Benchmark 3.0LN Series Gas Fired Low NOx Boiler System

Benchmark 3.0LN Series Gas Fired Low NOx Boiler System
Instruction
No.
GF-116
AERCO INTERNATIONAL, Inc., Northvale, New Jersey, 07647 USA
Installation, Operation
& Maintenance Instructions
Benchmark 3.0LN
Series
Gas Fired
Low NOx
Boiler System
Condensing, Modulating
Forced Draft, Hot Water Boiler
3,000,000 BTU/H Input
Applicable for Serial Numbers G-06-1069 and above
Printed in U.S.A.
REVISED JANUARY, 2009
Telephone Support
Direct to AERCO Technical Support
(8 to 5 pm EST, Monday through Friday):
1-800-526-0288
The information contained in this
installation, operation and maintenance manual is subject to
change without notice from
AERCO International, Inc.
AERCO International, Inc.
159 Paris Avenue
Northvale, NJ 07647-0128
www.aerco,com
© AERCO International, Inc., 2009
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-116 - AERCO BENCHMARK 3.0LN GAS FIRED LOW NOx BOILER
Operating & Maintenance Instructions
FOREWORD
A
Chapter 1 – SAFETY PRECAUTIONS
Para.
1-1
1-2
Subject
Warnings & Cautions
Emergency Shutdown
Page
1-1
1-2
1-1
Para.
1-3
Subject
Prolonged Shutdown
Chapter 2 – INSTALLATION
Para.
2.1
2.2
2.3
2.4
2.5
2.6
2.7
2.8
Subject
Introduction
Receiving the Unit
Unpacking
Site Preparation
Supply and Return Piping
Condensate Drains
Gas Supply Piping
AC Electrical Power Wiring
2-1
Page
2-1
2-1
2-1
2-1
2-3
2-3
2-5
2-6
Para.
2.9
2.10
2.11
2.12
2.13
Subject
Modes of Operation and Field
Control Wiring
I/O Box Connections
Auxiliary Relay Contacts
Flue Gas Vent Installation
Combustion Air
Chapter 3 – CONTROL PANEL COMPONENTS AND
OPERATING PROCEDURES
Para.
3.1
3.2
3.3
3.4
3.5
Subject
Introduction
Control Panel Description
Control Panel Menus
Operating Menu
Setup Menu
Page
3-1
3-1
3-4
3-5
3-5
Para.
3.6
3.7
3.8
3.9
Subject
Configuration Menu
Tuning Menu
Start Sequence
Start/Stop Levels
Chapter 4 – INITIAL START-UP
Para.
4.1
4.2
4.3
Subject
Initial Startup Requirements
Tools and Instruments for
Combustion Calibration
Natural Gas Combustion
Calibration
Page
1-2
Page
2-7
2-8
2-10
2-10
2-10
3-1
Page
3-6
3-7
3-7
3-9
4-1
Page
4-1
4-1
Para.
4.4
4.5
Subject
Unit Reassembly
Over-Temperature Limit Switch
Page
4-5
4-5
4-2
i
CONTENTS
Chapter 5 – MODE OF OPERATION
Para.
5.1
5.2
5.3
5.4
5.5
Subject
Introduction
Indoor/Outdoor Reset Mode
Constant Setpoint Mode
Remote Setpoint Mode
Direct Drive Modes
Page
5-1
5-1
5-2
5-2
5-3
5-1
Para.
5.6
5.7
Subject
Boiler Management System
(BMS)
Combination Control System
(CCS)
Page
5-4
5-5
Chapter 6 – SAFETY DEVICE TESTING PROCEDURES
6-1
Para.
6.1
6.2
6.3
6.4
6.5
6.6
6.7
Page
6-4
6-4
6-5
Subject
Testing of Safety Devices
Low Gas Pressure Fault Test
High Gas Pressure Test
Low Water Level Fault Test
Water Temperature Fault Test
Interlock Tests
Flame Fault Test
Page
6-1
6-1
6-2
6-2
6-2
6-3
6-3
Para.
6.8
6.9
6.10
6.11
6.12
Subject
Air Flow Fault Test
SSOV Proof of Closure Switch
Purge Switch Open During
Purge
Ignition Switch Open During
Ignition
Safety Pressure Relief Valve
Test
Chapter 7 – MAINTENANCE REQUIREMENTS
Para.
7.1
7.2
7.3
7.4
7.5
7.6
Subject
Maintenance Schedule
Spark Ignitor
Flame Detector
Combustion Calibration
Safety Device Testing
Burner
Page
7-1
7-1
7-2
7-2
7-3
7-3
Para.
7.7
7.8
7.9
ii
Subject
Introduction
Page
8-1
6-6
7-1
Subject
Condensate Drain Trap
Shutting the Boiler Down For An
Extended Period of Time
Placing The Boiler Back In
Service After A Prolonged
Shutdown
Chapter 8 – TROUBLESHOOTING GUIDE
Para.
8.1
6-5
Page
7-4
7-5
7-5
8-1
Para.
Subject
Page
CONTENTS
APPENDICES
App
A
B
C
D
E
F
Subject
Boiler Menu Item Descriptions
Startup, Status and Fault
Messages
Temperature Sensor Resistance
Chart
Indoor/Outdoor Reset Ratio
Charts
Boiler Default Settings
Dimensional and Part Drawings
Page
A-1
B-1
App
G
H
I
C-1
D-1
E-1
F-1
J
K
Subject
Piping Drawings
Wiring Schematics
Recommended Periodic Testing
Checklist
Benchmark Control Panel Views
Natural Gas Combustion
Calibration Procedure for Unit
Serial Nos. Below G-07-1901
Page
G-1
H-1
I-1
J-1
K-1
iii
FOREWORD
Foreword
The AERCO Benchmark 3.0LN Boiler is a modulating unit. It represents a true industry advance
that meets the needs of today's energy and environmental concerns. Designed for application
in any closed loop hydronic system, the Benchmark's modulating capability relates energy input
directly to fluctuating system loads. The Benchmark 3.0, with its 15:1 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 3.0 operates at inputs ranging from 200,000 BTU/hr. to 3,000,000 BTU/hr. The
output of the boiler is a function of the unit’s firing rate and return water temperature. Output
ranges from 198,000 BTU/hr. to 2,900,000 BTU/hr., depending on operating conditions.
When installed and operated in accordance with this Instruction Manual, the Benchmark 3.0
Boiler complies with the NOx emission standards outlined in:
• South Coast Air Quality Management District (SCAQMD), Rule 1146.1
Whether used in singular or modular arrangements, the Benchmark 3.0 offers the maximum
flexibility in venting with minimum installation space requirements. The Benchmark's advanced
electronics are available in several selectable modes of operation offering the most efficient
operating methods and energy management system integration.
For service or parts, contact your local sales representative or AERCO INTERNATIONAL.
NAME:
ORGANIZATION:
ADDRESS:
TELEPHONE:
INSTALLATION DATE: _____________________________________________
A
SAFETY PRECAUTIONS
CHAPTER 1
SAFETY PRECAUTIONS
1.1 WARNINGS & CAUTIONS
Installers and operating personnel MUST, at all
times, observe all safety regulations.
The
following warnings and cautions are general and
must be given the same attention as specific
precautions included in these instructions. In
addition to all the requirements included in this
AERCO Instruction Manual, the installation of
units MUST conform with local building codes,
or, in the absence of local codes, ANSI Z223.1
(National Fuel Gas Code Publication No. NFPA54). 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!
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
460 VAC MAY BE USED IN THIS
EQUIPMENT. THEREFORE THE
COVER ON THE UNIT’S POWER
BOX (LOCATED BEHIND THE
FRONT PANEL DOOR) MUST BE
INSTALLED AT ALL TIMES, EXCEPT
DURING
MAINTENANCE
AND
SERVICING.
CAUTIONS!
Must be observed to prevent
equipment damage or loss of
operating effectiveness.
CAUTION!
BEFORE ATTEMPTING TO PERFORM ANY MAINTENANCE ON THE
UNIT, SHUT OFF ALL GAS AND
ELECTRICAL INPUTS TO THE UNIT.
Many soaps used for gas pipe leak
testing are corrosive to metals. The
piping must be rinsed thoroughly with
clean water after leak checks have
been completed.
WARNING!
CAUTION!
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.
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
1.3 PROLONGED 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.
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.
IMPORTANT
The Installer must identify and indicate
the location of the emergency shutdown
manual gas valve to operating personnel.
Figure 1-1
Manual Gas Shutoff Valve
1-2
INSTALLATION
CHAPTER 2
INSTALLATION
2.1 INTRODUCTION
• Pressure/Temperature Gauge
This Chapter provides the descriptions and
procedures necessary to unpack, inspect and
install the AERCO Benchmark 3.0 Boiler. Brief
descriptions are also provided for each available
mode of operation. Detailed procedures for
implementing these modes are provided in
Chapter 5.
• Spare Spark Igniter
2.2 RECEIVING THE UNIT
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 be identified and stored in
a safe place until ready for installation or use.
Each Benchmark 3.0 System is shipped as a
single crated unit. The shipping weight is
approximately 2,170 pounds. The unit must be
moved with the proper rigging equipment for
safety and to avoid equipment damage. The unit
should be completely inspected for evidence of
shipping damage and shipment completeness at
the time of receipt from the carrier and before
the bill of lading is signed.
NOTE
AERCO is not responsible for lost or
damaged freight.
Each unit has a Tip-N-Tell indicator on the
outside of the crate. This indicates if the unit has
been turned on its side during shipment. If the
Tip-N-Tell indicator is tripped, do not sign for the
shipment. Note the information on the carrier’s
paperwork and request a freight claim and
inspection by a claims adjuster before
proceeding. Any other visual damage to the
packaging materials should also be made clear
to the delivering carrier.
2.3 UNPACKING
Carefully unpack the unit taking care not to
damage the unit enclosure when cutting away
packaging materials
A close inspection of the unit should be made to
ensure that there is no evidence of damage not
indicated by the Tip-N-Tell indicator. The freight
carrier should be notified immediately if any
damage is detected.
The following accessories come standard with
each unit and are either packed separately
within the unit’s packing container or are factory
installed on the boiler:
• Spare Flame Detector
• ASME Pressure Relief Valve
• Condensate Drain Trap
• 2” Gas Supply Shutoff Valve
2.4 SITE PREPARATION.
Ensure that the site selected for installation of
the Benchmark 3.0 Boiler includes:
• Access to AC Input Power corresponding to
the ordered power configuration. The
available power configurations are:
•
•
208 VAC, 3-Phase, 60 Hz @ 20 A
460 VAC, 3-Phase, 60 Hz @ 15 A
• Access to Natural Gas line at a static
pressure between 4 and 10 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 clearance dimensions, required by
AERCO, are listed below. However, if Local
Building Codes require additional clearances,
these codes shall supersede AERCO’s
requirements. Minimum acceptable clearances
required are:
• Sides:
24 inches
• Front :
24 inches
• Rear:
43 inches
• Top:
18 inches
All gas piping, water piping and electrical conduit
or cable must be arranged so that they do not
interfere with the removal of any panels, or
inhibit service or maintenance of the unit.
2-1
INSTALLATION
Figure 2-1 Benchmark 3.0 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 ensure proper condensate
drainage. If anchoring the unit, refer to the
dimensional drawings in Appendix F for anchor
locations. A total of 3 lifting tabs are provided at
the top of the primary heat exchanger as shown
in Figure 2-2. However, USE ONLY TABS 1
AND 2 SHOWN IN FIGURE 2-2 TO MOVE THE
ENTIRE UNIT. Tabs 1 and 3 are used only
when removing or replacing the unit’s primary
heat exchanger. Remove the front top panel
from the unit to provide access to the lifting tabs.
Remove the four (4) lag screws securing the unit
to the shipping skid. Lift the unit off the shipping
skid and position it on the 4 inch to 6 inch
housekeeping concrete pad (required) in the
desired location.
2-2
Figure 2-2
Lifting Lug 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 consideration. All piping must
include ample provisions for expansion.
If installing a Combination Control Panel (CCP)
system, it is important to identify the
Combination Mode Boilers in advance and place
them in the proper physical location. Refer to
Chapter 5 for information on Combination Mode
Boilers.
INSTALLATION
2.4.3 Removal of Support Rod
Prior to installation of water supply and return
piping, the 24” threaded rod shown in Figure 2-3
must be removed. This rod is installed prior to
shipment from the factory to prevent damage to
the insulated metal flex hose on the hot water
supply outlet of the boiler. In order to install the
water supply piping, this rod must be removed
as follows:
1. Refer to Figure 2-3 and back off the hex nut
on the outlet side of the flex hose.
2. Next, disconnect the coupling nut from the
flange stud.
3. Completely remove the threaded rod, hex
nut and coupling nut from the boiler.
5/8-11 x 24" LONG
THREADED ROD
5/8-11
HEX NUT
5/8-11
COUPLING NUT
Figure 2-4
Supply and Return Locations
OUTLET
FLANGE
(SEE IMPORTANT
NOTE BELOW)
EXHAUST
MANIFOLD
PARTIAL TOP VIEW - REAR
Figure 2-3
Location of Threaded Support Rod
IMPORTANT
THE INSULATED FLEX HOSE
SHOWN IN FIGURE 2-3 MUST BE
LEVEL OR SLOPING UPWARD AS
IT EXITS THE BOILER. FAILURE TO
PROPERLY POSITION THIS HOSE
MAY CAUSE INEFFECTIVE AIR
ELIMINATION RESULTING IN ELEVATED TEMPERATURES THAT
COULD COMPROMISE THE TOP
HEAD GASKET.
2.5 SUPPLY AND RETURN PIPING
2.6 CONDENSATE DRAINS
The Benchmark 3.0 Boiler is designed to
condense water vapor from the flue products.
Therefore, the installation must have provisions
for suitable condensate drainage or collection.
Two condensate drain connections are provided
on the rear of the unit as shown in Figure 2-5.
One drain connection is located on the exhaust
manifold and the other is located on the
connecting manifold.
The drain at the bottom of the exhaust manifold
also includes a condensate trap containing a
float assembly. When condensate collects in the
exhaust manifold, the float rises, thereby
allowing it to discharge through the drain
opening. The drain pipe located on the
connecting manifold must be connected to a
second condensate trap which is packed
separately within the unit’s shipping container.
The procedures to install and connect both of
the condensate drains are provided in
paragraphs 2.6.1 and 2.6.2.
The Benchmark 3.0 Boiler utilizes 4” 150#
flanges for the water system supply and return
piping connections. The physical location of the
supply and return piping connections are on the
rear of the unit as shown in Figure 2-4. Refer to
Appendix F, Drawing AP-A-811 for additional
dimensional data.
2-3
INSTALLATION
NOTE
EXHAUST
MANIFOLD
A
CONDENSATE
TRAP
A
DRAIN
SHELL DRAIN
VALVE
B
DRAIN
B
REAR VIEW
EXHAUST
MANIFOLD
CONDENSATE
TRAP
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.
CONNECTING
MANIFOLD
UNIT
FRAME
The condensate trap described in the
following steps can be installed on the
floor behind the unit as shown in Figure 26. There will be sufficient downward slope
from the drain pipe to the trap inlet to
drain the condensate by gravity. Ensure
that the outlet hose from the trap slopes
away (down) from the trap.
UNIT
FRAME
SHELL
3. Attach a length of 1½” I.D (part no. GM123352). hose between the connecting
manifold drain pipe and the inlet side of the
condensate trap (Figure 2-6). Secure both
ends of the hose with clamps.
4. Connect a second length of 1” I.D.
polypropylene hose to the outlet side of the
condensate trap and route it to a nearby floor
drain.
DRAIN
VALVE
DRAIN
HOSE
CLAMP
CONNECTING
MANIFOLD
1" I.D.
HOSE
TO
CONDENSATE
TRAP
TO FLOOR
DRAIN
VIEW “A - A”
CONDENSATE
DRAIN PIPE
VIEW “B - B”
Figure 2-5
Condensate Drain Connection Location
If desired, a Tee fitting may be used to connect the
two drain hoses from the exhaust manifold and the
outlet side of the of the condensate trap connected
in
If a floor drain is not available, a condensate pump
can be used to remove the condensate to drain.
The maximum condensate flow rate is 20 GPH.
The condensate drain trap, associated fittings and
drain lines must be removable for routine
maintenance. Therefore, DO NOT hard pipe.
2.6.1 Exhaust Manifold Condensate
Drain
Refer to Figure 2-5, View A – A and install as
follows:
1. Connect a length of 1 inch I.D. hose (part no.
91030) to the drain on the connecting manifold
and secure it in place with a hose clamp.
2. Route the hose to a nearby floor drain.
2.6.2 Connecting Manifold Condensate
Drain
The connecting manifold drain pipe shown in
Figure 2-5, View B – B must be connected to a
separate condensate drain trap external to the
unit. Refer to Figure 2-6 and install the trap as
follows:
2-4
Figure 2-6
Condensate Trap Installation
INSTALLATION
2.7 GAS SUPPLY PIPING
The AERCO Benchmark 3.0 Gas Components
and Supply Design Guide, GF-3030 must be
consulted prior to designing or installing any gas
supply piping.
WARNING
NEVER USE MATCHES, CANDLES,
FLAMES OR OTHER SOURCES OF
IGNITION TO CHECK FOR GAS
LEAKS.
CAUTION
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.
2.7.1 Gas Supply Specification
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 sufficient capacity to provide
3000 cfh while maintaining the gas pressure at 4
inches W.C. for FM or IRI gas trains.
2.7.2 Manual Gas Shutoff Valve
A manual shut-off valve must be installed in the
gas supply line upstream of the Boiler as shown
in Figure 2-7. Maximum allowable gas pressure
to the Boiler is 2 psi
NOTE
All gas piping must be arranged so that it
does not interfere with removal of any
covers, inhibit service/maintenance, or
restrict access between the unit and
walls, or another unit.
A 2 inch gas inlet connection is located on the
rear of the unit as shown in Figure 2-4.
Prior to installation, all pipes should be deburred and internally cleared of any scale, metal
chips or other foreign particles. Do Not install
any flexible connectors or unapproved gas
fittings. Piping must be supported from the floor,
ceiling or walls only and must not be supported
by the unit.
A suitable piping compound, approved for use
with natural gas, should be used. Any excess
must be wiped off to prevent clogging of
components.
To avoid unit damage when pressure testing gas
piping, isolate the unit from the gas supply
piping. At no time should the gas pressure
applied to the unit exceed 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.
Figure 2-7
Manual Gas Shut-Off Valve Location
2-5
INSTALLATION
2.7.3 IRI Gas Train Kit
2.8.1 Electrical Power Requirements
The IRI gas train is an optional gas train
configuration which is required in some areas for
code compliance or for insurance purposes.
The IRI gas train is factory pre-piped and wired.
See Appendix F, Drawing AP-A-803 for details.
The AERCO Benchmark 3.0 Boiler is available
in two different AC power configurations:
2.8 AC ELECTRICAL POWER WIRING
Each of the power configurations utilize a Power
Box with a terminal block that matches the
configuration ordered. The two different terminal
block configurations are shown in Figure 2-9. A
wiring diagram showing the required AC power
connections is provided on the front cover of the
Power Box.
The AERCO Benchmark 3.0 Electrical Power
Wiring Guide, GF-3060, must be consulted prior
to connecting any AC power wiring to the unit.
External AC power connections are made to the
unit inside the Power Box on the front 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 2-8).
NOTE
All electrical conduit and hardware must
be installed so that it does not interfere
with the removal of any unit covers, inhibit
service/maintenance, or prevent access
between the unit and walls or another
unit.
• 208 VAC/3-Phase/60 @20 amps
• 460 VAC/3-Phase/60 Hz @ 15 amps
Each Benchmark 3.0 Boiler 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 service switch) must be
installed near the 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 3.0 Electrical Power Wiring
Guide, (GF-3060).
Figure 2-9
AC Terminal Block Configurations
Figure 2-8
AC Input Terminal Block Location
2-6
INSTALLATION
2.9 MODES OF OPERATION AND FIELD
CONTROL WIRING
The Benchmark 3.0 Boiler is available in several
different modes of operation. While each unit is
factory configured and wired for its intended
mode, some additional field wiring may be
required to complete the installation. This wiring
is typically connected to the Input/Output (I/O)
Box located on the lower portion of the unit front
panel (Figure 2-10) behind the removable front
door.
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 (Figure 2-11) when making
all wiring connections.
In addition to the terminal strips shown in Figure
2-10, 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 Benchmark 3.0 Boiler. The VFD
utilizes this input signal to adjust the rotation
speed of the blower.
Figure 2-10.
Input/Output (I/O) Box Location
Brief descriptions of each mode of operation,
and their wiring requirements, are provided in
the following paragraphs. Additional information
concerning field wiring is provided in paragraphs
2.9.1 through 2.9.9. Refer to Chapter 5 for
detailed information on the available modes of
operation.
Figure 2-11. I/O Box Terminal Strip
2-7
INSTALLATION
2.9.1 Constant Setpoint Mode
The Constant Setpoint Mode is used when it is
desired to have a fixed setpoint that does not
deviate. No wiring connections, other than AC
electrical power connections, are required for
this mode. However, if desired, fault monitoring
or enable/disable interlock wiring can be utilized
(see paragraphs 2.9.9.1 and 2.9.10).
Mode) or firing rate (Direct Drive Mode) of the
Boiler. These formats are:
• 4 to 20 mA/1 to 5 VDC
• 0 to 20 mA/0 to 5 VDC
• PWM – (Pulse Width Modulated signal. See
para. 2.10.4)
• Network (RS485 Modbus. See para. 2.10.7)
This mode of operation increases supply water
temperature as outdoor temperatures decrease.
An outside air temperature sensor (AERCO Part
No. 122790) is required. The sensor MUST BE
wired to the I/O Box wiring terminals (see Figure
2-11). Refer to paragraph 2.10.1 for additional
information on outside air temperature sensor
installation.
While it is possible to control a boiler or boilers
using one of the previously described modes of
operation, it may not be the method best suited
for the application. Prior to selecting one of
these modes of operation, it is recommended
that you consult with your local AERCO
representative or the factory for the mode of
operation that will work best with your
application. For more information on wiring the
4 to 20 mA / 1to 5VDC or the 0 to 20 mA / 0 to 5
VDC, see paragraph 2.9.3.
2.9.3 Boiler Management System Mode
2.9.5 Combination Mode
2.9.2 Indoor/Outdoor Reset Mode
NOTE
BMS Model 168 can utilize either pulse
width modulation (PWM) or RS485
Modbus signaling to the Boiler. BMS II
Model 5R5-384 can utilize only RS485
signaling to the Boiler.
When using an AERCO Boiler Management
System (BMS), the field wiring is connected
between the BMS Panel and each Boiler’s I/O
Box terminal strip (Figure 2-11). Twisted
shielded pair wire from 18 to 22 AWG must be
utilized for the connections. The BMS Mode can
utilize either pulse width modulation (PWM)
signaling, or RS485 Modbus signaling. For PWM
signaling, connections are made from the
AERCO Boiler Management System to the
B.M.S. (PWM) IN terminals on the I/O Box
terminal strip. For RS485 Modus signaling,
connections are made from the BMS to the
RS485 COMM terminals on the I/O Box terminal
strip. Polarity must be maintained and the shield
must be connected only at the AERCO BMS.
The boiler end of the shield must be left floating.
For additional instructions, refer to Chapter 5,
paragraph 5.6 in this manual. Also, refer to GF108M (BMS Model 168) and GF-124 (BMS II
Model 5R5-384), BMS -Operations Guides.
2.9.4 Remote Setpoint and Direct Drive
Modes
The Benchmark 3.0 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
2-8
NOTE
Only BMS Model 168 can be utilized for
the Combination Mode, not the BMS II
(Model 5R5-384).
With a Combination Mode unit, field wiring is
between the unit’s I/O Box wiring terminals, the
CCP (Combination Control Panel), and the BMS
Model 168 (Boiler Management System). The
wiring must be accomplished using twistedshielded 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 connected to the I/O Box terminals
shown in Figure 2-11 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 mode of operation. It can
also be used with another mode if it is desired to
use the outdoor sensor enable/disable feature.
This feature allows the boiler to be enabled or
disabled based on the outdoor air temperature.
INSTALLATION
The factory default for the outdoor sensor is
DISABLED. To enable the sensor and/or select
an enable/disable outdoor temperature, see the
Configuration menu in Chapter 3.
2-11). Polarity must be maintained. The shield
must be connected only at the source end and
must be left floating (not connected) at the
Boiler’s I/O Box.
The outdoor sensor may be wired up to 200 feet
from the boiler.
It is connected to the
OUTDOOR SENSOR IN and SENSOR
COMMON terminals in the I/O Box (see Figures
2-10 and 2-11). Wire the sensor using a twisted
shielded pair wire from 18 to 22 AWG. There is
no polarity to observe when terminating these
wires. The shield is to be connected only to the
terminals labeled SHIELD in the I/O Box. The
sensor end of the shield must be left free and
ungrounded.
Regardless of whether voltage or current is used
for the drive signal, they are linearly mapped to
a 40°F to 240°F setpoint or a 0% to 100% firing
rate. No scaling for these signals is provided
When mounting the sensor, it must be located
on the North side of the building where an
average outside air temperature is expected.
The sensor must be shielded from direct sunlight
as well as impingement by the elements. If a
shield is used, it must allow for free air
circulation.
These terminals are used to connect the
AERCO Boiler Management System (BMS)
Model 168 to the unit. The BMS Model 168
utilizes a 12 millisecond, ON/OFF duty cycle.
This duty cycle is Pulse Width Modulated (PWM)
to control firing rate. A 0% firing rate = a 5% ON
pulse and a 100% firing rate = a 95% ON pulse.
2.10.2 AUX SENSOR IN
2.10.5 SHIELD
The AUX SENSOR IN terminals can be used to
add an additional temperature sensor for
monitoring purposes. This input is always
enabled and is a view-only input that can be
seen in the Operating Menu. The sensor must
be wired to the AUX SENSOR IN and SENSOR
COMMON terminals and must be similar to
AERCO BALCO wire sensor Part No. 12449. A
resistance chart for this sensor is provided in
Appendix C.
The SHIELD terminals are used to terminate any
shields used on sensor wires connected to the
unit. Only shields must be connected to these
terminals.
2.10.3 ANALOG IN
2.10.7 RS-485 COMM
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.
These terminals are used for RS-485 MODBUS
serial communication between the unit and an
external “Master” such as a Boiler Management
System (BMS), Energy Management System
(EMS), Building Automation System (BAS) or
other suitable device.
Either a 4 to 20 mA /1 to 5 VDC or a 0 to 20 mA
/ 0 to 5 VDC signal may be used to vary the
setpoint or firing rate. The factory default setting
is for 4 to 20 mA / 1 to 5 VDC, however this may
be changed to 0 to 20 mA / 0 to 5 VDC using the
Configuration Menu described in Chapter 3. If
voltage rather than current is selected as the
drive signal, a DIP switch must be set on the
PMC Board located inside the Control Box.
Contact the AERCO factory for information on
setting DIP switches.
All of the supplied signals must be floating
(ungrounded) signals. Connections between the
signal source and the Boiler’s I/O Box must be
made using twisted shielded pair wire from 18 to
22 AWG, such as Belden 9841 (see Figure
2.10.4 B.M.S. (PWM) IN
NOTE
Only BMS Model 168 can utilize Pulse
Width Modulation (PWM), not the BMS II
(Model 5R5-384).
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).
2.10.8 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 type switch (such as AERCO Part
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 interlocks are called the Remote
Interlock and Delayed Interlock (Figure 2-11).
The wiring terminals for these interlocks are
2-9
INSTALLATION
located inside the I/O Box on the unit front
panel. The I/O Box cover contains a wiring
diagram which shows the terminal strip locations
for these interlocks (REMOTE INTL’K IN and
DELAYED INTL’K IN). Both interlocks,
described below, are factory 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.
2.10.9.1 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 located inside the I/O
Box on the front panel. The circuit is 24 VAC
and is factory pre-wired in the closed (jumpered)
position.
2.10.9.2 DELAYED INTERLOCK IN
The delayed interlock is typically used in
conjunction with the auxiliary 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 by the Boiler’s auxiliary relay.
The delayed interlock must be closed for the
boiler to fire.
If the delayed interlock is connected to a proving
device that requires time to close (make), a time
delay (Aux Start On Dly) that holds the start
sequence of the boiler long enough for a proving
switch to make can be programmed. Should the
proving switch not prove within the programmed
time frame, the boiler will shut down. The Aux
Start On Dly can be programmed from 0 to 120
seconds.
This option is locate in the
Configuration Menu (Chapter 3, Table 3-4).
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 120 VAC and 5 amps at 30
VDC. The relay energizes when any fault
condition occurs and remains energized until the
fault is cleared and the CLEAR button is
depressed. The fault relay connections are
shown in Figure 2-11.
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 demand for heat is satisfied.
The relay is provided for the control of auxiliary
equipment, such as pumps and louvers, or can
be used as a Boiler status indictor (firing or not
firing). Its contacts are rated for 120 VAC @ 5
amps. Refer to Figure 2-11 to locate the AUX
RELAY terminals for wiring connections.
2.12 FLUE GAS VENT INSTALLATION
The minimum allowable vent diameter for a
single Benchmark 3.0 Boiler is 8 inches.
The
AERCO
Benchmark
Venting
and
Combustion Air Guide, GF-3050, 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-3050, must be used
for safety and code compliance. Since the unit is
capable of discharging low temperature exhaust
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 8 inch ducting. Fittings as well
as pipe lengths must be calculated as part of the
equivalent length.
For a natural draft installation the draft must not
exceed ±0.25 inch W.C. These factors must be
planned into the vent installation. If the
maximum allowable equivalent lengths of piping
are exceeded, the unit will not operate properly
or reliably.
2.13 COMBUSTION AIR
The
AERCO
Benchmark
Venting
and
Combustion Air Guide, GF-3050 MUST be
consulted before any flue or combustion supply
air venting is designed or implemented.
Combustion air supply is a direct requirement of
ANSI 223.1, NFPA-54, and local codes. These
codes should be consulted before a permanent
design is determined.
INSTALLATION
The combustion air must be free of chlorine,
halogenated hydrocarbons, or other chemicals
that can become hazardous when used in gasfired equipment. Common sources of these
compounds are swimming pools, degreasing
compounds, plastic processing and refrigerants.
Whenever the environment contains these types
of chemicals, combustion air must be supplied
from a clean area outdoors for the protection
and longevity of the equipment.
The AERCO Benchmark 3.0 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 concerning sealed combustion
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-3050.
2.13.1 Combustion Air From Outside the
Building
2.13.2 Combustion Air From Inside The
Building
When combustion air is provided from within the
building, it must be supplied through two
permanent openings in an interior wall. Each
opening must have a free area of not less than
one square inch per 1000 BTU/H of total boiler
input. The free area must take into account any
restrictions such as louvers.
2.13.3 Sealed Combustion
The AERCO Benchmark 3.0 Boiler is UL listed
for 100%-sealed combustion. For sealed
combustion installations, the screen on the air
inlet duct of the unit must be removed. The inlet
air ductwork must then be attached directly to
the unit’s air inlet.
In a sealed combustion air application, the
combustion air ducting pressure losses must be
taken into account when calculating the total
maximum allowable venting run. See the
AERCO Benchmark Venting and Combustion
Air Guide, GF-3050. When using the boiler in a
sealed combustion air configuration, each unit
must have a minimum 8 inch diameter
connection at the unit.
Air supplied from outside the building must be
provided through two permanent openings. Each
opening must have a free area of not less than
one square inch for each 4000 BTU/H boiler
input. The free area must take into account
restrictions such as louvers and bird screens.
2-11
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 3.0 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 DESCRIPTION
The Benchmark 3.0 Control Panel shown in
Figure 3-1 contains all of the controls, indicators
and displays necessary to operate, adjust and
troubleshoot the Benchmark 3.0 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.
1
CONTROL, INDICATOR
OR DISPLAY
LED Status Indicators
FUNCTION
Four Status LEDs indicate the current operating status as
follows:
COMM
Lights when RS-232 communication is occurring
MANUAL
Lights when the unit is being controlled using the front panel
keypad.
REMOTE
Lights when the unit is being controlled by an external signal
from an Energy Management System
DEMAND
Lights when there is a demand for heat.
2
OUTLET
TEMPERATURE
Display
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.
3
VFD Display
Vacuum Fluorescent Display (VFD) consists of 2 lines each
capable of displaying up to 16 alphanumeric characters. The
information displayed includes:
Startup Messages
Fault Messages
Operating Status Messages
Menu Selection
4
RS-232 Port
Port permits a Laptop Computer or External Modem to be
connected to the unit’s Control Panel.
5
FAULT Indicator
Red FAULT LED indicator lights when a boiler alarm
condition occurs. An alarm message will appear in the VFD.
6
CLEAR Key
Turns off the FAULT indicator and clears the alarm message
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.
7
READY Indicator
Lights ON/OFF switch is set to ON and all Pre-Purge
conditions have been satisfied.
8
ON/OFF Switch
Enables and disables boiler operation.
9
LOW WATER LEVEL
Allows operator to test operation of the water level monitor.
TEST/RESET Switches
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
11
CONTROL, INDICATOR
OR DISPLAY
MENU Keypad
FUNCTION
Consists of 6 keys which provide the following functions for
the Control Panel Menus:
MENU
Steps through the main menu categories shown in Figure 32. The Menu categories wrap around in the order shown.
BACK
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.
▲ (UP) Arrow
When in one of the main menu categories (Figure 3-2),
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.
▼ (DOWN) Arrow
When in one of the main menu categories (Figure 3-2),
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.
CHANGE
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.
ENTER
Saves the modified menu settings in memory. The display
will stop flashing.
AUTO/MAN Switch
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.
12
FIRE RATE Bargraph
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.
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.
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.
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 wrap3-4
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.
CONTROL PANEL OPERATING PROCEDURES
3.4 OPERATING MENU
The Operating Menu displays a number of key
operating parameters for the unit as listed in
Table 3-2. This menu is “Read-Only” and does
not allow personnel to change or adjust any
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
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).
Table 3-2. Operating Menu
Menu Item Display
Available Choices or Limits
Minimum
Maximum
Default
Status Message
Active Setpoint
40°F
240°F
Aux Temp
30°F
245°F
Outdoor Temp*
-70°F
130°F
Fire Rate In
0%
Max Fire Rate
Flame Strength
0%
100%
Run Cycles
0
999,999
Run Hours
0
999,999
Fault Log
0
9
0
Table 3-3. Setup Menu
Menu Item Display
Passsword
Available Choices or Limits
Minimum
Maximum
0
Language
9999
English
12:00 am
11:59 pm
Date
01/01/00
12/31/99
Comm Address
Baud Rate
Software
Fahrenheit or Celsius
0
127
2400, 4800, 9600, 19.2K
Ver 0.00
0
English
Time
Unit of Temp
Default
Fahrenheit
0
9600
Ver 9.99
3-5
CONTROL PANEL OPERATING PROCEDURES
3.6 CONFIGURATION MENU
NOTE
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.
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.
Table 3-4. Configuration Menu
Menu Item Display
Internal Setpt
3-6
Available Choices or Limits
Minimum
Maximum
Lo Temp Limit
Hi Temp Limit
Default
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
1.0 MBTU
Boiler Mode
Constant Setpoint,
Remote Setpoint,
Direct Drive
Combination
Outdoor Reset
Constant
Setpoint
Remote Signal
(If Mode = Remote
Setpoint, Direct Drive
or Combination)
4 – 20 mA/1 – 5V
0 -20 mA/0 – 5V
PWM Input (BMS)
Network
4 – 20 mA,
1-5V
Bldg Ref Temp
(If Mode = Outdoor
Reset)
40°F
230°F
70°F
Reset Ratio
(If Mode = Outdoor
Reset)
0.1
9.9
1.2
Outdoor Sensor
Enabled or Disabled
Disabled
System Start Tmp
(If Outdoor Sensor =
Enabled)
30°F
100°F
60°F
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.
CONTROL PANEL OPERATING PROCEDURES
Table 3-4. Configuration Menu - Continued
Available Choices or Limits
Minimum
Maximum
Default
Shutdown or Constant Setpt
Shutdown
*mA Output
(See CAUTION)
Setpoint, Outlet Temp,
Fire Rate Out, Off
*Fire Rate
Out
Low Fire Timer
2 sec.
Menu Item Display
Failsafe Mode
120 sec.
Setpt Limiting
Enabled or Disabled
Setpt Limit Band
0°F
10°F
2 sec.
Disabled
5°F
*CAUTION: DO NOT CHANGE mA Output Menu Itemfrom its Default setting.
these menu entries unless specifically requested
to do so by Factory-Trained personnel.
3.7 TUNING MENU
The Tuning Menu items in Table 3-5 are Factory
set for each individual unit. Do not change
Table 3-5. Tuning Menu
Menu Item Display
Available Choices or Limits
Minimum
Maximum
Default
Prop Band
1°F
120°F
70°F
Integral Gain
0.00
2.00
1.00
0.0 min
2.00 min
0.00 min
Derivative Time
Reset Defaults?
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
Yes
No
Are You Sure?
No
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.
• High Water Temperature switch
• High Gas Pressure switch
1. The DEMAND LED status indicator will light.
• Low Gas Pressure switch
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.
• 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.
3-7
CONTROL PANEL OPERATING PROCEDURES
AIR IN
TO BLOWER
DIAL
(DETAIL “A”)
STEPPER
MOTOR
100
DETAIL “A”
Figure 3-4.
Air/Fuel Valve In Purge Position
Figure 3-3.
SSOV Locations
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 fullopen 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.
3-8
Figure 3-5.
Blower Proof Switch
CONTROL PANEL OPERATING PROCEDURES
5. Upon completion of the purge cycle, the
Control Box initiates an ignition cycle and
the following events occur:
DIAL
(DETAIL “A”)
(a) The Air/Fuel Valve rotates to the lowfire 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.
STEPPER
MOTOR
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.
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.
25
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.
DETAIL “A”
Figure 3-6.
Air/Fuel Valve In Ignition
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: 14%
Normally, these settings should not require
adjustment.
3-9
INITIAL START-UP
CHAPTER 4
4.1 INITIAL START-UP REQUIREMENTS
The requirements for the initial start-up of the
Benchmark 3.0 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.
INITIAL START-UP
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.
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
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.
• 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.
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.
4-1
INITIAL START-UP
4. Install a NPT-to-barbed fitting into the
tapped plug port.
5. Attach one end of the plastic tubing to the
barbed fitting and the other end to the 16
inch W.C. manometer.
Figure 4.2
Analyzer Probe Hole Location
IMPORTANT
The Combustion Calibration procedure specified in paragraph 4.3
applies ONLY to units with serial
numbers G-07-1901 and above.
For units with serial numbers below
G-07-1901, use the Combustion
Calibration procedure provided in
Appendix K.
4.3 NATURAL GAS COMBUSTION
CALIBRATION
Figure 4-1.
1/8 Inch Gas Plug Location
4.2.3 Accessing the Vent Probe Port
The unit contains NPT plugs on both the left and
right side of 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
left or right side of the exhaust manifold.
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.
4-2
The Benchmark 3.0LN 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.
INITIAL START-UP
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.
10. Next, verify that the gas pressure
downstream of SSOV No. 1 is 1.8” W.C. for
both FM and IRI gas trains. If gas pressure
adjustment is required, remove the brass
hex nut on downstream SSOV No. 1
containing the gas pressure regulator
(Figure 4-3). Make gas regulator adjustments using a flat-tip screwdriver to obtain
1.8” W.C.
11. Raise the firing rate to 100% and verify that
the gas pressure downstream of SSOV No.
1 remains at 1.8” 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
90°F
80°F
<70°F
Oxygen %
± 0.2
4.8 %
5.0 %
5.2 %
5.3 %
Carbon
Monoxide
<100 ppm
<100 ppm
<100 ppm
<100 ppm
NOx
<30 ppm
<30 ppm
<30 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.
15. Once the oxygen level is within the specified
range at 100%, lower the firing rate to 70%.
Figure 4-3
Regulator Adjustment Screw Location
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
frequency (Hz) will appear in the right part of
the display.
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.
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 70%, 50%, 40%, 30% and 14% 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.
4-4
20. Press the M key again and observe the
frequency shown in the right part of the
display. The oxygen level at the 70% 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
70% Firing Rate
Oxygen %
± 0.2
6.0 %
Carbon
Monoxide
<100 ppm
NOx
<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.
INITIAL START-UP
22. Once the oxygen level is within the specified
range at 70%, lower the firing rate to 50%
and select VFD parameter 64. The oxygen
level at the 50% firing rate should be as
shown below.
Combustion Oxygen Level at
50% Firing Rate
Oxygen %
± 0.2
7.0 %
Carbon
Monoxide
<50 ppm
NOx
<20 ppm
23. Adjust the oxygen level as necessary to
obtain the required reading at the 50% firing
rate.
24. Once the oxygen level is within the specified
range at 50%, lower the firing rate to 40%
and select VFD parameter 63. The oxygen
level at the 40% firing rate should be as
shown below.
Combustion Oxygen Level at
40% Firing Rate
Oxygen %
± 0.2
7.8%
Carbon
Monoxide
<50 ppm
NOx
<20 ppm
NOTE
At a 14% fire rate, if parameter 61 is
above 326, the VFD software will use 326
by default. 326 corresponds to a
frequency of 32.6 Hz.
Combustion Oxygen Level at
14% Firing Rate
Oxygen %
± 0.2
8.5 %
Carbon
Monoxide
<50 ppm
NOx
<20 ppm
29. Adjust the oxygen level as necessary to
obtain the required reading at the 14% firing
rate.
30. This completes the combustion calibration
procedures.
4.4 UNIT REASSEMBLY
Once the combustion calibration adjustments
are properly set, the unit can be reassembled for
service operation.
25. Adjust the oxygen level as necessary to
obtain the required reading at the 40% firing
rate.
1. Set the ON/OFF switch in the OFF position.
26. Next, set the firing rate to 30% and select
VFD parameter 62. The oxygen level at the
30% firing rate should be as shown below.
3. Shut off the gas supply to the unit.
Combustion Oxygen Level at
30% Firing Rate
Oxygen %
± 0.2
8.0 %
Carbon
Monoxide
<50 ppm
NOx
<20 ppm
2. Disconnect AC power from 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.
27. Adjust the oxygen level as necessary to
obtain the required reading at the 30% firing
rate.
28. Finally, reduce the firing rate to 14% and
select VFD parameter 61. The oxygen level
at the 14% firing rate should be as shown in
the following tabular listing:
4-5
INITIAL START-UP
4.5 OVER-TEMPERATURE LIMIT
SWITCHES
The unit contains both automatic and manual
reset over-temperature limit switches. These
switches are mounted on a plate attached to the
boiler shell as shown in Figure 4-6. The switches
can be accessed by removing the left side
panels 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 overtemperature switch to the desired setting.
Figure 4-6
Over Temperature Limit Switch
Locations
4-6
MODE OF OPERATION
CHAPTER 5
MODE OF OPERATION
5.1 INTRODUCTION
The Benchmark 3.0 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 3.0 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.
5.2.3 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 3.0 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 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.
5.2.2 Building Reference Temperature
This is a temperature from 40°F to 230°F. Once
selected, it is the temperature that the system
references to begin increasing its temperature.
For instance, if a reset ratio of 1.6 is used, and
we select a building reference temperature of
70°F, then at an outside temperature of 69°F,
the supply header temperature will increase by
1.6° to 71.6°F.
5.2.4 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
supply header temperature data
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.
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.
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:
SETTING
Boiler Mode
Constant Setpoint
Internal Setpt
Select desired setpoint
using ▲ and ▼ arrow
keys (40°F to 240°F)
Refer to paragraph 3.3 for detailed instructions
on changing menu options.
5-2
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.
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
5.3.1 Setting the Setpoint
MENU OPTION
5.4 REMOTE SETPOINT MODES
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.
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 3.0 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)
network communication. For BMS programming
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 3.0 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 3.0 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)
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
3.0LN 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.
4. Place the unit in Manual Mode and adjust
the firing rate between 25 and 30%.
5. While the unit is firing, slowly close the
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 FAULT indicator should also start flashing.
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 460, 220,
120 AND 24 VOLTS AC. POWER
MUST BE REMOVED PRIOR TO
PERFORMING WIRE REMOVAL OR
OTHER TEST PROCEDURES THAT
CAN RESULT IN ELECTRICAL
SHOCK.
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.
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.
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 the upper
portion of Figure 6-1.
unit should not start. If the unit does start,
shut the unit off immediately and refer fault
to qualified service personnel.
7. Close the drain and pressure relief valve
used in draining the unit.
8. Open the water shut-off valve in the return
piping to the unit.
2. Install a 0 – 16” W.C. manometer (or W.C.
gauge) where the 1/8” plug was removed.
9. Open the water supply shut-off valve to the
unit to refill.
3. Slowly open the leak detection ball valve
10. After the shell is full, press the LOW
WATER LEVEL RESET button to reset the
low water cutoff.
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 SSOV No. 1.
6. The unit should shut down and display a
HIGH GAS PRESSURE fault message
when the gas pressure exceeds 2.6” W.C.
The FAULT indicator should also start
flashing.
7. Reduce the gas pressure back to 1.7” W.C.
8. Press the CLEAR button on the Control Box
to clear the fault.
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%.
6. Set the ON/OFF switch to the ON position.
The READY light should remain off and the
6-2
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 left side of the
unit as shown in Figure 6-2.
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.
SAFETY DEVICE TESTING
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%.
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
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.
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.
6.6 INTERLOCK TESTS
6. Press the CLEAR button to reset the fault
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
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%.
6-3
SAFETY DEVICE TESTING
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.
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.
9. The unit should shut down and display
FLAME LOSS DURING RUN.
5.
10. Open the valve previously closed in step 8.
6. Next, check the Blocked Inlet Switch by
closing the Iris Air Damper to position 8.
11. Press the CLEAR button. The unit should
restart and fire.
AIR
INLET
BLOCKED
INLET
SWITCH
BLOWER PROOF
SWITCH
BLOWER
Press the CLEAR button. The unit should
restart.
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 downstream SSOV (#1) shown in Figure
6-1 contains the proof of closure switch. The
proof of closure switch circuit is checked as
follows:
1. Set the unit’s ON/OFF switch to the OFF
position.
AIR/FUEL
VALVE
MANUAL GAS
SHUTOFF
VALVE
HANDLE
GAS
INLET
PARTIAL LEFT SIDE VIEW
Figure 6-3
Manual Gas Shut-Off Valve Location
6-4
2. Place the unit in Manual Mode and set the
firing rate between 25% and 30%
3. Refer to Figure 6-1 and locate downstream
SSOV #1.
4. Remove the cover from SSOV #1 by
loosening the screw shown in Figure 6-4. Lift
off the cover to access the terminal wiring
connections.
5. Disconnect wire #148 from SSOV #1 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.
6.11 IGNITION SWITCH OPEN DURING
IGNITION
9. Remove the wire again when the unit
reaches the purge cycle and PURGING is
displayed.
The Ignition Switch (and the Purge Switch) is
located on the Air/Fuel Valve. To check the
switch, proceed as follows:
10. The unit should shut down and display
SSOV FAULT DURING PURGE.
11. Replace the wire on SSOV #1 and press the
CLEAR button. The unit should restart.
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.
Figure 6-4
SSOV #1 Actuator Cover Location
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.
Figure 6-5
Air/Fuel Valve Cover Location
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.
6-5
2
17
16
9
SAFETY DEVICE TESTING
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
The unit requires regular routine maintenance to
keep up efficiency and reliability. For best
operation and life of the unit, the following
routine maintenance procedures should be
carried out in the time periods specified in Table
7-1. See Appendix I for a complete CSD-1
inspection check list.
5. The igniter is gapped at 1/8-inch. If there is a
substantial erosion of the spark gap or
ground electrode, the igniter should be
replaced. If carbon build-up is present, clean
the igniter using fine emery cloth. Repeated
carbon build-up on the igniter is an
indication that a check of the combustion
settings is required (see Chapter 4 for
combustion calibration.
WARNING
6. Prior to reinstalling the igniter, a high
temperature anti-seize compound must be
applied to the igniter threads.
7.1 MAINTENANCE SCHEDULE
TO AVOID PERSONAL, PRIOR TO
SERVICING:
• DISCONNECT THE AC SUPPLY BY
TURNING OFF THE SERVICE
SWITCH AND AC SUPPLY CIRCUIT
BREAKER.
7. Reinstall the igniter. Do not over tighten the
igniter. A slight snugging up is sufficient.
Reconnect the igniter cable.
8. Reinstall the side and top panels on the unit.
• SHUT OFF THE GAS SUPPLY AT
THE MANUAL SHUT-OFF VALVE
PROVIDED WITH THE UNIT
• ALLOW THE UNIT TO COOL TO A
SAFE WATER TEMPERATURE TO
PREVENT BURNING OR SCALDING
7.2 SPARK IGNITER
The spark igniter, part no. GP-122435-S, is
located in the body of the burner (see Figure 71). The igniter may be HOT. Care should be
exercised. It is easier to remove the igniter from
the unit after the unit has cooled to room
temperature.
To inspect/replace the Igniter:
1. Set the ON/OFF switch on the control panel,
to the OFF position. Disconnect AC power
from the unit
Figure 7-1
Spark Igniter and Flame Detector
Location – Top View
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.
7-1
MAINTENANCE
Table 7-1 - Maintenance Schedule
PARAGRAPH
7.2
7.3
7.4
7.5
7.6
7.7
6 Mos.
12 Mos.
24 Mos.
Labor
Time
*Inspect
Inspect
Replace
15 mins.
*Inspect
Inspect
Replace
15 mins.
*Check
Check
1 hr.
See CSD-1
Chart in
Appendix I
20 mins.
ITEM
Spark
Igniter
Flame
Detector
Combustion
Calibration
Testing of
Safety
Devices
Burner
Condensate
Drain Traps
Inspect
*Inspect
Inspect &
Clean
2 hrs.
1 hr.
* Only performed after initial 6 month period after initial startup.
7.3 FLAME DETECTOR
The flame detector, part no. 66006, is located in
the body of the burner (see Fig. 7-1). The flame
detector may be HOT. Allow the unit to cool
sufficiently before removing the flame detector.
To inspect or replace the flame detector:
1. Set the ON/OFF switch on the control 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)
BURNER
HOUSING
SPARK
IGNITER
FLAME
DETECTOR
4. Inspect the detector thoroughly. If eroded,
the detector should be replaced. Otherwise
clean the detector with a fine emery cloth.
5. Reinstall the flame detector and flame
detector gasket, if removed.
6. Reconnect the flame detector lead wire.
7. Reinstall the side and top panels on the unit.
7.4 COMBUSTION CALIBRATION
Combustion settings must be checked at the
intervals shown in Table 7-1 as part of the
maintenance requirements. Refer to Chapter 4
for combustion calibration instructions.
7-2
Figure 7-2
Spark Igniter and Flame Detector
Location Cut-Away View
MAINTENANCE
7.5 SAFETY DEVICE TESTING
Systematic and thorough tests of the operating
and safety devices should be performed to
ensure that they are operating as designed.
Certain code requirements, such as ASME
CSD-1, require that these tests be performed on
a scheduled basis. Test schedules must
conform to local jurisdictions. The results of the
tests should be recorded in a log book. See
Chapter 6-Safety Device Testing Procedures.
7.6 BURNER
The burner assembly is located at the top front
of the unit. The burner assembly may be HOT.
Allow the unit to cool sufficiently before
removing the burner assembly.
The following parts will be necessary for
reassembly after inspection:
Part No.
81030
81047
Description
Burner Gaskets (Qty=2)
Gas Injector Gasket (Qty=1)
To inspect or replace the burner assembly:
1. Set the ON/OFF switch on the control panel,
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.
9. Remove the grounding screw.
10. If there is an extension ring around the
burner, remove it.
11. Remove the burner by pulling straight up.
12. Remove and replace the burner gaskets.
13. Beginning with the burner removed in step
11, reinstall all the components in the
reverse order that they were removed.
However, if the burner was replaced, follow
the instructions in step 14.
14. If the burner is being replaced, measure the
outside diameter (O.D.) of the new burner
flange. If the O.D. is approximately 13”, do
not reinstall the extension ring. However, if
the O.D. of the new burner flange is
approximately 12.4”, the extension ring must
be reinstalled.
15. Make sure to align the Spark Igniter (S/I)
and Flame Rod (F/R) slots in the burner with
the heat exchanger top head.
16. Check to ensure that the grounding screw is
reinstalled.
3/8-16 NUTS (8)
STAGED IGNITION
ASSEMBLY
10-32 SCREWS (2)
GROUNDING
SCREW
3. Disconnect the lead wire from the flame
detector. Unscrew the flame detector.
4. Disconnect the igniter cable from the igniter
contactor. Unscrew the igniter.
5. Remove the two (2) 10-32 screws securing
the gas injector to the burner. Separate the
gas injector and gasket from the burner.
6. Disconnect the burner housing from the
blower by removing the six (6) 1/4-20
screws using a 3/8” wrench.
7. Remove the eight (8) 3/8-16 nuts from the
burner flange (Figure 7-3) using a 9/16”
wrench.
NOTE
The burner housing is heavy, weighing
approximately 20 pounds.
BURNER
BURNER
HOUSING
1/4-20
SCREWS
(6)
Figure 7-3
Burner Disassembly Diagram
8. Remove the burner housing from burner
flange by pulling straight up.
7-3
MAINTENANCE
7.7 CONDENSATE DRAIN TRAPS
The Benchmark 3.0 Boiler contains two
condensate traps as shown in Figure 2-5. One
trap is located external to the unit and attached
to the drain pipe from the connecting manifold.
The other trap is an integral part of the exhaust
manifold. These traps should be inspected and,
if necessary, cleaned to ensure proper
operation. Follow the procedures in paragraphs
7.7.1 and 7.7.2.
7.7.1 Connecting Manifold Condensate
Trap
To inspect and clean the trap, proceed as
follows:
1. Disconnect the external condensate trap by
loosening the hose clamps between the trap
and the connecting manifold drain pipe.
2. Remove the connections on the inlet and
outlet sides of the condensate trap shown in
Figure 7-4.
Figure 7-4
External Condensate Trap
7.7.2 Exhaust Manifold Condensate Trap
The exhaust manifold condensate trap also
contains a float and orifice gasket identical to
those shown in Figure 7-4. To inspect and clean
the trap, refer to Figure 7-5 and proceed as
follows:
3. Loosen the four (4) thumbscrews securing
the cover on the condensate trap. Remove
the cover.
1. Loosen the clamp securing the hose to the
condensate drain (Figure 7-5). Disconnect
the hose.
4. Remove the float from the condensate trap.
2. Remove the four bolts securing the flue to
the top of the exhaust manifold. Separate
the flue from the exhaust manifold.
5. Remove the orifice gasket from the trap.
6. Thoroughly clean the trap, float and gasket.
Also inspect the drain piping 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 condensate trap and
replace the trap cover.
8. Reassemble all piping and hose connections
to the condensate trap inlet and outlet.
Reconnect trap to connecting manifold drain
pipe.
7-4
3. From the top of the exhaust manifold,
remove the float and orifice gasket from the
condensate trap.
4. Thoroughly clean the trap, float and gasket.
Also, inspect the drain hose for blockage.
5. After the above items have been inspected
and cleaned, replace the gasket and float in
the condensate trap.
6. Replace the four bolts securing the flue to
the exhaust manifold and connect the hose
to the manifold condensate drain.
MAINTENANCE
FLUE
UNIT
FRAME
BOLTS
(4)
7.9 PLACING THE BOILER BACK IN
SERVICE AFTER A PROLONGED
SHUTDOWN
After a prolonged shutdown (one year or more),
the following procedures must be followed:
EXHAUST
MANIFOLD
1. Review installation requirements included in
Chapter 2.
2. Inspect all piping and connections to the
unit.
CONDENSATE
TRAP
3. Inspect exhaust vent, air duct (if applicable).
DRAIN
4. Perform initial startup per Chapter 4.
HOSE
CLAMP
5. Perform safety device testing and the
scheduled maintenance procedures per
Chapters 6 and 7 of this manual.
1" I.D.
HOSE
TO FLOOR
DRAIN
Figure 7-5
Exhaust Manifold Condensate Trap &
Drain
7.8 SHUTTING THE BOILER DOWN FOR
AN EXTENDED PERIOD OF TIME
If the boiler is to be taken out of service for an
extended period of time (one year or more), the
following instructions must be followed.
1. Set ON/OFF switch on the front panel to the
OFF position to shut down the boiler’s
operating controls.
2. Disconnect AC power from the unit.
3. Close the water supply and return valves to
isolate boiler.
4. Close external gas supply valve.
5. Open relief valve to vent water pressure.
7-5
TROUBLESHOOTING
Chapter 8- TROUBLESHOOTING GUIDE
8.1 INTRODUCTION
This troubleshooting guide is intended to aid
service/maintenance personnel in isolating the
cause of a fault in a Benchmark 3.0 Boiler. The
troubleshooting procedures contained herein are
presented in tabular form on the following pages.
These tables are comprised of three columns
labeled: Fault Indication, Probable Cause and
Corrective Action. The numbered items in the
Probable Cause and Corrective Action columns
correspond to each other.
For example,
Probable Cause No. 1 corresponds to Corrective
Action No. 1, etc.
When a fault occurs in the Benchmark Boiler,
proceed as follows to isolate and correct the
fault:
1. Observe the fault messages displayed in the
Control Box display.
3. Proceed to the Probable Cause column and
start with the first item (1) listed for the Fault
Indication.
4. Perform the checks and procedures listed in
the Corrective Action column for the first
Probable Cause candidate.
5. Continue checking each additional Probable
Cause for the existing fault until the fault is
corrected.
6. Paragraph 8.2 and Table 8-2 contain
additional troubleshooting information which
may apply when no fault message is
displayed.
7. If the fault cannot be corrected using the
information provided in the Troubleshooting
Tables, contact your local AERCO
Representative.
2. Refer to the Fault Indication column in
Troubleshooting Table 8-1 which follows and
locate the Fault that best describes the
existing conditions.
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
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.
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.
8-2
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.
TROUBLESHOOTING
TABLE 8-1. BOILER TROUBLESHOOTING – Continued
FAULT INDICATION
PROBABLE CAUSES
CORRECTIVE ACTION
AIRFLOW FAULT
DURING PURGE
1. Blower not running or running too slow
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.
2. Defective Air Flow Switch
3. Blocked Air flow Switch
4. Blocked Blower inlet or inlet ductwork.
AIRFLOW FAULT
DURING RUN
5. No voltage to switch from control box.
5. Measure for 24 VAC during start sequence from each side of the
switch to ground. If 24VAC is not present refer to qualified
service personnel.
6. PROBABLE CAUSES from 3 to 16
for AIRFLOW FAULT DURING
IGNITION applies for this fault
6. See CORRECTIVE ACTION from 3 to 16 for AIRFLOW
FAULT DURING IGNITION
1. Blower stopped running due to thermal
or current overload
2. Blocked Blower inlet or inlet ductwork
1. Check combustion blower for signs of excessive heat or high
current draw that may trip thermal or current overload devices.
2. Inspect the inlet to the combustion blower including any ductwork
leading up to the combustion blower for signs of blockage.
3. Remove the airflow switch and inspect for signs of blockage,
clean or replace as necessary.
4. Measure the airflow switch for continuity with the combustion
blower running. If there is an erratic resistance reading or the
resistance reading is greater than zero ohms, replace the switch.
5. Run unit to full fire. If the unit rumbles or runs rough, perform
combustion calibration.
3. Blocked airflow switch
4. Defective airflow switch
5. Combustion oscillations
6. PROBABLE CAUSES from 3 to 16
for AIRFLOW FAULT DURING
IGNITION applies for this fault
8-3
6. PROBABLE CAUSES from 3 to 16 for AIRFLOW FAULT
DURING IGNITION applies for this fault
TROUBLESHOOTING
TABLE 8-1. BOILER TROUBLESHOOTING – Continued
FAULT INDICATION
PROBABLE CAUSES
CORRECTIVE ACTION
DELAYED
INTERLOCK OPEN
1. Delayed Interlock Jumper not
installed or removed.
2. Device proving switch hooked to
interlocks is not closed
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)
DIRECT DRIVE
SIGNAL FAULT
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. 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.
FLAME LOSS
DURING IGN
1. Burner Ground Screw not installed
or loose.
2. Worn flame detector
1. Inspect and install/retighten Burner Ground Screw.
3. No spark from Spark Plug
4. Defective Ignition Transformer
5. Defective Ignition/Stepper (IGST)
Board
6. Defective SSOV
8-4
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.
TROUBLESHOOTING
TABLE 8-1. BOILER TROUBLESHOOTING – Continued
FAULT INDICATION
(continued)
PROBABLE CAUSES
7. Defective Differential Pressure
Regulator
8. Carbon or other debris on Burner
FLAME LOSS
DURING RUN
1. Remove and inspect the Flame Detector for signs of wear or
cracked ceramic. Replace if necessary.
2. Defective Differential Regulator.
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.
5. Blocked condensate drain.
HIGH EXHAUST
TEMPERATURE
HIGH GAS
PRESSURE
1. The Heat Demand Relays on the
Ignition/Stepper board failed to
activate when commanded
1. Press CLEAR button and restart the unit. If the fault persists,
replace Ignition/Stepper (IGST) Board.
2. Relay is activated when not in
Demand
1. Defective exhaust sensor.
2. Defective relay. Replace IGST Board.
2. Carboned heat exchanger due to
incorrect combustion calibration
1. Incorrect supply gas pressure.
2. Defective SSOV Supply Regulator.
8-5
7. Check gas pressure readings using gauge or manometer into
and out of the Air/Fuel Valve to ensure gas is getting to the
burner.
8. Remove the burner and inspect for any carbon or debris. Clean
and reinstall
1. Worn Flame Detector or cracked
ceramic.
3. Poor combustion calibration.
4. Debris on burner.
HEAT DEMAND
FAILURE
CORRECTIVE ACTION
1. Measure the actual exhaust temperature and continuity of the
o
exhaust sensor. If the exhaust temperature is less than 475 F
and the exhaust sensor shows continuity replace the sensor.
o
2. If exhaust temperature is greater than 500 F, check
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 1.8” W.C. (see para. 4.3, step 10), the SSOV Supply
Regulator may be defective.
TROUBLESHOOTING
TABLE 8-1. BOILER TROUBLESHOOTING – Continued
FAULT INDICATION
PROBABLE CAUSES
CORRECTIVE ACTION
continued
3. Defective High Gas Pressure Switch
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.
4. Gas pressure snubber not installed.
HIGH WATER TEMP
SWITCH OPEN
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.
HIGH WATER
TEMPERATURE
IGN BOARD
COMM FAULT
8-6
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
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.
TROUBLESHOOTING
TABLE 8-1. BOILER TROUBLESHOOTING – Continued
FAULT INDICATION
IGN SWTCH CLOSED
DURING PURGE
PROBABLE CAUSES
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
IGN SWTCH OPEN
DURING IGNITION
1. Air/Fuel Valve not rotating to ignition
position.
2. Defective ignition switch
3. Defective Power Supply Board or
fuse
4. Defective IGST Board
INTERLOCK
OPEN
8-7
1. Interlock jumper not installed or
removed
2. Energy Management System does
not have boiler enabled.
CORRECTIVE ACTION
1. Start the unit. The Air/Fuel Valve should rotate to the purge
(open) position. If the valve does not rotate at all or does not
rotate fully open, check the Air/Fuel Valve calibration. If
calibration is okay, the problem may be in the Air-Fuel Valve or
the Control Box. Refer to qualified service personnel
2. . If the Air/Fuel Valve does rotate to purge, check the ignition
switch for continuity between the N.O. and COM terminals. If the
switch shows continuity when not in contact with the cam replace
the switch.
3. Check to ensure that the switch is wired correctly (correct wire
numbers on the normally open terminals). If the switch is wired
correctly, replace the switch
4. Check DS1 & DS2 LEDs on Power Supply Board. If they are not
steady ON, replace Power Supply Board.
5. Check “Heartbeat” LED DS1 and verify it is blinking ON & OFF
every second. If not, replace IGST Board
1. Start the unit. The Air/Fuel Valve should rotate to the purge
(open) position, then back to ignition position (towards closed)
during the ignition cycle. If the valve does not rotate back to the
ignition position, check the Air/Fuel Valve calibration.
If
calibration is okay, the problem may be in the Air/Fuel Valve or
the Control Box. Refer fault to qualified service personnel.
2. If the Air/Fuel Valve does rotate to the ignition position, check the
ignition position switch for continuity between the N.O. and COM
terminals when in contact with the cam.
3. Check DS1 & DS2 LEDs on Power Supply Board. If they are not
steady ON, replace Power Supply Board.
4. Check “Heartbeat” LED DS1 and verify it is blinking ON & OFF
every second. If not, replace IGST Board.
1. Check for a jumper properly installed across the interlock
terminals in the I/O box
2. If there are two external wires on these terminals check any
Energy Management system to see if they have the units
disabled (a jumper may be temporarily installed to see if the
interlock circuit is functioning).
TROUBLESHOOTING
TABLE 8-1. BOILER TROUBLESHOOTING – Continued
FAULT INDICATION
continued
LINE VOLTAGE
OUT OF PHASE
LOW GAS
PRESSURE
PROBABLE CAUSES
3. Device proving switch hooked to
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
LOW WATER
LEVEL
1. Insufficient water level in system
2. Defective water level circuitry.
3. Defective water level probe.
MODBUS COMM
FAULT
PRG SWTCH CLOSED
DURING IGNITION
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
8-8
CORRECTIVE ACTION
3. Check that proving switch for any device hooked to the interlock
circuit is closing and that the device is operational.
1. Check hot and neutral in AC Power Box to ensure they are not
reversed
2. Check transformer wiring, in AC Power Box, against the power
box transformer wiring diagram to ensure it is wired correctly
1. Measure gas pressure upstream of the 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 may be in the Air/Fuel Valve or
the Control Box. Refer fault to qualified service personnel.
2. If the Air/Fuel Valve does rotate to the ignition position, check the
purge switch for continuity between the N.O. and COM terminals.
If the switch shows continuity when not in contact with the cam,
check to ensure that the switch is wired correctly (correct wire
numbers on the normally open terminals).
3. If the switch is wired correctly, replace the switch.
4. Check DS1 & DS2 LEDs on Power Supply Board. If they are not
steady ON, replace Power Supply Board.
5. Check “Heartbeat” LED DS1 and verify it is blinking ON & OFF
every second. If not, replace IGST Board.
TROUBLESHOOTING
TABLE 8-1. BOILER TROUBLESHOOTING – Continued
FAULT INDICATION
PRG SWTCH OPEN
DURING PURGE
PROBABLE CAUSES
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
OUTDOOR TEMP
SENSOR FAULT
1. Loose or broken wiring.
2. Defective Sensor.
3. Incorrect Sensor.
REMOTE SETPT
SIGNAL FAULT
RESIDUAL
FLAME
CORRECTIVE ACTION
1. If the air-fuel valve does rotate, check the purge switch for
continuity when closing. Replace switch if continuity does not
exist.
2. Measure for 24 VAC from each side of the switch to ground. If
24VAC is not present, refer fault to qualified service personnel.
3. Check to ensure that the switch is wired correctly (correct wire
numbers on the normally open terminals).
4. Check DS1 & DS2 LEDs on Power Supply Board. If they are not
steady ON, replace Power Supply Board.
5. Check “Heartbeat” LED DS1 and verify it is blinking ON & OFF
every second. If not, replace IGST Board.
1. Inspect Outdoor Temperature sensor for loose or broken wiring.
2. Check resistance of sensor to determine if it is within
specification.
3. Ensure that the correct sensor is installed.
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. 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.
1. SSOV not fully closed.
1. Check open/close indicator window of Safety Shut-Off Valve
(SSOV) and ensure that the SSOV is fully closed. If not fully
closed, replace the valve and or actuator.
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.
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
(continued)
SSOV FAULT
DURING PURGE
SSOV FAULT
DURING RUN
SSOV RELAY
FAILURE
SSOV
SWITCH OPEN
PROBABLE CAUSES
2. Defective Flame Detector
3.
1. SSOV switch closed for 15 seconds
during run.
1. Replace or adjust microswitch in SSOV actuator. If fault
persists, replace actuator.
1. SSOV relay failed on board.
1. Press CLEAR button and restart unit. If fault persists, replace
Ignition/Stepper (IGST) Board.
1. Actuator not allowing for full closure
of gas valve
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.
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
8-10
2. Replace Flame Detector.
See SSOV SWITCH OPEN
2. SSOV powered when it should not be
STEPPER MOTOR
FAILURE
CORRECTIVE ACTION
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.
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
Hard Light-Off
Fluctuating Gas Pressure
Air/Fuel Valve “hunting” at 80%
Firing Rate
8-11
PROBABLE CAUSES
1. Staged Ignition Ball Valve closed.
2. Clogged/damaged Gas Injector
(Figure 8-2).
3. Defective Staged Ignition Solenoid
(Figure 8-2)
1. Gas pressure going into unit is
fluctuating.
2. Damping Orifice not installed.
1. IGST and Power Supply Boards in
Control Box are outdated.
CORRECTIVE ACTION
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.
TROUBLESHOOTING
Figure 8-2
Staged Ignition Solenoid Location
Figure 8-1
High Pressure Gas Switch & Snubber Locations
Figure 8-3
Damping Orifice Location
8-12
TROUBLESHOOTING
Table 8-3
BMK 3.0 LN (3.3 KΩ) Temperature Sensor and Temperature
Transmitter Outputs
TEMP
ºC
TEMP
ºF
UA33
Resistance
Ohm
Volts
outputs
UA33
TEMP
ºC
TEMP
ºF
UA33
Resistance
Ohm
Volts
outputs
UA33
-40
-30
-20
-10
-5
0
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
-40
-22
-4
14
23
32
33.8
35.6
37.4
39.2
41
42.8
44.6
46.4
48.2
50
51.8
53.6
55.4
57.2
59
60.8
62.6
64.4
66.2
68
69.8
71.6
73.4
75.2
77
78.8
80.6
111177
58443
32814
18200
13972
10775
10240
9735
9256
8806
8380
7977
7595
7234
6891
6566
6260
5969
5692
5432
5184
4972
4759
4547
4334
4122
3958
3793
3629
3464
3300
3172
3044
0.289
0.523
0.904
1.560
1.972
2.459
2.564
2.680
2.791
2.906
3.022
3.143
3.267
3.387
3.514
3.643
3.772
3.900
4.040
4.170
4.310
4.440
4.570
4.710
4.860
5.020
5.150
5.290
5.520
5.580
5.740
5.870
6.010
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
82.4
84.2
86
87.8
89.6
91.4
93.2
95
96.8
98.6
100.4
102.2
104
105.8
107.6
109.4
111.2
113
114.8
116.6
118.4
120.2
122
123.8
125.6
127.4
129.2
131
132.8
134.6
136.4
138.2
140
2915
2787
2659
2549
2443
2343
2247
2156
2068
1984
1905
1830
1758
1688
1622
1559
1499
1441
1386
1334
1283
1234
1189
1145
1102
1061
1023
986
950
916
883
852
821
6.16
6.31
6.470
6.610
6.760
6.900
7.040
7.180
7.320
7.460
7.600
7.730
7.860
8.000
8.130
8.250
8.490
8.510
8.630
8.750
8.960
8.980
9.100
9.210
9.320
9.430
9.530
9.640
9.740
9.840
9.920
10.030
10.120
8-13
APPENDIX A
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
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
A-2
Internal Setpoint
Allows internal 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.
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
Specifies the amount of time to wait (0 to 120 sec.)
between activating the Aux Relay (due to a demand)
and checking the pre-purge string to start the boiler.
Default is 0 sec.
Failsafe Mode
Allows the Failsafe mode to be set to either
Constant Setpoint or Shutdown. Default is
Shutdown.
mA Output
Must be set to Fire Rate Out for Benchmark 3.0LN.
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
A-4
Prop Band
Generates 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.
APPENDIX B
APPENDIX B - STARTUP, STATUS AND FAULT MESSAGES
TABLE B-1. STARTUP AND STATUS MESSAGES
MESSAGE
DISABLED
HH:MM pm MM/DD/YY
STANDBY
DEMAND DELAY
XX sec
PURGING
XX sec
IGNITION TRIAL
XX sec
FLAME PROVEN
WARMUP
XX sec
WAIT
DESCRIPTION
Displayed if ON/OFF switch is set to OFF. The display also
shows the time and date that the unit was disabled.
Displayed when ON/OFF switch is in the ON position, but
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.
Prompts the operator to wait.
B-1
APPENDIX B
TABLE B-2. FAULT MESSAGES
FAULT MESSAGE
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
B-2
FAULT DESCRIPTION
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.
APPENDIX B
TABLE B-2. FAULT MESSAGES - Continued
FAULT MESSAGE
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
FAULT DESCRIPTION
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
APPENDIX C
TEMPERATURE SENSOR RESISTANCE CHART
(BALCO)
TEMPERATURE SENSOR
AERCO PART NO. 123449
R = RESISTANCE (OHMS) T = TEMPERATURE (°F)
R=.00161T^2+1.961T+854.841
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
APPENDIX D
APPENDIX D. - INDOOR/OUTDOOR RESET RATIO CHARTS
Table D-1. Header Temperature for a Building Reference Temperature of 50F
RESET RATIO
Air
Temp
0.6
0.8
1.0
1.2
1.4
1.6
1.8
2.0
2.2
2.4
50F
45F
40F
35F
30F
25F
20F
15F
10F
5F
0F
-5F
-10F
-15F
-20F
50
53
56
59
62
65
68
71
74
77
80
83
86
89
92
50
54
58
62
66
70
74
78
82
86
90
94
98
102
106
50
55
60
65
70
75
80
85
90
95
100
105
110
115
120
50
56
62
68
74
80
86
92
98
104
110
116
122
128
134
50
57
64
71
78
85
92
99
106
113
120
127
134
141
148
50
58
66
74
82
90
98
106
114
122
130
138
146
154
162
50
59
68
77
86
95
104
113
122
131
140
149
158
167
176
50
60
70
80
90
100
110
120
130
140
150
160
170
180
190
50
60
72
83
94
105
116
127
138
149
160
171
182
193
204
50
62
74
86
98
110
122
134
146
158
170
182
194
206
218
Table D-2. Header Temperature for a Building Reference Temperatrure of 60F
RESET RATIO
Air
Temp
0.6
0.8
1.0
1.2
1.4
1.6
1.8
2.0
2.2
2.4
60F
55F
50F
45F
40F
35F
30F
25F
20F
15F
10F
5F
0F
-5F
-10F
-15F
-20F
60
63
66
69
72
75
78
81
84
87
90
93
96
99
102
105
108
60
64
68
72
76
80
84
88
92
96
100
104
108
112
116
120
124
60
65
70
75
80
85
90
95
100
105
110
115
120
125
130
135
140
60
66
72
78
84
90
96
102
108
114
120
126
132
138
144
150
156
60
67
74
81
88
95
102
109
116
123
130
137
144
151
158
165
172
60
68
76
84
92
100
108
116
124
132
140
148
156
164
172
180
188
60
69
78
87
96
105
114
123
132
141
150
159
168
177
186
195
204
60
70
80
90
100
110
120
130
140
150
160
170
180
190
200
210
60
71
82
93
104
115
126
137
148
159
170
181
192
203
214
60
72
84
96
108
120
132
144
156
168
180
192
204
216
D-1
APPENDIX D
Table D-3. Header Temperature for a Building Reference Temperature of 65F
RESET RATIO
Air
Temp
0.6
0.8
1.0
1.2
1.4
1.6
1.8
2.0
2.2
2.4
65
60
55
50
45
40
35
30
25
20
15
10
5
0
-5
-10
-15
-20
65
68
71
74
77
80
83
86
89
92
95
98
101
104
107
110
113
116
65
69
73
77
81
85
89
93
97
101
105
109
113
117
121
125
129
133
65
70
75
80
85
90
95
100
105
110
115
120
125
130
135
140
145
150
65
71
77
83
89
95
101
107
113
119
125
131
137
143
149
155
161
167
65
72
79
86
93
100
107
114
121
128
135
142
149
156
163
170
177
201
65
73
81
89
97
105
113
121
129
137
145
153
161
169
177
185
193
218
65
74
83
92
101
110
119
128
137
146
155
164
173
182
191
200
209
65
75
85
95
105
115
125
135
145
155
165
175
185
195
205
215
65
76
87
98
109
120
131
142
153
164
175
186
197
208
219
65
77
89
101
113
125
137
149
161
173
185
197
209
Table D-4. Header Temperature for a Building Reference Temperature of 70F
RESET RATIO
Air
Temp
0.6
0.8
1.0
1.2
1.4
1.6
1.8
2.0
2.2
2.4
70F
65F
60F
55F
50F
45F
40F
35F
30F
25F
20F
15F
10F
5F
0F
-5F
-10F
-15F
-20F
70
73
76
79
82
85
88
91
94
97
100
103
106
109
112
115
118
121
124
70
74
78
82
86
90
94
98
102
106
110
114
118
122
126
130
134
138
142
70
75
80
85
90
95
100
105
110
115
120
125
130
135
140
145
150
155
160
70
76
82
88
94
100
106
112
118
124
130
136
142
148
154
160
166
172
178
70
77
84
91
98
105
112
119
126
133
140
147
154
161
168
175
182
189
196
70
78
86
94
102
110
118
126
134
142
150
158
166
174
182
190
198
206
214
70
79
88
97
106
115
124
133
142
151
160
169
178
187
196
205
214
70
80
90
100
110
120
130
140
150
160
170
180
190
200
210
70
81
92
103
114
125
136
147
158
169
180
191
202
213
70
82
94
106
118
130
142
154
166
178
190
202
214
D-2
APPENDIX D
Table D-5. Header Temperature for a Building Reference Temperature of 75F
RESET RATIO
Air
Temp
0.6
0.8
1.0
1.2
1.4
1.6
1.8
2.0
2.2
2.4
75F
70F
65F
60F
55F
50F
45F
40F
35F
30F
25F
20F
15F
10F
5F
0F
-5F
-10F
-15F
75
78
81
84
87
90
93
96
99
102
105
108
111
114
117
120
123
126
129
75
79
83
87
91
95
99
103
107
111
115
119
123
127
131
135
139
143
147
75
80
85
90
95
100
105
110
115
120
125
130
135
140
145
150
155
160
165
75
81
87
93
99
105
111
117
123
129
135
141
147
153
159
165
171
177
183
75
82
89
96
103
110
117
124
131
138
145
152
159
166
173
180
187
194
201
75
83
91
99
107
115
123
131
139
147
155
163
171
179
187
195
203
211
219
75
84
93
102
111
120
129
138
147
156
165
174
183
192
201
210
219
75
85
95
105
115
125
135
145
155
165
175
185
195
205
215
75
86
97
108
119
130
141
152
163
174
185
196
207
218
75
87
99
111
123
135
17
159
171
183
195
207
219
Table D-6. Header Temperature for a Building Reference Temperature of 80F
RESET RATIO
Air
Temp
0.6
0.8
1.0
1.2
1.4
1.6
1.8
2.0
2.2
2.4
80F
75F
70F
65F
60F
55F
50F
45F
40F
35F
30F
25F
20F
15F
10F
5F
0F
-5F
-10F
80
83
86
89
92
95
98
101
104
107
110
113
116
119
122
125
128
131
134
80
84
88
92
96
100
104
108
112
116
120
124
128
132
136
140
144
148
152
80
85
90
95
100
105
110
115
120
125
130
135
140
145
150
155
160
165
170
80
86
92
98
104
110
116
122
128
134
140
146
152
158
164
170
176
182
188
80
87
94
101
108
115
122
129
136
143
150
157
164
171
178
185
192
199
206
80
88
96
104
112
120
128
136
144
152
160
168
176
184
192
200
208
216
80
89
98
107
116
125
134
143
152
161
170
174
188
197
206
215
80
90
100
110
120
130
140
150
160
170
180
190
200
210
80
91
102
113
124
135
146
157
168
179
190
201
212
80
92
104
116
128
140
152
164
176
188
200
212
D-3
APPENDIX D
Table D-7. Header Temperature for a Building Reference Temperature of 90F
RESET RATIO
Air
Temp
0.6
0.8
1.0
1.2
1.4
1.6
1.8
2.0
2.2
2.4
90F
85F
80F
75F
70F
65F
60F
55F
50F
45F
40F
35F
30F
25F
20F
15F
10F
5F
0F
90
93
96
99
102
105
108
111
114
117
120
123
126
129
132
135
138
141
144
90
94
98
102
106
110
114
118
122
126
130
134
138
142
146
150
154
158
162
90
95
100
105
110
115
120
125
130
135
140
145
150
155
160
165
170
175
180
90
96
102
108
114
120
126
132
138
144
150
156
162
168
174
180
186
192
198
90
97
104
111
118
125
132
139
146
153
160
167
174
181
188
195
202
209
216
90
98
106
114
122
130
138
146
154
162
170
178
186
194
202
210
218
90
99
108
117
126
135
144
153
162
171
180
189
198
207
216
90
100
110
120
130
140
150
160
170
180
190
200
210
90
101
112
123
134
145
156
167
178
189
200
90
102
114
126
138
150
162
174
186
198
210
D-4
APPENDIX E
BOILER DEFAULT SETTINGS
MENU & OPTION
FACTORY DEFAULT
Setup Menu
Password
0
Language
English
Unit of Temp
Comm Address
Baud Rate
Fahrenheit
0
9600
Configuration Menu
Internal Setpt
130°F
Unit Type
Boiler
Unit Size
3.0 MBTU
Boiler Mode
Constant Setpoint
Remote Signal
(If Mode = Remote Setpoint, Direct Drive or
Combination)
4 – 20 mA / 1-5V
Bldg Ref Temp
(If Boiler Mode = Outdoor Reset)
70°F
Reset Ratio
(If Boiler Mode = Outdoor Reset)
1.2
Outdoor Sensor
System Start Tmp
(If Outdoor Sensor = Enabled)
Disabled
60°F
Setpt Lo Limit
60°F
Setpt Hi Limit
Temp Hi Limit
200°F
Max Fire Rate
215°F
100%
Pump Delay Timer
0 min
Aux Start On Dly
0 sec
Failsafe Mode
mA Output
Shutdown
Fire Rate Out
CAUTION: DO NOT Change
Lo Fire Timer
Setpt Limit Band (If Setpt Limiting = Enabled)
2 sec
5°F
Tuning Menu
Prop Band
70°F
Integral Gain
1.00
Derivative Time
0.0 min
E-1
210
160
240
TEST PRESS.
(PSIG)
16 3/16
(41.1)
DUAL-FUEL
WITH IRI
GAS TRAIN
5 1/4
(13.3)
13.5
(34.3)
42 1/8
(107.0)
23 3/16 (58.8)
12 1/16
(30.6)
N/A
FOR IRI
GAS TRAIN
OPTION
25 5/16
(64.3)
DIM.
"C"
54 5/16
(137.0)
12 3/4
(32.4)
"A" "C" "B"
5 7/8
(14.9)
2 5/8
(6.6)
6 7/8
(17.4)
2" NPT PROPANE GAS
INLET CONN.
1-1/2" NPT
FOR DUAL-FUEL
DRAIN CONN.
OPTION ONLY
1" NPT GAS
VENT CONN.
FOR "IRI" GAS
TRAIN OPTION" ONLY
2" NPT NATURAL GAS
INLET CONN.
CONDENSATE PORT
4"-150# FLG'D
COLD WATER
INLET CONN.
7 7/16
(18.9)
14 5/16
(36.4)
7 15/16
(20.1)
8" AIR INLET
8" EXHAUST
OUTLET
PRESS. RELIEF VALVE
3000
MIN. RELIEF VA.
CAPACITY MBH
38
(96.7)
33
(84.7)
CONDENSATE PORT
CONTROL
PANEL
DISPLAY
DWN.BY CZ
SCALE
CHKD.
REV.DATE
DATE072606
A
SIZE
APPD.
AP-A-811
BENCHMARK 3 MIL. LOW NOx BTU
GAS FIRED BOILER
DIMENSIONAL DRAWINGS
NORTHVALE, NJ 07647
79
(201.4)
36 1/4
(92.2)
18
(45.7)
15
(38.0)
28
(71.1)
3/4" ELECTRICAL
CONDUIT CONNECTION
23
(58.4)
DOOR SWING
LIFTING LUGS
AERCO
THIS AREA TO BE
ACCESSIBLE FOR
MAINTENANCE.
78 (198.1)
64 (162.6)
4" CONCRETE PAD - SET
23 5/8 (60.0)
UNIT FLUSH AT REAR
NOTES:
1) ALL DIMENSIONS SHOWN ARE IN INCHES (CENTIMETERS).
2) RELIEF VALVE, TRIDICATOR & CONDENSATE TRAP ARE INCLUDED SEPARATELY IN SHIPMENT.
3) FIELD PIPING TO THE BOILER MUST ENSURE THAT THE HOT WATER OUTLET CONNECTION FLEXIBLE PIPING
(LOCATED INSIDE THE BOILER) IS LEVEL OR SLOPING UP AS IT EXITS THE BOILER.
25 7/16
(64.6)
15 7/16
(39.2)
DUAL-FUEL
25 7/16
WITH FM
GAS TRAIN (64.6)
DIM.
"B"
N/A
DIM.
"A"
NAT. GAS 28 15/16
ONLY
(73.5)
BMK3.0 LN
MODEL
69 5/8
(176.9)
PRESS./TEMP. GAUGE
4"-150# FLG'D
HOT WATER OUTLET CONN. (SEE NOTE 3)
SECTION VIII STAMP U (SECONDARY H.X.)
178
HT'G SURFACE
SQ.FT.
ASME B & PV CODE: SECTION IV STAMP H (PRIMARY H.X.)
MAXIMUM
TEMP. (°F)
HEAT EXCHANGERS & COMBUSTION CHAMBER DESIGN STANDARDS
MAX. WORKING
PRESS. (PSIG)
D
REV.
APPENDIX F
F-1
APPENDIX F
F-2
APPENDIX F
F-3
APPENDIX F
F-4
APPENDIX F
F-5
APPENDIX F
F-6
APPENDIX F
EXHAUST MANIFOLD
ITEM PART NO. QTY
1
2
3
4
39033
49102
39036
DESCRIPTION
1
EXHAUST MANIFOLD
3 EXHAUST MANIFOLD SEAL
1 CONNECTING MANIFOLD
GAS TRAIN ASSEMBLY
ITEM PART NO. QTY
DESCRIPTION
STD FM GAS TRAIN ASSEMBLY
22026-1
IRI GAS TRAIN ASSEMBLY
22026-2
(3) 5
1
DUAL FUEL FM GAS TRAIN
22040-1
DUAL FUEL IRI GAS TRAIN
22040-2
HOSES,GASKETS, & INSULATION
ITEM PART NO. QTY
DESCRIPTION
27
88003
1
O-RING #2-339
28
59041
1
HOSE ASSEMBLY, 4"
29
80024-8
1
INSULATION 4" FLEX PIPE 8 LONG
30 80024-12
1
INSULATION 4" FLEX PIPE 12" LONG
31 80021-12
32
80022
33
80023
34
4-58
35
62005
36
59030
37
1
1
2
3
1
1
INSULATION 4" PIPE 12" LONG
CONNECTING INSULATION
TOP MANIFOLD INSULATION
4" FLANGE GASKET
CORD GRIP
HOSE ASSY, 4" (FLEXIBLE)
BURNER & AIR/FUEL VALVE
DESCRIPTION
ITEM PART NO. QTY
BURNER
ASSEMBLY
6
24030
1
(SEE PL-A-151)
7
24010
24010-1
1
A/F VALVE ASSEMBLY
DUEL FUEL A/F VALVE ASSY.
BMK3.0LN STAGED
IGNITION ASSY.
8
24039
1
9
81030
2
10
81019
HOUSING GASKET
1 BURNER
(PART OF BURNER ASS'Y)
(PART OF BURNER ASSY.)
BURNER GASKET
(PART OF BURNER ASS'Y)
HEAT EXCHANGER
ITEM PART NO. QTY
DESCRIPTION
11
80018
1
12
80019
1
13
80020
1
14
15
28030
28029
1
1
PRIMARY HEAT EXCH.
UPPER INSULATION
PRIMARY HEAT EXCH.
LOWER INSULATION
SECONDARY HEAT EXCH.
INSULATION
PRIMARY HEAT EXCH.
SECONDARY HEAT EXCH.
BLOWER
ITEM PART NO. QTY
DESCRIPTION
1
BLOWER ASSEMBLY
16
24045
17 123815
1
IRIS AIR DAMPER
18 123681
1 8"x6" REDUCING COUPLING
19
33028
1
BLOWER BRACKET
20 124245
4
5/16 DAMPENER
21
81057
1
BLOWER GASKET
22
96006
1
6" 90 DEG ELBOW
23
96009
1 6" DIAM. x 4" LG DUCT W/PORT
24
96008
1
6" DIAM. x 4" LG DUCT
25 123990
1 REDUCER OFFSET COVER
26 123583
1
CLAMP HOSE SAE #96
INC.
AERCO INTERNATIONAL,
NORTHVALE, NJ
07647
BENCHMARK 3.0 LOW NOx
BOILER PARTS LIST
DRAWN BY SD
DATE 12/02/08
PL - A - 150 E
(SHEET 1 OF 7)
F-7
APPENDIX F
OTHER DUAL FUEL COMPONENTS
CONTROLS
ITEM PART NO. QTY
DESCRIPTION
ITEM PART NO. QTY
DESCRIPTION
38
123966
1
OVER TEMP SWITCH AUTO
72031
1
"PROPANE" LABEL
(1)(5) 73
39
123552
1
OVER TEMP SWITCH MANUAL
72032
1
"NAT. GAS" LABEL
(1)(5) 74
BLOWER PROOF SWITCH
40 61002-7
1
DOUBLE GAS TRAIN WIRING
63032
1
(5)(6) 75
BLOCKED INLET SWITCH
41 61002-5
1
HARNESS
76
65024
1
FUEL
SELECTOR
SWITCH
42
161560
1
I /O WIRING BOX
(5)
43
1
C-MORE CONTROL BOX
44 GP-122464
45
33030
64012-1
46
64012-2
47
(4) 48
124310
(4) 49
124380
58009
(4) 50
1
1
IGNITION TRANSFORMER
VFD MOUNTING BRACKET
VFD (208-230 V)
VFD (460V)
1
1
1
460V TRANSFORMER
500 VAC, 4 AMP FUSE
460V Terminal Cover Kit
52
79002
53
61011
54
64018
55 GP-122569
56
63016
57
124320
1
1
1
1
1
1
460V TRANSFORMER LABEL
AIR TEMP SENSOR
TEMPERATURE TRANSMITTER
IGNITION CABLE ASSY.
BMK3.0LN SHELL HARNESS
BLOWER HARNESS
PROGRAMMED LOGICSTICK
(NON DUAL FUEL)
DUAL FUEL, NAT. GAS - STICK
DUAL FUEL, PROPANE - STICK
208V POWER WIRING BOX
460V POWER WIRING BOX
(4)
181197
1
24065
58
59
(1)(6)
(7)
1
24065-2
24065-3
64016
64017
1
60
63015
1
BMK3.0LN GAS TRAIN WIRING
HARNESS
61
62
122843
123449
1
1
LOW WATER CUT-OFF
SHELL TEMP. SENSOR
63
161521
1
THERMOWELL, DUAL AQUASTAT BULB
64
61002-1
1
65
77
33036
1
(5)
78
72030
1
FUEL SELECTOR SWITCH
MOUNTINGBRACKET
FUEL SELECTOR SWITCH LABEL
(5)
79
63034
1
DUAL FUEL WIRING HARNESS
SHEET METAL / PANEL ASSEMBLY
ITEM PART NO
QTY
DESCRIPTION
80
37004
1
LEFT REAR PANEL
81
37003
1
RIGHT REAR PANEL
82
49028
2
TOP RAIL
83
201233
1
MOUNTING PANEL
FRONT PANEL
84
201113
1
ENCLOSURE
85
201120
1
FRONT DOOR ASSY.
86 GP-122620
4
HANDLE
87
30022
2
TOP PANEL
88
37002
4
SIDE PANEL
89
74004
1
BMK3.0LN LOGO
OTHER PARTS
ITEM
90
PART NO
99017
61002-15
1
61002-16
DUAL FUEL HGPS - NAT. GAS
DUAL FUEL HGPS - PROPANE
OTHER ACCESORIES / PARTS
ITEM PART NO. QTY
DESCRIPTION
(1)(2) 66
1
PRESS./TEMP. GAUGE
69087 −
67 SEE SD-A-700 1
PRESSURE RELIEF VALVE
68 123540
(1) 69
91030
70 12820-11
71
59043
(1) 72
24060
DESCRIPTION
1
GAS PRESSURE SNUBBER PART OF GAS TRAIN
LOW GAS PRESSURE SWITCH
NOTES:
(1)
(2)
(1)(7)
QTY
HIGH GAS PRESSURE SWITCH
(NON DUAL FUEL)
61002-3
(6)(8)
(5)
1
1
1
1
1
EXT. MANUAL SHUT-OFF VALVE
1" DRAIN HOSE, 60" LG
1-1/2" NPT BALL VALVE
CONDENSATE FLOAT
COND. TRAP ASSEMBLY
(3)
NOT SHOWN IN DRAWING
-5 (30 AND 50 PSI RELIEF VALVE SETTING)
-6 (60,75,100 & 125 PSI RELIEF VALVE SETTING)
-7 (150 PSI RELIEF VALVE SETTING)
FOR PICTORAL PURPOSES ONLY,
FM GAS TRAIN (NON DUAL FUEL) IS SHOWN
FOR 460 V OPTION ONLY
ONLY NEEDED ON DUAL FUEL
PART OF GAS TRAIN ASSY.
TWO (2) REQUIRED FOR DUAL FUEL BMK3.0 LN
(4)
(5)
(6)
(7)
(8) SEE DRAWING AP-A-826 FOR DUAL FUEL DETAILS
INC.
AERCO INTERNATIONAL,
NORTHVALE, NJ
07647
BENCHMARK 3.0 LOW NOx
BOILER PARTS LIST
DRAWN BY SD
DATE 12/02/08
F-8
PL - A - 150 E
(SHEET 2 OF 7)
APPENDIX F
A
1
2
11
13
14
15
12
2
3
25 53
61
2
8
6
18
24
17
10
39
23
40
38
9
55
41
22
26
44
16
DETAIL A
SCALE 1 : 10
5
AERCO
INTERNATIONAL, INC.
NORTHVALE, NJ
07647
BENCHMARK 3.0 LOW NOx
BOILER PARTS LIST
DRAWN BY SD
DATE 12/02/08
PL - A - 150
(SHEET 3 OF 7)
F-9
E
APPENDIX F
67 34 30
31
28
20
19
B
B
71
SECTION B-B
SCALE 1 : 18
36
70
34
32
29
33
34
21
7
27
AERCO
35
63
62
07647
BENCHMARK 3.0 LOW NOx
BOILER PARTS LIST
DRAWN BY SD
DATE 12/02/08
F-10
INTERNATIONAL, INC.
NORTHVALE, NJ
PL - A - 150
(SHEET 4 OF 7)
E
APPENDIX F
46
59
50
49
DETAIL B:
43
B
45
C
42
58
SEE DETAIL C
52
48
DETAIL C:
FUEL SELECTOR SWITCH
(DUAL FUEL ONLY)
54
78
76 77 79
65
90
FM GAS TRAIN
(NON DUAL FUEL)
56
57
64
AERCO
INTERNATIONAL, INC.
NORTHVALE, NJ
07647
BENCHMARK 3.0 LOW NOx
BOILER PARTS LIST
DRWN BY SD
DATE 12/02/08
PL - A - 150
(SHEET 5 OF 7)
E
F-11
APPENDIX F
82
83
80
81
AERCO
INTERNATIONAL, INC.
NORTHVALE, NJ
07647
BENCHMARK 3.0 LOW NOx
BOILER PARTS LIST
84
F-12
DRWN BY SD
DATE 12/02/08
PL - A - 150
(SHEET 6 OF 7)
E
APPENDIX F
87
85
89
88
86
AERCO
INTERNATIONAL, INC.
NORTHVALE, NJ
07647
BENCHMARK 3.0 LOW NOx
BOILER PARTS LIST
DRWN BY SD
DATE 12/02/08
PL - A - 150
(SHEET 7 OF 7)
E
F-13
APPENDIX G
G-1
APPENDIX G
G-2
APPENDIX G
G-3
APPENDIX G
G-4
APPENDIX G
G-5
APPENDIX H
H-1
APPENDIX H
H-2
APPENDIX H
H-3
APPENDIX H
H-4
APPENDIX I
RECOMMENDED PERIODIC TESTING CHECK LIST
WARNING
NOTE: Periodic testing of all boiler controls and safety devices is required to determine that they are operating as
designed. Precautions shall be taken while tests are being performed to protect against bodily injury and property
damage. The owner or user of an automatic boiler system should set up a formal system of periodic preventive
maintenance and testing. Tests should be conducted on a regular basis and the results recorded in a log-book.
Accomplished
Frequency
By
Remarks
Refer to indicated paragraphs of this manual for detailed procedures
Gauges, monitors and
Visual inspection and record readings in operator
Daily
Operator
indicators
log
Instrument and
Visual check against factory recommended
Daily
Operator
equipment settings
specifications
Weekly
Operator
Verify factory settings
SemiService
Firing Rate Control
Verify factory settings
Annually
Technician
Service
Check with combustion calibration test
Annually
Technician equipment. See paragraph 7.4 and Chapter 4.
Flue, vent, stack or
Visually inspection condition and check for
Monthly
Operator
intake air duct
obstructions
Igniter
Weekly
Operator
See paragraph 7.2
Air/Fuel Valve position
Weekly
Operator
Check position indicator dial (paragraph 3.8)
Service
Check for leakage in accordance with the SSOV
SSOV Leakage test
Annually
Technician manufacturer’s (Siemens) recommendations.
Close manual gas shutoff valve and check safety
Flame failure
Weekly
Operator
shutdown. See paragraph 6.7
Check flame strength using the Control Panel
Flame signal strength
Weekly
Operator
Operating Menu. See paragraph 3.4.
Low water level cut off
Weekly
Operator
See paragraph 6.4
and alarm
Perform a slow drain test in accordance with
SemiSlow drain test
Operator
ASME Boiler and Pressure Vessel Code,
Annually
Section IV.
High water temperature
Service
Annually
See paragraph 6.4
safety control test
Technician
Operating controls
Annually
Operator
See paragraph 3.2
Low air flow
Monthly
Operator
See paragraph 6.6
High and low gas
Monthly
Operator
See paragraphs 6.2 and 6.3
pressure interlocks
Air/Fuel Valve purge
Service
Annually
See paragraph 6.10
position switch
Technician
Air/Fuel Valve ignition
Service
Annually
See paragraph 6.11
position switch
Technician
Check per A.S.M.E. Boiler and Pressure Vessel
Safety valves
As required
Operator
Code, Section IV
Inspect burner
SemiService
See paragraph 7.6
components
Annually
Technician
Item
I-1
APPENDIX J
BENCHMARK CONTROL PANEL EXPLODED VIEW
J-1
P1
P2
P3
P4
P5
P6
APPENDIX J
BENCHMARK CONTROL PANEL REAR VIEW
J-2
APPENDIX K
APPENDIX K
NATURAL GAS COMBUSTION CALIBRATION
PROCEDURE FOR UNIT SERIAL NUMBERS
BELOW G-07-1901
K-1
APPENDIX K
K-1. NATURAL GAS COMBUSTION
CALIBRATION
The combustion calibration procedures provided
in this Appendix apply only to Benchmark 3.0LN
units with serial numbers below G-07-1901.
All Benchmark 3.0LN Boilers are 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.
10. Next, verify that the gas pressure
downstream of SSOV No. 1 is 1.5” W.C. for
both FM and IRI gas trains. If gas pressure
adjustment is required, remove the brass
hex nut on downstream SSOV No. 1
containing the gas pressure regulator
(Figure K-1). Make gas regulator adjustments using a flat-tip screwdriver to obtain
1.5” W.C.
K-2
Figure K-1
Regulator Adjustment Screw Location
11. Raise the firing rate to 100% and verify that
the gas pressure downstream of SSOV No.
1 remains at 1.5” 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 K-1. Also, ensure that the
carbon monoxide (CO) and nitrogen oxide
(NOx) readings do not exceed the values
shown.
Table K-1
Combustion Oxygen Levels for a 100%
Firing Rate
Inlet Air
Temp
>100°F
90°F
80°F
<70°F
Oxygen %
± 0.2
4.8 %
5.0 %
5.2 %
5.3 %
Carbon
Monoxide
<100 ppm
<100 ppm
<100 ppm
<100 ppm
NOx
<30 ppm
<30 ppm
<30 ppm
<30 ppm
APPENDIX K
14. If necessary, adjust the iris air damper
shown in Figure K-2 until the oxygen level is
within the range specified in Table K-1.
16. Locate the Variable Frequency Drive (VFD)
behind the front door of the unit. Refer to the
VFD operating controls shown in Figure K-3.
15. Once the oxygen level is within the specified
range at 100%, lower the firing rate to 70%.
Figure K-3
VFD Controls and Displays
17. Press the M (Menu) programming key on
the VFD.
18. Using the up (▲) arrow key, select VFD
parameter 21. The selected parameter will
appear in the left part of the display and the
frequency (Hz) will appear in the right part of
the display.
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.
Figure K-2
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 70%, 50%, 30% and 14% as described
in the following steps. These steps
assume that the inlet air temperature is
within the range of 50°F to 100°F.
20. Press the M key again and observe the
frequency shown in the right part of the
display. The oxygen level at the 70% 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
70% Firing Rate
Oxygen %
± 0.2
6.0 %
Carbon
Monoxide
<100 ppm
NOx
<30 ppm
K-3
APPENDIX K
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.
22. Once the oxygen level is within the specified
range at 70%, lower the firing rate to 50%
and select VFD parameter 20. The oxygen
level at the 50% firing rate should be as
shown below.
Combustion Oxygen Level at
50% Firing Rate
Oxygen %
± 0.2
7.0 %
Carbon
Monoxide
<50 ppm
NOx
<20 ppm
23. Adjust the oxygen level as necessary to
obtain the required reading at the 50% firing
rate.
24. Next, set the firing rate to 30% and select
VFD parameter 19. The oxygen level at the
30% firing rate should be as shown below.
Combustion Oxygen Level at
30% Firing Rate
Oxygen %
± 0.2
8.0 %
Carbon
Monoxide
<50 ppm
NOx
<20 ppm
25. Adjust the oxygen level as necessary to
obtain the required reading at the 30% firing
rate.
K-4
26. Finally, reduce the firing rate to 14% and
select VFD parameter 15. The oxygen level
at the 14% firing rate should be as shown in
the following tabular listing:
NOTE
At a 14% fire rate, if parameter 15 is
above 326, the VFD software will use 326
by default. 326 corresponds to a
frequency of 32.6 Hz.
Combustion Oxygen Level at
14% Firing Rate
Oxygen %
± 0.2
8.5 %
Carbon
Monoxide
<50 ppm
NOx
<20 ppm
27. Adjust the oxygen level as necessary to
obtain the required reading at the 14% firing
rate.
28. This completes the combustion calibration
procedure.
29. Return to Chapter 4, paragraphs 4.4 and 4.5
for Unit Reassembly instructions and
information on Over-Temperature Limit
Switches.
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