AERCO BMK 2.0 LN for Mass User Manual

Instruction

GF-110LN-M

No.

AERCO INTERNATIONAL, Inc., Northvale, New Jersey, 07647 USA

Installation, Operation

& Maintenance Instructions

Benchmark™
Series
Gas Fired
Low NOx
Boiler System

Condensing, Modulating

Forced Draft, Hot Water Boiler

2,000,000 BTU/H Input

Applicable To Serial Numbers G-05-1393 and above

Patent # : 2.155.12

Printed in U.S.A. REVISED JANUARY, 2009

Telephone Support

Direct to AERCO Technical Support
(8 to 5 pm EST, Monday through

Friday)
[phone]

AERCO International, Inc.
159 Paris Avenue
Northvale, NJ 07647-0128

www.aerco.com

© AERCO International, Inc., 2008

The information contained in this
installation, operation and mainte­nance manual is subject to
change without notice from
AERCO International, Inc.

AERCO makes no warranty of any
kind with respect to this material,
including but not limited to implied
warranties of merchantability and
fitness for a particular application.
AERCO International is not liable
for errors appearing in this
manual. Nor for incidental or
consequential damages occurring
in connection with the furnishing,
performance, or use of this
material.

CONTENTS

GF-110LN-M - AERCO BENCHMARK 2.0 GAS FIRED LOW NOx BOILER

Operating & Maintenance Instructions

FOREWORD A

Chapter 1 – SAFETY PRECAUTIONS 1-1

Para. Subject Page

1-1 Safety Warnings 1-1
1-2 Emergency Shutdown 1-2

Chapter 2 – INSTALLATION PROCEDURES 2-1

Para. Subject Page

2.1 Receiving the Unit 2-1

2.2 Unpacking 2-1

2.3 Installation 2-2

2.4 Gas Supply Piping 2-3

2.5 Electrical Supply 2-5

2.6 Mode of Operation and Field
Control Wiring

2-5

Para. Subject Page

1-3 Prolonged Shutdown 1-2

Para. Subject Page

2.7 I/O Box Connections 2-7

2.8 Auxiliary Relay Contacts 2-9

2.9 Flue Gas Vent Installation 2-9

2.10 Combustion Air 2-9

Chapter 3 – CONTROL PANEL COMPONENTS AND OPERATING PROCEDURES 3-1

Para. Subject Page

3.1 Introduction 3-1

3.2 Control Panel Description 3-1

3.3 Control Panel Menus 3-3

3.4 Operating Menu 3-5

3.5 Setup Menu 3-5

Para. Subject Page

3.6 Configuration Menu 3-6

3.7 Tuning Menu 3-7

3.8 Start Sequence 3-7

3.9 Start/Stop Levels 3-9

Chapter 4 – INITIAL START-UP 4-1

Para. Subject Page

4.1 Initial Startup Requirements 4-1

4.2 Tools and Instruments for
Combustion Calibration

4.3 Natural Gas Combustion
Calibration

4-1
4-2

Para. Subject Page

4.4 Unit Reassembly 4-5

4.5 Over-Temperature Limit Switch 4-5

i

CONTENTS

Chapter 5 – MODE OF OPERATION 5-1

Para. Subject Page

5.1 Introduction 5-1

5.2 Indoor/Outdoor Reset Mode 5-1

5.3 Constant Setpoint Mode 5-2

5.4 Remote Setpoint Mode 5-2

5.5 Direct Drive Modes 5-3

Para. Subject Page

5.6 Boiler Management System
(BMS)

5.7 Combination Control System
(CCS)

5-4
5-5

Chapter 6 – SAFETY DEVICE TESTING PROCEDURES 6-1

Para. Subject Page

6.1 Testing of Safety Devices 6-1

6.2 Low Gas Pressure Fault Test 6-1

6.3 High Gas Pressure Test 6-1

6.4 Low Water Level Fault Test 6-2

6.5 Water Temperature Fault Test 6-2

6.6 Interlock Tests 6-2

6.7 Flame Fault Test 6-3

Para. Subject Page

6.8 Air Flow Fault Test 6-4

6.9 SSOV Proof of Closure Switch 6-4

6.10 Purge Switch Open During
Purge

6.11 Ignition Switch Open During
Ignition

6.12 Safety Pressure Relief Valve
Test

6-5
6-5
6-5

Chapter 7 – MAINTENANCE REQUIREMENTS 7-1

Para. Subject Page

7.1 Maintenance Schedule 7-1

7.2 Spark Igniter 7-1

7.3 Flame Detector 7-2

7.4 Combustion Calibration 7-2

7.5 Safety Device Testing 7-3

7.6 Burner 7-3

Para. Subject Page

7.7 Condensate Drain Trap 7-4

7.8 Shutting the Boiler Down For An
Extended Period of Time

7.9 Placing The Boiler Back In
Service After A Prolonged
Shutdown

7-4
7-4

Chapter 8 – TROUBLESHOOTING GUIDE 8-1

Para. Subject Page

8.1 Introduction 8-1

Para.

Subject Page

ii

CONTENTS

APPENDICES

App Subject Page

A Boiler Menu Item Descriptions A-1
B Startup, Status and Fault

Messages

C Temperature Sensor Resistance

Chart

D Indoor/Outdoor Reset Ratio

Charts

B-1
C-1
D-1

WARRANTIES W-1

App Subject Page

E Boiler Default Settings E-1
F Dimensional and Part Drawings F-1
G Piping Drawings G-1
H Wiring Schematics H-1
I Recommended Periodic Testing

Checklist

J Benchmark Control Panel Views J-1

I-1

iii

FOREWORD

Foreword

The AERCO Benchmark 2.0 LN Boiler is a true industry advance that meets the needs of
today's energy and environmental concerns. Designed for application in any closed loop
hydronic system, the Benchmark's modulating capability relates energy input directly to
fluctuating system loads. The Benchmark’s 20:1 turn down ratio and condensing capability,
provides extremely high efficiencies and makes it ideally suited for modern low temperature, as
well as, conventional heating systems.

When installed and operated in accordance with this Instruction Manual, the Benchmark 2.0 LN
Boiler complies with the NOx emission standards outlined in:

• South Coast Air Quality Management District (SCAQMD), Rule 1146.2

• Texas Commission on Environmental Quality (TCEQ), Title 30, Chaptr 117, Rule117.465

Whether used in singular or modular arrangements the Benchmark 2.0 LN offers the maximum
flexibility in venting with minimum installation space requirements. The Benchmark's advanced
electronics are available in several selectable modes of operation offering the most efficient
operating methods and energy management system integration.

For service or parts, contact your local sales representative or AERCO INTERNATIONAL.

NAME:

ORGANIZATION:

ADDRESS:

TELEPHONE:

INSTALLATION DATE: _____________________________________________

A

SAFETY PRECAUTIONS

CHAPTER 1 SAFETY PRECAUTIONS

1.1 WARNINGS & CAUTIONS

Installers and operating personnel MUST, at all
times, observe all safety regulations. The
following warnings and cautions are general and
must be given the same attention as specific
precautions included in these instructions. In
addition to all the requirements included in this
AERCO Instruction Manual, the installation of
units MUST conform with local building codes,
or, in the absence of local codes, ANSI Z223.1
(National Fuel Gas Code Publication No. NFPA-

54). Where ASME CSD-1 is required by local
jurisdiction, the installation must conform to
CSD-1.

Where applicable, the equipment shall be
installed in accordance with the current
Installation Code for Gas Burning Appliances
and Equipment, CGA B149, 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 1-2 and 1-3 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.

WARNINGS!

MUST BE OBSERVED TO PREVENT
SERIOUS INJURY.

WARNING!

BEFORE ATTEMPTING TO PER­FORM ANY MAINTENANCE ON THE
UNIT, SHUT OFF ALL GAS AND
ELECTRICAL INPUTS TO THE UNIT.

WARNING

DO NOT USE MATCHES, CANDLES,
FLAMES, OR OTHER SOURCES OF
IGNITION TO CHECK FOR GAS
LEAKS.

WARNING!

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.

WARNING!

FLUIDS UNDER PRESSURE MAY
CAUSE INJURY TO PERSONNEL
OR DAMAGE TO EQUIPMENT
WHEN RELEASED. BE SURE TO
SHUT OFF ALL INCOMING AND
OUTGOING WATER SHUTOFF
VALVES. CAREFULLY DECREASE
ALL TRAPPED PRESSURES TO
ZERO BEFORE PERFORMING
MAINTENANCE.

WARNING!

ELECTRICAL VOLTAGES UP TO
460 VAC 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.

CAUTIONS!

Must be observed to prevent
equipment damage or loss of
operating effectiveness.

CAUTION!

Many soaps used for gas pipe leak
testing are corrosive to metals. The
piping must

be rinsed thoroughly with
clean water after leak checks have
been completed.

CAUTION!

DO NOT use this boiler if any part has
been under water. Call a qualified
service technician to inspect and
replace any part that has been under
water.

1-1

SAFETY PRECAUTIONS

1.2 EMERGENCY SHUTDOWN

If overheating occurs or the gas supply fails to
shut off, close the manual gas shutoff valve
(Figure 1-1) located external to the unit.

IMPORTANT

The Installer must identify and indicate
the location of the emergency shutdown
manual gas valve to operating personnel.

1.3 PROLONGED SHUTDOWN

After prolonged shutdown, it is recommended
that the startup procedures in Chapter 4 and the
safety device test procedures in Chapter 6 of
this manual be performed, to verify all system­operating parameters. If there is an emergency,
turn off the electrical power supply to the
AERCO boiler and close the manual gas valve
located upstream the unit. The installer must
identify the emergency shut-off device.

Figure 1-1

Manual Gas Shutoff Valve

IMPORTANT – FOR MASSACHUSETTS INSTALLATIONS

Boiler Installations within the Commonwealth of Massachusetts must conform to the following
requirements:

• Boiler must be installed by a plumber or a gas fitter who is licensed within the Commonwealth of
Massachusetts.

• Prior to unit operation, the complete gas train and all connections must be leak tested using a
non-corrosive soap.

• If a glycol solution is used as anti-freeze protection, a backflow preventer must be installed
upstream of the Fill/Makeup Valve.

• 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
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.

. At the time of installation of the

1-2

Extracted Information From 248 CMR 5.08 (2) – Continued

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.

SAFETY PRECAUTIONS

2. APPROVED CARBON MONOXIDE DETECTORS.
required in accordance with the above provisions shall comply with NFPA 720 and be ANSI/UL
2034 listed and IAS certified.

3. SIGNAGE
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".

4. INSPECTION
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

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.
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.

. A metal or plastic identification plate shall be permanently mounted to the exterior

. The state or local gas inspector of the side wall horizontally vented gas fueled

: The following equipment is exempt from 248 CMR 5.08(2)(a)1 through 4:

Each carbon monoxide detector as

When

(d) MANUFACTURER REQUIREMENTS - GAS EQUIPMENT VENTING SYSTEM NOT PROVIDED.
When the manufacturer of a Product Approved side wall horizontally vented gas fueled equipment does
not provide the parts for venting the flue gases, but identifies "special venting systems", the following
requirements shall be satisfied by the manufacturer:

1. The identification of each "special venting system" shall include the listing of either the
website, phone number or manufacturer’s addres where the venting system installation
instructions can be obtained; and

2. The "special venting systems" shall be Product Approved by the Board, and the instructions
provided with the system shall include a parts list and detailed installation instructions.

(e) A copy of all installation instructions for the Product Approved side wall horizontally vented gas fueled
equipment and all the venting instructions, parts lists and/or design instructions for the venting system
shall remain with the appliance or equipment at the completion of the installation.

_______________________________ [End of Extracted Information From 248 CMR 5.08 (2)]

1-3

INSTALLATION

Chapter 2 - INSTALLATION

2.1 RECEIVING THE UNIT

Each Benchmark is shipped as a single crated
unit. The shipping weight is approximately 1850
pounds, and must be moved with the proper
rigging equipment for safety and to avoid dam­ages. The unit should be completely inspected
for shipping damage and completeness at the
time of receipt from the carrier and before the bill
of lading is signed.

NOTE:

AERCO is not responsible for lost or
damaged freight.

Each unit has a Tip-N-Tell indicator on the
outside of the crate. This indicates if the unit has
been turned on its side. 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.

2.2 UNPACKING

Carefully unpack the unit taking care not to
damage the unit jacket when cutting away
packaging materials. A close inspection of the
unit should be made to determine if there has
been any damage not indicated by the Tip-N­Tell. The freight carrier should be notified
immediately if any damage is detected. The
following accessories come standard with each
unit and are packed separately within the unit’s’
packing container or are factory installed on the
boiler.

• Pressure/Temperature Gauge

• Spare Spark Ignitor

• Spare Flame Detector

• ASME Pressure Relief Valve

• Regulator Adjustment Tool (One per

Site)

• Condensate Drain Trap

• 2” Gas Supply Shutoff Ball Valve

When ordered, optional accessories may be
packed separately or within the boiler shipping
container, or may be installed on the boiler. Any
standard or optional accessories shipped loose
should be identified and put in a safe place until
ready for installation or use.
.

Figure 2.1

Boiler Clearances

2-1

INSTALLATION

2.3 INSTALLATION

The unit must be installed by qualified personnel
(i.e. licensed plumber, gas fitter, etc.) in com­pliance with local and state regulations. The
prescribed clearances for service are shown in
Figure 2.1. The minimum
required by AERCO, are listed below. Local
building codes may require more clearance and
take precedence

Minimum clearances required:
Sides 24"
Rear 36”
Front 24"
Top 18”

All gas piping, water piping and electrical conduit
or cable must be arranged so that they do not
interfere with the removal of any cover, or inhibit
service or maintenance of the unit.

WARNING!

KEEP UNIT AREA CLEAR AND FREE FROM
COMBUSTIBLE MATERIALS AND FLAMMA-

BLE VAPORS AND LIQUIDS

CAUTION!

While packaged on the shipping skid the boiler
must be moved by pallet jack or forklift from the
rear only.

IMPORTANT

The boiler installation must be
installed by a plumber or gas fitter
who is licensed within the Common­wealth of Massachusetts. In addition,
the installation must comply with all
requirements specified in Chapter 1
(Safety Precautions), pages 1-2 & 1-3.

2.3.1. SETTING THE UNIT

The unit must be installed on a 4 to 6 inch
housekeeping pad for proper condensate
drainage. If anchoring the unit, see the
dimensional drawings in Appendix F for anchor
location. Lifting lugs are provided for moving the
unit when it has been removed from the shipping
skid (See Fig. 2.2). USE ONLY THE LIFTING
LUGS TO MOVE THE UNIT. Remove the rear
top panel from the unit to provide access to the
lifting lugs. Remove the four (4) lag screws
securing the boiler to the shipping skid. Lift the
unit off the shipping skid and position it on to the
4 to 6 inch housekeeping concrete pad
(required) in the desired location.

clearance dimensions,

.

In multiple unit installations, it is important to
plan the position of each unit. Sufficient space
for piping connections and future maintenance
requirements must be given. All piping must
include ample provision for expansion.

If installing a Combination Control (CCP)
system, it is important to identify and place the
Combination Mode units in the proper physical
location. If these boilers are not properly located,
it will be necessary to reprogram them.

Figure 2.2

Lifting Lug Location

2.3.2 SUPPLY AND RETURN PIPING

The Benchmark 2.0 utilizes 4" 150# flanges for
the water system supply and return piping
connections. See Appendix F for dimensional
data. The physical location of the supply and
return piping connections is on the rear of the
unit (See Fig 2.3 for details).

2-2

INSTALLATION

BOILER SUPPLY
(4"-150# FLG'D CONN.)

BOILER RETURN
(4"-150# FLG'D CONN.)

Figure 2.3

Supply and Return Location

2.3.3 CONDENSATE DRAIN & PIPING

The Benchmark Boiler is designed to condense
water vapor from the flue products. Therefore,
the installation must have provisions for suitable
drainage or collection. A 1/2” NPT drain
connection is provided on the exhaust manifold
(see Fig 2.4). A separate condensate drain trap
(part no. 24060) is shipped loose and must be
installed on the floor behind the unit. Connect
the trap to the exhaust manifold as follows:

1. First, install a 1/2” NPT nipple in the
condensate drain port (Fig. 2.4). Next,
connect a 3/4-to 1/2” reducer to the 1/2”
nipple.

2. On the condensate drain trap, install 3/4”
NPT nipples in the tapped inlet and outlet of
the trap.

3. Attach a length of 1” I.D. polypropylene hose
between the exhaust manifold drain and the
inlet side of the condensate trap (Fig 2.5).
Secure both ends of the hose with clamps.
Drainage from the condensate drain trap
outlet must be by gravity to a nearby floor
drain via a polypropylene hose or suitable
piping.

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 11
GPH. The condensate drain trap, associated
fittings and drain line must be removable for
routine maintenance. Do Not

hard pipe.

Figure 2.4

Condensate Drain Connection Location

Figure 2.5

Condensate Trap Installation

2.4. GAS SUPPLY PIPING

The AERCO Gas Fired Equipment Gas Compo­nents and Supply Design Guide (GF-2030LN-M)
must be consulted before any gas piping is
designed or started.

WARNING!

DO NOT USE MATCHES, CANDLES,
FLAMES OR OTHER SOURCES OF
IGNITION TO CHECK FOR GAS LEAKS

.

2-3

INSTALLATION

CAUTION!

Many soaps used for gas pipe leak testing
are corrosive to metals. Therefore, AERCO
recommends the use of non-corrosive
soaps for leak tests. The piping must be
rinsed thoroughly with clean water after leak
checks have been completed.

NOTE:

All gas piping must be arranged so that it
does not interfere with removal of any
cover, inhibit service or maintenance, or
prevent access between the Unit and walls,
or another unit.

The location of the 2" inlet gas connection is
located on the rear of the unit as shown in
Figure 2.5.

All pipes should be de-burred and internally
cleared of any scale or iron chips before
installation. No flexible connectors or non­approved gas fittings should be installed. Piping
should be supported from floor, ceiling or walls
only and must not be secured to the unit.

A suitable piping compound, approved for use
with natural gas or propane, should be used.
Any excess must be wiped off to prevent
clogging of components.

To avoid damage to the unit, when pressure
testing gas piping, isolate the unit from the gas
supply piping. At no time should there be more
than 14” W.C. to the unit. Leak test all external
piping thoroughly for leaks using a non-corrosive
soap and water solution or suitable equivalent.
The gas piping must meet all applicable codes.

When installing the gas supply regulator(s),
union connections should be placed in the
proper locations to allow for maintenance.

The gas supply regulator must be properly
vented to outdoors. Consult the local gas utility
for exact
supply gas regulators.

The regulator must be capable or regulating
2,000,000 BTU/HR of natural gas while
maintaining 5.3” W.C. to the boiler.

requirements concerning venting of

NOTE:

CAUTION!

A lockup style regulator must be used when
gas supply pressure exceeds 14” W.C.

2.4.2 MANUAL GAS SHUTOFF VALVE

A 2” manual gas shut-off valve is furnished with
each unit. The valve should be positioned on the
inlet to the unit, as shown in Figure 2.5,
upstream of the supply regulator in a readily
accessible location.

2.4.3 IRI GAS TRAIN KIT

The IRI gas train is an optional gas train
required in some areas by code or for insurance
purposes. The IRI gas train is factory pre-piped
and wired.

2.4.1 GAS SUPPLY SPECIFICATONS

− Natural Gas:
The maximum static pressure to the unit
must be no more than 2 psi. Minimum
natural gas operating pressure is 5.3“ W.C.
for FM gas trains & 5.5“ W.C. for IRI gas
trains when the unit is firing at maximum
input (2000 cfh). For Benchmark 2.0 Low
NOx boilers configured for De-Rated
capacity, the required minimum natural gas
operating pressure is 4.0” W.C. for FM gas
trains (4.2” W.C. for IRI gas trains) at maxi­mum input of 1,750,000 BTU/hr (1750 cfh).

A gas supply regulator must be positioned as
shown in Figure 2.5. If the gas supply pressure
will exceed 14" W.C., a lock -up style regulator is
required.

2-4

Figure 2.5

Manual Shut-Off Valve Location

INSTALLATION

2.5 ELECTRICAL SUPPLY

The AERCO Gas Fired Equipment Electrical
Power Wiring Guide, (GF-2060), must be
consulted in addition to the following material
before wiring to the unit is started. External AC
power connections are made to the unit inside
the power box on the front panel of the unit,
behind the removable front door (Figure 2.6).

NOTE:

All electrical conduit and hardware should
be installed so that it does not interfere with
the removal of any cover, inhibit service or
maintenance, or prevent access between
the unit and walls or another unit.

Each Benchmark Boiler must be connec ted to a
dedicated electrical circuit. No other devices
should be on the same electrical circuit as the
Benchmark Boiler. A means for disconnecting
AC power from the unit (such as a service
switch) must be installed near the unit for normal
operation and maintenance. All electrical
connections should be made in acc ordance with
the National Electrical Code and/or with any
applicable local codes.

For electrical power wiring diagrams, see the
Benchmark Electrical, Power Wiring Guide, GF­2060

220 VAC, 1 PHASE

GND

NEU

208 VAC, 3 PHASE

GND

NEU

L3

Figure 2.6

AC Input Terminal Location

2.5.1 ELECTRICAL REQUIREMENTS

The Benchmark Boiler is available in one three
different AC power configurations:

220 Vac/1 Phase/60 Hz @ 20 amps
208 Vac/3-Phase/60 @15 amps
460 Vac/3-Phase/60 Hz @ 15 amps

Each of the above power configurations contain
a Power Box with a terminal block which
matches the configuration ordered. The three
different terminal block configurations are shown
in Figure 2.7. A wiring diagram showing the
required AC power connections is provided on
the front panel of each Power Box.

L2

L1

220 VAC, 1 Phase

460 VAC, 3 PHASE

GND

L3

L2

L1

460 VAC, 3 Phase

L2

L1

208 VAC, 3 Phase

Figure 2.7

AC Terminal Block Configurations

2.6 MODE OF OPERATION and FIELD
CONTROL WIRING

The Benchmark Boiler is available in several
different modes of operation. While each unit is
factory configured and wired for a particular
mode, some field wiring may be required to
complete the installation. This wiring is typically
run to the Input/Output (I/O) Box located on the
front of the unit behind the removable front door

2-5

INSTALLATION

(see Fig. 2.8). A brief description of each mode
of operation, and their requirements, is
described in the following paragraphs. Additional
information concerning field wiring is provided in
paragraphs 2.7.1 through 2.7.9. For additional
information on modes of operation, refer to
Chapter 5.

Figure 2.8

I/O Box Terminal Location

OUTDOOR SENSOR IN

SENSOR COMMON

AUX SENSOR IN

NOT USED

SHIELD

+

­+

-

ANALOG IN

B.M.S. (PWM) IN

2.6.1 CONSTANT SETPOINT MODE

The Constant Setpoint Mode is used when it is
desired to have a fixed setpoint that does not
deviate. No wiring connections other than
electrical supply connections are required for
this mode. However, if desired, fault monitoring
or enable/disable interlock wiring can be utilized
(see paragraphs 2.7.9.1 and 2.7.10).

2.6.2 INDOOR/OUTDOOR RESET MODE

This mode of operation increases supply water
temperature as outdoor temperatures decrease.
An outside air temperature sensor (AERCO PN

122790) is required. The sensor MUST BE
wired to the I/O Box wiring terminals (see Fig.

2.9). For more information concerning the
outside air sensor installation, refer to paragraph

2.7.1

REMOTE INTL'K IN
EXHAUST SWITCH IN
DELAYED INTL'K IN

NOT USED

NC

FAULT RELAY

COM

120 VAC, 5A, RES

NO
NC

AUX RELAY

COM
NO

120 VAC, 5A, RES

NOT USED

2-6

mA OUT

RS-485
COMM.

NOT USED

+

­+

G

-

Figure 2.9 I/O Box Terminal Strip

RELAY CONTACTS:
120 VAC, 30 VDC
5 AMPS RESISTIVE

DANGER

120 VAC USED

IN THIS BOX

2.6.3 BOILER MANAGEMENT SYSTEM

(BMS) MODE

NOTE

BMS Model 168 can utilize either pulse
width modulation (PWM) or RS485
Modbus signaling to the Boiler. BMS II
Model 5R5-384 can utilize only RS485
signaling to the Boiler.

When using an AERCO Boiler Management
System (BMS), the field wiring is connected
between the BMS Panel and each Boiler’s I/O
Box terminal strip (Figure 2-9). Twisted shielded
pair wire from 18 to 22 AWG must be utilized for
the connections. The BMS Mode can utilize
either pulse width modulation (PWM) signaling,
or RS485 Modbus signaling. For PWM signaling,
connections are made from the AERCO Boiler
Management System to the B.M.S. (PWM) IN
terminals on the I/O Box terminal strip. For
RS485 Modbus signaling, connections are made
from the BMS to the RS485 COMM terminals on
the I/O Box terminal strip. Polarity must be
maintained and the shield must be connected
only at the AERCO BMS. The boiler end of the
shield must be left floating. For additional
instructions, refer to Chapter 5, paragraph 5.6 in
this manual. Also, refer to GF-108M (BMS
Model 168) and GF-124 (BMS II Model 5R5-

384), BMS -Operations Guides.

2.6.4 REMOTE SETPOINT and DIRECT

DRIVE MODES

The Benchmark Boiler can accept several types
of signal formats from an Energy Management
System or other source to control either the
setpoint (Remote Setpoint Mode) or firing rate
(Direct Drive Mode) of the Boiler. These formats
are:

4 to 20 mA/1 to 5 Vdc
0 to 20 mA/0 to 5 Vdc
PWM – (Pulse Width Modulated signal. See

paragraph 2.7.4)
Network – (RS485 Modbus. See para. 2.7.7)

While it is possible to control a boiler or boilers
using one of the previously described modes of
operation, it may not be the method best suited
for the application. Prior to selecting one of
these modes of operation, it is recommended
that you consult with your local AERCO
representative or the factory for the mode of

INSTALLATION

operation that will work best with your
application. For more information on wiring the
4 to 20 mA / 1to 5VDC or the 0 to 20 mA / 0 to 5
VDC, see paragraph 2.7.3.

2.6.5 COMBINATION MODE

NOTE

Only BMS Model 168 can be utilized for
the Combination Mode, not the BMS II
(Model 5R5-384).

With a Combination Mode unit, field wiring is
connected between the unit’s I/O Box wiring
terminals, the CCP (Combination Control Panel),
and the BMS Model 168 (Boiler Management
System). The wiring must be done using a
shielded twisted pair of 18- 22 AWG wire and
polarity must be maintained. For further
instructions and wiring diagrams, refer to the
GF-108 Boiler Management System Operations
Guide and the CCP-1 data sheet.

2.7 I/O BOX CONNECTIONS

The types of input and output signals and
devices to be connected to the I/O Box terminals
shown in Figure 2.9 are described in the
following paragraphs.

CAUTION!

DO NOT make any connections to the I/O Box
terminals labeled “NOT USED”. Attempting to
do so may cause equipment damage.

2.7.1 OUTDOOR SENSOR IN

An outdoor air temperature sensor (AERCO Part
No. 122790) will be required mainly 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 choose
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 and is connected to the
OUTDOOR SENSOR IN and SENSOR
COMMON terminals in the I/O box (see Figs. 2.8
and 2.9). Wire the sensor using a twisted
shielded pair cable of 18-22 AWG wire. There is
no polarity when terminating the wires. The

2-7

shield is to be connected only to the terminals
labeled SHEILD 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 from direct sunlight
as well as impingement by the elements. If a
shield is used, it must allow for free air
circulation.

2.7.2 AUX SENSOR IN

The AUX SENSOR IN terminals can be used to
add an additional temperature sensor for
monitoring purposes. This input is always
enabled and is a view only input that can be
seen in the operating menu. The sensor must be
wired to the AUX SENSOR IN and SENSOR
COMMON and must be similar to AERCO
BALCO wire sensor P/N 12449. A resistance
chart for this sensor can be found in APPENDIX
C.

2.7.3 ANALOG IN

The ANALOG IN + and – terminals are used
when an external signal is used to drive the
firing rate (Direct Drive Mode) or change the
setpoint (Remote Setpoint Mode) of the Boiler.

Either a 4 to 20 mA / 1 to 5 VDC or a 0 to 20 mA
/ 0 to 5 VDC signal may be used to vary the
setpoint or firing rate. The factory default setting
is for 4 to 20 mA / 1 to 5 VDC, however this may
be changed to 0 to 20 mA / 0 to 5 VDC using the
Configuration Menu described in Chapter 3. If
voltage rather than current is selected as the
drive signal, a DIP switch must be set on the
PMC Board located inside the Control Box.
Contact the AERCO factory for information on
setting DIP switches.

All 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(see Fig. 2.9). 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° to
240°F setpoint or a 0% to 100% firing rate. No
scaling for these signals is provided

2.7.4 B.M.S. (PWM) IN

NOTE

Only BMS Model 168 can utilize Pulse
Width Modulation (PWM), not the BMS II
(Model 5R5-384).

These terminals are used to connect the
AERCO Boiler Management System (BMS)
Model 168 to the unit. The BMS Model 168
utilizes a 12 millisecond, ON/OFF duty cycle.
This duty cycle is Pulse Width Modulated (PWM)
to control firing rate. A 0% firing rate = a 5% ON
pulse and a 100% firing rate = a 95% ON pulse.

2.7.5 SHIELD

The SHIELD terminals are used to terminate any
shields used on sensor wires connected to the
unit. Shields must only be connected to these
terminals.

2.7.6 mA OUT

These terminals provide a 4 to 20 mA output
that can be used to monitor setpoint ( 40

o

F), outlet temperature (30o to 240oF), or fire

240
rate (0% to 100%). This function is enabled in
the Configuration Menu (Chapter 3, Table 3.4).

o

to

2.7.7 RS-485 COMM

These terminals are used for RS-485 MODBUS
serial communication between the unit and an
external “Master” such as a Boiler Management
System or other suitable device.

2.7.8 EXHAUST SWITCH IN

These terminals permit an external exhaust
switch to be connected to the exhaust manifold
of the boiler. The exhaust sensor should be a
normally open type switch (such as AERCO Part
No. 123463) that closes (trips) at 500

o

F.

2.7.9 INTERLOCKS

The unit offers two interlock circuits for
interfacing with Energy Management Systems
and auxiliary equipment such as pumps or
louvers. These interlocks are called the Remote
Interlock and Delayed Interlock (Fig. 2.9). The
wiring terminals for thes e interlocks are located
inside the I/O Box on the unit front panel. The
I/O Box cover contains a wiring diagram which
shows the terminal strip locations for these
interlocks labeled REMOTE INTL’K IN and
DELAYED INTL’K IN. Both interlocks, described
below, are factory wired in the closed position.

2-8

INSTALLATION

NOTE:

Both the Delayed Interlock and Remote
Interlock must be in the closed position to
allow the unit to fire.

2.7.9.1 REMOTE INTERLOCK IN

The remote interlock circuit (REMOTE INTL’K
IN) is provided to remotely start (enable) and
stop (disable) the Boiler if desired. The circuit is
24 VAC and comes factory pre-wired closed
(jumped).

2.7.9.2 DELAYED INTERLOCK IN

The delayed interlock circuit (DELAYED INTL’K
IN) is typically used in conjunction with the
auxiliary relay described in paragraph 2.8. This
interlock circuit is located in the purge section of
the start string. It can be connected to the
proving device (end switch, flow switch etc.) of
an auxiliary piece of equipment started by the
Boiler’s auxiliary relay. The delayed interlock
must be closed for the boiler to fire. If the
delayed interlock is connected to a proving
device that requires time to close (make), a time
delay (Aux Start On Dly) that holds the start
sequence of the boiler long enough for a proving
switch to make can be programmed. Should the
proving switch not prove within the programmed
time frame, the boiler will shut down. The Aux
Start On Dly can be programmed from 0 to 120
seconds. This option is locate in the Configura­tion Menu (Chapter 3).

2.7.10 FAULT RELAY

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 2.9

2.8 AUXILIARY RELAY CONTACTS

Each Boiler is equipped with a single pole
double throw (SPDT) relay that is energized
when there is a demand for heat and de­energized after the demand for heat is satisfied.
The relay is provided for the control of auxiliary
equipment, such as pumps and louvers, or can
be used as a Boiler status indictor (firing or not
firing). Its contacts are rated for 120 VAC @ 5
amps. Refer to Figure 2.9 to locate the AUX
RELAY terminals for wiring connections.

2.9 FLUE GAS VENT INSTALLATION

The AERCO Venting and Combustion Air Guide,
GF-2050, must be consulted before any flue gas
vent or inlet air venting is designed or installed.
U/L listed, positive pressure, watertight vent
materials as specified in AERCO’s GF-2050,
must be used for safety and code compliance.
Because the unit is capable of discharging low
temperature exhaust gases, the flue must be
pitched back to the unit a minimum of 1/4" per
foot to avoid any condensate pooling and to
allow for proper drainage.

The combined pressure drop of vent and
combustion air systems must not exceed 140
equivalent feet of 8 inch ducting. Fittings as well
as pipe lengths must be calculated as part of the
equivalent length.

For a natural draft installation the draft must not
exceed -0.25”/+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.

The Heatfab Division of the Selkirk Corporation
provides vent systems which conform to all
applicable requirements for installations within
the Commonwealth of Massachusetts. Contact
information for this supplier are as follows:

Selkirk Corporation
Heatfab Division
130 Industrial Blvd.
Turners Falls, MA 01376
Phone: [phone]
www.heat-fab.com

2.10 COMBUSTION AIR

The AERCO Venting and Combustion Air Guide,
GF-2050, MUST be consulted before any flue or
combustion supply air venting is designed or
started. Combustion air supply is a direct
requirement of ANSI 223.1, NFPA-54, 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 us ed in gas­fired 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.

2-9

The Benchmark is UL listed for 100% sealed
combustion and can be ordered with a sealed
combustion option, or can be installed using
room air as long as there is an adequate supply.
(See paragraph 2.10.3 for more information
concerning sealed combustion air.)

If the sealed combustion air option is not being
used, an inlet screen will be attached at the
blower suction and the knockout at the top of the
unit will be and should remain in place.

The more common methods of supplying
combustion air are outlined below. For more
information concerning combustion air, consult
the AERCO GF-2050, Venting and Combustion
Air Guide.

2.10.1 COMBUSTION AIR FROM

OUTSIDE THE BUILDING

Air supplied from outside the building must be
provided through two permanent openings. Each
opening must have a free area of not less than
one square inch for each 4000 BTU boiler input.
The free area must take into account restrictions
such as louvers and bird screens.

2.10.2 COMBUSTION AIR FROM INSIDE

THE BUILDING

When combustion air is provided from within the
building, it must be supplied through two
permanent openings in an interior wall. Each
opening must have a free area of not less than
one square inch per 1000 BTUH of total boiler
input. The free area must take into account any
restrictions such as louvers.

2.10.3 SEALED COMBUSTION

The BENCHMARK boiler is UL listed for 100%­sealed combustion and can be ordered with a
sealed combustion option or without. Units
ordered in the sealed combustion configuration
will come with an air inlet assembly installed on
the blower. The knockout at the top of the boiler
must be removed and the combustion air
ductwork must be attached to the 6" x 8" adapter
that is provided just below the knockout.
Remove and discard the screen attached to the
adapter.

In a sealed combustion air application, the
combustion air ducting pressure los ses must be
taken into account when calculating the total
maximum allowable venting run. See the
AERCO Venting and Combustion Air Guide, GF-

2050. When using the boiler in a sealed
combustion air configuration, each unit must
have a minimum 8" diameter connection at the
unit.

2-10

CONTROL PANEL OPERATING PROCEDURES

Chapter 3 - CONTROL PANEL OPERATING PROCEDURES

3.1. INTRODUCTION

The information in this Chapter provides a guide
to the operation of the Benchmark Boiler using
the Control Panel mounted on the front of the
unit. It is imperative that the initial startup of this
unit be performed by factory trained personnel.
Operation prior to initial startup by factory
trained personnel will void the equipment
warranty. In addition, the following WARNINGS
and CAUTIONS must be observed at all times.

CAUTION:

All initial installation procedures must be
satisfied before attempting to start the unit.

WARNING:

THE ELECTRICAL VOLTAGES IN THIS
SYSTEM MAY INCLUDE 460, 220, 120
AND 24 VOLTS AC. IT MUST NOT BE
SERVICED OR ACCESSED BY OTHER
THAN FACTORY CERTIFIED SERVICE
TECHNICIANS.

WARNING:

DO NOT ATTEMPT TO DRY FIRE THE
BOILER. STARTING THE UNIT WITHOUT
A FULL WATER LEVEL CAN SERIOUSLY
DAMAGE THE UNIT AND MAY RESULT IN
PERSONNEL INJURY OR PROPERTY
DAMAGE. THIS SITUATION WILL VOID
ANY WARRANTY.

3.2. CONTROL PANEL DESCRIPTION

The Benchmark Control Panel shown in Figure
3-1 contains all of the controls, indicators and
displays necessary to operate, adjust and
troubleshoot the Benchmark Boiler. These
operating controls, indicators and displays are
listed and described in Table 3-1. Additional
information on these items are provided in the
individual operating procedures provided in this
Chapter.

2

1

3

4

12

11

10

9

5

6

7

8

Figure 3-1.

Control Panel Front View

3-1

CONTROL PANEL OPERATING PROCEDURES

Table 3-1 Operating Controls, Indicators and Displays

ITEM

NO.

CONTROL, INDICATOR

OR DISPLAY

1 LED Status Indicators Four Status LEDs indicate the current operating status as

follows:

COMM

MANUAL

REMOTE

DEMAND

2

OUTLET
TEMPERATURE

Display

3 VFD Display Vacuum Fluorescent Display (VFD) consists of 2 lines, each

4 RS-232 Port Port permits a Laptop Computer or External Modem to be

5 FAULT Indicator Red FAULT LED indicator lights when a boiler alarm

6 CLEAR Key Turns off the FAULT indicator and clears the alarm message

7 READY Indicator
8 ON/OFF Switch

9

LOW WATER LEVEL
TEST/RESET Switches

Lights when RS-232 communication is occurring
Lights when the unit is being controlled using the front panel

keypad.
Lights when the unit is being controlled by an external signal

from an Energy Management System
Lights when there is a demand for heat.

3–Digit, 7–Segment LED display continuously displays the

outlet water temperature. The °F or °C LED next to the

display lights to indicate whether the displayed temperature is
in degrees Fahrenheit or degrees Celsius.

capable of displaying up to 16 alphanumeric characters. The
information displayed includes:

Startup Messages
Fault Messages
Operating Status Messages
Menu Selection

connected to the boiler Control Panel.

condition occurs. An alarm message will appear in the VFD.

if the alarm is no longer valid. Lockout type alarms will be
latched and cannot be cleared by simply pressing this key.
Troubleshooting may be required to clear these types of
alarms.

Lights when all Pre-Purge conditions have been satisfied.

Enables and disables boiler operation.

Allows operator to test operation of the water level monitor.

Pressing TEST opens the water level probe circuit and

simulates a Low Water Level alarm.

Pressing RESET resets the water level monitor circuit.
Pressing CLEAR resets the display.

FUNCTION

3-2

CONTROL PANEL OPERATING PROCEDURES

Table 3-1 Operating Controls, Indicators and Displays - Continued

ITEM

NO.

10 Menu Keypad Consists of 6 keys which provide the following functions for

CONTROL, INDICATOR

OR DISPLAY

the Control Panel Menus:

MENU

BACK

▲ (UP) Arrow When in one of the main menu categories (Figure 3-2),

▼ (DOWN) Arrow When in one of the main menu categories (Figure 3-2),

CHANGE

Steps through the main menu categories shown in Figure
3-2. The Menu categories wrap around in the order shown.

Allows you to go back to the previous menu level without
changing any information. Continuously pressing this key
will bring you back to the default status display in the VFD.
Also, this key allows you to go back to the top of a main
menu category.

pressing the ▲ arrow key will select the displayed menu

category. If the CHANGE key was pressed and the menu

item is flashing, pressing the ▲ arrow key will increment the
selected setting.

pressing this key will select the displayed menu category. If

the CHANGE key was pressed and the menu item is

flashing, pressing the ▼ arrow key will decrement the
selected setting.

Permits a setting to be changed (edited). When the

CHANGE key is pressed, the displayed menu item will begin

to flash. Pressing the ▲ or ▼ arrow key when the item is
flashing will increment or decrement the displayed setting.

FUNCTION

ENTER

11 AUTO/MAN Switch This switch toggles the boiler between the Automatic and

12 FIRE RATE Bargraph 20 segment red LED bargraph continuously shows the Fire

Saves the modified menu settings in memory. The display
will stop flashing.

Manual modes of operation. When in the Manual (MAN)

mode, the front panel controls are enabled and the

MANUAL status LED lights.

When in the Automatic (AUTO) mode, the MANUAL status

LED will be off and the front panel controls disabled.

Rate in 5% increments from 0 to 100%

3-3

CONTROL PANEL OPERATING PROCEDURES

3.3. CONTROL PANEL MENUS

The Control Panel incorporates an extensive
menu structure which permits the operator to set
up, and configure the unit. The menu structure
consists of four major menu categories as
shown in Figure 3-2. Each of the menus shown,
contain options which permit operating parame­ters to be viewed or changed. The menus are
protected by a password to prevent unauthor­ized use.

Prior to entering the correct password, the
options contained in the Operating, 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 password (159) is entered, the
options listed in the Setup, Configuration and
Tuning Menus can be viewed and changed, if
desired.

3.3.1. Menu Processing Procedure

Accessing 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.

display the options in the Bottom-Up
sequence. The menu options will wrap­around after the first or last available option
is reached.

6. To change the value or setting of a displayed

menu option, press the CHANGE key. The

displayed option will begin to flash. Press
the ▲ or ▼ arrow key to scroll through the
available menu option choices for the option
to be changed. The menu option choices do
not wrap around.

7. To select and store a changed menu item,

press the ENTER key.

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

Figure 3-2. Menu Structure

NOTE:

The following paragraphs provide brief
descriptions of the options contained in
each menu. Refer to Appendix A for
detailed descriptions of each menu option.
Factory Default settings for all menu options
are listed in Appendix E. Refer to Appendix
B for listings and descriptions of displayed

startup, status and error messages.

3-4

CONTROL PANEL OPERATING PROCEDURES

3.4. OPERATING MENU

The Operating Menu displays a number of key
operating parameters for the unit as listed in
Table 3-2. This menu is “Read-Only” and does
not allow personnel to change or adjust any
other displayed items. Since this menu is “Read­Only”, it can be viewed at any time without
entering a password. Press the ▲ arrow key to
display the menu items in the order listed (Top­Down). Pressing the ▼ arrow key will display
the menu items in reverse order (Bottom-Up).

3.5. SETUP MENU

The Setup Menu (Table 3-3) permits the
operator to enter the unit password (159) which
is required to change the menu options. To
prevent unauthorized use, the password will
time-out after 1 hour. Therefore, the correct
password must be reentered when required. In
addition to permitting password entries, the

Table 3-2. Operating Menu

Available Choices or Limits

Menu Item Display Minimum Maximum Default

Status Message
Active Setpoint 40°F 240°F
Aux Temp 30°F 245°F
Outdoor Temp* -70°F 130°F
Fire Rate In 0% Max Fire Rate
Flame Strength 0% 100%
Run Cycles 0 999,999
Run Hours 0 999,999
Fault Log 0 9 0

Table 3-3. Setup Menu

Available Choices or Limits
Menu Item Display Minimum Maximum Default

Passsword 0 9999 0
Language English English
Time 12:00 am 11:59 pm
Date 01/01/00 12/31/99
Unit of Temp Fahrenheit

Comm Address 0 127 0
Baud Rate 2400, 4800

9600, 19.2K

Software Ver 0.00 Ver 9.99

Setup Menu is also used to enter date and time,
language to be used for display messages, units
of temperature measurements and entries
required for external communication and control
of the unit via the RS-232 port. A view-only
software version display is also provided to
indicate the current Control Box software
version.

NOTE:

The Outdoor Temp display item shown with
an asterisk in Table 3-2 will not be displayed
unless the Outdoor Sensor function has
been enabled in the Configuration Menu

(Table 3-4).

Fahrenheit

Celsius

9600

3-5

CONTROL PANEL OPERATING PROCEDURES

3.6. CONFIGURATION MENU

The Configuration Menu shown in Table 3-4
permits adjustment of the Internal Setpoint
(Setpt) temperature regardless of whether the
valid password has been entered. Setpt is
required for operation in the Constant Setpoint
mode. The remaining options in this menu
require the valid password to be entered, prior to
changing existing entries. This menu contains a
number of other configuration settings which
may or may not be displayed, depending on the
current operating mode setting.

Table 3-4. Configuration Menu

Available Choices or Limits
Menu Item Display Minimum Maximum Default

Internal Setpt Lo Temp Limit Hi Temp Limit 130°F
Unit Type Boiler

Water Heater

Unit Size 0.5 MBTU, 1.0 MBTU

1.5 MBTU, 2.0 MBTU

2.5 MBTU, 3.0 MBTU

Boiler Mode Constant Setpoint

Remote Setpoint

Combination

Outdoor Reset
Remote Signal
(If Mode = Remote
Setpoint, Direct Drive
or Combination)
Bldg Ref Temp
(If Boiler Mode =
Outdoor Reset)
Reset Ratio
(If Boiler Mode =
Outdoor Reset)
Outdoor Sensor Enabled or Disabled Disabled
System Start Tmp
(If Outdoor Sensor =
Enabled)
Setpt Lo Limit 40°F Setpt Hi Limit 60°F
Setpt Hi Limit Setpt Lo Limit 240°F 200°F
Temp Hi Limit 40°F 240°F 215°F
Max Fire Rate 40% 100% 100%
Pump Delay Timer 0 min 30 min 0 min
Aux Start On Dly 0 sec 120 sec 0 sec
Failsafe Mode Shutdown or Constant Setpt Shutdown
mA Output Setpoint, Outlet Temp,

Lo Fire Timer 2 sec 120 sec 2 sec
Setpt Limiting Enabled or Disabled Disabled
Setpt Limit Band 0°F 10°F 5°F

4 – 20 mA/1 – 5V

0 -20 mA/0 – 5V

BMS (PWM Input

40°F 240°F 70°F

0.1 9.9 1.2

30°F 100°F 60°F

Fire Rate Out, Off

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

Boiler

1.0 MBTU

Constant
Setpoint

Direct Drive

4 – 20 mA,
1-5V

Network

Off

3-6

CONTROL PANEL OPERATING PROCEDURES

3.7. TUNING MENU

The Tuning Menu items in Table 3-5 are Factory
set for each individual unit. Do not change these

Table 3-5. Tuning Menu

Available Choices or Limits
Menu Item Display Minimum Maximum Default

Prop Band 1°F 120°F 70°F
Integral Gain 0.00 2.00 1.00
Derivative Time 0.0 min 2.0 min 0.0 min
Reset Defaults? Yes

3.8. START SEQUENCE

When the Control Box ON/OFF switch is set to
the ON position, it checks all pre-purge safety

switches to ensure they are closed. These
switches include:

• Safety Shut-Off Valve Proof of Closure
(POC) switch

• Low Water Level switch

• High Water Temperature switch

• High Gas Pressure switch

• Low Gas Pressure switch

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:

menu entries unless specifically requested to do
so by Factory-Trained personnel.

No

No

Are You Sure?

If any of the Pre-Purge safety device switches
are open, the appropriate fault message will be
displayed. Also, the appropriate fault messages
will be displayed throughout the start sequence,

if the required conditions are not observed.

1. The DEMAND LED status indicator will light.

2. The unit checks to ensure that the proof of
closure switch in the Safety Shut-Off Valve
(SSOV) is closed (Figure 3-3).

Figure 3-3.

Safety Shut-Off Valve

3. With all required safety switches closed, a
purge cycle will be initiated and the following
events will occur:

3-7

CONTROL PANEL OPERATING PROCEDURES

(a) Blower relay energizes and turns on

blower.

(b) Air/Fuel Valve rotates to full-open purge

position and closes purge position
switch. The dial on the Air/Fuel Valve
(Figure 3-4) will read 100 to indicate that
it is full-open (100%).

(c) The FIRE RATE bargraph will show

100%.

5. Upon completion of the purge cycle, the
Control Box initiates an ignition cycle and the
following events occur:

(a) The Air/Fuel Valve rotates to the low-fire

ignition position and closes the ignition
switch. The dial on the Air/Fuel Valve
(Figure 3-6) will read between 25 and 35
to indicate that the valve is in the low­fire position.

Figure 3-5.

Blower Proof Switch

Figure 3-4.

Air/Fuel Valve In Purge Position

4. Next, the blower proof switch (Figure 3-5)

closes. The display will show Purging and

indicate the elapsed time of the purge cycle
in seconds. The normal (default) time for the
purge cycle is 7 seconds.

(b) Simultaneously, the ignition transformer

and the staged ignition solenoid valve
will be activated. The ignition trans­former provides ignition spark. The
activated (open) solenoid valve allows a
small volume of gas to flow directly to
the burner assembly (Appendix F).

(c) The gas Safety Shut-Off Valve (SSOV)

is energized (opened) allowing gas to
flow into the Air/Fuel Valve.

6. Up to 7 seconds will be allowed for ignition to
be detected. The igniter relay will be turned
off one second after flame is detected.

7. After 2 seconds of continuous flame, Flame
Proven will be displayed and the flame

strength will be indicated. After 5 seconds,
the current date and time will be displayed in
place of the flame strength.

3-8

CONTROL PANEL OPERATING PROCEDURES

8. With the unit firing properly, it will be
controlled by the temperature controller

circuitry. The FIRE RATE will be continu-

ously displayed on the front panel bargraph.

BLOWER

DIAL
(DETAIL "A")

2

5

BURNER

Once the demand for heat has been satisfied,
the Control Box will turn off the gas valve. The
blower relay will be deactivated and the Air/Fuel

Valve will be closed. Standby will be displayed.

3.9. START/STOP LEVELS

The start and stop levels are the fire rate
percentages that start and stop the unit, based
on load. These levels are Factory preset as
follows:

• Start Level: 20%

• Stop Level: 16%

Normally, these settings should not require
adjustment

DETAIL "A"

Figure 3-6.

Air/Fuel Valve In Ignition Position

3-9

INITIAL START-UP

Chapter 4 - INITIAL START- UP

4.1 INITIAL START- UP REQUIREMENTS

The initial start-up of the Benchmark Boiler is
comprised of the following steps:

• installation completed

• combustion calibration

• proper setting of controls and limits

• mode of operation settings (see Chapter 5)

• safety device testing (see Chapter 6)

Installation should be fully completed before
performing initial start-up; and the start-up must
be complete prior to putting the unit into service.
Starting a unit without the proper piping, venting,
or electrical systems can be dangerous and may
void the product warranty. The following start-up
instructions should be followed precisely in order
for the unit to operate safely, at a high thermal
efficiency, and with low flue gas emissions.

Initial unit start-up is to be performed ONLY by
AERCO factory trained start-up and service
personnel. After following the steps in this
chapter, it will be necessary to perform the mode
of operation settings in chapter 5, and the safety
control test procedures in chapter 6 to complete
the initial unit start-up.

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.

159 Paris Ave.
Northvale, NJ 07647

WARNING!

DO NOT ATTEMPT TO FIRE THE BOILER
WITHOUT FULL WATER LEVEL. THIS
CAN SERIOUSLY DAMAGE THE UNIT
AND MAY RESULT IN PERSONAL
INJURY OR PROPERTY DAMAGE. THIS
IS NOT COVERED BY WARRANTY.

CAUTION!

All installation procedures in Chapter 2 must
be completed before attempting to start the
unit.

4.2 TOOLS AND INSTRUMENTATION FOR COMBUSTION CALIBRATION

To properly perform combustion calibration, the
proper instruments and tools must be used and
correctly attached to the unit. The following
paragraphs outline the necessary tools and
instrumentation as well as their installation.

4.2.1 REQUIRED TOOLS AND INSTRUMENTATION

The following tools and instrumentation are
necessary to perform combustion calibration of
the unit:

1. A digital combustion analyzer with oxygen
accuracy to ± 0.2%, and carbon monoxide in
PPM.

2. A 16" W .C. manometer or equivalent gauge
and plastic tubing.

3. Adjustable wrench to remove 1/8” plug from
pressure sensing port on SSOV.

4. Two, 1/8" NPT to barbed fittings for use with
the gas supply regulator.

5. AERCO differential gas pressure regulator
adjustment tool P/N 123643

6. Small and large flat blade screwdrivers.

7. Tube of silicone adhesive

4.2.2 INSTALLING THE SUPPLY GAS

MANOMETER

1. Check to ensure that the 1/8” NPT ball valve
downstream of the SSOV is closed.

2. Remove the 1/8" NPT pipe plug from the ball
valve downstream
valve (SSOV) (see Figure 4.1).

3. Install a barbed fitting into the pipe plug
tapping.

4. Attach one end of a length of plastic tubing
to the barbed fitting and one end to the 16"
W.C. manometer.

5. Open the 1/8” NPT ball valve downstream of
the SSOV.

of the safety shut off

4-1

INITIAL START-UP

Figure 4.1

1/8” Gas Plug Location

4.2.3 PREPARING THE FLUE VENT
PROBE HOLE

1. Locate and remove the plug on the left or
right side of the exhaust manifold (see
Figure 4.2).

2. Adjust the stop on the combustion analyzer
probe, if so equipped, so that it extends
approximately midway into the flue gas flow.
Do not insert the probe at this time.

4.2.4 INSTALLING THE DIFFERENTIAL
REGULATOR ADJUSTMENT TOOL FOR
NATURAL GAS UNIT.

1. Remove the cap from the differential
pressure regulator (see Figure 4.3).

2. Place the gasket from the regulator cap onto
the regulator adjustment tool.

3. Prior to installing the tool on the regulator,
pull up the screwdriver blade of the tool.
Then thread the tool into the regulator and
hand tighten.

4. Engage the tool’s screwdriver blade into the
regulator’s adjustment screw slot.

REGULATOR CAP

CAP GASKET

REGULATOR
ADJUSTMENT
TOOL (P.N. 123643)

4-2

Figure 4.2

A Location nalyzer Probe Hole

DIFFERENTIAL

PRESSURE

REGULATOR

Figure 4.3

Differential Regulator Adjustment Tool

Installation For Natural Gas Unit

4.3 NATURAL GAS COMBUSTION

CALIBRATION

The Benchmark ships combustion calibrated
from the factory. Recalibration as part of a start­up is necessary due to altitude, gas BTU
content, gas supply piping and supply gas
pressure. Factory test data sheets are shipped
with each unit as a reference.

INITIAL START-UP

It is important to perform the following procedure
as outlined. This will keep readjustments to a
minimum and provide for optimum performance.

1. Open the water supply and return valves to
the unit and ensure that the system pumps
are running.

2. Open the natural gas supply valve to the
unit.

3. Set the ON/OFF switch in the OFF position.
Turn on 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 flashing Manual Fire
Rate message will be displayed with the
present rate in %. Also, the MANUAL LED
will light.

5. Adjust the rate to 0% by pressing the ▼
arrow key.

6. Ensure that the 1/4” ball valve downstream
of the SSOV is open.

7. Set the ON/OFF switch to the ON position.
Change the fire rate to 40% using the ▲
arrow key. The unit should begin its start
sequence and fire.

8. Next, gradually increase the firing rate to
100% in 20% increments and verify that the
gas pressure downstream of the SSOV is

4.8” W.C. for both FM and IRI gas trains at
100% firing rate. If not, remove the brass
hex nut on the droop eliminator using the
black plastic wrench from the Iris Damper.
Make the droop eliminator adjustment using
a flat-tip screwdriver to obtain 4.8” W.C (see
Figure 4.4). For Benchmark 2.0 Low NOx
boilers configured for De-Rated capacity
(see para. 2.4.1), the gas pressure
downstream of the SSOV must be 3.7” W.C.
for both FM and IRI gas trains at a 100%
firing rate.

CAUTION:

Turn the droop eliminator adjustment screw
very slowly. Unlike ordinary regulators, this
adjustment is very sensitive.

DROOP ELIMINATOR
ADJUSTMENT SCREW

Figure 4.4

Adjustment Screw Location

9. Lower the firing rate to 40% using the ▼
arrow key. Insert the combustion analyzer
probe into the exhaust manifold and allow
enough time for the combustion analyzer to
settle. Compare the measured oxygen level
to the oxygen range for inlet air temperature
in Table 1.

10. If needed, adjust the differential regulator
until the oxygen reading is within the
specified range in Table 1.

NOTE:

Adjust only the differential regulator at 40%
control signal. Do not adjust the iris air
damper.

Table 1 - Combustion Oxygen Levels for a

40% Firing Rate

Temp (°F)

130 4.6 <30ppm <20ppm
120 4.8 <30ppm <20ppm
110 5.0 <30ppm <20ppm
100 5.2 <25ppm <20ppm

90 5.3 <25ppm <20ppm
80 5.5 <25ppm <20ppm
70 5.6 <25ppm <20ppm
60 5.9 <25ppm <20ppm
50 6.2 <25ppm <20ppm
40 6.4 <25ppm <20ppm
30 6.5 <25ppm <20ppm
20 6.5 <25ppm <20ppm
10 6.5 <25ppm <20ppm

0 6.6 <25ppm <20ppm

-10 6.6 <25ppm <20ppm

-20 6.7 <25ppm <20ppm

-30 6.8 <25ppm <20ppm

-40 6.8 <25ppm <20ppm

40% Fire Rate

O2

CO

NOx (corrected to

3% O

)

2

4-3

INITIAL START-UP

11. If the required oxygen level from Table 1 is
achieved, proceed to step 18. If the oxygen
level is lower than the required value and
cannot be sufficiently raised using the
differential regulator, proceed to step 12.

12. Close the 1/4” ball valve in the staged
ignition assembly downstream of the SSOV.

13. If the oxygen level rises, it is an indication
that the staged ignition solenoid is stuck, or
is adding gas and preventing the proper
oxygen level from being achieved. The
solenoid will require replacement. Proceed
to step 14.

14. Set the green ON/OFF switch to the OFF
position. Turn off AC power to the unit.

15. Replace the staged ignition solenoid. See
Figure 8.2 for location of the solenoid.

16. Re-open the 1/4” ball valve downstream of
the SSOV.

17. Repeat combustion calibration starting from
step 1 of paragraph 4.3.

18. Once the oxygen level is within the specified
range at 40%, lower the firing rate to 16%.

19. Oxygen levels at the 16% firing rate should
be as shown in Table 2. No adjustment
should be necessary. Contact the Factory if
the oxygen or carbon monoxide levels are
not within the specified range.

NOTE:

If the port being used to sample combustion
products at 16% is too far from the unit, the
readings may be shifted.

Table 2 - Combustion Oxygen Levels for a

16% Firing Rate

16% Fire Rate

Temp (ºF)

130
120 <20ppm <20ppm
110 <20ppm <20ppm
100

90
80 <20ppm <20ppm
70 <20ppm <20ppm
60
50
40 <20ppm <20ppm
30 <20ppm <20ppm
20
10

0 <20ppm <20ppm

-10 <20ppm <20ppm

-20

-30

-40 <20ppm <20ppm

O2 CO

4.5-8.0

5.5-8.5

6.0-9.0

<20ppm <20ppm

<20ppm <20ppm
<20ppm <20ppm

<20ppm <20ppm
<20ppm <20ppm

<20ppm <20ppm
<20ppm <20ppm

<20ppm <20ppm
<20ppm <20ppm

NOx (corrected

to 3% O

)

2

20. Raise the firing rate to 100%. Gas pressure
should still be 4.8” W.C. If it is not, readjust
as necessary. For Benchmark 2.0 Low NOx
boilers configured for De-Rated capacity
(see para. 2.4.1), gas pressure should still
be 3.7” W.C. If not, readjust as necessary.

21. Allow the combustion analyzer to settle.
Compare the measured oxygen level with
the levels in Table 3.

22. If the measured oxygen reading is within the
specified level in Table 3, no further
adjustment is necessary.

23. If the measured oxygen level is not within
specified range in Table 3, adjust the iris
damper as necessary until the measured
oxygen reading is within specification. (See
Figure 4.5).

4-4

INITIAL START-UP

Table 3 - Combustion Oxygen Levels for

100% Firing Rate

100% Fire Rate

NOx (corrected to

Temp (ºF)

130 4.3 <100ppm <40ppm
120 4.5 <100ppm <40ppm
110 4.7 <100ppm <35ppm
100

90
80
70 5.1 <100ppm <30ppm
60 5.2 <100ppm <30ppm
50 5.3 <100ppm <30ppm
40
30
20
10 5.4 <100ppm <30ppm

0 5.4 <100ppm <30ppm

-10 5.4 <100ppm <30ppm

-20

-30

-40

O2 CO

4.8 <100ppm <30ppm

5.0 <100ppm <30ppm

5.1 <100ppm <30ppm

5.4 <100ppm <30ppm

5.4 <100ppm <30ppm

5.4 <100ppm <30ppm

5.4 <100ppm <30ppm

5.4 <100ppm <30ppm

5.4 <100ppm <30ppm

3% O

1. Put the green ON/OFF switch in the off
position. Disconnect the AC power supply to
the unit.

)

2

2. Shut off the gas supply to the unit.

3. Reinstall the brass hex nut back on the
droop eliminator.

4. Remove all of the manometers and barbed
fittings and reinstall the pipe plugs using a
suitable thread compound.

5. Remove the combustion analyzer probe
from the tapped hole in the exhaust
manifold. Replace the NPT plug previously
removed in para. 4.2.3, step 1.

6. Replace the unit’s panels.

4.5 OVER-TEMPERATURE LIMIT

SWITCH

The over-temperature limit switches are located
on the plate to the left of the boiler shell. One is a
fixed manual reset switch that will shutdown and
lock out the boiler if the water temperature
reaches 210°F. The other is an adjustable auto
reset which allows the boiler to restart, once the
temperature drops below its temperature setting.
Figure 4.6 shows the location of the over
temperature limit switch.

Figure 4.5

Iris Air Damper Location

24. Change the firing rate to 40%. Allow time for
the combustion analyzer to settle. Check the
measured oxygen reading to insure that it is
still within the range as per Table 1.

25. Continue this procedure until oxygen levels
at 40%, 16% and 100% firing rates are
within the ranges specified in Tables 1, 2
and 3.

4.4 UNIT REASSEMBLY

Once combustion calibration is set properly, the
unit can be re-assembled for permanent
operation. Proceed as follows:

Figure 4.6

Over Temperature Limit Switch Location

4-5

MODE OF OPERATION

CHAPTER 5 MODE OF OPERATION

5.1 INTRODUCTION

The Benchmark 2.0 Low NOx Boiler is capable
of being operated in any one of six different
modes. The following paragraphs in this Chapter
provide descriptions of each of these operating
modes. Each unit 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. The factory defaults are listed in
Appendix E. After reading this chapter,
parameters can be customized to suit the needs
of the specific application.

5.2 INDOOR/OUTDOOR RESET MODE

This mode of operation is based on outside air
temperatures. As the outside air temperature
decreases, the supply header temperature will
increase and vice versa. For this mode, it is
necessary to install an outside air sensor as well
as select a building reference temperature and a
reset ratio.

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.

5.2.3 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 Benchmark Boilr. Connections are made
at the terminals labeled OUTDOOR SENSOR IN
and SENSOR COMMON inside the I/O Box.
Use shielded 18 to 22 AWG wire for
connections. A wiring diagram is provided on
the cover of the I/O Box. Refer to Chapter 2,
paragraph 2.7.1 for additional wiring information.

5.2.4 Indoor/ Outdoor Startup

Startup in the Indoor/Outdoor Reset Mode is
accomplished as follows:

1. Refer to the Indoor/Outdoor reset ratio
charts in Appendix D.

2. Choose the chart corresponding to the
desired Building Reference Temperature.

3. Go down the left column of the chart to the
coldest design outdoor air temperature
expected in your area.

NOTE

A design engineer typically provides
design outdoor air temperature and

header temperature data

supply

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.

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).

5-1

MODE OF OPERATION

7. Press the CHANGE key. The display will
begin to flash.

8. Use the ▲ and ▼ arrow keys to select the
desired Building Reference Temperature.

9. Press ENTER to save any changes.

10. Next, scroll through the Configuration Menu
until the display shows Reset Ratio.

11. Press the CHANGE key. The display will
begin to flash.

12. Use the ▲ and ▼ arrow keys to select the
Reset Ratio determined in step 5.

13. Press ENTER to save the change.

Refer to paragraph 3.3 for detailed instructions
on menu changing.

5.3 CONSTANT SETPOINT MODE

The Constant Setpoint mode is used when a
fixed header temperature is desired. Common
uses of this mode of operation include water
source heat pump loops, and indirect heat
exchangers for potable hot water systems or
processes.

5.4 REMOTE SETPOINT MODES

The unit’s setpoint can be remotely controlled by
an Energy Management System (EMS) or
Building Automation System (BAS). The Remote
Setpoint can be driven by a current or voltage
signal within the following ranges:

4-20 mA/1-5 Vdc

0-20 mA/0-5 Vdc

The factory default setting for the Remote
Setpoint mode is 4 - 20 mA/1 - 5 Vdc. With this
setting, a 4 to 20 mA/1 to 5 Vdc signal, sent by
an EMS or BAS, is used to change the unit's
setpoint. The 4 mA/1V signal is equal to a 40°F
setpoint while a 20 mA /5V signal is equal to a
240°F setpoint. When a 0 to 20 mA/0 to 5 Vdc
signal is used, 0 mA is equal to a 40°F setpoint.

In addition to the current and voltage signals
described above, the Remote Setpoint mode
can also be driven by a RS485 Modbus Network
signal from an EMS or BAS.

The Remote Setpoint modes of operation can be
used to drive single as well as multiple units.

No external sensors are required to operate in
this mode. While it is necessary to set the
desired setpoint temperature, it is not necessary
to change any other temperature-related func­tions. The unit is factory preset with settings that
work well in most applications. Prior to changing
any temperature-related parameters, other than
the setpoint, it is suggested that an AERCO
representative be contacted. For descriptions of
temperature-related functions and their factory
defaults, see Appendices A and E.

5.3.1 Setting the Setpoint

The setpoint temperature of the unit is
adjustable from 40°F to 240°F. To set the unit
for operation in the Constant Setpoint Mode, the
following menu settings must be made in the
Configuration Menu:

MENU OPTION SETTING

Boiler Mode Constant Setpoint

Internal Setpt Select desired setpoint

using ▲ and ▼ arrow
keys (40°F to 240°F)

NOTE

If a voltage, rather than current signal is
used to control the remote setpoint, a DIP
switch adjustment must be made on the
PMC Board located in the Control Panel
Assembly. Contact your local AERCO
representative for details.

In order to enable the Remote Setpoint Mode,
the following menu setting must be made in the
Configuration Menu:

MENU OPTION SETTING

Boiler Mode Remote Setpoint

Remote Signal 4-20mA/1-5V,

0-20mA/0-5V, or

Network

Refer to paragraph 3.3 for detailed instructions
on changing menu options.

Refer to paragraph 3.3 for detailed instructions
on changing menu options.

5-2

MODE OF OPERATION

If the Network setting is selected for RS485
Modbus operation, a valid Comm Address must
be entered in the Setup Menu. Refer to Modbus
Communication Manual GF-114 for additional
information.

While it is possible to change the settings of
temperature related functions, the unit is factory
preset with settings that work well in most
applications. It is suggested that an AERCO
representative be contacted, prior to changing
any temperature related function settings. For
descriptions of temperature-related functions
and their factory defaults, refer to Appendices A
and E.

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 Benchmark Boiler. For either a 4­20mA/0-5V or a 0-20mA/0-5V setting, the
connections are made at the ANALOG IN
terminals in the I/O Box. For a Network setting,
the connections are made at the RS-485 COMM
terminals in the I/O Box. The signal must be
floating, (ungrounded) at the I/O Box and the
wire used must be a two wire shielded pair from
18 to 22 AWG. Polarity must be observed. The
source end of the shield must be connected at
the source. When driving multiple units, each
unit’s wiring must conform to the above.

5.4.2 Remote Setpoint Startup

Since this mode of operation is factory preset
and the setpoint is being externally controlled,
no startup instructions are necessary. In 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 fire rate 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 fire rate from 0% to 100%. A
4 mA/1V signal is equal to a 0% fire rate, while a
20 mA /5V signal is equal to a 100% fire rate.
When a 0-20 mA/0-5 Vdc signal is used, zero is
equal to a 0% fire rate.

In addition to the current and voltage signals
described above, the Direct Drive mode can also
driven by a RS485 Modbus Network signal from
an EMS or BAS.

When in a Direct Drive mode, the unit is a slave
to the EMS or BAS and does not have a role in
temperature control. Direct Drive can be used to
drive single, or multiple units.

NOTE

If a voltage, rather than current signal is
used to control the remote setpoint, a DIP
switch adjustment must be made on the
PMC Board located in the Control Box
Assembly. Contact your local AERCO
representative for details.

To enable the Direct Drive Mode, the following
menu setting must be made in the Configuration
Menu:

MENU OPTION SETTING

Boiler Mode Direct Drive

Remote Signal 4-20mA/1-5V,

0-20mA/0-5V, or

Network

Refer to paragraph 3.3 for instructions on
changing menu options.

5-3

MODE OF OPERATION

If the Network setting is selected for RS485
Modbus operation, a valid Comm Address must
be entered in the Setup Menu. Refer to Modbus
Communication Manual GF-114 for additional
information.

5.5.1 Direct Drive Field Wiring

The only wiring connections necessary for Direct
Drive mode are connection of the remote signal
leads from the source to the unit’s I/O Box. For
either a 4-20mA/0-5V or a 0-20mA/0-5V setting,
the connections are made at the ANALOG IN
terminals in the I/O Box. For a Network setting,
the connections are made at the RS-485 COMM
terminals in the I/O Box. The signal must be
floating, (ungrounded) at the I/O Box and the
wire used must be a two wire shielded pair from
18 to 22 AWG. Polarity must be observed. The
source end of the shield must be connected at
the source. When driving multiple units, each
unit’s wiring must conform to the above.

5.5.2 Direct Drive Startup

Since this mode of operation is factory preset
and the fire rate is being externally controlled, no
startup instructions are necessary. In this mode,
the REMOTE LED will light when the signal is
present.

To operate the unit in manual mode, press the
AUTO/MAN switch. The REMOTE LED will go
off and the MANUAL LED will light.

To change back to the Direct Drive mode, simply
press the AUTO/MAN switch. The REMOTE
LED will again light and the MANUAL LED will
go off.

5.6 BOILER MANAGEMENT SYSTEM

(BMS)

NOTE

BMS Model 168 can utilize either pulse
width modulation (PWM) or RS485
Modbus signaling to the Boiler. BMS II
Model 5R5-384 can utilize only RS485
signaling to the Boiler.

The BMS mode of operation is used in
conjunction with an AERCO Boiler Management
System. The BMS mode is used when it is
desired to operate multiple units in the most
efficient manner possible. The BMS can control
up to 40 boilers; 8 via pulse width modulation
(PWM) and up to 32 via Modbus (RS485)

network communication. For BMS programming
and operation, see GF-108M (BMS Model 168)
and GF-124 (BMS II 5R5-384), BMS Operations
Guides. For operation via an RS485 Modbus
network, refer to Modbus Communication
Manual GF-114.

To enable the BMS Mode, the following menu
settings must be made in the Configuration
Menu:

MENU OPTION SETTING

Boiler Mode Direct Drive

Remote Signal BMS (PWM Input)

or
Network (RS485)

Refer to paragraph 3.3 for instructions on
changing menu options.

5.6.1 BMS External Field Wiring

Wiring connections for BMS control using PWM
signaling are made between connector JP2 on
the BMS panel (boilers 1 through 8), and the
B.M.S. (PWM) IN terminals in the I/O Box on the
front of the Benchmark Boilers. Refer to the
wiring diagram provided on the cover of the I/O
Box.

Wiring connections for RS485 Modbus control
are made between connector JP11 on the BMS
(boilers 9 through 40) and the RS485 COMM
terminals in the I/O Box on the front of the
Benchmark Boilers.

Wire the units using shielded twisted pair wire
between 18 and 22 AWG. Observe the proper
polarity for the B.M.S. (PWM) IN and/or RS485
COMM wiring connections. Shields should be
terminated only at the BMS and the boiler end
must be left floating. Each unit’s wiring must
conform to the above.

5.6.2 BMS Setup and Startup

This mode of operation is factory preset and the
AERCO BMS controls the firing rate. There are
no setup instructions for each individual unit.

To operate the unit in manual mode, press the
AUTO/MAN switch. The REMOTE LED will go
off and the MANUAL LED will light

To change back to the BMS mode, simply press
the AUTO/MAN switch. The REMOTE LED will
again light and the MANUAL LED will go off.

5-4

MODE OF OPERATION

5.7 COMBINATION CONTROL SYSTEM

(CCS)

NOTE

Only BMS Model 168 can be utilized for
the Combination Mode, not the BMS II
(Model 5R5-384).

A Combination Control System (CCS) is one
that uses multiple boilers to cover both space­heating and domestic hot water needs. An
AERCO Boiler Management System (BMS)
Model 168 and a Combination Control Panel
(CCP) are necessary to configure this system.
Typically, an adequate number of boilers are
installed to cover the space-heating load on the
design day, however one or more units are used
for the domestic hot water load.

The theory behind this type of system is that the
maximum space-heating load and the maximum
domestic hot water load do not occur simul­taneously.+ Therefore, boilers used for the
domestic hot water are capable of switching
between constant setpoint and BMS modes of
operation. These boilers are the combination
units and are referred to as the combo boilers.
The combo boilers heat water to a constant
setpoint temperature. That water is then
circulated through a heat exchanger in a
domestic hot water storage tank.

When the space-heating load is such that all the
space-heating boilers are at 100% firing rate, the
BMS will then ask the Combination Control
Panel for the domestic boilers to become space­heating boilers. Provided the domestic hot
water load is satisfied, the combo (hot water)
boilers will then become space-heating boilers.
If the domestic hot water load is not satisfied,
the combo boiler(s) remain on the domestic hot
water load. If the combo boilers switch over to
space heating, but there is a call for domestic
hot water, the CCP switches the combo units
back to the domestic load.

When the combo units are satisfying the
domestic load they are in constant setpoint
mode of operation. When the combo units
switch over to space heating, their mode of
operation changes to the BMS mode. For more
information concerning the operation of the
Combination Control Panel see the AERCO
CCP-1 literature.

5.7.1 Combination Control System Field
Wiring

Wiring for this system is between the BMS
Model 168 panel, the CCP and the B.M.S.
(PWM) IN terminals in the I/O Box. Wire the
units using a shielded twisted pair of 18 to 22
AWG wire. When wiring multiple units, each
unit’s wiring must conform to the above. For a
complete CCP system-wiring diagram see the
AERCO CCP-1 literature.

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 240°F.

Enter the following settings in the Configuration
Menu:

MENU OPTION SETTING

Boiler Mode Combination

Remote Signal BMS (PWM Input)

Internal Setpt 40°F to 240°F

Refer to paragraph 3.3 for instructions on
changing menu options.

While it is possible to change other temperature­related functions for combination mode, thes
functions are preset to their factory default
values. These default settings work well in most
applications. It is suggested that AERCO be
contacted prior to changing settings other than
the unit’s setpoint. For a complete listing of
temperature related function defaults, see
Appendix E.

To set the unit to the manual mode, press the
AUTO/MAN switch. The MANUAL LED will
light.

To set the unit back to the auto mode, press the
AUTO/MAN switch. The MANUAL LED will go
off and the REMOTE LED will light.

When the boiler is switched to BMS mode, the
AERCO BMS controls the firing rate. There are
no setup requirements to the boiler(s) in this
mode.

5-5

Chapter 6 - SAFETY DEVICE TESTING PROCEDURES

6.1 TESTING OF SAFETY DEVICES

Periodic safety device testing is required to
ensure that the control system and safety
devices are operating as designed. The AERCO
control system comprehensively monitors all
combustion related safety devices before, during
and after the start sequence. The following tests
have been chosen to ensure that the system will
either not start or will shut-down as intended.

Operating and safety controls should be tested
on a regular basis or after a safety device has
been serviced or replaced. All testing must
conform to local codes such as ASME CSD-1.

NOTE:

MANUAL and AUTO modes are required to

perform the following tests. For a complete

explanation of these modes, see Chapter 3.

NOTE:

It will be necessary to remove the sheet
metal covers from the unit to perform the
following tests.

WARNING!

ELECTRICAL VOLTAGES IN THIS
SYSTEM MAY INCLUDE 460, 220, 120
AND 24 VOLTS AC. POWER MUST BE
REMOVED PRIOR TO PERFORMING
WIRE REMOVAL OR OTHER TESTING
PROCEDURES THAT CAN RESULT IN
ELECTRICAL SHOCK.

6.2 LOW GAS PRESSURE FAULT TEST

1. Referring to Figure 6.1, ensure that the 1/8"
NPT ball valve upstream of the SSOV is
closed (located at low gas pressure switch).

2. Remove the 1/8" plug from the ball valve,
upstream of the safety shutoff valve (SSOV).

3. Install a 0-16" W.C. manometer or W.C.
gauge where the 1/8" plug was removed.

4. Slowly open the 1/8" ball valve upstream of
the SSOV.

5. Place the unit in Manual Mode and fire the
unit at a firing rate between 25% and 30%.

6. While the unit is firing, slowly close the Man­ual gas shut-off valve located immediately

SAFETY DEVICE TESTING

outside the boiler. The unit should shut down
on a LOW GAS PRESSURE fault message
at 4.4” W.C. For Benchmark 2.0 Low NOx
boilers configured for De-Rated capacity
(see para. 2.4.1), the unit should shut down
on a LOW GAS PRESSURE fault message
at 3.6” W.C.

Figure 6.1

1/8” Pipe Plug Position for Manometer

Installation & Low Gas Pressure Testing

7. Fully open the manual gas shut-off valve and
press the CLEAR button on the Control Box.

8. The unit should restart.

9. Remove manometer and replace 1/8”NPT
plug.

NOTE:

After faulting the unit, the fault message will
be displayed and the fault indicator light will
flash until the CLEAR button is pressed.

6.3 HIGH GAS PRESSURE TEST

1. Start the unit in manual mode and fire
between 25% and 30%.

2. Remove either wire # 150 or wire #151 from
the high gas pressure switch. See Fig. 6.1.

3. The unit should shut down on a HIGH GAS
PRESSURE FAULT.

4. Reconnect the wire previously removed from
the high gas pressure switch and depress
the CLEAR button.

5. The unit should restart.

6-1

SAFETY DEVICE TESTING

6.4 LOW WATER LEVEL FAULT TEST

1. Place the ON/OFF switch in the OFF
position.

2. Close 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 it is necessary to vent the unit to
aid in draining, the unit’s relief valve may be
opened.

4. Drain the unit until the LOW WATER LEVEL
fault message is displayed and the FAULT
LED flashes.

5. Place the unit in the Manual Mode and raise
the firing rate above 25%.

6. Set the ON/OFF switch to ON. 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 to fill the shell.

9. Open the water shut-off valve in the supply
piping to the unit.

10. After the shell is full, press the LOW
WATER LEVEL RESET button to reset the
low water cutoff. Press the CLEAR switch to
reset the FAULT LED and clear the
displayed error message.

11. Set the ON/OFF switch to the ON position.
The unit is now ready for operation.

6.5 WATER TEMPERATURE FAULT

TEST

1. In the normal operating mode, allow the unit
to stabilize at its setpoint.

2. Lower the adjustable temperature limit
switch setting to match the displayed
OUTLET TEMPERATURE. (See Fig. 6.2)

RESET BUTTON FOR MANUAL
RESET TEMPERATURE LIMIT
SWITCH

HIGH LIMIT

ADJUSTABLE
TEMPERATURE
LIMIT SWITCH

MOUNTING PLATE
ON SHELL

Figure 6.2

Temperature Limit Switch Setting

3. Once the adjustable limit switch setting is
approximately at, or just below, the actual
outlet water temperature, the unit should
shut down. The FAULT LED should be
flashing and the message HIGH WATER
TEMP SWITCH OPEN should be displayed.
The unit should not start.

4. Reset the adjustable temperature limit
switch setting to its prior setting.

5. The unit should start once the adjustable
temperature limit switch setting is above the
actual outlet water temperature.

6.6 INTERLOCK TESTS

The unit is equipped with two interlock circuits
called the Remote Interlock and Delayed
Interlock. Terminal connections for these circuits
are located in the I/O Box and are labeled
REMOTE INTL’K IN and DELAYED INTL’K IN.
These circuits can shut down the unit in the
event that an interlock is opened. These
interlocks are shipped from the factory jumpered
(closed). However, each of these interlocks may
be utilized in the field as a remote stop and start,
an emergency cut-off, or to prove that a device
such as a pump gas booster, or louver is
operational.

6-2

6.6.1 REMOTE INTERLOCK

1. Remove the cover from the I/O Box and
locate the REMOTE INTL’K IN terminals.

2. Start the unit in manual mode and fire at
25% to 30% firing rate.

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 resume running.

6.6.2 DELAYED INTERLOCK

1. Remove the cover from the I/O Box and
locate the DELAYED INTL’K IN terminals.

2. Start the unit in manual mode and fire at a
25% to 30% firing rate.

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
DELAYED INTERLOCK OPEN. The FAULT
LED should be flashing.

5. Once the interlock connection is recon­nected, depress the CLEAR button. The
unit should start.

6.7 FLAME FAULT TEST

1. Place the ON/OFF switch in the OFF posi-
tion.

2. Place the unit in the Manual Mode and set
the firing rate between 25% and 30%.

3. Close the manual gas valve located between
the SSOV and the Air/Fuel Valve (see Fig.

6.3) and the 1/4” ball valve downstream of
the SSOV.

SAFETY DEVICE TESTING

MANUAL GAS
SHUT-OFF VALVE

DIFFERENTIAL GAS
PRESSURE REGULATOR

Figure 6.3

Manual Gas Shut-Off Valve Location

4. Place the ON/OFF switch in the ON position
to start the unit.

5. The unit should shut down after reaching the
Ignition cycle and display FLAME LOSS

DURING IGN.

6. Open the valves previously closed in step 3
and depress the CLEAR button.

7. Restart the unit and allow it to prove flame.

8. Once flame is proven, close the manual gas
valve located between the safety shut-off
valve and the differential regulator.

9. The unit should shut down and display
FLAME LOSS DURING RUN.

10. Open the valve previously closed in step 8
and depress the CLEAR button. The unit
should restart and fire.

6.8 AIR FLOW FAULT TEST

1. Start the unit in manual mode and set the
fire rate between 25% and 30%.

2. Once the unit has proved flame, remove
either wire #154 or #155 from the blower
proof switch (see Fig. 6.4) located on the
air/fuel valve.

3. The unit should shut down and display
AIRFLOW FAULT DURING RUN.

4. Replace the wire previously removed from
the blower-proof switch and depress the
CLEAR button. The unit should restart.

6-3

SAFETY DEVICE TESTING

Figure 6.4

Blower Proof Switch Location and Wiring

6.9 SSOV PROOF OF CLOSURE SWITCH

1. Set the unit’s ON/OFF switch to the OFF
position. Place the unit in manual mode and
set the fire rate between 25% and 30%.

2. Remove the Safety Shut-Off Valve (SSOV)
cover (see Fig. 6.5).

NOTE:

For units with IRI gas trains, the proof of
closure switch is located in the downstream
SSOV (part no.69005) shown in Fig. 6.5. A
second (upstream) SSOV (part no. 69038)
is also provided, however it does not
contain a regulator and looks physically
different. Refer to drawings AP-A-796-M &
AP-A-801-M (De-Rated) in Appendix F for
IRI gas trains.

3. Disconnect either wire #149 or #148 from
the SSOV.

4. The unit should fault and display SSOV
SWITCH OPEN.

5. Replace the wire previously disconnected
and depress the CLEAR button.

6. Start the unit.

7. Disconnect the wire again when the unit
reaches the purge cycle.

8. The unit should shut down and display
SSOV FAULT DURING PURGE.

9. Replace the wire previously disconnected
and depress the CLEAR button. The unit
should restart.

SSOV

ACTUATOR

COVER

SSOV

ACTUATOR

COVER

SCREW

Figure 6.5

SSOV Actuator Cover Screw Location

6.10 PURGE SWITCH OPEN DURING

PURGE

1. Set the unit’s ON/OFF switch to the OFF
position. Place the unit in manual mode and
set the fire rate between 25% and 30%.

2. Remove the air/fuel valve cover by rotating
the cover counterclockwise to unlock it and
then pulling it towards you (see Fig. 6.6).

3. Disconnect one of the two wires from the
purge position switch (Fig. 6.7) and start the
unit.

4. The unit should begin to start, then shut
down and display PRG SWITCH OPEN
DURING PURGE.

5. Replace the wire on the purge position
switch and depress the CLEAR button. The
unit should restart.

6-4

SAFETY DEVICE TESTING

6.11 IGNITION SWITCH OPEN DURING

IGNITION

1. Set the unit’s ON/OFF switch to the off
position. Place the unit in manual mode and
set the fire rate between 25% and 30%.

2. Remove the air/fuel valve cover (Fig. 6.8) by
rotating the cover counterclockwise to
unlock it then pulling it towards you.

3. Disconnect one of the two wires from the
ignition position switch (Fig. 6.7) and start
the unit.

4. The unit should begin to start then shut
down and display IGN SWITCH OPEN
DURING IGNITION.

Figure 6.6

Air/Fuel Valve Cover Location

5. Replace the wire on the ignition switch and
depress the CLEAR button. The unit should
restart.

6.12 SAFETY PRESSURE RELIEF VALVE

TEST

Figure 6.7

Air/Fuel Valve Purge and Ignition Switch

Locations

Test the Safety Pressure Relief Valve in
accordance with ASME Boiler and Pressure
Vessel Code, Section VI.

6-5

Chapter 7 - MAINTENANCE

7.1 MAINTENANCE SCHEDULE

The unit requires regular routine m aintenance to
keep up efficiency and reliability. For best
operation and life of the unit, the following
routine maintenance procedures should be
carried out in the time periods s pecified in Table
7-1.

See Appendix I for complete CSD-1
inspection check list

WARNING!

TO AVOID PERSONAL INJURY, BEFORE
SERVICING:
(A) DISCONNECT THE AC SUPPLY BY
TURNING OFF THE SERVICE SWITCH
AND AC SUPPLY CIRCUIT BREAKER
(B) SHUT OFF THE GAS SUPPLY AT THE
MANUAL SHUT-OFF VALVE PROVIDED
WITH THE UNIT
(C) ALLOW THE UNIT TO COOL TO A
SAFE TEMPERATURE TO PREVENT
BURNING OR SCALDING

7.2 SPARK IGNITER

The spark igniter , part number GP-122435-S, is
located in the body of the burner (see Fig. 7.1).
The igniter may be HOT, therefore care should
be exercised. It is easier to remove the igniter
from the unit after the unit has cooled to room
temperature.

To inspect/replace the Igniter:

1. Set the ON/OFF switch on the contr ol panel,
to the OFF position. Disconnect AC power
from the unit.

2. Remove the side and top panels from the
unit.

3. Disconnect the igniter cable from the igniter

4. Using a 15/16” wrench, unscrew the igniter
from the burner head. Remove the igniter
from the burner shell, by grasping the
contact end of the igniter.

MAINTENANCE

Figure 7.1

Spark Igniter and Flame Detector Location

Top View

CAUTION!

The igniter may be hot

5. The igniter is gapped at 1/8-inch. If there is a
substantial erosion of the spark gap or
ground electrode, the igniter should be
replaced. If carbon build-up is pres ent, clean
the igniter using fine emery cloth. Repeated
carbon build-up on the igniter is an indication
that a check of the combustion settings is
required (see Chapter 4 for combustion
calibration).

6. Prior to reinstalling the igniter, a high tem­perature anti-seize compound must
applied to the igniter threads.

7. Reinstall the igniter Do not over tighten the
igniter. A slight snugging up is sufficient.
Reconnect the igniter cable.

8. Reinstall the side and top panels on the unit.

be

7-1

MAINTENANCE

Table 7-1. - Maintenance Schedule

PARAGRAPH ITEM 6 Mos. 12 Mos. 24 Mos.

7.2

7.3

7.4

7.5

7.6 Burner Inspect 2 hrs.

7.7

* Only performed after initial 6 month period after initial startup.

7.3 FLAME DETECTOR

The flame detector, part number 66006, is
located in the body of the burner (see Fig. 7.1).
The flame detector may be HOT. Allow the unit
to cool sufficiently before removing the flame
detector.

To inspect or replace the flame detector:

1. Set the ON/OFF switch on the contr ol panel,
to the OFF position. Disconnect AC power
from the unit.

2. Remove the top panels from the unit.

3. Disconnect the flame detector lead wire.
Unscrew the flame detector and remove it.
(See Fig 7.2)

4. Inspect the detector thoroughly. If eroded,
the detector should be replaced. Otherwise
clean the detector with a fine emery cloth.

5. Reinstall the flame detector and flame detec­tor gasket, if removed.

6. Reconnect the flame detector lead wire.

7. Reinstall the side and top panels on the unit.

Spark Igniter
(GP-122435-S)
Flame Detector

(66006)

Combustion

Adj.

Testing of

Safety Devices

Condensate

Drain Trap

*Inspect Inspect Replace 15 mins.
*Inspect Inspect Replace 15 mins.

*Check Check 1 hr.

See CSD-1

Inspect

Chart in

Appendix

Inspect &

Clean

I

1 hr.

7.4 COMBUSTION CALIBRATION

Combustion settings must be checked at the
intervals shown in Table 7-1 as part of the
maintenance requirem ents. Refer to Chapter 4
for combustion calibration instructions.

Figure 7.2

Spark Igniter and Flame Detector Location

Cut-Away View

Labor

Time

20 mins.

7-2

MAINTENANCE

7.5 SAFETY DEVICE TESTING

Systematic and thorough tests of the operating
and safety devices should be performed to
ensure that they are operating as designed.
Certain code requirements, s uch as ASME CSD­1, require that these tests be performed on a
scheduled basis. Test schedules must conform
to local jurisdictions. The results of the tests
should be recorded in a logbook. See Chapter 6­Safety Device Testing Procedures.

7.6 BURNER

The burner assembly is located at the top of the
unit. The burner assembly may be HOT. Allow
the unit to cool sufficiently before removing the
burner assembly.

The following parts will be necessary for
reassembly after inspection:

81030 Burner Gaskets (Qty=2)

To inspect or replace the burner assembly:

1. Set the ON/OFF switch on the control panel,
to the OFF position and disconnect AC
power to the unit and turn off the gas supply.

2. Remove the side and top panels from the
unit.

3. Disconnect the lead wire from the flame
detector. Unscrew the flame detector.

4. Disconnect the igniter cable from the igniter
contactor. Unscrew the igniter.

5. Remove the two (2) 10-32 screws securing
the gas injector to the burner. Separate the
gas injector and gasket from the burner.

6. Disconnect the burner housing from the
venturi by removing the six (6) 1/4-20 screws
(Fig. 7.3) using a 3/8” wrench.

7. Remove the eight (8) 3/8-16 nuts from the
burner flange (see Fig 7.3) using a 9/16”
wrench.

NOTE:

The burner housing is heavy, weighing
approximately 20 pounds.

8. Remove the burner housing from burner
flange by pulling straight up.

9. Remove the grounding screw.

10. If there is an extension ring around the
burner, remove it.

11. Remove the burner by pulling straight up.

12. Remove and replace the burner gaskets.

13. Beginning with the burner removed in step
11, reinstall all the components in the
reverse order that they were removed.
However, if the burner was replaced, f ollow
the instructions in step 14.

14. If the burner is being replac ed, measure the
outside diameter (O.D.) of the new burner
flange. If the O.D. is approximately 13”, do

reinstall the extension ring. However, if

not
the O.D. of the new burner flange is
approximately 12.4”, the extension ring must
be reinstalled.

15. Make sure to align the Spark Igniter (S/I)
and Flame Rod (F/R) s lots in the burner with
the heat exchanger top head.

16. Check to ensure that the grounding screw
was re-installed.

3/8-16 NUTS (8)

GAS
INJECTOR

10-32 SCREWS (2)

GROUNDING
SCREW

BURNER

BURNER
HOUSING

1/4-20
SCREWS
(6)

Figure 7.3

Burner Disassembly Diagram

7-3

MAINTENANCE

7.7 CONDENSATE DRAIN TRAP 7. 8 SHUTTING THE BOI L ER DOWN FOR

The boiler contains a condensate drain trap
connected to the drain line of the exhaust
manifold (see Figures 2.4 & 2.5). The trap
should be inspected and, if necessary, cleaned
to ensure proper operation. Proceed as follows:

1. Disconnect the ex ternal condensate trap by
loosening the hose clamps between the trap
and the condensate drain connection on the
exhaust manifold of the boiler (Figure 2.5).

2. Remove the connections on the inlet and
outlet sides of the condensate trap shown in
Figure 7.4.

3. Loosen the four (4) thumbscrews securing
the cover on the condensate trap. Remove
the cover.

4. Remove the float from the condensate trap.

5. Remove the orifice gasket from the trap.

6. Thoroughly clean the trap, f loat and gasket.
Also inspect the dr ain piping for blockage. If
the trap cannot be thoroughly cleaned,
replace the trap.

7. Check the condensate drain tapped hole in
the exhaust manif old (Figure 2.4) to ensure
it is clear of blockage.

8. After the above items have been inspected
and thoroughly cleaned, replace the orifice
gasket and float in the condensate trap and
replace the trap cover.

9. Reass em ble all piping and hose connections
to the condensate trap inlet and outlet.
Reconnect trap to condensate drain
connection on the exhaust manifold.

AN EXTENDED PERIOD OF TIME

If the boiler is to be taken out of s ervice for an
extended period of time, one year or more, the
following instructions must be followed.

1. Set the ON/OFF s witch on the front panel to
the OFF position to shut down the boiler’s
operating control.

2. Disconnect AC power from the unit.

3. Close supply and return valves to isolate
boiler.

4. Close external gas supply valve.

5. Open relief valve to vent water pressure.

7.9 PLACING THE BOILER BACK IN

SERVICE AFTER A PROLONGED
SHUTDOWN

After a prolonged shutdown (a year or more), the
following procedures must be followed:

1. Review installation requirements as shown
in Chapter 2

2. Inspect all piping and connection to the unit

3. Inspect exhaust vent, air duct(if applicable)
and

4. Perform initial startup per Chapter 4

5. Perform safety device and maintenance
procedures per Chapters 6 and 7 of this
manual.

7-4

Figure 7.4

External Condensate Trap

TROUBLESHOOTING

Chapter 8- TROUBLESHOOTING GUIDE

8.1 INTRODUCTION

This troubleshooting guide is intended to aid
service/maintenance personnel in isolating the
cause of a fault in a Benchmark Series Boiler.
The troubleshooting procedures contained
herein are presented in tabular form on the
following pages. These tables are comprised of
three columns labeled: Fault Indication, Probable
Cause and Corrective Action. The numbered
items in the Probable Cause and Corrective
Action columns correspond to each other. For
example, Probable Cause No. 1 corresponds to
Corrective Action No. 1, etc.

When a fault occurs in the Benchmark Boiler,
proceed as follows to isolate and correct the
fault:

1. Observe the fault messages displayed in the
Control Box display.

2. Refer to the Fault Indication column in
Troubleshooting Table 8-1 which follows and
locate the Fault that best describes the
existing conditions.

3. Proceed to the Probable Cause column and
start with the first item (1) listed for the Fault
Indication.

4. Perform the checks and procedures listed in
the Corrective Action column for the first
Probable Cause candidate.

5. Continue checking each additional Probable
Cause for the existing fault until the fault is
corrected.

6. Paragraph 8.2 and Table 8-2 contain
additional troubleshooting information which
may apply when no fault message is
displayed.

7. If the fault cannot be corrected using the
information provided in the Troubleshooting
Tables, contact your local AERCO
Representative.

8-1

TROUBLESHOOTING

TABLE 8-1. BOILER TROUBLESHOOTING

FAULT INDICATION PROBABLE CAUSES CORRECTIVE ACTION

AIRFLOW FAULT

DURING IGNITION

AIRFLOW FAULT

DURING PURGE

AIRFLOW FAULT

DURING RUN

1. Blower stopped running due to thermal
or current overload

2. Blocked Blower inlet or inlet ductwork

3. Blocked airflow switch

4. Defective airflow switch

1. Blower not running or running too slow

2. Defective Air Flow Switch

3. Blocked Air flow Switch

4. Blocked Blower inlet or inlet ductwork.

5. No voltage to switch from control box.

1. Blower stopped running due to thermal
or current overload

2. Blocked Blower inlet or inlet ductwork

3. Blocked airflow switch

4. Defective airflow switch

5. Combustion oscillations

1. Check combustion blower for signs of excessive heat or high
current drain that may trip thermal or current overload devices.

2. Inspect the inlet to the combustion blower including any ductwork
leading up to the combustion blower for signs of blockage.

3. Remove the airflow switch and inspect for signs of blockage,
clean or replace as necessary.

4. Measure the airflow switch for continuity with the combustion
blower running. If there is an erratic resistance reading or the
resistance reading is greater than zero ohms, replace the switch.

1. Start the unit. If the blower does not run check the blower solid
state relay for input and output voltage. If the relay is okay, check
the blower.

2. Start the unit. If the blower runs, check the airflow switch for
continuity. Replace the switch if there is no continuity.

3. Remove the air flow switch and inspect for signs of blockage,
clean or replace as necessary.

4. Inspect the inlet to the combustion blower including any ductwork
leading up to the combustion blower for signs of blockage.

5. Measure for 24 VAC during start sequence from each side of the
switch to ground. If 24VAC is not present refer to qualified
service personnel.

1. Check combustion blower for signs of excessive heat or high
current draw that may trip thermal or current overload devices.

2. Inspect the inlet to the combustion blower including any ductwork
leading up to the combustion blower for signs of blockage.

3. Remove the airflow switch and inspect for signs of blockage,
clean or replace as necessary.

4. Measure the airflow switch for continuity with the combustion
blower running. If there is an erratic resistance reading or the
resistance reading is greater than zero ohms, replace the switch.

5. Run unit to full fire. If the unit rumbles or runs rough, perform
combustion calibration.

8

-2

TROUBLESHOOTING

TABLE 8-1. BOILER TROUBLESHOOTING – Continued

FAULT INDICATION PROBABLE CAUSES CORRECTIVE ACTION

DELAYED

INTERLOCK OPEN

DIRECT DRIVE
SIGNAL FAULT

FLAME LOSS

DURING IGN

1. Delayed Interlock Jumper not
installed or removed.

2. Device proving switch hooked to
interlocks is not closed

1. Direct drive signal is not present:
Not yet installed.
Wrong polarity.
Signal defective at source.
Broken or loose wiring.

2. Signal is not isolated (floating).

3. Control Box signal type selection
switches not set for correct signal
type (voltage or current).

1. Burner Ground Screw not installed
or loose.

2. Worn flame detector

3. No spark from Spark Plug

4. Defective Ignition Transformer

5. Defective Ignition/Stepper (IGST)
Board

6. Defective SSOV

1. Check for a jumper properly installed across the delayed
interlock terminals in the I/O box.

2. If there are 2 external wires on these terminals, check to see if
an end switch for a device such as a pump, louver, etc. is tied
these interlocks. Ensure that the device and or its end switch
are functional. (jumper may be temporarily installed to test
interlock)

1. Check I/O Box to ensure signal is hooked up.
Hook up if not installed.
If installed, check polarity.
Measure signal level.
Check continuity of wiring between source and boiler.

2. Check signal at source to ensure it is isolated.

3. Check DIP switch on PMC board to ensure it is set correctly for
the type of signal being sent. Check control signal type set in
Configuration Menu.

1. Inspect and install/retighten Burner Ground Screw.

2. Remove and inspect the flame detector for signs of wear.
Replace if necessary.

3. Close the internal gas valve in the boiler. Install and arc a spark
ignitor outside the unit.

4. If there is no spark, check for 120VAC at the primary side to the
ignition transformer during the ignition cycle.

5. If 120VAC is not present, the IGST Board in the Control Box
may be defective. Refer fault to qualified service personnel.

6. While externally arcing the spark ignitor, observe the
open/close indicator in the Safety Shut-Off Valve to ensure it is
opening. If the valve does not open, check for 120VAC at the
valves input terminals. If 120VAC is not present, the IGST
board in the Control Box may be defective. Refer fault to
qualified service personnel.

8-3

TROUBLESHOOTING

TABLE 8-1. BOILER TROUBLESHOOTING – Continued

FAULT INDICATION PROBABLE CAUSES CORRECTIVE ACTION

(continued) 7. Defective Differential Pressure

Regulator

8. Carbon or other debris on Burner

FLAME LOSS
DURING RUN

HEAT DEMAND

FAILURE

HIGH EXHAUST

TEMPERATURE

HIGH GAS

PRESSURE

1. Worn Flame Detector or cracked
ceramic.

2. Defective Differential Regulator.

3. Poor combustion calibration.

4. Debris on burner.

5. Blocked condensate drain.

1. The Heat Demand Relays on the
Ignition/Stepper board failed to
activate when commanded

2. Relay is activated when not in
Demand

1. Defective exhaust sensor.

2. Carboned heat exchanger due to
incorrect combustion calibration

1. Incorrect supply gas pressure.

2. Defective droop eliminator.

7. Check gas pressure readings using gauge or manometer into
and out of the Air/Fuel Valve to ensure gas is getting to the
burner.

8. Remove the burner and inspect for any carbon or debris. Clean
and reinstall

1. Remove and inspect the Flame Detector for signs of wear or
cracked ceramic. Replace if necessary.

2. Check gas pressure readings using a gauge or manometer into
and out of the Air/Fuel Valve to ensure that the gas pressure
into and out of the valve is correct.

3. Check combustion calibration. Adjust as necessary.

4. Remove the burner and inspect for any carbon or debris. Clean
and reinstall.

5. Remove blockage in condensate drain.

1. Press CLEAR button and restart the unit. If the fault persists,
replace Ignition/Stepper (IGST) Board.

2. Defective relay. Replace IGST Board.

1. Measure the actual exhaust temperature and continuity of the
exhaust sensor. If the exhaust temperature is less than 475
and the exhaust sensor shows continuity replace the sensor.

2. If exhaust temperature is greater than 500
combustion calibration. Calibrate or repair as necessary.

1. Check to ensure gas pressure at inlet of SSOV is 2 psig
maximum.

2. If gas supply pressure downstream of SSOV cannot be lowered,
to 4.8” W.C. (see para. 4.3, step 8), the droop eliminator may be
defective. For Benchmark 2.0 Low NOx boilers configured for
De-Rated capacity (see para. 2.4.1), if gas supply pressure
downstream of the SSOV cannot be lowered to 3.7” W .C.

o

F, check

o

F

8-4

TROUBLESHOOTING

TABLE 8-1. BOILER TROUBLESHOOTING – Continued

FAULT INDICATION PROBABLE CAUSES CORRECTIVE ACTION

continued 2. continued (see para.4.3, step 8) the droop eliminator may be defective.

3. Defective High Gas Pressure Switch

4. Gas pressure snubber not installed.

HIGH WATER TEMP

SWITCH OPEN

HIGH WATER

TEMPERATURE

IGN BOARD

COMM FAULT

1. Faulty Water temperature switch.

2. Incorrect PID settings.

3. Faulty shell temperature sensor.

4. Unit in Manual mode

5. Unit setpoint is greater than Over
Temperature Switch setpoint.

6. Boiler Management System PID or
other settings not correctly setup.

7. No interlock to boiler or BMS to
disable boiler(s) in event that system
pumps have failed.

8. System flow rate changes are
occurring faster than boilers can
respond.

1. See HIGH WATER TEMPERATURE
SWITCH OPEN.

2. Temp HI Limit setting is too low.

1. Communication fault has occurred
between the PMC board and
Ignition/Stepper (IGST) board

3. Remove the leads from the high gas pressure switch and
measure continuity across the common and normally closed
terminals with the unit not firing. Replace the switch if it does not
show continuity.

4. See figure 8-1. Make sure gas pressure snubber is installed at
the high gas pressure switch.

1. Test the temperature switch to insure it trips at its actual water
temperature setting.

2. Check PID settings against Menu Default settings in the
Appendix. If the settings have been changed, record the current
readings then reset them to the default values.

3. Using the resistance charts in the Appendix C, Measure the
resistance of Shell sensor and BTU sensor at a known water
temperature.

4. If unit is in Manual Mode switch to Auto Mode.

5. Check setpoint of unit and setpoint of Temperature Switch;
Ensure that the temperature switch is set higher than the unit’s
setpoint.

6. Check the BMS for changes to PID default values, correct as
necessary.

7. If system pump is controlled by Energy Management System
other than BMS or pumps are individually controlled by boiler,
check to see if there are flow switches interlocked to the BMS or
boiler.

8. If the system is a variable flow system, monitor system flow
changes to ensure that the rate of flow change is not faster than
what the boilers can respond to.

1. See HIGH WATER TEMPERATURE SWITCH OPEN.

2. Check Temp HI Limit setting.

1. Press CLEAR button and restart unit. If fault persists, contact
qualified Service Personnel.

8-5

TROUBLESHOOTING

FAULT INDICATION PROBABLE CAUSES CORRECTIVE ACTION

IGN SWTCH CLOSED

DURING PURGE

IGN SWTCH OPEN

DURING IGNITION

INTERLOCK

OPEN

TABLE 8-1. BOILER TROUBLESHOOTING – Continued

1. Air/Fuel Valve not rotating

2. Defective or shorted switch

3. Switch wired incorrectly

4. Defective Power Supply Board or
fuse

5. Defective IGST Board

1. Air/Fuel Valve not rotating to ignition
position.

2. Defective ignition switch

3. Defective Power Supply Board or
fuse

4. Defective IGST Board

1. Interlock jumper not installed or
removed

2. Energy Management System does
not have boiler enabled.

1. Start the unit. The Air/Fuel Valve should rotate to the purge
(open) position. If the valve does not rotate at all or does not
rotate fully open, check the Air/Fuel Valve calibration. If
calibration is okay, the problem may be in the Air-Fuel Valve or
the Control Box. Refer to qualified service personnel

2. . If the Air/Fuel Valve does rotate to purge, check the ignition
switch for continuity between the N.O. and COM terminals. If the
switch shows continuity when not in contact with the cam replace
the switch.

3. Check to ensure that the switch is wired correctly (correct wire
numbers on the normally open terminals). If the switch is wired
correctly, replace the switch

4. Check DS1 & DS2 LEDs on Power Supply Board. If they are not
steady ON, replace Power Supply Board.

5. Check “Heartbeat” LED DS1 and verify it is blinking ON & OFF
every second. If not, replace IGST Board

1. Start the unit. The Air/Fuel Valve should rotate to the purge
(open) position, then back to ignition position (towards closed)
during the ignition cycle. If the valve does not rotate back to the
ignition position, check the Air/Fuel Valve calibration. If
calibration is okay, the problem may be in the Air/Fuel Valve or
the Control Box. Refer fault to qualified service personnel.

2. If the Air/Fuel Valve does rotate to the ignition position, check the
ignition position switch for continuity between the N.O. and COM
terminals when in contact with the cam.

3. Check DS1 & DS2 LEDs on Power Supply Board. If they are not
steady ON, replace Power Supply Board.

4. Check “Heartbeat” LED DS1 and verify it is blinking ON & OFF
every second. If not, replace IGST Board.

1. Check for a jumper properly installed across the interlock
terminals in the I/O box

2. If there are two external wires on these terminals check any
Energy Management system to see if they have the units
disabled (a jumper may be temporarily installed to see if the
interlock circuit is functioning).

8-6

TROUBLESHOOTING

TABLE 8-1. BOILER TROUBLESHOOTING – Continued

FAULT INDICATION PROBABLE CAUSES CORRECTIVE ACTION

continued 3. Device proving switch hooked to

LINE VOLTAGE

OUT OF PHASE

LOW GAS

PRESSURE

LOW WATER

LEVEL

MODBUS COMM

FAULT

PRG SWTCH CLOSED

DURING IGNITION

interlocks is not closed.

1. Line and Neutral switched in AC
Power Box.

2. Incorrect power supply transformer
wiring.

1. Incorrect supply gas pressure.

2. Defective Low Pressure Gas Switch

1. Insufficient water level in system

2. Defective water level circuitry.

3. Defective water level probe.

1. Boiler not seeing information from
modbus network

1. A/F Valve rotated open to purge and
did not rotate to ignition position

3. Check that proving switch for any device hooked to the interlock
circuit is closing and that the device is operational.

1. Check hot and neutral in AC Power Box to ensure they are not
reversed

2. Check transformer wiring, in AC Power Box, against the power
box transformer wiring diagram to ensure it is wired correctly

1. Measure gas pressure upstream of the droop eliminator with the
unit firing. Ensure it is at least 5.3” WC (5.5” WC for IRI). For
Benchmark 2.0 Low NOx boilers configured for De-Rated
capacity (see para. 2.4.1), ensure gas pressure upstream of the
droop eliminator, with the unit firing, is at least 4.0” W.C. (4.2”
W.C. for IRI).

2. Measure gas pressure at the low gas pressure switch, if it is
greater than 4.4” WC measure continuity across the switch and
replace if necessary For Benchmark 2.0 Low NOx boilers
configured for De-Rated capacity (see para. 2.4.1), if measured
gas pressure at the low gas pressure switch is greater than 3.6”
W.C., measure continuity across the switch and replace if
necessary.

1. Check system for sufficient water level.

2. Test water level circuitry using the Control Box front panel LOW
WATER TEST and RESET buttons. Replace water level
circuitry if it does not respond.

3. Check continuity of probe end to the shell, change probe if there
is no continuity.

1. Check network connections. If fault persists, contact qualified
Service Personnel.

1. Start the unit. The Air/Fuel Valve should rotate to the purge
(open) position, then back to ignition position (towards closed)
during the ignition cycle. If the valve does not rotate back to the
ignition position, check the Air/Fuel Valve calibration. If
calibration is okay, the problem may be in the Air/Fuel Valve or
the Control Box. Refer fault to qualified service personnel.

8-7

TROUBLESHOOTING

TABLE 8-1. BOILER TROUBLESHOOTING – Continued

FAULT INDICATION PROBABLE CAUSES CORRECTIVE ACTION

continued 2. Defective or shorted switch.

3. Switch wired incorrectly.

4. Defective Power Supply Board or
fuse

5. Defective IGST Board

PRG SWTCH OPEN

DURING PURGE

OUTDOOR TEMP

SENSOR FAULT

REMOTE SETPT

SIGNAL FAULT

1. Defective purge switch.

2. No voltage present at switch.

3. Switch wired incorrectly.

4. Defective Power Supply Board or
fuse

5. Defective IGST Board

1. Loose or broken wiring.

2. Defective Sensor.

6. Incorrect Sensor.

1. Remote setpoint signal not present:
Not yet installed.
Wrong polarity.
Signal defective at source.
Broken or loose wiring.

2. Signal is not isolated (floating) if 4 to
20 mA.

2. If the Air/Fuel Valve does rotate to the ignition position, check
the purge switch for continuity between the N.O. and COM
terminals. If the switch shows continuity when not in contact
with the cam, check to ensure that the switch is wired correctly
(correct wire numbers on the normally open terminals).

3. If the switch is wired correctly, replace the switch.

4. Check DS1 & DS2 LEDs on Power Supply Board. If they are not
steady ON, replace Power Supply Board.

5. Check “Heartbeat” LED DS1 and verify it is blinking ON & OFF
every second. If not, replace IGST Board.

1. If the air-fuel valve does rotate, check the purge switch for

continuity when closing. Replace switch if continuity does not
exist.

2. Measure for 24 VAC from each side of the switch to ground. If

24VAC is not present, refer fault to qualified service personnel.

3. Check to ensure that the switch is wired correctly (correct wire

numbers on the normally open terminals).

4. Check DS1 & DS2 LEDs on Power Supply Board. If they are not

steady ON, replace Power Supply Board.

5. Check “Heartbeat” LED DS1 and verify it is blinking ON & OFF

every second. If not, replace IGST Board.

1. Inspect Outdoor Temperature sensor for loose or broken wiring.

2. Check resistance of sensor to determine if it is within

specification.

6. Ensure that the correct sensor is installed.

1. Check I/O Box to ensure signal is hooked up.

Hook up if not installed.
If installed, check polarity.
Measure signal level.
Check continuity of wiring between source and boiler.

2. Check signal at source to ensure it is isolated.

8-8

TROUBLESHOOTING

TABLE 8-1. BOILER TROUBLESHOOTING – Continued

FAULT INDICATION PROBABLE CAUSES CORRECTIVE ACTION

continued 3. Control Box signal type selection

switches not set for correct signal
type (voltage or current).

RESIDUAL

FLAME

SSOV FAULT

DURING PURGE

SSOV FAULT

DURING RUN

SSOV RELAY

FAILURE

SSOV

SWITCH OPEN

STEPPER MOTOR

FAILURE

1. SSOV not fully closed.

2. Defective Flame Detector.

See SSOV SWITCH OPEN

1. SSOV switch closed for 15 seconds
during run.

1. SSOV relay failed on board. 1. Press CLEAR button and restart unit. If fault persists, replace

1. Actuator not allowing for full closure
of gas valve

2. SSOV powered when it should not be

3. Defective Switch or Actuator

4. Incorrectly wired switch.

1. Air/Fuel Valve out of calibration.

2. Air/Fuel Valve unplugged.

3. Loose wiring connection to the
stepper motor.

1. Check DIP switch on PMC board to ensure it is set correctly for
the type of signal being sent. Check control signal type set in
Configuration Menu.

1. Check open/close indicator window of Safety Shut-Off Valve
(SSOV) and ensure that the SSOV is fully closed. If not fully
closed, replace the valve and or actuator.

Close gas shut-off valve downstream of SSOV. Install a
manometer or gauge in a gas test port between the SSOV and
the gas shut off valve. If a gas pressure reading is observed
replace the SSOV valve and or actuator.

2. Replace Flame Detector.

1. Replace or adjust microswitch in SSOV actuator. If fault
persists, replace actuator.

Ignition/Stepper (IGST) Board.

1. Observe operation of the Safety Shut-Off Valve (SSOV) through
indicator on the Valve actuator and ensure that the valve is fully
and not partially closing.

2. If the SSOV never closes, it may be powered continuously. Close
the gas supply and remove power from the unit. Refer fault to
qualified service personnel.

3. Remove the electrical cover from the SSOV and check switch
continuity. If the switch does not show continuity with the gas
valve closed, either adjust or replace the switch or actuator.

4. Ensure that the SSOV Proof of Closure switch is correctly wired.

1. Refer to GF-112 and perform Stepper Test (para. 6.3.5) to
ensure stepper motor rotates properly between the 0% (fully
closed) and 100% (fully open) positions. Verify that the FIRE
RATE bargraph and the dial on the Air/Fuel Valve track each
other to indicate proper operation. If operation is not correct,
perform the Stepper Feedback Calibration (GF-112, para. 6.2.1).

2. Check that the Air/Fuel Valve is connected to the Control Box.

3. .Inspect for loose connections between the Air/Fuel Valve motor
and the wiring harness.

8-9

TROUBLESHOOTING

TABLE 8-1. BOILER TROUBLESHOOTING – Continued

FAULT INDICATION PROBABLE CAUSES CORRECTIVE ACTION

continued 4. Defective Air/Fuel Valve stepper

motor.

5. Defective Power Supply Board or
fuse.

6. Defective IGST Board

8.2 ADDITIONAL FAULTS WITHOUT SPECIFIC FAULT MESSAGES

Refer to Table 8-2 to troubleshoot faults which may occur without a specific fault message being displayed.

TABLE 8-2. BOILER TROUBLESHOOTING WITH NO FAULT MESSAGE DISPLAYED

4. Replace stepper motor.

5. Check DS1 & DS2 LEDs on Power Supply Board. If they are not
steady ON, replace Power Supply Board.

6. Check “Heartbeat” LED DS1 and verify it is blinking ON & OFF
every second. If not, replace IGST Board.

OBSERVED INCIDENT PROBABLE CAUSES CORRECTIVE ACTION

Hard Light-Off 1. Staged Ignition Ball Valve closed.

2. Clogged/damaged Gas Injector
(Figure 8.2).

3. Defective Staged Ignition Solenoid
(figure 8.2)

Fluctuating Gas Pressure 1. Gas pressure going into unit is

fluctuating.

2. Damping Orifice not installed.

Air/Fuel Valve “hunting” at 80%

Firing Rate

8-10

1. IGST and Power Supply Boards
outdated.

1. Open the 1/4” Ball Valve downstream of the SSOV.

2. Remove and inspect Gas Injector to ensure it is not clogged or
damaged.

3. Close the 2” Ball Valve downstream of the Differential Regulator
and the 1/4” Ball Valve downstream of the SSOV. Start the unit
and listen for a “clicking” sound that the Staged Ignition Solenoid
makes during Ignition Trial. If “clicking” sound is not heard after 2
or 3 attempts, replace the Staged Ignition Solenoid.

1. Stabilize gas pressure going into unit. If necessary, troubleshoot
Building Supply Regulator.

2. Check that the Damping Orifice is installed on the droop
eliminator (Figure 8.3).

1. Check to ensure that the IGST and Power Supply Boards are
Rev. E or higher.

TROUBLESHOOTING

HIGH GAS
PRESSURE
SWITCH

GAS PRESSURE
SNUBBER

Figure 8.1

High Pressure Gas Switch & Gas Pressure

Damping Orifice Location

Snubber Locations

Figure 8.3

Staged Ignition Solenoid Location

8-11

Figure 8.2

APPENDIX A

BOILER MENU ITEM DESCRIPTIONS

MENU LEVEL & OPTION DESCRIPTION

OPERATING MENU
Active Setpoint This is the setpoint temperature to which the

control is operating when operating in the
Constant Setpoint, Remote Setpoint or Outdoor
Reset Mode. When in the Constant Setpoint
Mode, this value is equal to the Internal Setpoint
setting in the Configuration Menu. When in the
Remote Setpoint Mode, this value is the setpoint
equivalent to the remote analog signal supplied to
the unit. When in the Outdoor Reset Mode, this is

the derived value from the charts in Appendix D.
Aux Temp For monitoring purposes only
Outdoor Temp Displayed only if an outdoor sensor is installed and

enabled in the Configuration Menu.
Fire Rate In Indicates desired input fire rate. This will normally

be the same as the fire rate shown on the bar-

graph (fire rate out) when the boiler is operating.
Flame Strength Displays flame strength from 0 to 100%.
Run Cycles Displays the total number of run cycles from 0 to

999,999.
Run Hours Displays total run time of unit in hours from 0 to

999,999.
Fault Log Displays information on the last 9 faults.

A-1

APPENDIX A

MENU LEVEL & OPTION DESCRIPTION

BOILER MENU ITEM DESCRIPTIONS - Continued

SETUP MENU

Password Allows password to be entered.

Language English only.
Time Displays time from 12:00am to 11:59pm.
Date Displays dates from 01/01/00 to 12/31/99
Unit of Temp Permits selection of temperature displays in

Comm Address For RS-485 (MODBUS) communications (0 to 127).

Baud Rate Allows communications Baud Rate to be set (2400

Software Version Identifies the current software version of the control

Once the valid password (159) is entered, options in
the Setup, Configuration and Tuning Menus can be
modified.

degrees Fahrenheit (°F) or degrees Celsius (°C).
Default is °F.

Default address is 0. RS-232 should have its own
(programmable) password.

to 19.2K). Default is 9600.

box.
CONFIGURATION MENU
Internal Setpoint Allows internal setpoint to be set . Default is 130°F.
Unit Type Allows selection of Boiler or Water Heater. Default

Unit Size Sets unit size from 0.5 to 3.0 MBTUs. Default is 1.0

Boiler Mode It allows selection of: Constant Setpoint, Remote

Remote Signal Used to set the type of external signal which will be

Bldg Ref Temp

is Boiler.

MBTU.

Setpoint, Direct Drive, Combination, or Outdoor

Reset Mode. Default is Constant Setpoint Mode.

used when operating in the Remote Setpoint, Direct

Drive or Combination Mode. The factory default is

4-20 mA/1-5V.

Allows the building reference temperature to be set

when operating a boiler in the Outdoor Reset Mode.

Default is 70°F.

A-2

APPENDIX A

BOILER MENU ITEM DESCRIPTIONS - Continued

MENU LEVEL & OPTION DESCRIPTION

Reset Ratio Permits setting of Reset Ratio when operating boiler

in the Outdoor Reset Mode. Reset Ratio is

adjustable from 0.1 to 9.9. Default is 1.2.
Outdoor Sensor Allows outdoor sensor function to be enabled or

disabled. Default is Disabled.
System Start Tmp If outdoor sensor is enabled in the Configuration

Menu, this menu item allows the system start

temperature to be set from 30°F to 100°F. Default

is 60°F.
Setpoint Lo Limit Used to set the minimum allowable setpoint (40°F to

Setpoint Hi Limit). Default is 60°F
Setpoint Hi Limit Used to set the maximum allowable setpoint

(Setpoint Lo Limit to 220°F). Default is 200°F.
Temp Hi Limit Used to set the maximum allowable outlet

temperature (40°F to 240°F). Any temperature

above this setting will turn off the unit. The

temperature must then drop 5°F below this setting

to allow the unit to run. Default Temp Hi Limit is

210°F.
Max Fire Rate Sets the maximum allowable fire rate for the unit

(40% to 100%). Default is 100%.
Pump Delay Timer Specifies the amount of time (0 to 30 min.) to keep

the pump running after the unit turns off. Default is

zero.
Aux Start On Dly Specifies the amount of time to wait (0 to 120 sec.)

between activating the Aux Relay (due to a demand)

and checking the pre-purge string to start the boiler.

Default is 0 sec.
Failsafe Mode Allows the Failsafe mode to be set to either

Constant Setpoint or Shutdown. Default is

Shutdown.
mA Output Can be set to allow this output to monitor Setpoint,

Outlet Temperature, Fire Rate Out or be set to OFF.

Default is OFF.
Lo Fire Timer Specifies how long (2 to 120 sec.) to remain in the

low fire position after ignition, before going to the

desired output. Default is 2 sec.

A-3

APPENDIX A

BOILER MENU ITEM DESCRIPTIONS - Continued

MENU LEVEL & OPTION DESCRIPTION

Setpt Limiting Allows Setpoint Limiting to be enabled or disabled.

Default is disabled.
Setpt Limit Band If Setpoint Limiting is enabled, this menu item allows

the Setpt Limit Band to be set from 0°F to 10°F.

Default is 5°F.
TUNING MENU
Prop Band Generates a fire rate based on the error that exists

Integral Gain This sets the fraction of the output, due to setpoint

Derivative Time This value (0.0 to 2.00 min.) responds to the rate of

Reset Defaults? Allows Tuning Menu options to be reset to their

between the setpoint temperature and the actual

outlet temperature. If the actual error is less than

the proportional band setting (1 to 120°F), the fire

rate will be less than 100%. If the error is equal to

or greater than the proportional band setting, the fire

rate will be 100%. Default is 70°F.

error, to add or subtract from the output each minute

to move towards the setpoint. Gain is adjustable

from 0.00 to 2.00. Default is 1.00.

change of the setpoint error. This is the time that

this action advances the output. Default is 0.0 min.

Factory Default values.

A-4

MESSAGE DESCRIPTION

DISABLED

HH:MM pm MM/DD/YY

STANDBY Displayed when ON/OFF switch is in the ON position, but

DEMAND DELAY

XX sec

PURGING

XX sec

IGNITION TRIAL

XX sec

FLAME PROVEN

WARMUP

XX sec

WAIT Prompts the operator to wait.

APPENDIX B

STARTUP, STATUS AND FAULT MESSAGES

STARTUP AND STATUS MESSAGES

Displayed if ON/OFF switch is set to OFF. The display also
shows the time and date that the unit was disabled.

there is no demand for heat. The time and date are also
displayed.
Displayed if Demand Delay is active.

Displayed during the purge cycle during startup. The
duration of the purge cycle counts up in seconds.
Displayed during ignition trial of startup sequence. The
duration of cycle counts up in seconds.
Displayed after flame has been detected for a period of 2
seconds. Initially, the flame strength is shown in %. After 5
seconds has elapsed, the time and date are shown in place
of flame strength.
Displayed for 2 minutes during the initial warmup only.

B-1

APPENDIX B

FAULT MESSAGE FAULT DESCRIPTION

HIGH WATER TEMP

SWITCH OPEN

LOW WATER

LEVEL

LOW GAS

PRESSURE

HIGH GAS

PRESSURE

INTERLOCK

OPEN

DELAYED

INTERLOCK OPEN

AIRFLOW FAULT
DURING PURGE

PRG SWTCH OPEN

DURING PURGE

IGN SWTCH OPEN

DURING IGNITION

IGN SWTCH CLOSED

DURING PURGE

PRG SWTCH CLOSED

DURING IGNITION

AIRFLOW FAULT

DURING IGN

AIRFLOW FAULT

DURING RUN

SSOV

SWITCH OPEN

SSOV FAULT

DURING PURGE

SSOV FAULT

DURING IGN

SSOV FAULT
DURING RUN
SSOV RELAY

FAILURE

FLAME LOSS

DURING IGN

FLAME LOSS

DURING RUN

HIGH EXHAUST
TEMPERATURE

LOSS OF POWER

FAULT MESSAGES

The High Water Temperature Limit Switch is open.

The Water Level Control board is indicating low water level.

The Low Gas Pressure Limit Switch is open.

The High Gas Pressure Limit Switch is open.

The Remote Interlock is open.

The Delayed Interlock is open.

The Blower Proof Switch opened during purge.

The Purge Position Limit switch on the air/fuel valve opened
during purge.
The Ignition Position Limit switch on the air/fuel valve opened
during ignition.
The Ignition Position Limit switch on the air/fuel valve closed
during purge.
The Purge Position Limit switch on the air/fuel valve closed
during ignition.
The Blower Proof Switch opened during ignition.

The Blower Proof Switch opened during run.

The SSOV switch opened during standby.

The SSOV switch opened during purge.

The SSOV switch closed or failed to open during ignition.

The SSOV switch closed for more than 15 seconds during
run.
A failure has been detected in one of the relays that control
the SSOV.
The Flame signal was not seen during ignition or lost within 5
seconds after ignition.
The Flame signal was lost during run.

The High Exhaust Temperature Limit Switch is closed.

A power loss had occurred. The time and date when power
was restored is displayed.

B-2

APPENDIX B

FAULT MESSAGES - Continued

FAULT MESSAGE FAULT DESCRIPTION

RESIDUAL

FLAME

HEAT DEMAND

FAILURE

IGN BOARD

COMM FAULT
DIRECT DRIVE
SIGNAL FAULT

REMOTE SETPT

SIGNAL FAULT

OUTDOOR TEMP

SENSOR FAULT

OUTLET TEMP

SENSOR FAULT

FFWD TEMP

SENSOR FAULT

HIGH WATER

TEMPERATURE

LINE VOLTAGE

OUT OF PHASE

STEPPER MOTOR

FAILURE

NETWORK COMM

FAULT

The Flame signal was seen for more than 60 seconds during
standby.
The Heat Demand Relays on the Ignition board failed to
activate when commanded.
A communication fault has occurred between the PMC board
and Ignition board.
The direct drive signal is not present or is out of range.

The remote setpoint signal is not present or is out of range.

The temperature measured by the Outdoor Air Sensor is out
of range.
The temperature measured by the Outlet Sensor is out of
range.
The temperature measured by the FFWD Sensor is out of
range.
The temperature measured by the Outlet Sensor exceeded
the Temp Hi Limit setting.
The High AC voltage is out of phase from the low AC voltage.

The stepper motor failed to move the valve to the desired
position.
The RS-485 network information is not present or is
corrupted.

B-3

Temperature Sensor Resistance Chart

(Balco)

APPENDIX C

C-1

Air

Temp

50F
45F
40F
35F
30F
25F
20F
15F
10F

5F
0F

-5F

-10F

-15F

-20F

Air

Temp

60F
55F
50F
45F
40F
35F
30F
25F
20F
15F
10F

5F
0F

-5F

-10F

-15F

-20F

APPENDIX D

INDOOR/OUTDOOR RESET RATIO CHARTS

Header Temperature for a Building Reference Temperature of 50F

RESET RATIO

0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0 2.2 2.4

50 50 50 50 50 50 50 50 50 50
53 54 55 56 57 58 59 60 60 62
56 58 60 62 64 66 68 70 72 74
59 62 65 68 71 74 77 80 83 86
62 66 70 74 78 82 86 90 94 98
65 70 75 80 85 90 95 100 105 110
68 74 80 86 92 98 104 110 116 122
71 78 85 92 99 106 113 120 127 134
74 82 90 98 106 114 122 130 138 146
77 86 95 104 113 122 131 140 149 158
80 90 100 110 120 130 140 150 160 170
83 94 105 116 127 138 149 160 171 182
86 98 110 122 134 146 158 170 182 194
89 102 115 128 141 154 167 180 193 206
92 106 120 134 148 162 176 190 204 218

Header Temperature for a Building Reference Temperatrure of 60F

RESET RATIO

0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0 2.2 2.4

60 60 60 60 60 60 60 60 60 60
63 64 65 66 67 68 69 70 71 72
66 68 70 72 74 76 78 80 82 84
69 72 75 78 81 84 87 90 93 96
72 76 80 84 88 92 96 100 104 108
75 80 85 90 95 100 105 110 115 120
78 84 90 96 102 108 114 120 126 132
81 88 95 102 109 116 123 130 137 144
84 92 100 108 116 124 132 140 148 156
87 96 105 114 123 132 141 150 159 168
90 100 110 120 130 140 150 160 170 180
93 104 115 126 137 148 159 170 181 192
96 108 120 132 144 156 168 180 192 204

99 112 125 138 151 164 177 190 203 216
102 116 130 144 158 172 186 200 214
105 120 135 150 165 180 195 210
108 124 140 156 172 188 204

D-1

APPENDIX D

Header Temperature for a Building Reference Temperature of 65F

Air

Temp

65
60
55
50
45
40
35
30
25
20
15
10

5
0

-5

-10

-15

-20

Air

Temp

70F
65F
60F
55F
50F
45F
40F
35F
30F
25F
20F
15F
10F

5F
0F

-5F

-10F

-15F

-20F

0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0 2.2 2.4

65 65 65 65 65 65 65 65 65 65
68 69 70 71 72 73 74 75 76 77
71 73 75 77 79 81 83 85 87 89
74 77 80 83 86 89 92 95 98 101
77 81 85 89 93 97 101 105 109 113
80 85 90 95 100 105 110 115 120 125
83 89 95 101 107 113 119 125 131 137
86 93 100 107 114 121 128 135 142 149
89 97 105 113 121 129 137 145 153 161
92 101 110 119 128 137 146 155 164 173
95 105 115 125 135 145 155 165 175 185

98 109 120 131 142 153 164 175 186 197
101 113 125 137 149 161 173 185 197 209
104 117 130 143 156 169 182 195 208
107 121 135 149 163 177 191 205 219
110 125 140 155 170 185 200 215
113 129 145 161 177 193 209
116 133 150 167 201 218

Header Temperature for a Building Reference Temperature of 70F

0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0 2.2 2.4

70 70 70 70 70 70 70 70 70 70

73 74 75 76 77 78 79 80 81 82

76 78 80 82 84 86 88 90 92 94

79 82 85 88 91 94 97 100 103 106

82 86 90 94 98 102 106 110 114 118

85 90 95 100 105 110 115 120 125 130

88 94 100 106 112 118 124 130 136 142

91 98 105 112 119 126 133 140 147 154

94 102 110 118 126 134 142 150 158 166

97 106 115 124 133 142 151 160 169 178
100 110 120 130 140 150 160 170 180 190
103 114 125 136 147 158 169 180 191 202
106 118 130 142 154 166 178 190 202 214
109 122 135 148 161 174 187 200 213
112 126 140 154 168 182 196 210
115 130 145 160 175 190 205
118 134 150 166 182 198 214
121 138 155 172 189 206
124 142 160 178 196 214

RESET RATIO

RESET RATIO

D-2

APPENDIX D

Header Temperature for a Building Reference Temperature of 75F

RESET RATIO

Air

Temp

75F
70F
65F
60F
55F
50F
45F
40F
35F
30F
25F
20F
15F
10F

5F
0F

-5F

-10F

-15F

Air

Temp

80F 80 80 80 80 80 80 80 80 80 80
75F 83 84 85 86 87 88 89 90 91 92
70F 86 88 90 92 94 96 98 100 102 104
65F 89 92 95 98 101 104 107 110 113 116
60F 92 96 100 104 108 112 116 120 124 128
55F 95 100 105 110 115 120 125 130 135 140
50F 98 104 110 116 122 128 134 140 146 152
45F 101 108 115 122 129 136 143 150 157 164
40F 104 112 120 128 136 144 152 160 168 176
35F 107 116 125 134 143 152 161 170 179 188
30F 110 120 130 140 150 160 170 180 190 200
25F 113 124 135 146 157 168 174 190 201 212
20F 116 128 140 152 164 176 188 200 212
15F 119 132 145 158 171 184 197 210
10F 122 136 150 164 178 192 206

5F 125 140 155 170 185 200 215
0F 128 144 160 176 192 208

-5F 131 148 165 182 199 216

-10F 134 152 170 188 206

0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0 2.2 2.4

75 75 75 75 75 75 75 75 75 75
78 79 80 81 82 83 84 85 86 87
81 83 85 87 89 91 93 95 97 99
84 87 90 93 96 99 102 105 108 111
87 91 95 99 103 107 111 115 119 123
90 95 100 105 110 115 120 125 130 135
93 99 105 111 117 123 129 135 141 17
96 103 110 117 124 131 138 145 152 159

99 107 115 123 131 139 147 155 163 171
102 111 120 129 138 147 156 165 174 183
105 115 125 135 145 155 165 175 185 195
108 119 130 141 152 163 174 185 196 207
111 123 135 147 159 171 183 195 207 219
114 127 140 153 166 179 192 205 218
117 131 145 159 173 187 201 215
120 135 150 165 180 195 210
123 139 155 171 187 203 219
126 143 160 177 194 211
129 147 165 183 201 219

Header Temperature for a Building Reference Temperature of 80F

RESET RATIO

0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0 2.2 2.4

D-3

APPENDIX D

Header Temperature for a Building Reference Temperature of 90F

RESET RATIO

Air

Temp

90F
85F
80F
75F
70F
65F
60F
55F
50F
45F
40F
35F
30F
25F
20F
15F
10F

5F
0F

0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0 2.2 2.4

90 90 90 90 90 90 90 90 90 90

93 94 95 96 97 98 99 100 101 102

96 98 100 102 104 106 108 110 112 114

99 102 105 108 111 114 117 120 123 126
102 106 110 114 118 122 126 130 134 138
105 110 115 120 125 130 135 140 145 150
108 114 120 126 132 138 144 150 156 162
111 118 125 132 139 146 153 160 167 174
114 122 130 138 146 154 162 170 178 186
117 126 135 144 153 162 171 180 189 198
120 130 140 150 160 170 180 190 200 210
123 134 145 156 167 178 189 200
126 138 150 162 174 186 198 210
129 142 155 168 181 194 207
132 146 160 174 188 202 216
135 150 165 180 195 210
138 154 170 186 202 218
141 158 175 192 209
144 162 180 198 216

D-4

APPENDIX E

MENU & OPTION FACTORY DEFAULT

BOILER DEFAULT SETTINGS

Setup Menu

Password 0

Language English

Unit of Temp Fahrenheit

Comm Address 0

Baud Rate 9600

Configuration Menu

Internal Setpt 130°F

Unit Type Boiler

Unit Size 1.0 MBTU

Boiler Mode Constant Setpoint

Remote Signal
(If Mode = Remote Setpoint, Direct Drive or
Combination)

Bldg Ref Temp
(If Boiler Mode = Outdoor Reset)

4 – 20 mA / 1-5V

70°F

Reset Ratio
(If Boiler Mode = Outdoor Reset)

Outdoor Sensor Disabled

System Start Tmp
(If Outdoor Sensor = Enabled)

Setpt Lo Limit 60°F

Setpt Hi Limit 200°F

Temp Hi Limit

Max Fire Rate 100%

Pump Delay Timer 0 min

Aux Start On Dly 0 sec

Failsafe Mode Shutdown

mA Output Off

Lo Fire Timer 2 sec

Setpt Limit Band (If Setpt Limiting = Enabled) 5°F

1.2

60°F

215°F

Tuning Menu

Prop Band 70°F

Integral Gain 1.00

Derivative Time 0.0 min

E-1

APPENDIX F

F-1

APPENDIX F

F-2

APPENDIX F

F-3

APPENDIX F

F-4

APPENDIX F

F-5

APPENDIX F

F-6

APPENDIX F

B

TEST

COCK

HIGH GAS PRESS.

SWITCH

(INSTALL

1/8" NPT PLUG

P/N: 61002-12

MANOMETER HERE)

INTERNATIONAL, INC.

NORTHVALE, NJ 07647

AP-A-800-M

FM GAS TRAIN

APPD.CHKD.

SIZESCALE

DATE REV.

DE-RATED OPTION)

CZ 021406

BENCHMARK2.0 LOW NOx

2" SAFETY

SHUT-OFF

GAS VALVE

P/N 124136

SWITCH

P/N: 61002-11

LOW GAS PRESS.

2" SAFETY SHUT-OFF

VALVE ACTUATOR w/

DROOP ELIMINATOR

P/N 64048

NTS

(1.75 MIL. BTU/HR INPUT

DWN.BY

2" NPT DIFFERENTIAL GAS

PRESSURE REGULATOR

P/N 123541

BOILER BOUNDARY

2" NPT

FULL PORT

P/N: 123540

BALL VALVE

TO AIR-FUEL VALVE ASS'Y

2"-SCH.40 PIPE

F-7

APPENDIX F

F-8

APPENDIX F

F-9

APPENDIX F

F-10

APPENDIX F

F-11

APPENDIX F

F-12

LEGEND

ISOLATION VALVE

Y STRAINER

UNION

PRESSURE &

BALANCING VALVE

P&T

TEMPERATURE GAUGE

AT MAXIMUM BTU/HR INPUT,

MAINTAIN MINIMUM GAS PRESSURE AT

APPENDIX G

B

REV

SD-A-671

INTERNATIONAL, INC.

NORTHVALE, NJ 07647

BENCHMARK 2 MIL. BTU LOW NOx

021506

GAS FIRED BOILER

SINGLE UNIT INSTALLATION

DATE

DATE

SD

NTS

APPD.

DWN.BY

SCALE

GAS SUPPLY

AERCO

* 2" MANUAL

SHUTOFF

VALVE

5.3" W.C.(FM GAS TRA IN); 5.5" W.C. (IRI).

MAX. GAS PRESSURE = 2.0 PSIG. (SEE NOTE 6)

DIRT TRAP

AUTOMATIC

SYSTEM

PUMP

CHECK

VALVE

HEATING

RELIEF VALVE (TYP.)

AIR VENT

(TYP.)

SUPPLY

SYSTEM

AIR

SEPARATOR

WATER

SUPPLY

REDUCING

PRESSURE

FILL VALVE

P&T

LINE SIZE BYPASS

BACKFLOW PREVENTER

(SEE NOTE 7)

Diagram 1

EXPANSION TANK

DIAPHRAGM TYPE

MAINTAIN A REGULATED

5.3" W.C. (FM), 5.5 W.C. (IRI)

GAS PRESSURE AT MAX

BTU/HR INPUT

SYSTEM

RETURN

HEATING

DRAIN TRAP

* CONDENSATE

1-1/2" NPT

DRAIN CONN.

GAS SUPPLY

DRIP TRAP

* 2" MANUAL

SHUTOFF

VALVE

ELECTRIC CONNECTIONS (SERVICE SWITCHES, CONDUIT BOXES) SHOULD LIKEWISE

BE 6'' AWAY FROM SIDE PANELS.

DOWNSTREAM OF THE 2" MANUAL SHUTOFF VALVE TO BRING THE GAS PRESSURE DOWN TO 2.0 PSIG.

(TO BOILER)

NOTES:

1) FOR ACTUAL SIZES AND LOCATIONS OF PIPING AND OTHER CONNECTIONS TO THE BOILER, SEE DIMENSIONAL DRAWING (AP-A-739).

2) SHELL DRAIN VALVE AND CONDENSATE DRAIN TRAP SHOULD BE ARRANGED TO PERMIT THE FLUIDS TO DRAIN

FREELY, BY GRAVITY, TO A CONVENIENT FLOOR DRAIN. RELIEF VALVE SHOULD BE PIPED VERTICALLY TO A

FITTINGS TO PREVENT INTERFERENCE WITH REMOVAL OF BOILER PANELS AND COVERS. ALL PIPING AND

4) LOCATE WATER INLET AND OUTLET FITTINGS (i.e. UNIONS, ELBOWS, ETC.) A MINIMUM OF 6'' FROM BOILER

3) ALL (*) ITEMS ARE INCLUDED SEPARATELY IN SHIPMENT FROM FACTORY.

HEIGHT 18'' ABOVE FLOOR.

5) THIS IS A TYPICAL INSTALLATION DRAWING. LOCAL CODES AND AUTHORITIES SHOULD BE CONSULTED.

6) WHEN AVAILABLE GAS PRESSURE IS GREATER THAN 2.0 PSIG, A LOCK-UP STYLE REGULATOR MUST BE INSTALLED

SEE DIAGRAM 1

7) A GAS REGULATOR IS MANDATORY FOR THE STATE OF MASSACHUSETTS, REGARDLESS OF SUPPLY PRESSURE.

G-1

APPENDIX G

B

REV

LEGEND

RELIEF

Y STRAINER

VALVE (TYP.)

ISOLATION VALVE

UNION

BALANCING VALVE

PRESSURE &

P&T

TEMPERATURE GAUGE

* 2" MANUAL

SHUTOFF

VALVE

AT MAXIMUM BTU/HR INPUT,

MAINTAIN MINIMUM GAS

PRESSURE AT 5.3" W.C.

(FM GAS TRAIN); 5.5" W.C.(IRI).

MAX. GAS PRESSURE=2.0 PSIG.

(SEE NOTE 6)

P&T

DIRT TRAP

P&T

HEATING

SYSTEM

RETURN

GAS SUPPLY

INTERNAT IONAL, INC.

NORTHVALE, NJ 07647

AERCO

SD-A-672

021506

GAS FIRED BOILER

DATE

MULTIPLE UNIT INSTALLATION

SD

BENCHMARK 2 MIL. BTU LOW NOx

NTS

DWN.BY

SCALE

DATE

APPD.

CHECK

SYSTEM

AUTOMATIC

PUMP

VALVE

(TYP.)

SYSTEM

HEATING

AIR VENT

SUPPLY

AIR

SEPARATOR

WATER

SUPPLY

REDUCING

PRESSURE

FILL VALVE

DRAIN TRAP

* CONDENSATE

1-1/2" NPT

DRAIN CONN.

EXPANSION TANK

DIAPHRAGM TYPE

GAS SUPPLY

DRIP TRAP

LINE

SIZE

BACKFLOW PREVENTER

BYPASS

(SEE NOTE 7)

Diagram 1

MAINTAIN A REGULATED

5.3" W.C. (FM), 5.5 W.C. (IRI)

GAS PRESSURE AT MAX

BTU/HR INPUT

* 2" MANUAL

SHUTOFF

VALVE

(TO BOILER)

NOTES:

CONVENIENT FLOOR DRAIN. RELIEF VALVE SHOULD BE PIPED VERTICALLY TO A HEIGHT 18'' ABOVE FLOOR.

2) SHELL DRAIN VALVE AND CONDENSATE DRAIN TRAP SHOULD BE ARRANGED TO PERMIT THE FLUIDS TO DRAIN FREELY, BY GRAVITY, TO A

1) FOR ACTUAL SIZES AND LOCATIONS OF PIPING AND OTHER CONNECTIONS TO THE BOILER, SEE DIMENSIONAL DRAWING (AP-A-739).

3) ALL (*) ITEMS ARE INCLUDED SEPARATELY IN SHIPMENT FROM FACTORY.

4) LOCATE WATER INLET AND OUTLET FITTINGS (i.e. UNIONS, ELBOWS, ETC.) A MINIMUM OF 6'' FROM BOILER

ELECTRIC CONNECTIONS (SERVICE SWITCHES, CONDUIT BOXES) SHOULD LIKEWISE BE 6" AWAY FROM SIDE PANELS.

FITTINGS TO PREVENT INTERFERENCE WITH REMOVAL OF BOILER PANELS AND COVERS. ALL PIPING AND

6) WHEN AVAILABLE GAS PRESSURE IS GREATER THAN 2.0 PSIG, A LOCK-UP STYLE REGULATOR MUST BE INSTALLED

5) THIS IS A TYPICAL INSTALLATION DRAWING. LOCAL CODES AND AUTHORITIES SHOULD BE CONSULTED.

SEE DIAGRAM 1

DOWNSTREAM OF THE 2" MANUAL SHUTOFF VALVE TO BRING THE GAS PRESSURE DOWN TO 2.0 PSIG.

7) A GAS REGULATOR IS MANDATORY FOR THE STATE OF MASSACHUSETTS, REGARDLESS OF SUPPLY PRESSURE.

G-2

APPENDIX G

G-3

APPENDIX G

G-4

APPENDIX G

G-5