Watts Benchmark Aerco OMM-0122 Installation and operation manual

Installation and Startup Manual
Benchmark®Boilers
Natural Gas, Propane Gas and Dual Fuel
Fired Modulating & Condensing Boilers
Models 750 through 3000
Other documents for this product include:
OMM-0122, GF-206 Operation & Maintenance 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 number:
G-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-0121_D • GF-205 • 5/9/2019

Benchmark 750-3000 Boiler Installation & Startup Manual
CONTENTS
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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 ..............................................................................................................................17
2.5 LIFTING PROVISIONS.......................................................................................................19
2.5.1 BMK 750 – 1000 lifting Provisions..................................................................................................19
2.5.2 BMK 1500 – 3000 Lifting Provisions ...............................................................................................20
2.6 SUPPLY AND RETURN PIPING.........................................................................................21
2.6.1 BMK 750 – 1000 Supply and Return Piping....................................................................................21
2.6.2 BMK 1500 – 3000 Supply and Return Piping.................................................................................. 21
2.7 PRESSURE RELIEF VALVE INSTALLATION ....................................................................23
2.8 CONDENSATE DRAIN AND PIPING..................................................................................24
2.9 GAS SUPPLY PIPING ........................................................................................................26
2.9.1 Gas Supply Specifications ...............................................................................................................27
2.9.2 Manual Gas Shutoff Valve .........................................................................................................27
2.9.3 External Gas Supply Regulator.................................................................................................28
2.10 AC ELECTRICAL POWER WIRING..................................................................................30
2.10.1 Electrical Power Requirements ....................................................................................................30
2.10.2 Power Box Locations ....................................................................................................................31
2.10.3 Electrical Power Box Internal Components.................................................................................. 32
2.11 FIELD CONTROL WIRING ...............................................................................................34
2.11.1 Outdoor Air & Air Sensor Common.............................................................................................. 35
2.11.2 AIR TEMP SENSOR ........................................................................................................................36
2.11.3 O2SENSOR (+ & –) ........................................................................................................................ 36
2.11.4 SPARK SIGNAL (+ & –)................................................................................................................... 36
2.11.5 ANALOG IN ................................................................................................................................... 36
2.11.6 VALVE FEEDBACK.......................................................................................................................... 36
2.11.7 SHIELD (SHLD & SHLD).................................................................................................................. 37
2.11.8 ANALOG OUT................................................................................................................................ 37
2.11.9 RS485 Comm (+, GND, & -)...........................................................................................................37
2.11.10 RS232 Comm (TxD & RxD).......................................................................................................... 37
2.11.11 VFD/Blower (0-10 & AGND) .......................................................................................................37
2.11.12 Interlocks.................................................................................................................................... 38
2.11.13 Fault Relay (NC, COM, & NO) .....................................................................................................38
2.11.14 Auxiliary Relay Contacts (NC, COM, & NO) ................................................................................ 38

Benchmark 750-3000 Boiler Installation & Startup Manual
CONTENTS
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2.12 FLUE GAS VENT INSTALLATION....................................................................................39
2.12.1 MASSACHUSETTS INSTALLATIONS ...............................................................................................39
2.13 COMBUSTION AIR...........................................................................................................40
2.13.1 DUCTED COMBUSTION AIR ..........................................................................................................40
2.14 BENCHMARK PUMP RELAY ...........................................................................................41
2.15 SEQUENCING ISOLATION VALVE INSTALLATION........................................................42
SECTION 3: START SEQUENCE ........................................................................45
3.1 INTRODUCTION.................................................................................................................45
3.2 START SEQUENCE ...........................................................................................................45
3.3 START/STOP LEVELS.......................................................................................................51
3.4 START/STOP LEVELS – AIR/FUEL & ENERGY INPUT.....................................................52
3.4.1 BMK 750/1000 Air/Fuel Valve Position and Energy Input ............................................................. 52
3.4.2 BMK 1500 Air/Fuel Valve Position and Energy Input .....................................................................53
3.4.3 BMK 2000 Air/Fuel Valve Position and Energy Input .....................................................................54
3.4.4 BMK 2500 Air/Fuel Valve Position and Energy Input .....................................................................55
3.4.5 BMK 3000 Air/Fuel Valve Position and Energy Input .....................................................................56
SECTION 4: INITIAL START-UP ........................................................................57
4.1 INITIAL START-UP REQUIREMENTS................................................................................57
4.2 TOOLS & INSTRUMENTS FOR COMBUSTION CALIBRATION........................................57
4.2.1 Required Tools & Instrumentation................................................................................................. 57
4.2.2 Installing Gas Supply Manometer .................................................................................................. 58
4.2.3 Accessing the Analyzer Probe Port................................................................................................. 60
4.3 FUEL TYPES AND COMBUSTION CALIBRATION............................................................61
4.4 COMBUSTION CALIBRATION...........................................................................................62
4.4.1 NATURAL GAS Combustion Calibration.......................................................................................... 63
4.4.2 PROPANE GAS COMBUSTION CALIBRATION..................................................................................67
4.5 REASSEMBLY....................................................................................................................71
4.6 DUAL FUEL SWITCHOVER ...............................................................................................71
4.6.1 Switchover from NATURAL GAS to PROPANE ................................................................................72
4.6.2 Switchover from PROPANE to NATURAL GAS ................................................................................ 73
4.7 OVER-TEMPERATURE LIMIT SWITCHES........................................................................74
4.7.1 Digital Alarm Switch Checks and Adjustments............................................................................... 75
SECTION 5: SAFETY DEVICE TESTING ..............................................................77
5.1 TESTING OF SAFETY DEVICES.......................................................................................77
5.2 LOW GAS PRESSURE TEST.............................................................................................78
5.2.1 LOW GAS PRESSURE TEST: BMK 750 – 2500 .................................................................................. 78
5.2.2 LOW GAS PRESSURE TEST: BMK 3000 Only....................................................................................80
5.3 HIGH GAS PRESSURE TEST............................................................................................82
5.3.1 HIGH GAS PRESSURE TEST: BMK 750 – 2500 ................................................................................. 82
5.3.2 HIGH GAS PRESSURE TEST: BMK 3000 Only................................................................................... 84
5.4 LOW WATER LEVEL FAULT TEST....................................................................................86
5.5 WATER TEMPERATURE FAULT TEST.............................................................................87
5.6 INTERLOCK TESTS...........................................................................................................89
5.6.1 Remote Interlock Test ....................................................................................................................89
5.6.2 Delayed Interlock Test.................................................................................................................... 89

Benchmark 750-3000 Boiler Installation & Startup Manual
CONTENTS
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5.7 FLAME FAULT TEST..........................................................................................................90
5.8 AIR FLOW FAULT TESTS - BLOWER PROOF & BLOCKED INLET SWITCHES ..............91
5.8.1 Blower Proof Switch Test ............................................................................................................... 91
5.8.2 Blocked Inlet Switch Test................................................................................................................93
5.9 SSOV PROOF OF CLOSURE SWITCH CHECK................................................................94
5.10 PURGE SWITCH OPEN DURING PURGE.......................................................................94
5.11 IGNITION SWITCH OPEN DURING IGNITION.................................................................97
5.12 SAFETY PRESSURE RELIEF VALVE TEST....................................................................97
SECTION 6: BOILER SEQUENCING TECHNOLOGY ............................................99
6.1 INTRODUCTION.................................................................................................................99
6.1.1 Installation Notes ......................................................................................................................... 100
6.2 AERCO BST QUICK START CHART ...............................................................................100
6.3 BST IMPLEMENTATION INSTRUCTION.........................................................................101
6.3.1 OPTION 1 - Constant Setpoint With Direct Wired Header Sensor ...............................................101
6.3.2 OPTION 2 - Constant Setpoint With Modbus Wired Header Sensor ........................................... 102
6.3.3 OPTION 3 - Outdoor Reset With Direct Wired Header Sensor And Direct Wired Outdoor Sensor
...............................................................................................................................................................103
6.3.4 OPTION 4 - Outdoor Reset With Modbus Header Sensor And Modbus Outdoor Sensor............ 105
6.3.5 OPTION 5 - Remote Setpoint With Direct Wired Header Sensor And 4-20ma Setpoint Drive .... 107
6.3.6 OPTION 6 - Remote Setpoint With Direct Wired Header Sensor And Modbus Setpoint Drive ... 109
6.3.7 OPTION 7 - Remote Setpoint With Modbus Header Sensor And 4-20ma Setpoint Drive ........... 111
6.3.8 OPTION 8 - Remote Setpoint With Modbus Header Sensor And Modbus Setpoint Drive ..........113
APPENDIX A: DIMENSIONAL AND CLEARANCE DRAWINGS .............................115

Benchmark 750-3000 Boiler Installation & Startup Manual
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FOREWORD
The AERCO Benchmark (BMK) 750, 1000, 1500, 2000, 2500, and 3000 natural gas and
propane 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, the Benchmark's modulating capability relates
energy input directly to fluctuating system loads. These BMK models provide extremely high
efficiency operation and are ideally suited for modern low temperature, as well as, conventional
heating systems.
The Benchmark models operate within the input and output ranges listed below. All
measurements apply to both natural gas and propane models, unless otherwise specified.
Benchmark Boiler Intake and Output Ranges
MODEL
INPUT RANGE (BTU/HR.) OUTPUT RANGE (BTU/HR.)
MINIMUM MAXIMUM MINIMUM MAXIMUM
BMK 750 50,000 (14.6 kW) 750,000 (220 kW) 47,750 (14.0 kW) 716,250 (210 kW)
BMK 1000 50,000 (14.6 kW) 1,000,000 (293 kW) 48,300 (14.2 kW) 968,000 (284 kW)
BMK 1500 75,000 (22 kW) 1,500,000 (440 kW) 64,500 (18.9 kW) 1,395,000 (409 kW)
BMK 2000 100,000 (29.3 kW) 2,000,000 (586 kW) 86,000 (25.2 kW) 1,860,000 (545 kW)
BMK 2500 167,000 (48.9 kW) 2,500,000 (732 kW) 144,000 (42.2 kW) 2,395,000 (702 kW)
BMK 3000 200,000 (58.6 kW) 3,000,000 (879 kW) 174,000 (51.0 kW) 2,874,000 (842 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. In addition, the BMK 750 & 1000 comply with the Bay Area Air
Quality Management District regulation 9, Rule 7.
Whether used in singular or modular arrangements, the BMK 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. In
addition, the BMK 750 & 1000 models are also approved for PVC and CPVC, 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.

Benchmark 750-3000 Boiler Installation & Startup Manual
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AERCO Technical Terminology Meanings
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 m
3
/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 Meanings
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 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 thousand
th
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
NOxNitrogen Oxide
NPT National Pipe Thread
O2Oxygen
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
Controller
P/N Part Number
POC
Proof of Closure
PPM Parts per Million
PSI Pounds per Square Inch (1 PSI = 6.89 kPa)

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AERCO Technical Terminology Meanings
TERMINOLOGY MEANING
PTP Point-to-Point (usually over RS232 networks)
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 million
th
of an ampere)

Benchmark 750-3000 Boiler Installation & Startup Manual
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 Instruction Manual is an integral part of the product and must be maintained in legible
condition. It must be given to the user by the installer and kept in a safe place for future
reference.
WARNING!
•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 up to 120 VAC (BMK 750 – 2000) and 208 or 460 VAC (BMK
2500/3000) 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 single-pole (120 VAC units) or three-pole (220 VAC and higher units) 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.

Benchmark 750-3000 Boiler Installation & Startup Manual
SECTION 1 – SAFETY PRECAUTIONS
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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
4.10: Shutting Boiler Down For Extended Period in the Benchmark 750-3000 Operation and
Maintenance Guide, OMM-0122 (GF-206).
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