Watts Aerco Benchmark OMM-0124 Installation and operation manual

Installation and Startup Manual
Benchmark®Boilers
Natural Gas, Propane Gas and Dual Fuel
Fired Modulating & Condensing Boilers
Models 5000 and 6000
Other documents for this product include:
OMM-0124, GF-208 Operation-Service Manual
TAG-0019, GF-2070 Boiler Application Guide
TAG-0022, GF-2050 Vent-Combustion Air Guide
TAG-0047, GF-2030 Benchmark Gas Guide
TAG-0048, GF-2060 Benchmark Power Guide
Applies to serial numbers:
N-19-0001 and above
Disclaimer
The information contained in this manual is subject to change without notice
from AERCO International, Inc. AERCO makes no warranty of any kind with
respect to this material, including, but not limited to, implied warranties of
merchantability and fitness for a particular application. AERCO International is
not liable for errors appearing in this manual, not for incidental or
consequential damages occurring in connection with the furnishing,
performance, or use of these materials
OMM-0123_E •GF-207 •12/17/2019

Benchmark 5000-6000 Boiler Installation & Startup Manual
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TABLE OF CONTENTS
FOREWORD ....................................................................................................5
SECTION 1: SAFETY PRECAUTIONS..................................................................9
1.1 WARNINGS & CAUTIONS .....................................................................................................................9
1.2 EMERGENCY SHUTDOWN.................................................................................................................10
1.3 PROLONGED SHUTDOWN.................................................................................................................10
1.4 IMPORTANT –FOR MASSACHUSETTS INSTALLATIONS...............................................................11
SECTION 2: INSTALLATION ...........................................................................13
2.1 INTRODUCTION...................................................................................................................................13
2.2 RECEIVING THE UNIT.........................................................................................................................13
2.3 UNPACKING.........................................................................................................................................13
2.4 SITE PREPARATION ...........................................................................................................................14
2.4.1 Installation Clearances...................................................................................................................14
2.4.2 Setting the Unit...............................................................................................................................16
2.4.3 LIFTING PROVISIONS ..................................................................................................................17
2.4.4 MULTIPLE UNIT INSTALLATIONS ...............................................................................................17
2.5 SUPPLY AND RETURN PIPING..........................................................................................................17
2.6 PRESSURE RELIEF VALVE INSTALLATION .....................................................................................19
2.7 PRESSURE/TEMPERATURE GAUGE INSTALLATION.....................................................................19
2.8 CONDENSATE DRAIN AND PIPING...................................................................................................20
2.9 GAS SUPPLY PIPING..........................................................................................................................22
2.9.1 Gas Supply Specifications..............................................................................................................22
2.9.2 Manual Gas Shutoff Valve..............................................................................................................22
2.9.3 External Gas Supply Regulator......................................................................................................22
2.10 AC ELECTRICAL POWER WIRING...................................................................................................24
2.10.1 Electrical Power Requirements ....................................................................................................24
2.10.2 Power Box Location......................................................................................................................24
2.11 FIELD CONTROL WIRING.................................................................................................................26
2.11.1 Outdoor Air & Air Sensor Common..............................................................................................27
2.11.2 AIR TEMP SENSOR ....................................................................................................................28
2.11.3 O2SENSOR (+ & –) .....................................................................................................................28
2.11.4 SPARK SIGNAL (+ & –) ...............................................................................................................28
2.11.5 ANALOG IN..................................................................................................................................28
2.11.6 VALVE FEEDBACK......................................................................................................................28
2.11.7 SHIELD (SHLD & SHLD) .............................................................................................................29
2.11.8 ANALOG OUT..............................................................................................................................29
2.11.9 RS485 Comm (+, GND, & -).........................................................................................................29
2.11.10 RS232 Comm (TxD & RxD) .......................................................................................................29
2.11.11 VFD/Blower (0-10 & AGND).......................................................................................................29
2.11.12 Interlocks....................................................................................................................................29
2.11.13 Fault Relay (NC, COM, & NO) ...................................................................................................30
2.11.14 Auxiliary Relay Contacts (NC, COM, & NO) ..............................................................................30
2.12 FLUE GAS VENT INSTALLATION.....................................................................................................31
2.12.1 MASSACHUSETTS INSTALLATIONS ........................................................................................31
2.13 COMBUSTION AIR.............................................................................................................................32
2.13.1 DUCTED COMBUSTION AIR......................................................................................................32
2.14 BENCHMARK PUMP RELAY.............................................................................................................32
2.15 SEQUENCING ISOLATION VALVE INSTALLATION ........................................................................34
SECTION 3: START SEQUENCE.......................................................................37

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3.1 INTRODUCTION...................................................................................................................................37
3.2 START SEQUENCE .............................................................................................................................37
3.3 START/STOP LEVELS.........................................................................................................................42
3.4 START/STOP LEVELS –AIR/FUEL & ENERGY INPUT.....................................................................42
3.4.1 Benchmark 5000 Air/Fuel Valve Position and Energy Input ..........................................................42
3.4.2 Benchmark 6000 Air/Fuel Valve Position and Energy Input ..........................................................43
3.5 BOILER ENERGY INPUT CHARTS.....................................................................................................44
SECTION 4: INITIAL START-UP.......................................................................47
4.1 INITIAL START-UP REQUIREMENTS.................................................................................................47
4.2 TOOLS & INSTRUMENTS FOR COMBUSTION CALIBRATION........................................................48
4.2.1 Required Tools & Instrumentation..................................................................................................48
4.2.2 Installing Gas Supply Manometer ..................................................................................................48
4.2.3 Accessing the Analyzer Probe Port................................................................................................49
4.3 PILOT IGNITION...................................................................................................................................50
4.4 FUEL TYPES AND COMBUSTION CALIBRATION.............................................................................50
4.5 COMBUSTION CALIBRATION.............................................................................................................51
4.5.1 NATURAL GAS Combustion Calibration........................................................................................51
4.5.2 PROPANE GAS COMBUSTION CALIBRATION...........................................................................55
4.6 REASSEMBLY......................................................................................................................................58
4.7 DUAL FUEL SWITCHOVER.................................................................................................................58
4.7.1 Switchover from NATURAL GAS to PROPANE ............................................................................59
4.7.2 Switchover from PROPANE to NATURAL GAS ............................................................................60
4.8 OVER-TEMPERATURE LIMIT SWITCHES.........................................................................................61
4.8.1 Digital Alarm Switch Checks and Adjustments ..............................................................................61
SECTION 5: SAFETY DEVICE TESTING.............................................................63
5.1 TESTING OF SAFETY DEVICES.........................................................................................................63
5.2 LOW GAS PRESSURE TEST ..............................................................................................................63
5.3 HIGH GAS PRESSURE TEST .............................................................................................................65
5.4 LOW WATER LEVEL FAULT TEST.....................................................................................................67
5.5 WATER TEMPERATURE FAULT TEST..............................................................................................68
5.6 INTERLOCK TESTS.............................................................................................................................69
5.6.1 Remote Interlock Test ....................................................................................................................69
5.6.2 Delayed Interlock Test....................................................................................................................69
5.7 FLAME FAULT TEST............................................................................................................................70
5.8 AIR FLOW FAULT TESTS....................................................................................................................70
5.8.1 Blower Proof Switch Test ...............................................................................................................71
5.8.2 Blocked Inlet Switch Test ...............................................................................................................72
5.9 SSOV PROOF OF CLOSURE SWITCH CHECK.................................................................................73
5.10 PURGE SWITCH OPEN DURING PURGE........................................................................................74
5.11 IGNITION SWITCH OPEN DURING IGNITION .................................................................................75
5.12 SAFETY PRESSURE RELIEF VALVE TEST.....................................................................................76
SECTION 6: BOILER SEQUENCING TECHNOLOGY...........................................77
6.1 INTRODUCTION...................................................................................................................................77
6.1.1 Installation Notes............................................................................................................................78
6.2 AERCO BST QUICK START CHART...................................................................................................78
6.3 BST IMPLEMENTATION INSTRUCTION ............................................................................................79
6.3.1 OPTION 1 - Constant Setpoint With Direct Wired Header Sensor ................................................79
6.3.2 OPTION 2 - Constant Setpoint With Modbus Wired Header Sensor.............................................80

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6.3.3 OPTION 3 - Outdoor Reset With Direct Wired Header Sensor And Direct Wired Outdoor Sensor
.................................................................................................................................................................81
6.3.4 OPTION 4 - Outdoor Reset With Modbus Header Sensor And Modbus Outdoor Sensor.............83
6.3.5 OPTION 5 - Remote Setpoint With Direct Wired Header Sensor And 4-20ma Setpoint Drive......85
6.3.6 OPTION 6 - Remote Setpoint With Direct Wired Header Sensor And Modbus Setpoint Drive.....87
6.3.7 OPTION 7 - Remote Setpoint With Modbus Header Sensor And 4-20ma Setpoint Drive.............89
6.3.8 OPTION 8 - Remote Setpoint With Modbus Header Sensor And Modbus Setpoint Drive............91
APPENDIX A: DIMENSIONAL AND CLEARANCE DRAWINGS..............................93

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FOREWORD
AERCO Benchmark (BMK) 5000 MBH (1465 kW) and 6000 MBH (1758 kW) natural gas and
dual fuel propane/natural gas fueled boilers are modulating and condensing units. They
represent a true industry advance that meets the needs of today's energy and environmental
concerns. Designed for application in any closed loop hydronic system, their modulating
capability relates energy input directly to fluctuating system loads. The maximum turn down ratio
for the BMK 5000 and 6000 is 15:1. These Benchmark models provide extremely high
efficiency, which makes them ideally suited for modern low temperature, as well as conventional
heating systems.
IMPORTANT!
Unless otherwise specified:
•All descriptions provided in this document apply to the Benchmark Series boilers.
•All measurements apply to both natural gas and propane models, unless otherwise
specified.
The Benchmark 5000 and 6000 models operate within the input and output ranges listed below.
Benchmark 5000 and 6000 Intake and Output Ranges
MODEL
INPUT RANGE (BTU/HR.)
OUTPUT RANGE (BTU/HR.)
MINIMUM
MAXIMUM
MINIMUM
MAXIMUM
5000
400,000 (117 kW)
5,000,000 (1465 kW)
348,000 (102 kW)
4,750,000 (1392 kW)
6000
400,000 (117 kW)
6,000,000 (1758 kW)
348,000 (102 kW)
5,700,000 (1670 kW)
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, these boilers comply
with the NOxemission standards outlined in: South Coast Air Quality Management District
(SCAQMD), Rule 1146.2.
Whether used in singular or modular arrangements, BMK 5000 and BMK 6000 boilers offer the
maximum venting flexibility with minimum installation space requirements. These boilers are
Category II and IV, positive pressure appliances. Single and/or multiple breeched units are
capable of operation in the following vent configurations:
•Room Combustion Air:
oVertical Discharge
oHorizontal Discharge
•Ducted Combustion Air:
oVertical Discharge
oHorizontal Discharge
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.

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AERCO Technical Terminology
TERMINOLOGY
MEANING
A (Amp)
Ampere
ACS
AERCO Control System, AERCO’s boiler management systems
ADDR
Address
AGND
Analog Ground
ALRM
Alarm
ANSI
American National Standards Institute,
ASME
American Society of Mechanical Engineers
AUX
Auxiliary
BAS
Building Automation System, often used interchangeably with EMS
(see below)
Baud Rate
Symbol rate, or simply the number of distinct symbol changes
(signaling events) transmitted per second. It is not equal to bits per
second, unless each symbol is 1 bit long.
BMK (Benchmark)
AERCO’s Benchmark series boilers
BMS or BMS II
AERCO Boiler Management Systems
BLDG (Bldg)
Building
BST
AERCO on-board Boiler Sequencing Technology
BTU
British Thermal Unit. A unit of energy approximately equal to the heat
required to raise 1 pound (0.45 kg) of water 1°F (0.55 °C)
BTU/HR
BTUs per Hour (1 BTU/hr = 0.29 W)
CCP
Combination Control Panel
CCS
Combination Control System
C-More Controller
A control system developed by AERCO and currently used in all
Benchmark, Innovation and KC1000 Series product lines.
CFH
Cubic Feet per Hour (1 CFH = 0.028 m3/hr)
CO
Carbon Monoxide
COMM (Comm)
Communication
Cal.
Calibration
CNTL
Control
CPU
Central Processing Unit
DBB
Double Block and Bleed, a gas trains containing 2 Safety Shutoff
Valves (SSOVs) and a solenoid operated vent valve.
DIP
Dual In-Line Package, a type of switch
ECU
Electronic Control Unit (O2 sensor)
EMS
Energy Management System; often used interchangeably with BAS
FM
Factory Mutual. Used to define boiler gas trains.
GF-xxxx
Gas Fired (an AERCO document numbering system)
GND
Ground

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AERCO Technical Terminology
TERMINOLOGY
MEANING
HDR
Header
Hex
Hexadecimal Number (0 –9, A –F)
HP
Horse Power
HX
Heat Exchanger
Hz
Hertz (Cycles Per Second)
I.D.
Inside Diameter
IGN
Ignition
IGST Board
Ignition/Stepper Board, contained in the C-More Controller
INTLK (INTL’K)
Interlock
I/O
Input/Output
I/O Box
Input/Output (I/O) Box currently used on Benchmark, Innovation and
KC1000 Series products
IP
Internet Protocol
ISO
International Organization for Standardization
Lbs.
Pounds (1 lb = 0.45 kg)
LED
Light Emitting Diode
LN
Low Nitrogen Oxide
MA (mA)
Milliampere (1 thousandth of an ampere)
MAX (Max)
Maximum
MBH
1000 BTUs per Hour
MIN (Min)
Minimum
Modbus®
A serial, half-duplex data transmission protocol developed by AEG
Modicon
NC (N.C.)
Normally Closed
NO (N.O.)
Normally Open
NOx
Nitrogen Oxide
NPT
National Pipe Thread
O2
Oxygen
O.D.
Outside Diameter
OMM & O&M
Operation and Maintenance Manual
onAER
AERCO’s on-line remote monitoring system
PCB
Printed Circuit Board
PMC Board
Primary Micro-Controller (PMC) board, contained in the C-More
P/N
Part Number
POC
Proof of Closure
PPM
Parts per Million
PSI
Pounds per Square Inch (1 PSI = 6.89 kPa)
PTP
Point-to-Point (usually over RS232 networks)

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AERCO Technical Terminology
TERMINOLOGY
MEANING
P&T
Pressure and Temperature
ProtoNode
Hardware interface between BAS and a boiler or water heater
PVC
Poly Vinyl Chloride, a common synthetic plastic
PWM
Pulse Width Modulation
REF (Ref)
Reference
RES.
Resistive
RS232
(or EIA-232)
A standard for serial, full-duplex (FDX) transmission of data based on
the RS232 Standard
RS422
(or EIA-422)
A standard for serial, full-duplex (FDX) transmission of data based on
the RS422 Standard
RS485
(or EIA-485)
A standard for serial, half-duplex (HDX) transmission of data based
on the RS485 Standard
RTN (Rtn)
Return
SETPT (Setpt)
Setpoint Temperature
SHLD (Shld)
Shield
SPDT
Single Pole Double Throw, a type of switch
SSOV
Safety Shut Off Valve
TEMP (Temp)
Temperature
Terminating Resistor
A resistor placed at each end of a daisy-chain or multi-drop network
in order to prevent reflections that may cause invalid data in the
communication
Tip-N-Tell
A device that indicates if a package was tipped during shipping
UL
A business that tests and validates products
VAC
Volts, Alternating Current
VDC
Volts, Direct Current
VFD
Vacuum Fluorescent Display, also Variable Frequency Drive
W
Watt
W.C.
Water Column, a unit of pressure (1 W.C. = 249 Pa)
µA
Micro amp (1 millionth of an ampere)

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SECTION 1: SAFETY PRECAUTIONS
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SECTION 1: SAFETY PRECAUTIONS
1.1 WARNINGS & CAUTIONS
Installers and operating personnel MUST, at all times, observe all safety regulations. The
following warnings and cautions are general and must be given the same attention as specific
precautions included in these instructions. In addition to all the requirements included in this
AERCO Instruction Manual, the installation of units MUST conform with local building codes, or,
in the absence of local codes, ANSI Z223.1 (National Fuel Gas Code Publication No. NFPA-54)
for gas-fired boilers and ANSI/NFPASB for LP gas-fired boilers. Where applicable, the
equipment shall be installed in accordance with the current Installation Code for Gas Burning
Appliances and Equipment, CSA B149.1, and applicable Provincial regulations for the class;
which should be carefully followed in all cases. Authorities having jurisdiction should be
consulted before installations are made.
See Section 1.4 for important information regarding installation of units within the
Commonwealth of Massachusetts.
IMPORTANT!
This Guide is an integral part of the product and must be maintained in legible condition. It
must be given to the user by the installer and kept in a safe place for future reference.
WARNING!
•Do not use matches, candles, flames, or other sources of ignition to check for gas leaks.
•Fluids under pressure may cause injury to personnel or damage to equipment when
released. Be sure to shut off all incoming and outgoing water shutoff valves. Carefully
decrease all trapped pressures to zero before performing maintenance.
•Before attempting to perform any maintenance on the unit, shut off all gas and electrical
inputs to the unit.
•The exhaust vent pipe of the unit may operate under a positive pressure and therefore
must be completely sealed to prevent leakage of combustion products into living spaces.
•Electrical voltages of 120, 208, 460, 575 AND 24 volts AC may be used in this
equipment. Therefore the cover on the unit’s power box (located behind the front panel
door) must be installed at all times, except during maintenance and servicing.
•A three-pole switch must be installed on the electrical supply line of the unit. The switch
must be installed in an easily accessible position to quickly and safely disconnect
electrical service. Do not affix switch to unit sheet metal enclosures.
CAUTION!
•Many soaps used for gas pipe leak testing are corrosive to metals. The piping must be
rinsed thoroughly with clean water after leak checks have been completed.
•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.

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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.
Figure 1-1: Manual Gas Shutoff Valve
In addition, to ensure safety an emergency shutdown procedure that addresses the following
points should be designed and implement at the site:
•For automatically operated unattended boilers located in a boiler room, provide a
manually operated remote shutdown switch or circuit breaker located just inside or
outside each boiler room door. Design the system so activation of the emergency
shutdown switch or circuit breaker will immediately shut off the fuel supply to the unit(s).
•For automatically operated unattended boilers in a location other than a boiler room,
provide a manually operated remote shutdown switch or circuit breaker marked for easy
identification at a location readily accessible in the event of boiler mis-operation.
•Design the system so activation of the emergency shutdown switch or circuit breaker will
immediately shut off the fuel.
•For boilers monitored and/or operated from a continuously occupied control room,
provide an emergency shutdown switch in the control room that is hard-wired to
immediately shut off the fuel upon activation.
1.3 PROLONGED SHUTDOWN
If there is an emergency, turn off the electrical power supply to the unit and close the manual
gas valve located upstream the unit. The installer must identify the emergency shut-off device.
If the boiler needs to be shut down for a prolonged period, follow the instructions in Section
4.12: Shutting Boiler Down For Extended Period in the Benchmark 5000 –6000 Operation and
Maintenance Guide, OMM-0124 (GF-208), and review the procedures in Appendix J of the
same manual.
After prolonged shutdown, it is recommended that the procedures in Section 4: Initial Startup
and Section 5: Safety Device Testing of this manual be performed to verify that all system-
operating parameters are correct.
VALVE
OPEN
VALVE
CLOSED

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1.4 IMPORTANT –FOR MASSACHUSETTS INSTALLATIONS
REQUIREMENTS FOR MASSACHUSETTS INSTALLATIONS
Boiler Installations within the Commonwealth of Massachusetts must conform to the
following requirements:
•Boiler must be installed by a plumber or a gas fitter who is licensed within the
Commonwealth of Massachusetts.
•Prior to unit operation, the complete gas train and all connections must be leak
tested using a non-corrosive soap.
•The vent termination must be located a minimum of 4 feet above grade level. If
side-wall venting is used, the installation must conform to the following
requirements extracted from 248 CMR 5.08 (2):
(a) For all side wall horizontally vented gas fueled equipment installed in every dwelling,
building or structure used in whole or in part for residential purposes, including those owned or
operated by the Commonwealth and where the side wall exhaust vent termination is less than
seven (7) feet above finished grade in the area of the venting, including but not limited to decks
and porches, the following requirements shall be satisfied:
1. INSTALLATION OF CARBON MONOXIDE DETECTORS: At the time of installation of the
side wall horizontal vented gas fueled equipment, the installing plumber or gasfitter shall
observe that a hard wired carbon monoxide detector with an alarm and battery back-up is
installed on the floor level where the gas equipment is to be installed. In addition, the
installing plumber or gasfitter shall observe that a battery operated or hard wired carbon
monoxide detector with an alarm is installed on each additional level of the dwelling,
building or structure served by the side wall horizontal vented gas fueled equipment. It shall
be the responsibility of the property owner to secure the services of qualified licensed
professionals for the installation of hard wired carbon monoxide detectors.
a. In the event that the side wall horizontally vented gas fueled equipment is installed in a
crawl space or an attic, the hard wired carbon monoxide detector with alarm and battery
back-up may be installed on the next adjacent floor level.
b. In the event that the requirements of this subdivision can not be met at the time of
completion of installation, the owner shall have a period of thirty (30) days to comply with
the above requirements; provided, however, that during said thirty (30) day period, a
battery operated carbon monoxide detector with an alarm shall be installed.
2. APPROVED CARBON MONOXIDE DETECTORS: Each carbon monoxide detector as
required in accordance with the above provisions shall comply with NFPA 720 and be
ANSI/UL 2034 listed and IAS certified.
3. SIGNAGE: A metal or plastic identification plate shall be permanently mounted to the
exterior of the building at a minimum height of eight (8) feet above grade directly in line
with the exhaust vent terminal for the horizontally vented gas fueled heating appliance or
equipment. The sign shall read, in print size no less than one-half (1/2) inch in size, "GAS
VENT DIRECTLY BELOW. KEEP CLEAR OF ALL OBSTRUCTIONS". (Continued)

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REQUIREMENTS FOR MASSACHUSETTS INSTALLATIONS
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 Section 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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SECTION 2: INSTALLATION
2.1 INTRODUCTION
This section provides the descriptions and procedures necessary to unpack, inspect and install
the AERCO 5000 and 6000 Benchmark boilers.
2.2 RECEIVING THE UNIT
Each Benchmark boiler is shipped as a single crated unit. The shipping weight for the BMK
5000 and 6000 models is approximately 3500 pounds (1588 kg).
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. Check for indications that the unit has
been turned on its side during shipment. If you see any such signs, do not sign for the
shipment. Note the information on the carrier’s paperwork and request a freight claim and
inspection by a claims adjuster before proceeding. Any other visual damage to the packaging
materials should also be made clear to the delivering carrier.
2.3 UNPACKING
The unit is shipped mounted on a skid and shrouded in a plastic wrap. It can be moved while on
the skid using a forklift.
Carefully remove the plastic wrap from the unit taking care not to damage the unit enclosure
panels when cutting away the plastic wrap.
After unpacking, make a close inspection of the unit to ensure there is no evidence of damage.
The freight carrier should be notified immediately if any damage is detected.
The following accessories come standard with each unit and are either packed separately within
the unit’s shipping container or are factory installed on the unit:
•Pressure/Temperature Gauge
•ASME Pressure Relief Valve
•Condensate Drain Trap (P/N 24441)
•2” Natural Gas Supply Shutoff Valve, and a Propane Shutoff Valve on Propane and
Dual Fuel units
When optional accessories are ordered, they may be packed within the unit’s shipping
container, factory installed on the unit, or packed and shipped in a separate container. Any
standard or optional accessories shipped loose should be identified and stored in a safe place
until ready for installation or use.

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Figure 2-1: Benchmark 5000/6000 Mounted on Shipping Skid
2.4 SITE PREPARATION
Ensure that the site selected for installation of the Benchmark boiler includes access to:
•One of the following AC Input Power:
o208 VAC, Three-Phase, 60 Hz @ 30 Amps
o460 VAC, Three-Phase, 60 Hz @ 20 Amps
o575 VAC, Three-Phase, 60 Hz @ 20 Amps
•NATURAL GAS: Access to 2 inch (2.54 cm) line with a minimum pressure of 14 inches
W.C. (3.49 kPa) with the unit at FULL FIRE (approximately 20” W.C. (4.98 kPa) static).
•PROPANE GAS (Dual Fuel and Propane only units): Access to 1-1/2 inch (3.8 cm) line
with a minimum pressure of 14 inches W.C. (3.49 kPa) with the unit at FULL FIRE
(approximately 20” W.C. (4.98 kPa) static)
2.4.1 Installation Clearances
Benchmark 5000 and 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 (91 cm)
•Sides: 24 inches (61 cm)
•Rear: 24 inches (61 cm)
•Top: 18 inches (45.7 cm)
All gas piping, water piping and electrical conduit or cable must be arranged so that they do not
interfere with the removal of any panels, or inhibit service or maintenance of the unit.

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NOTE:
Benchmark 5000 and 6000 units may be installed with zero side clearances in pairs only.
The perimeter clearances still apply (see Figure 2-2 and the drawings in Appendix A:
Dimensional Drawings).
IMPORTANT!
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 2.8 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” (10.2 cm) above the floor. See Condensate Neutralizer Tank Instructions TID-
0074 for details.
Figure 2-2: Benchmark Model 5000 & 6000 Clearances
Housekeeping pad
should not extend
under the condensate
assembly
4” – 8”(10.2–20.3 cm)
MINIMUM

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WARNING!
Keep the unit area clear and free from all combustible materials and flammable vapors or
liquids.
FOR MASSACHUSETTS ONLY:
For Massachusetts installations, the unit must be installed by a plumber or gas-fitter licensed
within the Commonwealth of Massachusetts. In addition, the installation must comply with all
requirements specified in Section 1.4, above.
2.4.2 Setting the Unit
Benchmark 5000 and 6000 units must be installed on a level 4 to 8 inch (10.2 to 20.3 cm) thick
housekeeping pad to ensure proper condensate drainage. If anchoring the unit, refer to Figure
2-3 for anchor locations.
NOTE:
When using the AERCO Condensate Neutralizer Tank for proper condensate drainage, the
Neutralizer Tank must be stored in a pit, OR the boiler and AERCO Condensate Trap must
be elevated higher than 4” (10.2 cm) above the floor. Ensure that the 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.
•All holes are flush with the bottom surface of the frame.
•All dimensions shown are in inches [millimeters]
Figure 2-3. Benchmark 5000 and 6000 Anchor Bolt Locations
REAR
FRONT

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2.4.3 LIFTING PROVISIONS
Two (2) lifting lugs are provided at the top of the primary heat exchanger as shown in Figure 2-
4. The location of the lifting tabs is marked on the shrink-wrap coving the unit for shipping.
Remove the four (4) lag screws securing the unit to the shipping skid, and, if still in place,
remove the front Top Panel. Lift the unit off the shipping skid using a spreader bar and position
it on the (required) concrete Housekeeping Pad in the desired location.
WARNING!
When lifting or moving the boiler, do not attempt to manipulate the unit using the gas train or
blower. A spreader bar is required for all vertical lifts. Failure to use a spreader bar can put
excessive force on the unit and can cause boiler failure.
Figure 2-4: Lifting Lug Locations
2.4.4 MULTIPLE UNIT INSTALLATIONS
In multiple unit installations, it is important to plan the position of each unit in advance. Sufficient
space for piping connections and future service/maintenance requirements must also be taken
into consideration. All piping must include ample provisions for expansion.
2.5 SUPPLY AND RETURN PIPING
The Benchmark 5000 and 6000 boiler utilizes 6” (15.24 cm) 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 2-5. Refer to Appendix A: Dimensional and Clearance
Drawings for additional dimensional data.
LIFTING LUGS
NOTE:
The front top panel must be
removed to access the front
lifting lug.

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When connecting the hot water outlet and cold water inlet to building piping, first make sure the
mating surfaces are thoroughly clean. AERCO recommends using Loctite ® 7649 to prime the
mating surfaces and then Loctite 567 as pipe dope. Do NOT use Teflon tape.
See Sections 2.12 and 2.13 for information on the flue vent and air intake.
Figure 2-5: Supply and Return Locations (Dual Fuel Model Shown)
WATER OUTLET
6” (15.24 cm)
AIR INLET
14” (35.6 cm)
6” (15.24 cm)
WATER INLET
2” NATURAL
GAS INLET
DRAIN VALVE
CONDENSATE
DRAIN
1-1/2” PROPANE GAS INLET
(DUEL FUEL & PROPANE
ONLY)

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2.6 PRESSURE RELIEF VALVE INSTALLATION
Depending on the pressure required, Benchmark 5000 and 6000 boilers are supplied with an
ASME rated Pressure Relief Valves. The pressure relief valve supplied with the boiler must be
installed to meet code and safety requirements. The pressure rating for the relief valve must be
specified on the sales order. Available pressure ratings range from 30 to 160 psi (207 to 1034
kPa). The pressure relief valve is furnished as a kit (P/N 58053-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 valve, nipples and bushings
are connected to 45º street elbows already installed on the heat exchanger of the boiler. The
relief valve is installed on the top of the boiler as shown in Figure 2-6. A suitable pipe joint
compound should be used on all threaded connections. Any excess should be wiped off to
avoid getting any joint compound into the valve body. The relief valve must be piped to within
12 inches (30.5 cm) of the floor to prevent injury in the event of a discharge. The discharge
piping must be full size, without reduction. No valve or size reductions are allowed in the full port
discharge line. In multiple unit installations, the discharge lines must NOT be manifolded
together; each must be individually run to a suitable discharge location.
Figure 2-6. Pressure Relief Valve Installation Location
2.7 PRESSURE/TEMPERATURE GAUGE INSTALLATION
A Pressure/Temperature Gauge is included in the loose parts kit 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 2-7 for sample installations.

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Figure 2-7: Pressure/Temperature Gauge Installation Location
2.8 CONDENSATE DRAIN and PIPING
The Benchmark Boiler is designed to condense water vapor from the flue products. Therefore,
the installation must have provisions for suitable condensate drainage or collection.
The condensate drain port is located on the exhaust manifold (Figure 2-8) at the rear of the unit.
This drain port must be connected to the condensate trap (P/N 24441), which is packed
separately within the unit’s shipping container. The condensate trap outlet connection features a
tapped 3/4” NPT drain port.
Figure 2-8: Condensate Drain Connection Location
A sample condensate trap installation is shown in Figure 2-9. However, the actual installation
details for the trap will vary depending on the available clearances, housekeeping pad height
and 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 2-9) must be level with, or lower than the exhaust manifold
condensate drain port.
•The base of the condensate trap must be supported to ensure that it is level (horizontal).
CORRECT LOCATION
Typically located 6” to 18” (15 to 46 cm) from
the boiler outlet connection
CONDENSATE
DRAIN PORT
ANALYZER PORTS
(2, ONE ON EACH SIDE)
2” NATURAL
GAS INLET
DRAIN VALVE