER SUCTION IS VERY STRONG AND CAN PULL NEARBY
OBJECTS INTO THE BLOWER’S FAN BLADE S. DO ALLOW ANYT HING
TO BE PULLED INTO THE BLOWER. DO NOT W EAR ANYTH ING THAT
COULD GET CAUGHT AND PULL YOU INTO THE BLOWER.
3. Turn off the gas supply ball valve to the boiler and then complete the following steps:
a) Use jumper wires to jump out the Low Gas Pressure Switch and the Blower Proof
Switch.
b) Remove the black connector boot from the Flame Detector.
c) Connect the Flame Signal Generator to the black connector boot.
CONNECTOR BOOT
Figure 6.5a: Connecting the Flame Signal Generator
d) Keep the alligator clip away from bare metal parts until step 4c.
4. Complete the following with the boiler operating in Manual mode:
a) Ramp the boiler up to 100% fire r ate and then turn on the main ON/O FF switch on the
front of the Control Panel.
b) Push the BACK button three (3) times to return to the upper level menu.
c) When the Controller gets into the ignition phase, the Control Panel will show IGNITION
TRIAL. At that point attach the alligator clip (see Figure 6.5a) to any bare metal surface
or ground. The C-Mor e display should now show FLAME PROVEN and begin to ramp
up to 100% fire rate. Note that no gas or flame is present in the boiler at this time.
5. Wait for the boiler to ramp up to at least 90% before continuing.
Page 90 of 219AERCO International, Inc. • 100 Oritani Dr. • Blauvelt, NY 10913 OMM-0096_0B
03/21/2014 Ph.: 800-526-0288 GF-141
For both the Natural Gas and Propane gas trains, the downstream SSOV (see Figure 6-1B)
contains the proof of closure (POC) switch. The proof of closure switch circuit is checked as
follows:
SSOV Proof of Closure Switch
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 6-1B to locate the downstream SSOV.
4. Remove the cover from the SSOV by loosening the screw shown in Figure 6-7. 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 the ON position to start the unit.
9. Remove the wire again when the unit reaches the purge cycle and PURGING is displayed.
10. The unit should shut down and display SSOV FAULT DURING PURGE.
11. Replace the wire on the SSOV and press the CLEAR button. The unit should restart.
The unit requires regular routine maintenance to keep up efficiency and reliability. For best
operation and life of the unit, the following routine maintenance procedur es should be performed
in the time periods specified in Table 7-1. For a complet e inspection check list see ASME CSD-1
chart.
In order to perform the maintenance tasks specified in Table 7-1, the f ollowing maintenance k its
are available through your local AERCO Sales Representative:
• Annual Maintenance Kit, Part No. 58025-11
• 24-Month Waterside/Fireside Inspection Kit, Part No. 58025-12 (See NOTE below)
NOTE
The 24-Month Waterside/Fireside Inspection Kit also includes the items
contained in the Annual Maintenance Kit (58025-11). Therefore, only Kit
Part No. 58025-12 is required when performing the waterside/fireside
inspections. Refer to Appendix L for recommended spares.
TO AVOID PERSONAL INJURY, PRIOR TO SERVICI NG ENSURE THAT
THE FOLLOWING GUIDELINES ARE STRICTLY OBSERVED:
• DISCONNECT THE AC SUPPLY BY TURNING OFF THE SERVICE
SWITCH AND AC SUPPLY CIRCUIT BRE AKER.
• SHUT OFF THE GAS SUPPLY AT THE MANU AL SHUT-OFF VALVE
PROVIDED WITH THE UNIT
• ALLOW THE UNIT TO COOL TO A SAFE WATER TEMPERATURE TO
PREVENT BURNING OR SCALDING
The Pilot Burner (part no. 29700) is located on the right-front of the Burner Plate. It contains an
ignition cable and a Pilot gas line connected to the bushing. Fig ure 7-1 shows the location of t he
Pilot Burner and related components.
DETECTOR
BURNER
DETECTOR
GAS LINE
Figure 7-1: Pilot Burner, Main & Pilot Flame Detector Mounting Locations
The Pilot Burner may be hot, therefor e care should be exercised to avoid burns. It is easier to
remove the Pilot Burner from the unit after it has cooled to room temperature. To inspect/replace
the Pilot Burner, perform the following procedure:
Pilot Burner Maintenance Procedure
1. Set the ON/OFF switch on the control panel, to the OFF position. Disconnect AC power
from the unit
2. For easy access, open the front panel and right side door. If you are working on the left unit
of a t wo-unit, zero side clearance installation, you may want to remove the top panel and
service the unit from above.
3. Disconnect the ignition cable from the Pilot Burner (Figure 7-1).
4. Using a 1/2” open-end wrench, disconnect the Pilot gas line from the reducer fitting and
elbow shown in Figure 7-1.
5. First, remove the reducer fitting and then the elbow from the Pilot Burner.
6. Remove one of the two Pilot Flame Detectors to provide clearance for Pilot Burner
7. Using a 1-1/2” open end wrench, loosen and remove the Pilot Burner from the Burner
Page 98 of 219AERCO International, Inc. • 100 Oritani Dr. • Blauvelt, NY 10913 OMM-0096_0B
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8. Check the Pilot Burner tip for evidence of erosion or carbon build-up. If there is evidence of
substantial erosion or carbon build-up, the Pilot Burner should be replaced. If carbon buildup is present, clean the component using a wire brush. Check to ensure that the vanes are
not bent out of the proper position of a 20º incline. 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.
9. Prior to reinstalling the Pilot Burner, a high temperature, conductive, anti-seize compound
must be applied to the threads.
10. Reinstall the Pilot Burner on the Burner Plate. Ensure that the tapped hole for the elbow is
facing outward toward the edge of the Burner Plate to permit connection of the Pilot Burner
gas line. Torque to 170 - 180 in-lbs.
11. Reassemble the remaining components in the reverse order that they were removed.
12. Reconnect the ignition cable.
13. Close the right side door and front panel. Replace the top panel if the unit was serviced
from above.
7.3 MAIN FLAME DETECTOR
The Main Flam e Detector (part no. 65136) is located on the Blower Flange near the top of the
unit (see Figures 7-1). The Main Flame Detector may be hot. Allow t he unit to cool sufficiently
before removing the Main Flame Detector. Inspect or replace the Main Flame Detector as
follows:
Main Flame Detector Maintenance Procedure
1. Set the control panel ON/OFF switch to the OFF position. Disconnect AC power from the
unit.
2. Remove the front panel from the unit by grasping the top handle and pulling straight out.
3. Disconnect the Main Flame Detector lead wire. Be careful not to yank the wire when it
pops off the Main Flame Detector.
4. Remove the Main Flame Detector from the Blower Flange.
5. Thoroughly inspect the Main Flame Detector. If eroded, the detector should be replaced.
Otherwise clean the detector with a fine emery cloth.
6. Apply a small amount of high temperature TFE-Based thread sealant and reinstall the Main
Flame Detector on the Blower Flange.
7. Reconnect the Main Flame Detector lead wire.
8. Replace the front panel on the unit.
OMM-0096_0B AERCO International, Inc. • 100 Oritani Dr. • Blauvelt, NY 10913 Page 99 of 219
GF-141 Ph.: 800-526-0288 03/21/2014
The O2 sensor (part no. 61026) is located on the back plate at t he right side of t he unit as shown
in Figure 7-2. As t his Figure shows, there is also a g as suction line that supplies a sampling of
the exhaust gases from the exhaust manifold to ensure accurate sampling of the O
sensor and the suction line may be hot, therefore allow the unit to cool sufficiently before
removing or replacing the O
sensor.
2
NOTE
The O2 Sensor needs to be replaced only once every 5 years
The O
Sensor is removed and inspected by performing the following procedural steps:
2
O2 Sensor Maintenance Procedures
1. Set the ON/OFF switch on the control panel, to the OFF position. Disconnect AC power
from the unit.
2. Remove the rear right-side panel from the unit by removing the screws at the top and rear
(Figure 7-2).
le vels. The
2
3. Disconnect the O
s ensor lead wire by pushing in on the release tab and pulling apart the
2
connector.
4. Next, loosen and remove the O
sensor and crush washer from the back plate using a
2
15/16" open-end wrench.
5. Thoroughly inspect the O
sensor. If corroded, the sensor should be replaced. Ensur e that
2
the hole in the refractory is clean and that the gas sample suction tube is not clogged.
6. Reinstall the O
sensor and crush washer on the back plate.
2
7. Reconnect the sensor lead wire.
8. Reinstall the rear right side panel on the unit.
Page 100 of 219AERCO International, Inc. • 100 Oritani Dr. • Blauvelt, NY 10913 OMM-0096_0B
03/21/2014 Ph.: 800-526-0288 GF-141
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