AERCO BMK 1.5 LN User Manual May 2009

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

Instruction

No.

GF-120

Installation, Operation

& Maintenance Instructions

Benchmark 1.5LN
Series
Gas Fired
Low NOx
Boiler System

Condensing, Modulating

Forced Draft, Hot Water Boiler

1,500,000 BTU/H Input

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

Telephone Support

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

1-800-526-0288

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

www.aerco,com

© AERCO International, Inc., 2009

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-120 - AERCO BENCHMARK 1.5LN GAS FIRED LOW NOx BOILER

Operating & Maintenance Instructions

FOREWARD A

Chapter 1 – SAFETY PRECAUTIONS 1-1

Para. Subject Page

1-1 Warnings & Cautions 1-1
1-2 Emergency Shutdown 1-2

Chapter 2 – INSTALLATION 2-1

Para. Subject Page

2.1 Introduction 2-1

2.2 Receiving the Unit 2-1

2.3 Unpacking 2-1

2.4 Site Preparation 2-1

2.5 Supply and Return Piping 2-3

2.6 Condensate Drains 2-3

2.7 Gas Supply Piping 2-4

2.8 AC Electrical Power Wiring 2-5

Para. Subject Page

1-3 Prolonged Shutdown 1-2

Para. Subject Page

2.9 Modes of Operation and Field
Control Wiring

2.10 I/O Box Connections 2-7

2.11 Auxiliary Relay Contacts 2-9

2.12 Flue Gas Vent Installation 2-9

2.13 Combustion Air 2-9

2-5

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 3-4

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
Switches

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 6-2

6.4 Low Water Level Fault Test 6-2

6.5 Water Temperature Fault Test 6-2

6.6 Interlock Tests 6-3

6.7 Flame Fault Test 6-4

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

6-6

Chapter 7 – MAINTENANCE REQUIREMENTS 7-1

Para. Subject Page

7.1 Maintenance Schedule 7-1

7.2 Spark Ignitor 7-1

7.3 Flame Detector 7-2

7.4 Combustion Calibration 7-2

7.5 Safety Device Testing 7-3

7.6 Burner Assembly 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 1. 5LN Boiler is a m odulating unit. It represents a true industry advance
that meets the needs of today's ener gy and environmental concerns. Designed for application
in any closed loop hydronic system, the Benchmark's modulating capability relates energ y input
directly to fluctuating system loads. The Benchmark 1.5, with its 20:1 turn down ratio and
condensing capability, provides extremely high efficiencies and makes it ideally suited for
modern low temperature, as well as, conventional heating systems.

The Benchmark 1.5 operates at inputs ranging from 75, 000 BTU/hr. to 1,500,000 BTU/hr. The
output of the boiler is a f unction of the unit’s firing rate and return water temperat ure. Output
ranges from 74,250 BT U/hr. to 1,450,000 BTU/hr . , depending on operating conditions.

When installed and operated in accordance with this Instruction Manual, the Benchmark 1.5
Boiler complies with the NOx emission standards outlined in:

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

Whether used in singular or modular arrangements, the Benchmark 1.5 offers the maximum
flexibility in venting with minimum installation space requirements. The Benchmark 's advanced
electronics are available in several selectable modes of operation offering the most efficient
operating methods and energy manag em ent system integration.

For service or parts, contact your local sales represent at ive or AERCO I NTERNATIONAL.

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.

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!

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

WARNING!

ELECTRICAL VOLTAGES UP TO
120 VAC MAY BE USED IN THIS
EQUIPMENT. THEREFORE THE
COVER ON THE UNIT’S POWER
BOX (LOCATED BEHIND THE
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
clean water after leak checks have
been completed.

be rinsed thoroughly with

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.

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 is to
identify the emergency shut-off device.

Figure 1-1

Manual Gas Shutoff Valve

1-2

INSTALLATION

CHAPTER 2 INSTALLATION

2.1 INTRODUCTION

This Chapter provides the descriptions and
procedures necessary to unpack, inspect and
install the AERCO Bench mark 1.5 Boiler. Brief
descriptions are also pr ovided f or each avai lable
mode of operation. Detailed procedures for
implementing these modes are provided in
Chapter 5.

2.2 RECEIVING THE UNIT

Each Benchmark 1.5 System is shipped as a
single crated unit. The shipping weight is
approximately 1551 pounds. The unit must be
moved with the proper rigging equipment for
safety and to avoid equipment dam age. The unit
should be complete ly inspected for evidence of
shipping damage and ship ment com pleteness 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. T his indic ates if the un it has
been turned on its side during shipment. If the
Tip-N-Tell indicat or is trip ped, do not s ign 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 s hould also be made clear
to the delivering carrier.

2.3 UNPACKING

Carefully unpack the unit taking care not to
damage the unit enclosure when cutting away
packaging materials

A close inspection of the unit s hould be made to
ensure that there is no evidence of dam age not
indicated by the T ip-N-Tell indicator. The f reight
carrier should be notified immediately if any
damage is detected.

The following accessories come standard with
each unit and are either packed separately
within the unit’s pack ing container or are fac tory
installed on the boiler:

• Pressure/Temperature Gauge

• Spare Spark Igniter

• Spare Flame Detector

• ASME Pressure Relief Valve

• Condensate Drain Trap

• 1-1/2” Gas Supply Shutoff Valve

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

2.4 SITE PREPARATION.

Ensure that the site selected for installation of
the Benchmark 1.5 Boiler includes:

• Access to AC Input Power at 120 VAC, 1-

Phase, 60 Hz @ 20

• Access to Natural Gas line at a minimum

pressure of 4 inches W.C.

2.4.1 Installation Clearances

The unit must be installed with the prescribed
clearances for service as shown in Figure 2-1.
The minimum
AERCO, are listed below. However, if Local
Building Codes require additional clearances,
these codes shall supersede AERCO’s
requirements. Minimum acceptable clearances
required are:

• Sides: 24 inches

• Front : 24 inches

• Rear: 30 inches

• Top: 18 inches

All gas piping, water piping and el ec tric al c on du it
or cable must be arranged so that they do not
interfere with the removal of any panels, or
inhibit service or maintenance of the unit.

clearance dimens ions , requir ed by

2-1

INSTALLATION

Figure 2-1 Benchmark 1.5 Boiler Clearances

WARNING

KEEP THE UNIT AREA CLEAR AND
FREE FROM ALL COMBUSTIBLE
MATERIALS AND FLAMMABLE
VAPORS OR LIQUIDS

.

CAUTION

While packaged in the shipping
container, the boiler must be moved
by pallet jack or forklift from the
FRONT ONLY.

2.4.2 Setting the Unit

The unit must be installed on a 4 inch to 6 inch
housekeeping pad to e nsure proper conde nsate
drainage. If anchoring the unit, refer to the
dimensional drawings in Appendix F for anchor
locations. Two lifting t abs ar e provided a t the top
of the heat exchanger as shown in Figure 2-2.
USE THE TABS SHOWN IN FIGURE 2-2 TO
LIFT AND MOVE THE UNIT . Remove the front
top panel from the unit to prov ide access to the
lifting tabs. Remove the four (4) lag screws
securing the unit to the shipping skid. Lift the
unit off the shipping sk id and position it on the 4
inch to 6 inch housekeeping concrete pad
(required) in the desired location.

BLOWER

LIFTING

TAB

AIR/FUEL

VALVE

FRONT

LIFTING

Figure 2-2

Partial Top View Showing Lifting Tab

Locations

In multiple unit installations, it is important to
plan the position of each unit in advance.
Sufficient space for piping connections and
future service/maintenance requirements must
also be taken into cons ider ation. All pipin g m ust
include ample provisions for expansion.

TAB

2-2

If installing a Combina tion Control Panel (CCP)
system, it is important to identify the
Combination Mode B oilers in adv ance and plac e
them in the proper physical location. Refer to
Chapter 5 for inform ation on Combination Mode
Boilers.

2.5 SUPPLY AND RETURN PIPING

The Benchmark 1.5 Boiler utilizes 3” 150#
flanges for the water system supply and return
piping connectio ns. The physical location of the
supply and return p iping connections are on the
rear of the unit as shown in Figure 2-3. Ref er to
Appendix F, Drawing AP-A-832 for additional
dimensional data.

INSTALLATION

Figure 2-4

Condensate Drain Connection Location

2.6.1 Exhaust Manifold Condensate

Drain

The exhaust manifold drain pipe connection
shown in Figure 2-4, must be connected to a
condensate drain trap external to th e unit. Refer
to Figure 2-5 and install the trap as follows:

Figure 2-3

Supply and Return Locations

2.6 CONDENSATE DRAIN

The Benchmark 1.5 Boiler is designed to
condense water vapor from the flue products.
Therefore, the insta llation must have provisions
for suitable condensate drainage or collection.

The drain pipe located on the exhaust manifold
must be connected to a c ondensate trap which
is packed separately within the unit’s shipping
container.

1. Position the supplied condensate trap (part

no. 24060) on the floor at the rear of the
unit.

2. Install 3/4” NPT nipples in the tapped inlet

and outlet of the condensate trap.

3. Attach a length of 1” I.D. hose between t he

exhaust manifold drain pipe and the inlet
side of the condensate trap (Figure 2-5).
Secure both ends of the hose with clamps.

4. Connect a second length of 1” I.D. h ose to

the outlet side of the condensate trap and
route it to a nearby floor drain.

If a floor drain is not available, a condensate
pump can be used to remove the condens ate to
drain. The max imum condensate flow rate is 2 0
GPH. The condensate drain trap, associated
fittings and drain lines must be removable for
routine maintenance. Therefore, DO NOT hard
pipe.

The procedure to install and connect the
condensate drain is provided in paragraph 2.6.1.

2-3

INSTALLATION

Figure 2-5

Condensate Trap Installation

2.7 GAS SUPPLY PIPING

The AERCO Benchmark 1.5 Gas Components
and Supply Design Guide, GF-4030 must be
consulted prior to des ignin g or installi ng an y gas
supply piping.

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

To avoid unit damage whe n pres sur e tes ting gas
piping, isolate the unit from the gas supply
piping. At no time should the gas pressure
applied to the unit exceed 2 psi. Leak test all
external piping thoroughly using a soap and
water solution or suitable equivalent. The gas
piping used must meet all applicable codes.

2.7.1 Gas Supply Specifications.

The gas supply input specifications to the unit
for Natural Gas are as follows:

The maximum static pressure to the unit must
not exceed 2 psi. The minimum operating gas
pressure for natural gas is 4 inches W.C. for
both FM and IRI gas trains when the unit is firing
at maximum input. The gas supply pressure to
the unit must be of suff icient capacity to provide
1500 cfh while maintain ing the gas press ure at 4
inches W.C. for FM or IRI gas trains.

WARNING

NEVER USE MATCHES, CANDLES,
FLAMES OR OTHER SOURCES OF
IGNITION TO CHECK FOR GAS
LEAKS

Many soaps used for gas pipe leak
testing are corrosive to metals. There­fore, piping must be rinsed thoroughly
with clean water after leak checks
have been completed.

All gas piping m ust be arranged so that it
does not interfere with removal of any
covers, inhibit service/maintenance, or
restrict access between the unit and
walls, or another unit.

A 1-1/2 inch gas inlet connection is located on
the rear of the unit as shown in Figure 2-3.

.

CAUTION

NOTE

2.7.2 Manual Gas Shutoff Valve

A manual shut-off valve must be installed in th e
gas supply line upstream of the Boiler as shown
in Figure 2-6. M aximum allowable gas pressure
to the Boiler is 2 psi

NATURAL

GAS

SUPPLY

1-½” MANUAL

GAS SHUTOFF

VALVE

DIRT

TRAP

Prior to installation, all pipes should be de­burred and internally clear ed of any scale, m etal
chips or other foreign particles. Do Not install
any flexible connectors or unapproved gas
fittings. Piping must be s upported from the floor,
ceiling or walls onl y and must not be supported
by the unit.

2-4

Figure 2-6

Manual Gas Shut-Off Valve Location

INSTALLATION

2.7.3 IRI Gas Train Kit

The IRI gas train is an optional gas train
configuration which is r e qui red i n s ome areas for
code compliance or for insurance purposes.
The IRI gas train is factor y pre-piped and wired.
See Appendix F, Drawing AP- A-830 f or details.

2.8 AC ELECTRICAL POWER WIRING

The AERCO Benchmark 1.5 Electrical Power
Wiring Guide, GF-40 60, must be co nsulted prior
to connecting any AC power wiring to the unit.
External AC power connect ions are made to the
unit inside the Power Box on the front panel of
the unit. Remove the front door of the unit to
access the Power Box mounted directly above
the Control Box. Loosen the four Power Box
cover screws and remove cover to access the
AC terminal connections inside the Power Box
(Figure 2-7).

NOTE

All electrical conduit and hardware must
be installed so that it does not interfere
with the removal of any un it cover s, inh ibit
service/maintenance, or prevent access
between the unit and walls or another
unit.

2.8.1 Electrical Power Requirements

The AERCO Benchmark 1.5 Boiler accepts 120
VAC, single-phase, 60 Hz @ 20 A. The Power
Box contains a terminal block as shown in
Figure 2-8. In addition, a wiring diagr am showing
the required AC power connections is provided
on the front cover of the Power Box.

Each Benchmark 1.5 Boil er must be connected
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 ser vice switch) mus t be
installed near th e unit for normal operation and
maintenance. All electrical connections should
be made in accordance with the National
Electrical Code and/ or with any applicable local
codes.

For electrical power wiring diagrams, see the
AERCO Benchmark 1.5 Electrical Power W iring
Guide, (GF-4060).

Figure 2-7

AC Input Terminal Block Location

Figure 2-8

AC Terminal Block Configurations

2.9 MODES OF OPERATION AND FIELD

CONTROL WIRING

The Benchmark 1.5 B oiler is available in severa l
different modes of operation. W hile each unit is
factory configured and wired for its intended
mode, some additional field wiring may be
required to complete th e installation. This wir ing
is typically connected to the Input/Output (I/O)
Box located on the lower por tion of the unit fr ont
panel (Figure 2-9) behind the removable front
door.

2-5

INSTALLATION

To access the I/O Box terminal strips shown in
Figure 2-10, loosen the four cover screws and
remove the cover. All field wiring is installed
from the rear of the panel by routing the wires
through one of the four bushings provided.

Refer to the wiring diagram provided on the
cover of the I/O Box (Figur e 2-10) when making
all wiring connections.

In addition to the term inal strips s hown in Figure
2-9, the I/O Box also contains a pre-wired
temperature transmitter which receives inlet air
temperature sensor readings and transmits this
signal to the variable frequency drive (VFD)
contained in the Benchm ark 1.5 Boil er. T he VFD
utilizes this input signal to adjust the rotation
speed of the blower.

Brief descriptions of each mode of operation,
and their wiring requirements, are provided in
the following paragr aphs. Additional information
concerning field wiring is prov ided in paragr aphs

2.9.1 through 2.9.9. Refer to Chapter 5 for
detailed information on the available modes of
operation.

Figure 2-9.

Input/Output (I/O) Box Location

Figure 2-10. I/O Box Terminal Strip

2-6

INSTALLATION

2.9.1 Constant Setpoint Mode

The Constant Setpoi nt Mode is used when it is
desired to have a fixed setpoint that does not
deviate. No wiring connections, other than AC
electrical power connections, are required for
this mode. However, if desired, fault monitor ing
or enable/disable in terlock wiring c an be utilized
(see paragraphs 2.9.9.1 and 2.9.10).

2.9.2 Indoor/Outdoor Reset Mode

This mode of operation increases supply water
temperature as outdoor te mperatures decrease.
An outside air temperatur e sensor (AERCO Part
No. 122790) is requ ired. The sensor MUST BE
wired to the I/O Box wiring term inals (see Figure
2-10). Refer to paragraph 2.10.1 for additional
information on outside air temperature sensor
installation.

2.9.3 Boiler Management System Mode

When using an AERCO Boiler Management
System (BMS), the field wiring is connected
between the BMS Panel and each Boiler’s I/O
Box terminal strip (Figure 2-10). Twisted
shielded pair wire f rom 18 to 22 AWG must be
utilized for the connections. The BMS Mode can
utilize either pulse width modulation (PWM)
signaling, or RS485 Modbu s s ignaling. F or PWM
signaling, connections are made from the
AERCO Boiler Management System to the
B.M.S. (PWM) IN terminals on the I/O Box
terminal strip. For RS485 Modus signaling,
connections are made from the BMS to the
RS485 COMM term inals on the I/O Box ter minal
strip. Polarity m ust be maintain ed and the shie ld
must be connected only at the AERCO BMS.
The boiler end of the shi eld m ust be left f loating.
For additional instructions, refer to Chapter 5,
paragraph 5.6 in t his manual. Also, ref er to GF­108M, BMS -Operations Guide.

2.9.4 Remote Setpoint and Direct Drive
Modes

The Benchmark 1.5 Boiler can accept several
types of signal formats from an Energy
Management System (EMS), Building
Automation System (BAS) or other source, to
control either the setpoint (Remote Setpoint
Mode) or 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 W idth Modulated signal. See

para. 2.10.4)

• Network (RS485 Modbus. See para. 2.10.7)

While it is possible to c ontrol a boiler or boilers
using one of the previously described m odes of
operation, it ma y not be the method best suited
for the application. Prior to selecting one of
these modes of operation, it is recommended
that you consult with your local AERCO
representative or the factory for the mode of
operation that will work best with your
application. For m ore information on wir ing the
4 to 20 mA / 1to 5VDC or the 0 to 20 m A / 0 to 5
VDC, see paragraph 2.9.3.

2.9.5 Combination Mode

With a Combination Mode unit, field wiring is
between the unit’s I/O Box wiring terminals, the
CCP (Combination Contr ol Panel), an d the BMS
(Boiler Management System). The wiring must
be accomplished using twisted-shielded pair
wire from 18 to 22 AWG. Polarity must be
maintained. For further instructions and wiring
diagrams, refer to the GF-108 Boiler
Management System Operations Guide and the
CCP-1 data sheet.

2.10 I/O BOX CONNECTIONS

The types of input and output signals and
devices to be connecte d to the I/O Box terminals
shown in Figure 2-10 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.

2.10.1 OUTDOOR SENSOR IN

An outdoor air temperature sensor (AERCO Part
No. 122790) will be required primarily for the
Indoor/Outdoor reset m ode of operation. It can
also be used with anoth er m ode if it is desired to
use the outdoor sensor enable/disable feature.
This feature allows the boiler to be enabled or
disabled based on the outdoor air temperature.

The factory default for the outdoor sensor is
DISABLED. To enable the sensor and/or select
an enable/disable o utdoor temperature, see the
Configuration menu in Chapter 3.

The outdoor sensor m ay be wired up t o 200 feet
from the boiler. It is connected to the
OUTDOOR SENSOR IN and SENSOR
COMMON terminals in the I/O Box (see Figures
2-9 and 2-10). Wire the sensor using a twisted
shielded pair wire fr om 18 to 22 AWG. There is
no polarity to observe when terminating these
wires. The shield is to be c onnected only to the

2-7

INSTALLATION

terminals labeled SHIELD in the I/O Box. The
sensor end of the shield must be left free and
ungrounded.

When mounting the sensor, it must be located
on the North side of the building where an
average outside air temperature is expected.
The sensor must be shield ed f r om dir ect sunli ght
as well as impingement by the elements. If a
shield is used, it must allow for free air
circulation.

2.10.2 AUX SENSOR IN

The AUX SENSOR IN terminals can b e 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 S ENSOR IN and SENSOR
COMMON terminals and must be similar to
AERCO BALCO wire se nsor Part No. 124 49. A
resistance chart for this sensor is provided in
Appendix C.

2.10.3 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 t o 20 mA
/ 0 to 5 VDC signal may be used to vary the
setpoint or firing rate. T he factory def ault setting
is for 4 to 20 mA / 1 to 5 VDC, howev er this m a y
be changed to 0 to 20 mA / 0 to 5 VDC usi ng 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
CPU Board located inside the Control Box.
Contact the AERCO factory for information on
setting DIP switches.

All of the supplied signals must be floating
(ungrounded) signals . Connectio ns bet ween the
signal source and the Boiler’s I/O Box must be
made using twiste d shiel ded pa ir wire fr om 18 to
22 AWG, such as Belden 9841 (see Figure
2-10). Polarity mu st be maintained. The shi eld
must be connected only at the source end and
must be left floating (not connected) at the
Boiler’s I/O Box.

Regardless of whether volt age or curr ent is used
for the drive signal, the y are linearly mapped to
a 40°F to 240°F setpoint or a 0% to 100% f iring
rate. No scaling for these signals is provided

2.10.4 B.M.S. (PWM) IN

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

2.10.5 SHIELD

The SHIELD terminals are us ed to terminate any
shields used on sensor wires connected to the
unit. Only shields m ust be connected to these
terminals.

2.10.6 mA OUT

These terminals provide a 4 to 20 mA output to
the VFD to control the rotational speed of the
blower. This function is enabled in the
Configuration Menu (Chapter 3, Table 3.4).

2.10.7 RS-485 COMM

These terminals are used for RS-485 MODBUS
serial communication between the unit and an
external “Master” suc h as a Boiler Management
System (BMS), Energy Management System
(EMS), Building Automation System (BAS) or
other suitable device.

2.10.8 EXHAUST SWITCH IN

These terminals permit an external exhaust
switch to be connected to the exhaust manifold
of the boiler. The exhaust switch should be a
normally open t ype s witc h (such as AERCO Par t
No. 123463) that closes (trips) at 500°F.

2.10.9 INTERLOCKS

The unit offers two interlock circuits for
interfacing with Energy Management Systems
and auxiliary equipment such as pumps or
louvers. These interlock s are called the Rem ote
Interlock and Delayed Interlock (Figure 2-10).
The wiring terminals for these interlocks are
located inside the I/O Box on the unit front
panel. The I/O Box cover contains a wiring
diagram which s hows th e ter m inal str ip locat ions
for these interlocks (REMOTE INTL’K IN and
DELAYED INTL’K IN). Both interlocks,
described below, are fac tory wired in the closed
position.

NOTE

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

2-8

INSTALLATION

2.10.9.1 REMOTE INTERLOCK IN

The remote interlock circuit is provided to
remotely start (enable) and stop (disable) the
Boiler, if desired. The circuit is labeled
REMOTE INTL’K IN and is loc ate d i nsid e th e I/O
Box on the front panel. The circuit is 24 VAC
and is factory pre-wired in the c losed (jum pered)
position.

2.10.9.2 DELAYED INTERLOCK IN

The delayed interlock is typically used in
conjunction with the aux iliary relay described in
paragraph 2.10. 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 b y the Boiler’s a uxiliary rela y.
The delayed interlock must be closed for the
boiler to fire.

If the delayed interl ock is connec ted t o a pr oving
device that requir es tim e to clos e (mak e), a tim e
delay (Aux Start On Dly) that holds the start
sequence of the boiler lon g enoug h for a proving
switch to make can be progr amm ed. Should the
proving switch not prove within the programm ed
time frame, the boiler will shut down. The Aux
Start On Dly can be progr ammed from 0 to 120
seconds. This option is locate in the
Configuration Menu (Chapter 3, Table 3-4).

2.12 FLUE GAS VENT INSTALLATION

The minimum allowable vent diameter for a
single Benchmark 1.5 Boiler is 6 inches.

The AERCO Benchmark Venting and
Combustion Air Guide, GF-4050, 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-4050, must be used
for safety and code com pliance. S ince the u nit is
capable of dischar ging low temperature ex haust
gases, horizontal sections of the flue vent
system must be pitched back to the unit a
minimum of 1/4 inch per foot to avoid
condensate pooling and allow for proper
drainage.

The combined pressure drop of vent and
combustion air systems must not exceed 140
equivalent feet of 6 inc h ducting. Fittings as we ll
as pipe lengths must be calculate d as part of the
equivalent length.

For a natural draf t installation the draf t must not
exceed ±0.25 inch W .C. These factors must be
planned into the vent installation. If the
maximum allowabl e equivalent lengt hs of piping
are exceeded, the unit will not operate properly
or reliably.

2.10.10 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 12 0 VAC and 5 amps at 30
VDC. The relay energizes when any fault
condition occurs and remains energized until the
fault is cleared and the CLEAR button is
depressed. The fault relay connections are
shown in Figure 2-10.

2.11 AUXILIARY RELAY CONTACTS

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 dem and for heat is satisf ied.
The relay is prov ided for the control of auxiliary
equipment, such as pumps and louvers, or can
be used as a Boiler status indictor (firing or n ot
firing). Its contacts are r ated for 120 VAC @ 5
amps. Refer to Figure 2- 10 to locate the AUX
RELAY terminals for wiring connections.

2.13 COMBUSTION AIR

The AERCO Benchmark Venting and
Combustion Air Guide, GF-4050 MUST be
consulted before any flue or com bustion supply
air venting is designed or implemented.
Combustion air supp ly is a direct r equirem ent 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 ha zardous when used in gas­fired equipment. Common sources of these
compounds are swimming pools, degreasing
compounds, plastic proc essing and refrigerants.
Whenever the env ironment c ontains thes e t ypes
of chemicals, combustion air must be supplied
from a clean area outdoors for the protection
and longevity of the equipment.

2-9

INSTALLATION

The AERCO Benchm ark 1.5 Boiler is UL listed
for 100% sealed combustion. It can also be
installed using room air, provided there is an
adequate supply. (See paragraph 2.13.3 for
more information conc erning sealed com bustion
air). If the sealed combustion air option is not
being used, an inlet screen will be attached at
the air inlet on the top of the unit

The more common methods of supplying
combustion air are outlined below. For more
information concerning combustion air, consult
the AERCO Benchmark Venting and
Combustion Air Guide, GF-4050.

2.13.1 Combustion Air From Outside the
Building

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

2.13.2 Combustion Air From Inside The

Building

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

2.13.3 Sealed Combustion

The AERCO Benchm ark 1.5 Boiler is UL listed
for 100%-sealed combustion. For sealed
combustion installations, the screen on the air
inlet duct of the unit m ust be removed. T he inlet
air ductwork must then be attached directly to
the unit’s air inlet.

In a sealed combustion air application, the
combustion air ducting pre ssure losses must be
taken into account when calculating the total
maximum allowable venting run. See the
AERCO Benchmark Venting and Combustion
Air Guide, GF-40 50. When using the bo iler in a
sealed combustion air configuration, each unit
must have a minimum 8 inch 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 1.5 Boiler
using the Control Panel mounted on the front of
the unit. It is imperative that the initial startup of
this unit be performed by factory trained
personnel. Operation prior to initial startup by
factory trained personnel will void the equipment
warranty. In addition, the following WARNINGS
and CAUTIONS must be observed at all times.

CAUTION

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

WARNING

ELECTRICAL VOLTAGES IN THIS
SYSTEM MAY INCLUDE 460, 208
AND 24 VOLTS AC. IT MUST BE
SERVICED ONLY BY FACTORY
CERTIFIED SERVICE TECHNICIANS

WARNING

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

3.2 CONTROL PANEL DESCRIPTIO N

The Benchmark 1.5 Control Panel shown in
Figure 3-1 contains all of the controls, indicators
and displays necessary to operate, adjust and
troubleshoot the Benchmark 1.5 Boiler. These
operating controls, indicators and displays are
listed and described in Table 3-1. Additional
information on these items are provided in the
individual operating procedures provided in this
Chapter.

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

OUTLET

2

TEMPERATURE

Display

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

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

FUNCTION

Menu Selection

RS-232 Port

4

FAULT Indicator Red FAULT LED indicator lights when a boiler alarm

5

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

6

READY Indicator

7

ON/OFF Switch

8

LOW WATER LEVEL

9

TEST/RESET Switches

Port permits a Laptop Computer or External Modem to be
connected to the unit’s 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 ON/OFF switch is set to ON and all Pre-Purge

conditions have been satisfied.

Enables and disables boiler operation.

Allows operator to test operation of the water level monitor.

Pressing TEST opens the water level probe circuit and

simulates a Low Water Level alarm.

Pressing RESET resets the water level monitor circuit.
Pressing the CLEAR key (item 6) resets the display.

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

11

12

ENTER

AUTO/MAN Switch

FIRE RATE Bargraph

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

This switch toggles the boiler between the Automatic and

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

mode, the front panel controls are enabled and the

MANUAL status LED lights.
When in the Automatic (AUTO) mode, the MANUAL status

LED will be off and the front panel controls disabled.

20 segment red LED bargraph continuously shows the Fire
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 and initiating each menu and option
is accomplished using the Menu Keys shown in
Figure 3-1. Therefore, it is imperative that you
be thoroughly familiar with the following basic
steps before attempting to perform specific
menu procedures.

around after the first or last available option
is reached.

6. To change the value or setting of a

displayed menu option, press the CHANGE

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

7. To select and store a changed menu item,

press the ENTER key.

1. The Control Panel will normally be in the
Operating Menu and the VFD will display the
current unit status. Pressing the ▲ or ▼
arrow key will display the other available
data items in the Operating Menu.

2. Press the MENU key. The display will show

the Setup Menu, which is the next menu
category shown in Figure 3-2. This menu
contains the Password option which must be
entered if other menu options will be
changed.

3. Continue pressing the MENU key until the

desired menu is displayed.

4. With the desired menu displayed, press the
▲ or ▼ arrow key. The first option in the
selected menu will be displayed.

5. Continue to press the ▲ or ▼ arrow key
until the desired menu option is displayed.
Pressing the ▲ arrow key will display the
available menu options in the Top-Down
sequence. Pressing the ▼ arrow key will
display the options in the Bottom-Up
sequence. The menu options will wrap-

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. Refer to
Appendix B for listings and descriptions of
displayed startup, status and error
messages.

3-4

CONTROL PANEL OPERATING PROCEDURES

3.4 OPERATING M ENU

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

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

Table 3-2. Operating Menu

Available Choices or Limits

Menu Item Display Minimum Maximum Default

Status Message

time-out after 1 hour. Therefore, the correct
password must be reentered when required. In
addition to permitting password entries, the
Setup Menu is also used to enter date and time,
units of temperature measurements and entries
required for external communication and control
of the unit via the RS-232 port. A view-only
software version display is also provided to
indicate the current Control Box software
version.

NOTE

The Outdoor Temp display item shown with
an asterisk in Table 3-2 will not be displayed
unless the Outdoor Sensor function has
been enabled in the Configuration Menu
(Table 3-4).

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 or Celsius Fahrenheit

Comm Address 0 127 0

Baud Rate 2400, 4800, 9600, 19.2K 9600

Software Ver 0.00 Ver 9.99

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 or Water Heater Boiler

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

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.

1.0 MBTU

Constant

Setpoint

Direct Drive

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

Bldg Ref Temp
(If Mode = Outdoor
Reset)

Reset Ratio
(If 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 220°F 200°F

Temp Hi Limit 40°F 240°F 210°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.

4 – 20 mA/1 – 5V

0 -20 mA/0 – 5V

PWM Input (BMS)

Network

40°F 230°F 70°F

0.1 9.9 1.2

30°F 100°F 60°F

4 – 20 mA,

1-5V

3-6

CONTROL PANEL OPERATING PROCEDURES

Table 3-4. Configuration Menu - Continued

Available Choices or Limits

Menu Item Display Minimum Maximum Default

Failsafe Mode Shutdown or Constant Setpt Shutdown

*mA Output

(See CAUTION)

Low Fire Timer 2 sec. 120 sec. 2 sec.

Setpt Limiting Enabled or Disabled Disabled

Setpt Limit Band 0°F 10°F 5°F

*CAUTION: DO NOT CHANGE mA Output Menu Item from its Default setting.

Setpoint, Outlet Temp,

Fire Rate Out, Off

*Fire Rate

Out

3.7 TUNING MENU

The Tuning Menu items in Table 3-5 are Factory set for each individual unit. Do not change these menu
entries unless specifically requested to do so by Factory-Trained personnel.

Table 3-5. Tuning Menu

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 2.00 min 0.00 min

Reset Defaults? Yes

No

Are You Sure?

No

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

• Blower Proof switch

If all of the above switches are closed, the

READY light above the ON/OFF switch will light

and the unit will be in the Standby mode.

When there is a demand for heat, the following
events will occur:

NOTE

If any of the Pre-Purge safety device
switches are open, the appropriate fault
message will be displayed. Also, the
appropriate fault messages will be displayed
throughout the start sequence, if the
required conditions are not observed.

1. The DEMAND LED status indicator will light.

2. The unit checks to ensure that the Proof of
Closure (POC) switch in the downstream
Safety Shut-Off Valve (SSOV) is closed.
See Figure 3-3 for SSOV locations.

3-7

CONTROL PANEL OPERATING PROCEDURES

STEPPER

Figure 3-3.

SSOV Locations

MOTOR

DIAL
(DETAIL “A”)

100

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

(a) The Blower relay energizes and turns

on blower.

(b) The Air/Fuel Valve rotates to the full-

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

(c) The FIRE RATE bargraph will show

100%.

4. Next, the blower proof switch on the Air/Fuel
Valve (Figure 3-5) closes. The display will

show Purging and indicate the elapsed time

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

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

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

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

(b) The igniter relay is activated and

provides ignition spark.

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

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

DETAIL “A”

Figure 3-4.

Air/Fuel Valve In Purge Position

Figure 3-5.

Blower Proof Switch

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 boiler’s FIRE RATE will be

continuously displayed on the front panel
bargraph.

Once the demand for heat has been satisfied,
the Control Box will turn off the dual SSOV gas
valves. The blower relay will be deactivated and

the Air/Fuel Valve will be closed. Standby will

be displayed.

DIAL
(DETAIL “A”)

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.

Note that the energy input of the boiler is not
linearly related to the fire rate percentage
(Air/Fuel Valve position). Refer to Table 3-6 on
the following page for the relationship between
the energy input and fire rate percentage for a
unit running on natural gas.

STEPPER

MOTOR

5

2

DETAIL “A”

Figure 3-6.

Air/Fuel Valve In Ignition

3-9

CONTROL PANEL OPERATING PROCEDURES

Table 3-6.

Relationship Between Air/Fuel Valve Position and Energy Input For Unit Running On Natural Gas

Fire Rate,

Air/Fuel Valve

Position

(% Open)

0% 0 0

10% 0 0

16 %

(Stop Level)

20% 157,000 10%

30% 310,000 21%

40% 534,000 36%

50% 783,000 52%

60% 970,000 65%

70% 1,140,000 76%

80% 1,240,000 83%

90% 1,370,000 91%

100% 1,500,000 100%

Energy Input

(BTU/Hr)

75,000 5.0%

Boiler Energy Input
(% of Full Capacity)

3-10

CHAPTER 4 INITIAL START-UP

INITIAL START-UP

4.1 INITIAL START-UP REQUIREMENTS

The requirements for the initial start-up of the
Benchmark 1.5 Boiler consists of the following:

• Complete installation

• Perform combustion calibration

• Set proper controls and limits

• Set up mode of operation (see Chapter 5)

• Test safety devices (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
to operate the unit safely and at a high thermal
efficiency, with low flue gas emissions.

Initial unit start-up is to be performed ONLY by
AERCO factory trained start-up and service
personnel. After following the steps in this
chapter, it will be necessary to perform the Mode
of Operation settings in Chapter 5, and the
Safety Device Testing procedures in Chapter 6
to complete the initial unit start-up.

An AERCO Gas Fired Startup Sheet, included
with each Benchmark Boiler, 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

CAUTION

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

4.2 TOOLS AND INSTRUMENTATION
FOR COMBUSTION CALIBRATION

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

4.2.1 Required Tools & Instrumentation

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

• Digital Combustion Analyzer: Oxygen
accuracy to ± 0.4%; Carbon Monoxide
(CO) and Nitrogen Oxide (NOx) resolution
to 1PPM.

• 16 inch W.C. manometer or equivalent
gauge and plastic tubing.

• 1/8 inch NPT-to-barbed fittings for use with
gas supply manometer or gauge.

• Small and large flat blade screwdrivers.

• Tube of silicone adhesive

4.2.2 Installing Gas Supply Manometer

The gas supply manometer is installed in the
gas train as follows:

1. Close the main manual gas supply shut-off
valve upstream of the unit.

WARNING

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

2. Remove the front door and left side panels
from the boiler to access the gas train
components.

3. Remove the 1/8 inch NPT pipe plug from the
leak detection ball valve on the downstream
side of the Safety Shut Off Valve (SSOV)
No. 1 as shown in Figure 4-1.

4. Install a NPT-to-barbed fitting into the
tapped plug port.

4-1

INITIAL START-UP

5. Attach one end of the plastic tubing to the
barbed fitting and the other end to the 16
inch W.C. manometer.

Figure 4-1.

1/8 Inch Gas Plug Location

4.2.3 Accessing the Vent Probe Port

The unit contains NPT plug on the exhaust
manifold at the rear of the unit as shown in
Figure 4-2. Prepare the port for the combustion
analyzer probe as follows:

1. Remove the plug from the probe port on the

right side of the exhaust manifold.

left or

2. If necessary, adjust the stop on the
combustion analyzer probe so that it will
extend mid-way into the flue gas flow. DO
NOT install the probe at this time.

4.3 NATURAL GAS COMBUSTION
CALIBRATION

The Benchmark 1.5LN Boiler is combustion
calibrated at the factory prior to shipping.
However, recalibration as part of initial start-up
is necessary due to changes in the local altitude,
gas BTU content, gas supply piping and supply
regulators. Factory Test Data sheets are
shipped with each unit. These sheets must be
filled out and returned to AERCO for proper
Warranty Validation.

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

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

2. Open the natural gas supply valve(s) to the
unit.

3. Set the control panel ON/OFF switch to the
OFF position.

4. Turn on external AC power to the unit. The

display will show LOSS OF POWER and the

time and date.

5. Set the unit to the Manual Mode by pressing

the AUTO/MAN key. A flashing Manual Fire
Rate message will be displayed with the
present rate in %. Also, the MANUAL LED

will light.

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

7. Ensure that the leak detection ball valve
down-stream of SSOV No. 2 is open.

8. Set the ON/OFF switch to the ON position.

9. Change the fire rate to 29% using the ▲
arrow key. The unit should begin its start
sequence and fire.

4-2

Figure 4.2

Analyzer Probe Hole Location

10. Next, verify that the gas pressure
downstream of the SSOV is 3” W.C. for both
FM and IRI gas trains. If gas pressure
adjustment is required, remove the brass
hex nut on the downstream SSOV actuator
(IRI gas train) containing the gas pressure
regulator (Figure 4-3). Make gas regulator
adjustments using a flat-tip screwdriver to
obtain 3” W.C.

AIR/FUEL

VALVE

INITIAL START-UP

AIR INLET

Figure 4-3

Regulator Adjustment Screw Location

11. Raise the firing rate to 100% and verify that
the gas pressure downstream of the SSOV
remains at 3” W.C. Readjust pressure if
necessary.

12. With the firing rate at 100%, insert the
combustion analyzer probe into the flue
probe opening and allow enough time for the
combustion analyzer to settle.

13. Compare the measured oxygen level to the
oxygen range for the inlet air temperature
shown in Table 4-1. Also, ensure that the
carbon monoxide (CO) and nitrogen oxide
(NOx) readings do not exceed the values
shown.

Table 4-1

Combustion Oxygen Levels for a 100%

Firing Rate

Inlet Air

Temp

>100°F 4.8 % <100 ppm <30 ppm

90°F 5.0 % <100 ppm <30 ppm
80°F 5.2 % <100 ppm <30 ppm

<70°F 5.3 % <100 ppm <30 ppm

14. If necessary, adjust the iris air damper
shown in Figure 4-4 until the oxygen level is
within the range specified in Table 4-1.

Oxygen %

± 0.2

Carbon

Monoxide NOx

A

USE 1/2"
WRENCH TO
INCREASE (CW)
OR DECREASE
(CCW) INLET AIR

IRIS ADJUSTMENT

VIEW A - A

A

IRIS AIR

DAMPER

FRONT

Figure 4-4

Iris Air Damper Location/Adjustment

NOTE

The remaining combustion calibration
steps utilize the Variable Frequency Drive
(VFD) located behind the front door of the
unit. The VFD controls will be used to
adjust the oxygen level (%) at firing rates
of 80%, 60%, 45%, 30% and 12% as
described in the following steps. These
steps assume that the inlet air
temperature is within the range of 50°F to
100°F.

16. Locate the Variable Frequency Drive (VFD)
behind the front door of the unit. Refer to the
VFD operating controls shown in Figure 4-5.

15. Once the oxygen level is within the specified
range at 100%, lower the firing rate to 80%.

4-3

INITIAL START-UP

Figure 4-5

VFD Controls and Displays

17. Press the M (Menu) programming key on

the VFD.

18. Using the up (▲) arrow key, select VFD

parameter 65. The selected parameter will

appear in the left part of the display and the
voltage frequency (Hz) will appear in the
right part of the display. This is thee
frequency of the AC voltage sent to the
blower.

19. With the selected VFD parameter display

flashing, press the M key. Code will be

displayed, requesting the valid code to be

entered. Enter code 59 using the arrow

keys.

20. Press the M key again and observe the

frequency shown in the right part of the
display. The oxygen level at the 80% firing
rate should be as shown in the following
tabular listing. Also, ensure that the carbon
monoxide (CO) and nitrogen oxide (NOx)
readings do not exceed the values shown.

Combustion Oxygen Level at

80% Firing Rate

Oxygen %

± 0.2

6.0 % <100 ppm <30 ppm

21. If the oxygen level is not within the specified
range, adjust the level using the up (▲) and
down (▼) arrow keys on the VFD. Using the
up (▲) arrow key will increase oxygen level
and the down (▼) arrow key will decrease
the oxygen level.

Carbon

Monoxide

NOx

22. Once the oxygen level is within the specified
range at 80%, lower the firing rate to 60%

and select VFD parameter 64. The oxygen

level at the 60% firing rate should be as
shown below.

Combustion Oxygen Level at

60% Firing Rate

Oxygen %

± 0.2

6.3 % <50 ppm <30 ppm

23. Adjust the oxygen level as necessary to
obtain the required reading at the 60% firing
rate.

24. Next, set the firing rate to 45% and select

VFD parameter 63. The oxygen level at the

45% firing rate should be as shown below.

Carbon

Monoxide

NOx

Combustion Oxygen Level at

45% Firing Rate

Oxygen %

± 0.2

7.0 % <50 ppm <30 ppm

25. Adjust the oxygen level as necessary to
obtain the required reading at the 45% firing
rate.

26. Next, set the firing rate to 30% and select

VFD parameter 62. The oxygen level at the

30% firing rate should be as follows:

Carbon

Monoxide

NOx

Combustion Oxygen Level at

30% Firing Rate

Oxygen %

± 0.2

7.0 % <50 ppm <30 ppm

27. Adjust the oxygen level as necessary to
obtain the required reading at the 30% firing
rate.

28. Finally, reduce the firing rate to 16% and

select VFD parameter 61. The oxygen level

at the 16% firing rate should be as shown in
the following tabular listing:

Carbon

Monoxide

NOx

NOTE

At a 16% fire rate, if parameter 61 is

above 326, the VFD software will use 326
by default. 326 corresponds to a voltage
of 3.26 volts.

4-4

INITIAL START-UP

Combustion Oxygen Level at

16% Firing Rate

Oxygen %

± 0.2

8.0 % <50 ppm <30 ppm

29. Adjust the oxygen level as necessary to
obtain the required reading at the 16% firing
rate.

30. This completes the Natural Gas combustion
calibration procedures.

Carbon

Monoxide

NOx

4.4 UNIT REASSEMBLY

Once the combustion calibration adjustments
are properly set, the unit can be reassembled for
service operation.

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

2. Disconnect AC power from the unit.

3. Shut off the gas supply to the unit.

4. Remove the manometer and barbed fittings
and reinstall the NPT plug using a suitable
pipe thread compound.

5. Remove the combustion analyzer probe
from the vent hole. Replace the NPT plug in
the vent hole using a suitable pipe joint
compound.

6. Replace the unit’s side panels and front
door.

4.5 OVER- TEMPER ATURE LIMIT

SWITCHES

The unit contains both automatic and manual
reset over-temperature limit switches. These
switches are mounted on a plate next to the
VFD as shown in Figure 4-6. The switches can
be accessed by opening the front panel door of
the unit. The manual reset switch is not
adjustable and is permanently fixed at 210°F.
This switch will shut down and lock out the boiler
if the water temperature exceeds 210°F.
Following an over-temperature condition, it must
be manually reset by pressing the RESET
button before the boiler can be restarted. The
automatic reset over-temperature switch is
adjustable and allows the boiler to restart, once
the temperature drops below its temperature
setting. Set the automatic over-temperature
switch to the desired setting.

Figure 4-6

Over Temperature Limit Switch

Locations

4-5

MODE OF OPERATION

CHAPTER 5 MODE OF OPERATION

5.1 INTRODUCTION

The Benchmark 1.5 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 Benchmark 1.5 Boiler is shipped from the
factory tested and configured for the ordered
mode of operation. All temperature related
parameters are at their factory default values
which work well in most applications. However, it
may be necessary to change certain parameters
to customize the unit to the system environment.
A complete listing and descriptions of the
temperature related parameters are included in
Appendix A. Factory defaults are listed in
Appendix E. After reading this chapter,
parameters can be customized to suit the needs
of the specific application.

5.2 INDOOR/OUTDOOR RESET MODE

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

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 1.5 Boiler. Connections are
made at the terminals labeled OUTDOOR
SENSOR IN and SENSOR COMMON inside the
I/O Box. Use shielded 18 to 22 AWG wire for
connections. A wiring diagram is provided on
the cover of the I/O Box. Refer to Chapter 2,
paragraph 2.9.1 for additional wiring information.

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

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

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

MENU OPTION SETTING

Boiler Mode Direct Drive

Remote Signal BMS (PWM Input)

or
Network (RS485)

Refer to paragraph 3.3 for instructions on
changing menu options.

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 1.5 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 1.5 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.

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

5-4

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.

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

SAFETY DEVICE TESTING

CHAPTER 6 SAFETY DEVICE TESTING

6.1 TESTING OF SAFETY DEVICES

Periodic safety device testing is required to
ensure that the control system and safety
devices are operating properly. The Benchmark

1.5LN control system comprehensively monitors

all combustion-related safety devices before,
during and after the start sequence. The
following tests check to ensure that the system
is operating as designed.

Operating controls and safety devices should be
tested on a regular basis or following service or
replacement. All testing must conform to local
codes such as ASME CSD-1.

NOTE

MANUAL and AUTO modes of operation
are required to perform the following
tests. For a complete explanation of these
modes, see Chapter 3.

NOTE

It will be necessary to remove the front
door and side panels from the unit to
perform the following tests.

WARNING

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

4. Place the unit in Manual Mode and adjust
the firing rate between 25 and 30%.

5. While the unit is firing, slowly
external manual gas shut-off valve.

6. The unit should shut down and display a
LOW GAS PRESSURE fault message at
approximately 2.6” W.C. The FAUL
cator shou

ld also start flashing.

close the

T indi-

Figure 6-1

Low & High Gas Pressure Testing

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

8. The fault message should clear and the
FAULT indicator should go off. The unit
should restart.

6.2 LOW GAS PRESSURE FAULT TEST

Refer to Figure 6-1 and ensure that the leak
detection ball valve located at the high gas
pressure switch is closed.

1. Remove the 1/8 “ plug from the ball valve at
the low gas pressure switch shown in the
lower portion of Figure 6-1.

2. Install a 0 – 16 “ W.C. manometer or a W.C.
gauge where the 1/8" plug was removed.

3. Slowly open the ball valve near the low gas
pressure switch.

9. Upon test completion, close the ball valve
and remove the manometer. Replace the
1/8 “ plug removed in step 1.

6-1

SAFETY DEVICE TESTING

6.3 HIGH GAS PRESSURE TEST

To simulate a high gas pressure fault, refer to
Figure 6-1 and proceed as follows:

1. Remove the 1/8“ plug from the leak
detection ball valve shown in Figure 6-1.

2. Install a 0 – 16” W.C. manometer (or W.C.
gauge) where the 1/8” plug was removed.

3. Slowly open the leak detection ball valve

4. Start the unit in Manual mode at a firing rate
between 25 and 30%.

5. Slowly increase the gas pressure using the
adjustment screw on the SSOV.

6. The unit should shut down and display a
HIGH GAS PRESSURE fault message
when the gas pressure exceeds 4.7” W.C.
The FAULT indicator should also start
flashing.

7. Reduce the gas pressure back to 3.0” W.C.

8. Press the CLEAR button on the Control Box
to clear the fault.

shut the unit off immediately and refer fault
to qualified service personnel.

7. Close the drain and pressure relief valve
used in draining the unit.

8. Open the water shut-off valve in the return
piping to the unit.

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

10. After the shell is full, press the LOW
WATER LEVEL RESET button to reset the
low water cutoff.

11. Press the CLEAR button to reset the
FAULT LED and clear the displayed error
message.

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

6.5 WATER TEMPERATURE FAULT

TEST

A high water temperature fault is simulated by
adjusting the automatic over-temperature switch.
This switch is accessible from the front of the
unit as shown in Figure 6-2.

9. The fault message should clear and the
FAULT indicator should go off. The unit
should restart.

10. Upon test completion, close the ball valve
and remove the manometer. Replace the
1/8“ plug removed in step 1.

6.4 LOW WATER LEVEL FAULT TEST

To simulate a low water level fault:

1. Set the ON/OFF switch to the OFF position

2. Close the water shut-off valves in the supply
and return piping to the unit.

3. Slowly open the drain valve on the rear of
the unit. If necessary the unit’s relief valve
may be opened to aid in draining.

4. Continue draining the unit until a LOW
WATER LEVEL fault message is displayed
and the FAULT indicator flashes.

5. Place the unit in the Manual Mode and raise
the firing rate above 30%.

1. Start the unit in the normal operating mode.
Allow the unit to stabilize at its setpoint.

2. Lower the adjustable over-temperature
switch setting to match the displayed
OUTLET TEMPERATURE.

3. Once the adjustable over-temperature
switch setting is approximately at, or just
below, the actual outlet water temperature,
the unit should shut down. The FAULT
indicator should start flashing and a HIGH
WATER TEMP SWITCH OPEN fault
message should be displayed. It should not
be possible to restart the unit.

4. Reset the adjustable over-temperature
switch to its original setting.

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

6. Set the ON/OFF switch to the ON position.
The READY light should remain off and the
unit should not start. If the unit does start,

6-2

SEE

DETAIL “A”

FRONT VIEW

SAFETY DEVICE TESTING

6.6 INTERLOCK TESTS

The unit is equipped with two interlock circuits
called the Remote Interlock and Delayed
Interlock. Terminal connections for these circuits
are located in the I/O Box (Figure 2-9) and are
labeled REMOTE INTL’K IN and DELAYED
INTL’K IN. These circuits can shut down the
unit in the event that an interlock is opened.
These interlocks are shipped from the factory
jumpered (closed). However, each of these
interlocks may be utilized in the field as a remote
stop and start, an emergency cut-off, or to prove
that a device such as a pump, gas booster, or
louver is operational.

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 the Manual Mode and set
the firing rate between 25% and 30%.

RESET BUTTON FOR

MANUAL RESET

TEMPERATURE

LIMIT SWITCH

MOUNTING

PLATE

DETAIL “A”

ADJUSTABLE

TEMPERATURE

LIMIT SWITCH

VFD

Figure 6-2

Temperature Limit Switch Setting

6. Once the adjustable over-temperature
switch setting is approximately at, or just
below, the actual outlet water temperature,
the unit should shut down. The FAULT
indicator should start flashing and a HIGH
WATER TEMP SWITCH OPEN fault
message should be displayed. It should not
be possible to restart the unit.

7. Reset the adjustable over-temperature
switch to its original setting.

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

3. If there is a jumper across the REMOTE
INTL’K IN terminals, remove one side of the
jumper. If the interlock is being controlled by
an external device, either open the interlock
via the external device or disconnect one of
the wires leading to the external device.

4. The unit should shut down and display
INTERLOCK OPEN.

5. Once the interlock connection is
reconnected, the INTERLOCK OPEN
message should automatically clear and the
unit should restart.

6.6.2 DELAYED INTERLOCK

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

2. Start the unit in the Manual Mode at a firing
rate between 25% and 30%.

3. If there is a jumper across the DELAYED
INTL’K IN terminals, remove one side of the
jumper. If the interlock is connected to a
proving switch of an external device,
disconnect one of the wires leading to the
proving switch.

4. The unit should shut down and display a
DELAYED INTERLOCK OPEN fault
message. The FAULT LED should be
flashing.

5. Reconnect the wire or jumper removed in
step 3 to restore the interlock.

6-3

SAFETY DEVICE TESTING

6. Press the CLEAR button to reset the fault

7. The unit should start.

6.7 FLAME FAULT TESTS

Flame faults can occur during ignition or while
the unit is already running. To simulate each of
these fault conditions, proceed as follows:

1. Set the ON/OFF switch to the OFF position.

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

3. Close the manual gas shutoff valve located
between the Safety Shut-Off Valve (SSOV)
and the Air/Fuel Valve (see Figure 6-3).

4. Set the ON/OFF switch to the ON position to
start the unit.

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

DURING IGN.

6. Open the valve previously closed in step 3
and press the CLEAR button.

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

8. Once flame is proven, close the manual gas
valve located between the SSOV and the
Air/Fuel Valve.

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

10. Open the valve previously closed in step 8.

11. Press the CLEAR button. The unit should
restart and fire.

6.8 AIR FLOW FAULT TESTS

These tests check the operation of the Blower
Proof Switch and Blocked Inlet Switch shown in
Figure 6-3.

1. Start the unit in the Manual Mode at a firing
rate between 25% and 30%.

2. Once the unit has proved flame, remove the
memory stick from the Variable Frequency
Drive (VFD).

3. The Blower Proof Switch will open and the
blower should stop. The unit should shut
down and display AIRFLOW FAULT
DURING RUN.

4. Replace the memory stick in the VFD.

5. Press the CLEAR button. The unit should
restart.

6. Next, check the Blocked Inlet Switch by
closing the Iris Air Damper to position 8.

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

8. Return the Iris Air Damper to its previous
setting.

9. Press the CLEAR button. The unit should
restart.

6.9 SSOV PROOF OF CLOSURE SWITCH

The SSOV shown in Figure 6-1 contains the
proof of closure switch. The proof of closure
switch circuit is checked as follows:

Figure 6-3

Manual Gas Shut-Off Valve Location

6-4

1. Set the unit’s ON/OFF switch to the OFF
position.

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

3. Refer to Figure 6-1 and locate the SSOV.

4. Remove the cover from the SSOV by
loosening the screw shown in Figure 6-4. Lift
off the cover to access the terminal wiring
connections.

5. Disconnect wire #148 from the SSOV to
“open” the proof of closure switch circuit.

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

7. Replace wire #148 and press the CLEAR
button.

SAFETY DEVICE TESTING

8. Set the ON/OFF switch to ON to start the
unit.

9. Remove the wire again when the unit
reaches the purge cycle and PURGING is
displayed.

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

11. Replace the wire on the SSOV and press
the CLEAR button. The unit should restart.

Figure 6-4

SSOV Actuator Cover Location

6.11 IGNITION SWITCH OPEN DURING
IGNITION

The Ignition Switch (and the Purge Switch) is
located on the Air/Fuel Valve. To check the
switch, proceed as follows:

1. Set the unit’s ON/OFF switch to the OFF
position.

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

3. Remove the Air/Fuel Valve cover (Figure
6-5) by rotating the cover counterclockwise
to unlock and lift up to remove.

4. Remove one of the two wires (#169 or #170)
from the Ignition Switch (Figure 6-6).

5. Initiate a unit start sequence.

6. The unit should begin it’s start sequence
and then shut down and display IGN
SWITCH OPEN DURING IGNITION.

7. Replace the wire on the Ignition Switch and
press the CLEAR button. The unit should
restart.

6.10 PURGE SWITCH OPEN DURING
PURGE

The Purge Switch (and Ignition Switch) is
located on the Air/Fuel Valve. To check the
switch, proceed as follows:

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

2. Remove the Air/Fuel Valve cover by rotating
the cover counterclockwise to unlock it and
then lift up (see Figure 6-5).

3. Remove one of the two wires (#171 or #172)
from the Purge Switch (Figure 6-6).

4. Initiate a unit start sequence.

5. The unit should begin it’s start sequence,
then shut down and display PRG SWITCH
OPEN DURING PURGE.

6. Replace the wire on the Purge Switch and
depress the CLEAR button. The unit should
restart.

Figure 6-5

Air/Fuel Valve Cover Location

6-5

SAFETY DEVICE TESTING

9

6

1

1

7

2

Figure 6-6

Air/Fuel Valve Purge and Ignition Switch

Locations

6.12 SAFETY PRESSURE RELIEF

VALVE TEST

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

6-6

MAINTENANCE

CHAPTER 7 MAINTENANCE

7.1 MAINTENANCE SCHEDULE

The unit requires regular routine maintena nce 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 tim e periods spec ified in T able
7-1. See Appendix I for a complete CSD-1
inspection check list.

WARNING

TO AVOID PERSONAL, PRIOR TO
SERVICING:

• DISCONNECT THE AC SUPPLY BY
TURNING OFF THE SERVICE
SWITCH AND AC SUPPLY CIRCUIT
BREAKER.

• SHUT OFF THE GAS SUPPLY AT
THE MANUAL SHUT-OFF VALVE
PROVIDED WITH THE U NIT

• ALLOW THE UNIT T O COOL TO A
SAFE WATER TEMPERATURE TO

PREVENT BURNING OR SCALDING

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 buil d-up is pres ent, clean
the igniter using fine emery cloth. Repeate d
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 tig hten the
igniter. A slight snugging up is sufficient.
Reconnect the igniter cable.

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

be

7.2 SPARK IGNITER

The spark igniter (part no. GP-122435-S) is
located in the bod y of the burner (see Figure 7-

1). The igniter may be HOT. Care should be
exercised. It is easier to re move 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 control pa nel,
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.

Figure 7-1

Spark Igniter and Flame Detector

Location – Top View

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 (par t no. 66006)is loca ted 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:

Spark Igniter
(GP-122435-S)
Flame Detector

(66006)

Combustion

Calibration

Testing of

Safety Devices

Condensate
Drain Traps

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

*Check Check 1 hr.

See CSD-1

Chart in

20 mins.

Appendix I

*Inspect

Inspect &

Clean

1 hr.

Labor

Time

1. Set the ON/O FF s witch on the c ontrol 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 replac ed. 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.

7.4 COMBUSTION CALIBRATION

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

Figure 7-2

Burner Assembly Spark Igniter and

Flame Detector Location

7-2

7.5 SAFETY DEVICE TESTING

Systematic and thorough tests of the operating
and safety devices should be performed to
ensure that they are operating as designed.
Certain code requirements, such as ASME
CSD-1, require that t hese tests be perform ed on
a scheduled basis. Test schedules must
conform to local jurisdictions. The results of the
tests should be recorded in a log book. See
Chapter 6-Safety Device Testing Procedures.

7.6 BURNER ASSEMBLY

The burner assem bly (part no. 24012) is loc ated
at the top of the unit. T he burner assembl y may
be HOT. Allow the un it to c ool suf ficiently bef ore
removing the burner assembly.

It should be noted that the complete burner
assembly also includes the blower and air/fuel
valve in addition t o the Benchm ark 1.5 low NOx
burner. It can be removed as one complete
assembly.

The following parts will be necessary for
reassembly after inspection :

Part No. Description

81063 Burner Gaskets (Qty=2)
81047 Gas Injector Gasket (Qty=1)
81064 Blower Gasket

To inspect or replace the burner assembly:

MAINTENANCE

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

NOTE

The burner assembly is heavy, weighing
approximately 25 pounds.

9. Remove the burner assembly from burner
flange by pulling straight up.

10. Remove the grounding screw.

11. Remove and replace the burner gaskets.

12. Beginning with the burner assembly
removed in step 9, reinstall all the
components in the reverse order that they
were removed.

13. Make sure to align the S/I and F/R slots in
the burner with the heat exchanger top
head.

14. Check to ensure that the ground ing screw is
reinstalled.

AIR/FUEL

VALVE

FLAME

DETECTOR

3/8-16

NUTS (8)

BLOWER

1. Set the ON/OFF switch on the con trol pa nel,
to the OFF position. Disconnect AC power
from 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 cabl e from the igniter
contactor. Unscrew the igniter.

5. Remove the two (2) 10-32 screws sec uring
the gas injector to the burner. Sep arate the
gas injector and gasket from the burner.

6. Disconnect the gas train from the air/fuel
valve by removing the four 1/2” screws.

7. Disconnect the flex hose from the air/fuel
valve by loosening the hose clamp.

BURNER

PLATE

SPARK

IGNITER

STAGED

IGNITION

ASSEMBLY

PARTIAL TOP VIEW

Figure 7-3

Burner Disassembly Diagram

GAS

TRAIN

7-3

MAINTENANCE

7.7 CONDENSATE DRAIN TRAP

The Benchmark 1.5 Boiler contains a
condensate trap as shown in Figure 2-5. The
trap is located external to t he unit and attached
to the drain pipe fr om the exhaus t m anifold. T his
traps should be inspected and, if necessary,
cleaned to ensure proper operation. To inspect
and clean the trap, proceed as follows:

1. Disconnect the external condensate trap b y
loosening the hose c lam ps between the trap
and the exhaust manifold drain pipe.

2. Remove the connections on the inlet and
outlet sides of the condensate tr ap 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 drain pipin g for blockage. If
the trap cannot be thoroughly cleaned,
replace the trap.

7. After the above items have been inspected
and thoroughly cleaned, replace the orifice
gasket and float in the condensat e trap and
replace the trap cover.

8. Reassemble all piping and hose connections
to the condensate trap inlet and outlet.
Reconnect trap to exhaust manifold drain
pipe.

7.8 SHUTTING THE BOILER DOWN FOR
AN EXTENDED PERIOD OF TIME

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

1. Set ON/OFF sw itch on the f ront panel to the
OFF position to shut down the boiler’s
operating controls.

2. Dis c onnect AC po wer fr om the unit.

3. Close the water supply and return valv es to
isolate boiler.

4. Close external gas supply valve.

5. O pen relief valve to vent water pressure.

7.9 PLACING THE BOILER BACK IN

SERVICE AFTER A PROLONGED
SHUTDOWN

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

1. Review installation requirements inc luded in
Chapter 2.

2. Inspect all piping and connections to the
unit.

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

4. Perform initial startup per Chapter 4.

5. Perform safety device testing and the
scheduled 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 Benchm ark 1.5 Boiler. The
troubleshooting procedures contained her ein are
presented in tabular form on the f ollowing 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 Ac tion 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 m essages dis played in the
Control Box display.

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

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

4. Perform the c hecks 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

1. Blower stopped running due to thermal
or current overload

2. Blocked Blower inlet or inlet ductwork

3. Blocked Blower proof switch

4. Blocked blocked-air inlet switch

5. Defective Blower proof switch

6. Defective blocked-air inlet switch

7. Loose temperature transmitter to
VFD’s analog input wire connection

8. Loose temperature sensor to
temperature transmitter wire
connection.

9. Defective temperature transmitter

10. Defective temperature sensor

11. Loose wire connection between the 4­20 mA signal from I/O box to VFD
analog input

12. Defective I/O box

13. Wrong 4-20 mA output selection on
the control box

14. Defective air-fuel valve potentiometer

15. Defective or missing VFD’s logic stick

16. Defective program on the logic stick or
Defective VFD.

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 Blower proof switch and inspect for signs of
blockage, clean or replace as necessary.

4. Remove the blocked-air inlet switch and inspect for signs of
blockage, clean or replace as necessary.

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

6. Measure the blocked-air inlet switch for continuity with the
combustion blower running. If there is an erratic resistance
reading or the resistance reading is greater than zero ohms,
replace the switch.

7. Check the actual inlet air temperature and measure voltage at
temperature transmitter and VFD analog input. Verify that the
voltage conforms to Table 8-3 for the inlet air temperature.

8. Refer to CORRECTIVE ACTION 7 and verify that the resistance
conforms to Table 8-3.

9. See CORRECTIVE ACTION 7.

10. See CORRECTIVE ACTION 8.

11. Measure amperage at the I/O box output and VFD analog input,
4mA equates to 0% fire rate and 20 mA equates to 100% fire
rate

12. See CORRECTIVE ACTION 11.

13. Check C-More configuration menu, mA OUT – Fire Rate should
be selected

14. Check air fuel valve position at 0%, 50% and 100% fire rates,

the position on the c-more barograph should match the valve

15. Confirm that the logic stick is securely mounted on the VFD

16. Check the following VFD parameters: Max Hz = 67, Min Hz = 0,

parameter 59 & 60 should be set to 2.

8

-2

TROUBLESHOOTING

TABLE 8-1. BOILER TROUBLESHOOTING – Continued

FAULT INDICATION PROBABLE CAUSES CORRECTIVE ACTION

AIRFLOW FAULT

DURING PURGE

AIRFLOW FAULT

DURING RUN

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.

PROBABLE CAUSES from 3 to 16

6.
for AIRFLOW FAULT DURING
IGNITION applies for this fault

1. Blower stopped running due to thermal
or current overload

2. Blocked Blower inlet or inlet ductwork

3. Blocked airflow switch

4. Defective airflow switch

5. Combustion oscillations

PROBABLE CAUSES from 3 to 16

6.
for AIRFLOW FAULT DURING
IGNITION applies for this fault

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 eac h side of the
switch to ground. If 24VAC is not present refer to qualified
service personnel.

6. See

1. Check combustion blower for signs of excessive heat or high

2. Inspect the inlet to the combustion blower including any ductwork

3. Remove the airflow switch and inspect for signs of blockage,

4. Measure the airflow switch for continuity with the combustion

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

6.

CORRECTIVE ACTION from 3 to 16 for AIRFLOW

FAULT DURING IGNITION

current draw that may trip thermal or current overload devices.

leading up to the combustion blower for signs of blockage.

clean or replace as necessary.

blower running. If there is an erratic resistance reading or the
resistance reading is greater than zero ohms, replace the switch.

combustion calibration.

PROBABLE CAUSES from 3 to 16 for AIRFLOW FAULT

DURING IGNITION applies for this fault

8-3

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.

8-4

TROUBLESHOOTING

TABLE 8-1. BOILER TROUBLESHOOTING – Continued

FAULT INDICATION PROBABLE CAUSES CORRECTIVE ACTION

(continued) 7. Carbon or other debris on Burner.

8. Staged ignition ball valve closed.

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 SSOV Supply Regulator.

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

8. Open ball valve downstream of SSOV (see Figure 8-1).

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 f ault 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 1.5” W.C. (see para. 4.3, step 10), the SSOV Supply
Regulator may be defective.

o

F, check

o

F

8-5

TROUBLESHOOTING

TABLE 8-1. BOILER TROUBLESHOOTING – Continued

FAULT INDICATION PROBABLE CAUSES CORRECTIVE ACTION

continued 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. Ensure that the gas pressure snubber is installed
at the high gas pressure switch.

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

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

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

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

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

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

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

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

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.

8-6

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 m ay 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).

8-7

TROUBLESHOOTING

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

TABLE 8-1. BOILER TROUBLESHOOTING – Continued

3. Check that proving switch for any device hooked to the interlock

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

2. Defective or shorted switch.

3. Switch wired incorrectly.

4. Defective Power Supply Board or
fuse

5. Defective IGST Board

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 supply gas regulator with
the unit firing. Ensure it is between 4” W.C. and 2 psig (see para.

2.7.1).

2. Measure gas pressure at the low gas pressure switch. If it is
greater than 2.6” W.C., measure continuity across the switch and
replace if necessary.

1. Check system for sufficient water level.

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

3. Check continuity of probe end to the shell, change probe if there
is no 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 m ay 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
purge switch for continuity between the N.O. and COM terminals.
If the switch shows c ontinuity 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 ver ify it is blinking ON & OFF
every second. If not, replace IGST Board.

8-8

TROUBLESHOOTING

TABLE 8-1. BOILER TROUBLESHOOTING – Continued

FAULT INDICATION PROBABLE CAUSES CORRECTIVE ACTION

PRG SWTCH OPEN

DURING PURGE

OUTDOOR TEMP

SENSOR FAULT

REMOTE SETPT

SIGNAL FAULT

RESIDUAL

FLAME

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.

3. 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.

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

1. SSOV not fully closed. 1. Check open/close indicator window of Safety Shut-Off Valve

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 f rom 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 ver ify 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.

3. 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.

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.

(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.

8-9

TROUBLESHOOTING

TABLE 8-1. BOILER TROUBLESHOOTING – Continued

FAULT INDICATION PROBABLE CAUSES CORRECTIVE ACTION

(continued) 2. Defective Flame Detector

SSOV FAULT

DURING PURGE

SSOV FAULT
DURING RUN
SSOV RELAY

FAILURE

SSOV

SWITCH OPEN

STEPPER MOTOR

FAILURE

3. 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.

4. Defective Air/Fuel Valve stepper
motor.

5. Defective Power Supply Board or
fuse

6. Defective IGST Board

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.

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.

8-10

TROUBLESHOOTING

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

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

1. IGST and Power Supply Boards in
Control Box are outdated.

1. Open the 1/4” Ball Valve downstream of the SSOV (Fig. 8-1).

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

3. Close the 2” and the 1/4” Ball Valve downstream of the SSOV
(Fig. 8-1). Start the unit and listen for a “clicking” sound that the
Staged Ignition Solenoid makes during Ignition Trial. If “clicking”
sound is not heard after 2 or 3 attempts, replace the Staged
Ignition Solenoid.

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

2. Check to ensure that the Damping Orifice is installed in the
downstream SSOV/Regulator Actuator (Figure 8-3).

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

8-11

TROUBLESHOOTING

Figure 8-2

Staged Ignition Solenoid Location

8-12

Figure 8-1

High Pressure Gas Switch & Snubber Locations

Figure 8-3

Damping Orifice Location

TROUBLESHOOTING

Table 8-3

BMK 1.5 LN (3.3 KΩ) Temperature Sensor and Temperature

Transmitter Outputs

TEMP

ºC

-40 -40 111177 0.289 28 82.4 2915 6.16

-30 -22 58443 0.523 29 84.2 2787 6.31

-20 -4 32814 0.904 30 86 2659 6.470

-10 14 18200 1.560 31 87.8 2549 6.610

-5 23 13972 1.972 32 89.6 2443 6.760
0 32 10775 2.459 33 91.4 2343 6.900
1 33.8 10240 2.564 34 93.2 2247 7.040
2 35.6 9735 2.680 35 95 2156 7.180
3 37.4 9256 2.791 36 96.8 2068 7.320
4 39.2 8806 2.906 37 98.6 1984 7.460
5 41 8380 3.022 38 100.4 1905 7.600
6 42.8 7977 3.143 39 102.2 1830 7.730
7 44.6 7595 3.267 40 104 1758 7.860
8 46.4 7234 3.387 41 105.8 1688 8.000
9 48.2 6891 3.514 42 107.6 1622 8.130

10 50 6566 3.643 43 109.4 1559 8.250
11 51.8 6260 3.772 44 111.2 1499 8.490
12 53.6 5969 3.900 45 113 1441 8.510
13 55.4 5692 4.040 46 114.8 1386 8.630
14 57.2 5432 4.170 47 116.6 1334 8.750
15 59 5184 4.310 48 118.4 1283 8.960
16 60.8 4972 4.440 49 120.2 1234 8.980
17 62.6 4759 4.570 50 122 1189 9.100
18 64.4 4547 4.710 51 123.8 1145 9.210
19 66.2 4334 4.860 52 125.6 1102 9.320
20 68 4122 5.020 53 127.4 1061 9.430
21 69.8 3958 5.150 54 129.2 1023 9.530
22 71.6 3793 5.290 55 131 986 9.640
23 73.4 3629 5.520 56 132.8 950 9.740
24 75.2 3464 5.580 57 134.6 916 9.840
25 77 3300 5.740 58 136.4 883 9.920
26 78.8 3172 5.870 59 138.2 852 10.030
27 80.6 3044 6.010 60 140 821 10.120

TEMP

ºF

UA33

Resistance

Ohm

Volts

outputs

UA33

TEMP

ºC

TEMP

ºF

UA33

Resistance

Ohm

Volts

outputs

UA33

8-13

APPENDIX A - BOILER MENU ITEM DESCRIPTIONS

MENU LEVEL & OPTION DESCRIPTION

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

control is set 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

APPENDIX A

Outdoor Temp Displayed only if outdoor sensor is installed and

enabled.

Fire Rate In Desired input fire rate. This would 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

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

A-1

APPENDIX A

APPENDIX A - BOILER MENU ITEM DESCRIPTIONS - Continued

MENU LEVEL & OPTION DESCRIPTION

SETUP MENU

Password Allows password to be entered.

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

Language Permits selection of English, Spanish or French for

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

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

°F.
Comm Address For RS-485 communications (0 to 127). Default

address is 0. RS-232 should have its own

(programmable) password.
Baud Rate Allows communications Baud Rate to be set (2400

to 19.2K). Default is 9600.
Software Version Identifies the current software version of the control

box (Ver 0.0 to Ver 9.9).
CONFIGURATION MENU
Internal Setpoint Allo ws inter nal setpoint to be set . Default is 130°F.
Unit Type Allows selection of Boiler or Water Heater.
Unit Size Sets unit size from 0.5 to 3.0 MBTUs. Default is 1.0

MBTU.
Boiler Mode It allows selection of: Constant Setpoint, Remote

Setpoint, Direct Drive, Combination, or Outdoor

Reset Mode. Default is Constant Setpoint Mode.
Remote Signal Used to set the type of external signal which will be

used when operating in the Remote Setpoint, Direct

Drive or Combination Mode. The factory default is

4-20 mA/1-5V.
Bldg Ref Temp

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

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, this menu item allows

the system start temperature to be set from 30 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 240°F). Default is 200°F.
Temp Hi Limit This is the maximum allowable outlet temperature

(40 to 240°F). Any temperature above this setting

will turn off the unit. The temperature must then drop

5° below this setting to allow the unit to run. Default

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 Specif ies th e 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 Must be set to Fire Rate Out for Benchmark 1.5LN.
Lo Fire Timer Specifies how long (2 to 600 sec.) to remain in the

low fire position after ignition, before going to the

desired output. Default is 2 sec.

A-3

APPENDIX A

APPENDIX A - BOILER MENU ITEM DESCRIPTIONS - Continued

MENU LEVEL & OPTION DESCRIPTION

TUNING MENU

Prop Band G ener ates a fire rate based on the error that exists

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

error, to add or subtract from the output each minute

to move towards the setpoint. Gain is adjustable

from 0.00 to 1.00 (Default is 0.10).
Derivative Time This value (0.0 to 20.0 min.) responds to the rate of

change of the setpoint error. This is the time that

this action advances the output.
Reset Defaults? Allows Tuning Menu options to be reset to their

Factory Default values.

A-4

APPENDIX B - STARTUP, STATUS AND FAULT MESSAGES

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

TABLE B-1. 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

TABLE B-2. 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,
or air inlet is blocked.
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

TABLE B-2. 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)

TEMPERATURE SENSOR
AERCO PART NO. 123449

R = RESISTANCE (OHMS) T = TEMPERATURE (°F)

R=.00161T^2+1.961T+854.841

APPENDIX C

TEMP (°F) RES. (OHMS)

-40 779.0

-30 797.5

-20 816.3

-10 835.4
0 854.8

10 874.6
20 894.7
30 915.1
40 935.9
50 956.9
60 978.3
70 1000.0
80 1022.0

90 1044.4
100 1067.0
110 1090.0
120 1113.3
130 1137.0
140 1160.9
150 1185.2
160 1209.5
170 1234.7
180 1260.0
190 1285.6
200 1311.4
210 1337.7
220 1364.2
230 1391.0
240 1418.2
250 1445.7

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

APPENDIX D. - INDOOR/OUTDOOR RESET RATIO CHARTS

Table D-1. 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

Table D-2. 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

Table D-3. 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

Table D-4. 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

Table D-5. 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

Table D-6. 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

Table D-7. 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 1.5 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 Fire Rate Out

CAUTION: DO NOT Change

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

A

REV

REAR

INTERNATIONAL, INC.

NORTHVALE, NJ 07647

GAS FIRED BOILER

AERCO

BENCHMARK 1.5 LOW NOx

SD -A -730

*NOT TO SCALE*

ANCHOR BOLT LOCATION

DRWN BY: SJD

DATE: 10/12/07

F-2

FRONT

1) ALL HOLES ARE FLUSH WITH THE BOTTOM SURFACE OF

THE FRAME

2) ALL DIMENSIONS SHOWN ARE IN INCHES (CENTIMETERS)

NOTES:

APPENDIX F

F-3

APPENDIX F

A

REV

24"

42"*

24"

28"

24"

FRONT

REAR

1) REAR CLEARANCE MAY BE REDUCED TO 30" DEPENDENT UPON

NOTES:

AND LOCAL CODE REQUIREMENTS

PIPING AND VENTING COMPONENT SELECTION, ARRANGEMENT,

INTERNATIONAL, INC.

NORTHVALE, NJ 07647

BENCHMARK 1.5 LOW NOx

AERCO

GAS FIRED BOILER

INSTALLATION CLEARANCES

DRWN BY: SJD

SD - A - 731

*NOT TO SCALE*

DATE: 10/12/07

SIDE VIEW TOP VIEW

18"

44.5"

101"

79"

LEFT & RIGHT SIDES: 24"

FRONT: 24"

REAR: 42" *

CEILING HIEGHT: 101"

F-4

INSTALLATION CLEARANCES:

1) THIS APPLIANCE MAY BE INSTALLED ON COMBUSTIBLE FLOORING

2) MINIMUM CLEARANCES TO ADJACENT CONSTRUCTION ARE AS

FOLLOWS:

APPENDIX F

B

REV

TO AIR-FUEL

VALVE ASSY

AP - A - 829

INTERNATIONAL, INC.

1.5" NPT P/N: 92006-7

FULL PORT BALL VALVE

TEST COCK

NORTHVALE, NJ 07647

FM GAS TRAIN

SAFETY SHUT-OFF VALVE

ACTUATOR W/REGULATOR

BENCHMARK 1.5 LOW NOx

AERCO

P/N 64048

VALVE P/N: 124150

1.5" SAFETY SHUT-OFF

1.5" - SCH.40 PIPE

DRWN BY: SJD

*NOT TO SCALE*

DATE: 12/18/07

HIGH GAS PRESS

SWITCH P/N: 61002-12

1/8" NPT PLUG

(INSTALL MANOMETER HERE)

LOW GAS PRESS

SWITCH P/N: 61002-1

ENTIRE BMK1.5 LN FM

GAS TRAIN P/N: 22039-1

F-5

APPENDIX F

1.5" FULL

PORT BALL

VALVE

P/N: 92006-7

B

REV

TEST

COCK

LOW GAS PRESSURE

HERE)

SWITCH P/N: 61002-1

INTERNATIONAL, INC.

NORTHVALE, NJ 07647

1/8" NPT PLUG

(INSTALL MANOMETER

AP -A -830

IRI GAS TRAIN

*NOT TO SCALE*

BENCHMARK 1.5 LOW NOx

VENT TO ATMOSPHERE

PER ANSI Z223.1 (NFPA54)

P/N: 124178

HIGH GAS PRESSURE

SWITCH P/N: 61002-12

CONNECTING FLANGE

1.5" DOUBLE BODY SSOV

1.5" SCH.40 PIPE

3/4" SCH.40 PIPE

DRWN BY: SJD

DATE: 10/11/07

F-6

SAFETY SHUT-OFF VALVE ACTUATOR

W/ REGULATOR P/N: 64048

1.5" DOUBLE BODY

SSOV P/N: 124137

ENTIRE BMK 1.5 LN IRI GAS

TRAIN P/N: 22039-2

NORMALLY OPEN

VENT VALVE

P/N: 122774

SAFETY SHUT OFF VALVE ACTUATOR WITHOUT

PROOF OF CLOSURE SWITCH P/N: 69038

APPENDIX F

B

REV

PL -A -156

INTERNATIONAL INC.

23

159 PARIS AVE, NORTHVALE, N.J.

BMK1.5 LOW NOX

*DRAWING NOT TO SCALE*

BLOWER, BURNER, & AIR /FUEL

VALVE ACCESSORIES

DRWN. BY: SJD DATE: 102907

9

18

13 21

10

16

19

15

1 1 42048 PLATE, BURNER

2 1 81063 GASKET, BURNER

4 1 46015 BURNER, BMK 1.5 LOW NOX

3 1 81063 GASKET, BURNER

5 1 81064 GASKET, BLOWER

6 1 24111 BLOWER, AMETEK 8.9"

7 1 59072 OBSERVATION PORT 1/2 NPT

8 1 122435-s SPARK IGNITOR, BMK BOILER

9 1 24113 STAGED IGNITION ASSY, BMK 1.5 LOW NOX

10 1 66006 FLAME ROD, BMK 2.0 LOW NOX

11 1 42049 ADAPTOR, BLOWER-A/F VALVE

24 1 24010-2 A/F VALVE ASSY 1.5 MM

13 1 81057 GASKET, BLOWER

14 1 88004 O-RING #2-244 BUNA-N

15 1 81047 GASKET, GAS INJECTOR

16 1 81048 GASKET, FLAME ROD LOW NOX

17 2 54016 SCREW, MACH #10-32 X .50 LG

18 1 122377 SCREW, MACH #10-32 X 3/8 LG

19 1 54015 SCREW, MACH #8-32 X 3/8 LG

20 6 54027 SCREW, SOC HD CAP M8x1.25 X 16 MM LG

21 6 122544 BOLT, HEX HD 1/4-20 X .75 LG

22 4 54028 SCREW, HEX HD SERRATED 5/16-18

ITEM NO. QTY PART NUMBER DESCRIPTION

23 1 88003 O-RING #2-339

17

11 2420

17

14

6

2

7

5

22

1

4

3

8

APPLY HI TEMP

PRIOR TO ASSY

CONDUCTIVE ANTI -SIEZE

F-7

EXHAUST MANIFOLD

APPENDIX F

F-8

DESCRIPTIONQTYPART NO.ITEM

1
2

EXHAUST MANIFOLD143045

EXHAUST MANIFOLD SEAL184020

3

GAS TRAIN ASSEMBLY

ITEM PART NO. QTY DESCRIPTION

STD FM GAS TRAIN ASSEMBLY

IRI GAS TRAIN ASSEMBLY

1

DUAL FUEL FM GAS TRAIN

DUAL FUEL IRI GAS TRAIN

(3)

4

22039-1
22039-2
22039-3
22039-4

BURNER & AIR/FUEL VALVE

DESCRIPTIONQTYPART NO.ITEM

BLOWER, BURNER, & A/F

240125

1

VALVE ASSEMBLY

(SEE PL-A-156)

A/F VALVE ASSEMBLY124010-26

HOSES,GASKETS, & INSULATION

ITEM PART NO. QTY DESCRIPTION

22 88003

1

O-RING #2-339 (A/F VALVE)
23 59041 1 HOSE ASSEMBLY, 4"
24 88004 1

O-RING #2-244 BUNA - N (BLOWER)

25 62005 1 CORD GRIP
26

1241137

2810638

IGNITION ASSY.

(PART OF BURNER ASSY.)

BURNER GASKET

(PART OF BURNER ASS'Y)

9

HEAT EXCHANGER

DESCRIPTIONQTYPART NO.ITEM

BMK1.5LN STAGED

18003610
18003511
12801712

HEAT EXCHANGER

UPPER INSULATION

HEAT EXCHANGER

LOWER INSULATION

HEAT EXCHANGER

13

BLOWER

ITEM PART NO. QTY DESCRIPTION

14 24111 1 BLOWER ASSEMBLY
15 123815 1 IRIS AIR DAMPER
16 81064

1BLOWER GASKET
17 39054 1 ADAPTOR, AIR INLET
18 39059 1
19 97004-18

CAP, SCREENED, AIR INLET 6"

1 HOSE, FLEXIBLE 6" I.D. - A/F
20 123583 3 CLAMP HOSE SAE #96
21 81057 1 BLOWER GASKET (A/F)

AERCO

INTERNATIONAL, INC.

NORTHVALE, NJ 07647

BENCHMARK 1.5 LOW NOx

BOILER PARTS LIST

DRAWN BY:
DATE: 12/08/08

*NOT TO SCALE*

SJD

PL - A - 157

(SHEET 1 OF 7)

B

CONTROLS

APPENDIX F

F-9

ITEM PART NO. QTY DESCRIPTION

27 123966 1 OVER TEMP SWITCH AUTO
28 123552 1 OVER TEMP SWITCH MANUAL
29 61002-5 1
30 61014 1

BLOCKED INLET SWITCH

BLOWER PROOF SWITCH

31 161560 1 I /O WIRING BOX
32 181197 1 C-MORE CONTROL BOX

GP-122464

33

1 IGNITION TRANSFORMER

34 33048 1 VFD MOUNTING BRACKET
35 64034 1 VFD (120 V)

(1)

36 61012 1 AIR TEMP SENSOR
37 64018 1 TEMPERATURE TRANSMITTER

(1)
(1)

(1)

GP-122569

38

1 IGNITION CABLE ASSY.

39 63016 1 BMK1.5LN SHELL HARNESS
40 63038 1

24065-4

41

24065-5

1

BLOWER HARNESS

PROGRAMMED LOGICSTICK

(NON DUAL FUEL)
DUAL FUEL, NAT. GAS - STICK
DUAL FUEL, PROPANE - STICK24065-6

42 64031 1 120V POWER WIRING BOX

(1)

(5)

44

122843 1 LOW WATER CUT-OFF

BMK1.5LN GAS TRAIN WIRING

116145043

HARNESS

45 123449 1 SHELL TEMP. SENSOR
46 161521 1

(6)

47 61002-1 1

61002-12

(7)(5)

48

61002-12

61002-3

THERMOWELL, DUAL AQUASTAT BULB

LOW GAS PRESSURE SWITCH

HIGH GAS PRESSURE SWITCH

(NON DUAL FUEL)

1

DUAL FUEL HGPS - NAT. GAS
DUAL FUEL HGPS - PROPANE

49

OTHER DUAL FUEL COMPONENTS

ITEM PART NO. QTY

(4)(1)
(4)(1)
(5)(4)(1)

58

63032

(4)

59

(4)

(1)

(4)
(4)(1)

62

1

13303660

FUEL SELECTOR SWITCH LABEL

17203061

DUAL FUEL WIRING HARNESS163034

DESCRIPTION
"PROPANE" LABEL17203156
"NAT. GAS" LABEL17203257

DOUBLE GAS TRAIN WIRING

HARNESS

FUEL SELECTOR SWITCH165024

FUEL SELECTOR SWITCH

MOUNTINGBRACKET

63

SHEET METAL / PANEL ASSEMBLY

ITEM PART NO QTY DESCRIPTION

64 37017 1 LEFT REAR PANEL
65 37018 1 RIGHT REAR PANEL
66 49064 2 TOP RAIL
67 201233 1 MOUNTING PANEL

68 201113 1

FRONT PANEL

ENCLOSURE

69 201120 1 FRONT DOOR ASSY.

GP-122620

70
71

4 HANDLE

TOP PANEL237019

SIDE PANEL43700272

BMK1.5LN LOGO17400373

OTHER PARTS

ITEM PART NO QTY DESCRIPTION

74 99017 1
75 59050 1 LOGICSTICK LANYARD

GAS PRESSURE SNUBBER -

PART OF GAS TRAIN

PART NO.ITEM

(2)

(1)

SEE SD-A-751

51

(1)(6)

52

(1)
(5)
(1)

OTHER ACCESORIES / PARTS

DESCRIPTIONQTY

PRESS./TEMP. GAUGE169087- 50

1 PRESSURE RELIEF VALVE

EXT. MANUAL SHUT-OFF VALVE

192006-7

1" DRAIN HOSE, 60" LG19103053
1-1/2" NPT BALL VALVE192006-754

12406055

COND. TRAP ASSEMBLY

NOTES:

NOT SHOWN IN DRAWING

(1)
(2)

-5 (30 AND 50 PSI RELIEF VALVE SETTING)

-6 (60,75,100 & 125 PSI RELIEF VALVE SETTING)

-7 (150 PSI RELIEF VALVE SETTING)

(3)

FOR PICTORAL PURPOSES ONLY,
FM GAS TRAIN (NON DUAL FUEL) IS SHOWN

(4)

ONLY NEEDED ON DUAL FUEL

(5)

PART OF GAS TRAIN ASSY.

(6)

TWO (2) REQUIRED FOR DUAL FUEL BMK1.5 LN

(7)

SEE DRAWING AP-A-833 FOR DUAL FUEL DETAILS

AERCO

INTERNATIONAL, INC.

NORTHVALE, NJ 07647

BENCHMARK 1.5 LOW NOx

BOILER PARTS LIST

DRAWN BY:
DATE 12/08/08

*NOT TO SCALE*

SJD

PL - A - 157

(SHEET 2 OF 7)

B

23

APPENDIX F

F-10

7

45

51

35

10

11

A

12

5 20

18

17
15

19

4

DETAIL A

1

AERCO

INTERNATIONAL, INC.

NORTHVALE, NJ 07647

BENCHMARK 1.5 LOW NOx

2

DRWN BY: SJD
DATE: 12/08/08

BOILER PARTS LIST

PL - A - 157

*NOT TO SCALE*

(SHEET 3 OF 7)

REV

B

16

APPENDIX F

F-11

25

47

14

46

44

B

24
21

22

30

6

29
54

8

48

DETAIL B

AERCO

INTERNATIONAL, INC.

NORTHVALE, NJ 07647

BENCHMARK 1.5 LOW NOx

BOILER PARTS LIST

12/08/08

DATE:

*NOT TO SCALE*

SJDDRWN BY:

PL - A - 157

(SHEET 4 OF 7)

REV

B

42

APPENDIX F

F-12

32

284127

35

C

31

37

48

74

75

DETAIL C

34

FUEL SELECTOR SWITCH

(DUAL FUEL ONLY)

61

59

47

AERCO

INTERNATIONAL, INC.

NORTHVALE, NJ 07647

BENCHMARK 1.5 LOW NOx

BOILER PARTS LIST

DRWN BY:
DATE:

SJD

12/08/08

*NOT TO SCALE*

PL - A - 157

(SHEET 5 OF 7)

REV

B

67

APPENDIX F

F-13

66

68

64 65

AERCO

INTERNATIONAL, INC.

NORTHVALE, NJ 07647

BENCHMARK 1.5 LOW NOx

BOILER PARTS LIST

DRWN BY:

SJD

12/08/08DATE:

*NOT TO SCALE*

PL - A - 157

(SHEET 6 OF 7)

REV

B

73

APPENDIX F

F-14

69

71

72

70

AERCO

INTERNATIONAL, INC.

NORTHVALE, NJ 07647

BENCHMARK 1.5 LOW NOx

BOILER PARTS LIST

DRWN BY:

SJD

12/08/08DATE:

*NOT TO SCALE*

PL - A - 157

(SHEET 7 OF 7)

REV

B

APPENDIX G

G-1

APPENDIX G

LEGEND

UNION

BALANCING VALVE

ISOLATION VALVE

Y STRAINER

PRESSURE &

P&T

TEMPERATURE GAUGE

C

REV

GAS SUPPLY

* 1-1/2" MANUAL

SHUTOFF

VALVE

AT MAXIMUM BTU/HR INPUT,

MAINTAIN MINIMUM GAS

PRESSURE AT 4.0" W.C.

(FM GAS TRAIN); 4.2" W.C.(IRI).

MAX. GAS PRESSURE=2.0 PSIG.

(SEE NOTE 6)

P&T

DRIP TRAP

SYSTEM

RETURN

HEATING

INTERNATIONAL, INC.

NORTHVALE, NJ 07647

BENCHMARK 1.5 MIL. BTU LOW NOx

AERCO

SD-A-735

102307

GAS FIRED BOILER

DATE

DATE

MULTIPLE UNIT INSTALLATION

JK

NTS

APPD.

DWN.BY

SCALE

RELIEF

VALVE (TYP.)

P&T

AUTOMATIC

AIR VENT

AIR

SEPARATOR

DRAIN TRAP

* CONDENSATE

SYSTEM

PUMP

CHECK

VALVE

(TYP.)

1-1/2" NPT

DRAIN CONN.

EXPANSION TANK

DIAPHRAGM TYPE

GAS SUPPLY

DRIP TRAP

G-2

LINE

SIZE

BACKFLOW PREVENTER

BYPASS

SUPPLY

SYSTEM

HEATING

WATER

SUPPLY

PRESSURE

REDUCING

FILL VALVE

(SEE N OTE 7)

Diagram 1

MAINTAIN A REGULATED

4.0" W.C. (FM), 4.2 W.C. (IRI)

GAS PRESSURE AT MAX

BTU/HR INPUT

* 1-1/2" 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.

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

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

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 MASSAC HUSETTS, REGARDLESS OF SUPPLY PRESSURE.

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

APPENDIX G

G-3

APPENDIX G

G-4