AER MODULEX EXT 321 User manual

MODULEX EXT GF-143
User Manual OMM-0087_0F
AERCO International, Inc. •100 Oritani Dr. •Blauvelt, New York 10913 •Phone: [phone]
USER MANUAL
Installation, Operation and Maintenance
MODULEX EXT
Light Commercial Series
Modular Condensing Boilers
Natural Gas Modulating &
Condensing Modular Hot
Water Boiler
LIGHT COMMERCIAL SERIES
Covering Models:
• EXT 321
• EXT 481
• EXT 641
• EXT 802
• EXT 962
• EXT 1123
Latest Update: 07/13/2015

MODULEX EXT 321, 481, 641, 802, 962, 1123 BOILERS
Installation, Operation & Maintenance Manual
Page 2of 146 AERCO International, Inc. •100 Oritani Dr. •Blauvelt, NY 10913 OMM-0087_0F
07/13/15 Phone: [phone] GF-143
DISCLAIMER
The information contained in this manual is subject to change without notice from AERCO
International, Inc. AERCO makes no warranty of any kind with respect to this material, including,
but not limited to, implied warranties of merchantability and fitness for a particular application.
AERCO International is not liable for errors appearing in this manual, nor for incidental or
consequential damages occurring in connection with the furnishing, performance, or use of
these materials.
AERCO Technical Support:
(Mon–Fri, 8am-5pm EST)
1 [phone]
AERCO Document Conventions
In this document, some types of information are presented as shown in the following examples:
Message Type Example and Description
Notes
NOTE
NOTE messages indicate specific information related to the
surrounding contextual information, and highlighted for special
attention.
Cautions
CAUTION!
CAUTION messages inform of potential problems relating to the
functioning of equipment, safety to persons, harm to the
environment, and/or damage to property or equipment.
Warnings
WARNING!
WARNING messages warn of potential dangerous situations that
may result in serious injury and/or death to persons or animals.
Text is red within a red box.
Instructions
How Instructions are Presented
1. Instructions are shown in a blue box with an underlined title.
2. All text, excepting in accompanying illustrations, is colored blue.
3. All procedures are listed in steps starting with “1.” and using
letters [a), b), c), etc.] indicating sub=steps.
4. Steps that are continued on the next page have a “- Continued”
appended to the instruction title.

MODULEX EXT 321, 481, 641, 802, 962, 1123 BOILERS
Installation, Operation & Maintenance Manual
OMM-0087_0F AERCO International, Inc. •100 Oritani Dr. •Blauvelt, NY 10913 Page 3of 146
GF-143 Phone: [phone]/15
TABLE OF CONTENTS
CHAPTER 1: GENERAL INFORMATION ................................................................................................ 7
1.1 Correct Use of the Appliance...............................................................................................................................7
1.2 Water Treatment .................................................................................................................................................7
1.3 Information to Be Made Available To The User ..................................................................................................7
1.4 Safety Warnings...................................................................................................................................................8
1.5 Modifications To Parts Connected To The Appliance ..........................................................................................8
1.6 For Appliances Operating With Propane Gas ......................................................................................................9
1.7 Data Plate ..........................................................................................................................................................10
1.8 Operational Requirements ................................................................................................................................11
General Requirements............................................................................................................................111.8.1
Regulatory Requirements .......................................................................................................................111.8.2
Water Quality Requirements ..................................................................................................................121.8.3
1.9 Tools, Materials, And Additional Equipment.....................................................................................................13
1.10 Disposal............................................................................................................................................................13
1.11 General Warnings ............................................................................................................................................13
Using the Operation and Maintenance Manual ...................................................................................131.11.1
Installation and Servicing Personnel.....................................................................................................131.11.2
Installation Materials ............................................................................................................................131.11.3
Preparing Boiler for Servicing ...............................................................................................................141.11.4
Returning a Boiler to Service ................................................................................................................141.11.5
Change in Ownership............................................................................................................................141.11.6
1.12 Operational Limits of the Boiler.......................................................................................................................14
CHAPTER 2: TECHNICAL FEATURES AND DIMENSIONS ................................................................ 15
2.1 Modulex EXT Technical Features .......................................................................................................................15
Temperature Control Devices:................................................................................................................152.1.1
Control Panel (E8) Includes:....................................................................................................................152.1.2
Other Features Include: ..........................................................................................................................152.1.3
2.2 General Boiler Operation...................................................................................................................................16
2.3 Dimensional Drawings .......................................................................................................................................17
2.4 Performance Data.............................................................................................................................................21
CHAPTER 3: INSTALLATION INSTRUCTIONS ................................................................................... 23
3.1 General Warnings ..............................................................................................................................................23
Appropriate Use of the Boiler.................................................................................................................233.1.1
Prerequisite System Flushing..................................................................................................................233.1.2
Installation Personnel Qualifications ......................................................................................................233.1.3
Carbon Monoxide Detector Installation .................................................................................................233.1.4
3.2 Code and Standards Approvals..........................................................................................................................24
3.3 Packaging ...........................................................................................................................................................24
3.4 Transporting and Securing the Boiler Safely......................................................................................................27
3.5 Removal From Boiler Bed And Installation Of Boiler Feet .................................................................................28
3.6 Boiler Location Inside A Boiler Room.................................................................................................................29
Boiler Room Safety Concerns .................................................................................................................303.6.1
Products to Avoid in the Boiler Room.....................................................................................................303.6.2
3.7 Recommended Clearances for Servicing ...........................................................................................................31
3.8 Boiler Connections.............................................................................................................................................32
Changing Exhaust Outlet Location..........................................................................................................323.8.1
Reversing Gas Manifold Connections .....................................................................................................333.8.2
Reversing Cold/Hot Water Flow & Return Connections.........................................................................343.8.3
3.8.3.1 Reversing Cold/Hot Water Flow & Return Piping Connectors.............................................................34
3.8.3.2 Reversing Flow & Return Temperature Sensors ..................................................................................35

MODULEX EXT 321, 481, 641, 802, 962, 1123 BOILERS
Installation, Operation & Maintenance Manual
Page 4of 146 AERCO International, Inc. •100 Oritani Dr. •Blauvelt, NY 10913 OMM-0087_0F
07/13/15 Phone: [phone] GF-143
3.8.3.3 Reversing Boiler Sensor Kf And Automatic Air Vent ............................................................................35
3.9 Gas Connection General Information ................................................................................................................36
Natural Gas Connections ........................................................................................................................373.9.1
3.9.1.1 Natural Gas Piping Sizes.......................................................................................................................37
3.9.1.2 Natural Gas Piping Connections ..........................................................................................................37
3.9.1.3 Natural Gas Supply Pressure Requirements ........................................................................................37
Propane Gas Connections.......................................................................................................................373.9.2
3.9.2.1 Propane Gas Piping Sizes .....................................................................................................................37
3.9.2.2 Propane Gas Piping Connections .........................................................................................................37
3.9.2.3 Propane Gas Supply Pressure Requirements.......................................................................................38
3.10 Flow And Return Pipe Connections .................................................................................................................38
3.11 Pressure Relief Valve .......................................................................................................................................38
3.12 CSD-1 Manifold Assembly (Supplied) ..............................................................................................................39
3.13 Determination of Primary Boiler Pump Or Boiler System Pump .....................................................................40
3.14 Condensate Piping and Drain ..........................................................................................................................42
3.15 Water Treatment .............................................................................................................................................43
3.16 Important Installation Warnings......................................................................................................................44
Oxygen Levels in the System Water Warning.......................................................................................443.16.1
Antifreeze Compatibility Warning ........................................................................................................443.16.2
Lime Scale and Corrosive Water Damage Warning ..............................................................................443.16.3
Connection to Refrigeration System Warning ......................................................................................443.16.4
3.17 Air Intake Connection ......................................................................................................................................44
3.18 Flue Manifold Connection ...............................................................................................................................45
3.19 Flue Exhaust Piping to Vent .............................................................................................................................46
3.20 Vent Starter Pieces ..........................................................................................................................................46
3.21 Combustion Air and Ventilation Openings ......................................................................................................48
Insufficient Ventilations and Combustion Air .......................................................................................483.21.1
Room Air Combustion...........................................................................................................................493.21.2
Sealed Combustion ...............................................................................................................................493.21.3
3.22 Installation of the Exhaust and Air Intake System ...........................................................................................49
Important Factors for Terminal Orientation and Location ...................................................................503.22.1
Minimum and Maximum Wall Thickness..............................................................................................513.22.2
3.23 Vent Pipe Sizing ...............................................................................................................................................51
3.24 Electrical Connections......................................................................................................................................53
Regulations in Force .............................................................................................................................533.24.1
Mains Electrical Supply Connection (120 V – 60 Hz) ............................................................................533.24.2
Service Relay Requirement ...................................................................................................................543.24.3
Electrical Requirements ........................................................................................................................543.24.4
3.25 Functional Wiring Diagram ..............................................................................................................................57
3.26 Ladder Diagrams ..............................................................................................................................................59
3.27 General Ladder Diagram ..................................................................................................................................60
3.28 E8 Controller and BCM Terminal Assignments ................................................................................................60
3.29 Installation Examples.......................................................................................................................................63
3.30 Starting Up: Filling and Deaerating the Boiler .................................................................................................65
Necessary Precautions for Safety .........................................................................................................653.30.1
Supply Voltage, Gas Pressure, and Water pressure..............................................................................653.30.2
3.31 Filling the System.............................................................................................................................................65
Necessary Precautions While Filling the System ..................................................................................653.31.1
Filling Locations and Preparation..........................................................................................................663.31.2
3.32 Testing The Ignition Safety Shut Off Device.....................................................................................................68
3.33 Burner Calibration ...........................................................................................................................................69
Installing the Gas Analyzer Probe .........................................................................................................693.33.1
Maximum Output Calibration...............................................................................................................703.33.2
Minimum Output Calibration ...............................................................................................................713.33.3
Final Check and Ignition Failure Adjustment Procedure.......................................................................713.33.4

MODULEX EXT 321, 481, 641, 802, 962, 1123 BOILERS
Installation, Operation & Maintenance Manual
OMM-0087_0F AERCO International, Inc. •100 Oritani Dr. •Blauvelt, NY 10913 Page 5of 146
GF-143 Phone: [phone]/15
3.34 Sweeper Mode (Manual Control) ....................................................................................................................74
3.35 High Altitude Adjustment ................................................................................................................................75
3.36 High Altitude Conversion Label........................................................................................................................76
3.37 Conversion From Natural Gas To Propane Gas................................................................................................77
3.38 Controls And Emergency Functions.................................................................................................................78
3.39 Initial Boiler Ignition.........................................................................................................................................79
Preliminary Checks................................................................................................................................793.39.1
CHAPTER 4: E8 CONTROLLER AND BCM MODULES ...................................................................... 81
4.1 E8 Controller ......................................................................................................................................................81
E8 Controller Features and Functions.....................................................................................................814.1.1
E8 Display Functions ...............................................................................................................................824.1.2
E8 HEATING Mode Selection ..................................................................................................................834.1.3
E8 MENU Mode Operation (Door Open) ................................................................................................844.1.4
E8 MENU Navigation and Parameter Settings ........................................................................................854.1.5
E8 Parameter Navigation, Selection, and Setting ...................................................................................864.1.6
4.2 BCM (Boiler Communication Module)...............................................................................................................87
BCM Features and Functions ..................................................................................................................874.2.1
BCM Description .....................................................................................................................................874.2.2
CHAPTER 5: OPERATION..................................................................................................................... 91
5.1 Installation Menu: Initializing the E8 Controller ................................................................................................92
5.2 Quick Start Instructions .....................................................................................................................................93
Setting Maximum and Minimum Flow Temperature .............................................................................935.2.1
Setting Room Temperature and Outdoor Compensation ......................................................................935.2.2
Setting Heating Programs and Pumps ....................................................................................................945.2.3
5.3 Menu And Sub-Menu Descriptions....................................................................................................................96
Menus (Top Level): .................................................................................................................................965.3.1
Sub-Menus:.............................................................................................................................................965.3.2
5.4 General Menu ....................................................................................................................................................97
5.5 Service Menu .....................................................................................................................................................99
5.6 Display Menu ...................................................................................................................................................101
5.7 User Menu .......................................................................................................................................................103
5.8 Time Program Menu ........................................................................................................................................105
5.9 Expert Menu ....................................................................................................................................................106
5.10 Other Possible Settings..................................................................................................................................110
Settings for Heating Circuit 1/2 ..........................................................................................................1105.10.1
5.10.1.1 Heating Adjustment With Constant Flow Temp ..............................................................................110
5.10.1.2 Temperature Settings For Heating Circuits......................................................................................110
5.10.1.3 A Second DHW Storage Tank ...........................................................................................................111
5.10.1.4 Temperature Setting For Second DHW Storage Tank......................................................................111
5.10.1.5 Swimming Pool ................................................................................................................................111
5.10.1.6 Swimming Pool Temperature Setting ..............................................................................................111
5.10.1.7 Screed Dry Program (For Floor Heating Installation).......................................................................111
5.10.1.8 Temperature Setting For Screed Program .......................................................................................111
5.10.1.9 Signal 0 – 10 V.................................................................................................................................111
5.10.1.10 Slope And Temperature Setting with 0 – 10 V Signal ...................................................................111
Setting of DHW Circuit ........................................................................................................................1125.10.2
5.10.2.1 Operation of Pumps In Parallel........................................................................................................112
5.10.2.2 Use of a DHW Storage Tank Thermostat (On/Off)...........................................................................112
5.10.2.3 Antilegion.........................................................................................................................................112
5.10.2.4 Setting for Solar Panel Use ..............................................................................................................112
5.11 ACCESS CODE SETTING ..................................................................................................................................112

MODULEX EXT 321, 481, 641, 802, 962, 1123 BOILERS
Installation, Operation & Maintenance Manual
Page 6of 146 AERCO International, Inc. •100 Oritani Dr. •Blauvelt, NY 10913 OMM-0087_0F
07/13/15 Phone: [phone] GF-143
CHAPTER 6: TROUBLESHOOTING ................................................................................................... 113
6.1 E8 Controller Error Codes ................................................................................................................................113
E8 Controller Fault Codes .....................................................................................................................1156.1.1
BCM (Boiler Communications Module) Fault Codes.............................................................................1176.1.2
BMM (Burner Management Module) Fault Codes ...............................................................................1186.1.3
CHAPTER 7: MAINTENANCE SCHEDULE ........................................................................................ 121
7.1 Instructions for Inspection and Maintenance..................................................................................................122
7.2 Periodic Examination Of Venting System ........................................................................................................122
7.3 Proper Procedure For Cleaning Exhaust Flue ..................................................................................................122
Cleaning the Condensate Drain Line.....................................................................................................1237.3.1
7.4 Checking CSD-1 Manifold Flow Switch ............................................................................................................123
7.5 Visual Inspection Of The Flame .......................................................................................................................124
7.6 Proper Reassembly and Resealing of the Vent-Air Intake System...................................................................124
7.7 Pressure Switch Hoses And Connections.........................................................................................................125
7.8 Burner / Heat Exchanger Cleaning Procedure .................................................................................................126
7.9 Heat and Return Sensor Resistance Values .....................................................................................................126
7.10 Unit Disassembly ...........................................................................................................................................127
7.11 Cleaning the Burner Module and Combustion Chamber...............................................................................134
7.12 Reassembly of the Burner Modules...............................................................................................................136
7.13 Final Procedures After Maintenance .............................................................................................................136
7.14 Maintenance Kit Part Number.......................................................................................................................137
7.15 Accessory Kit Part Numbers...........................................................................................................................138
CHAPTER 8: SPARE PARTS DRAWING AND LISTS ....................................................................... 139

MODULEX EXT 321, 481, 641, 802, 962, 1123 BOILERS
Installation, Operation & Maintenance Manual
OMM-0087_0F AERCO International, Inc. •100 Oritani Dr. •Blauvelt, NY 10913 Page 7of 146
GF-143 Phone: [phone]/15
CHAPTER 1: GENERAL INFORMATION
1.1 Correct Use of the Appliance
The MODULEX EXT boiler has been designed utilizing the latest heating technologies and in
compliance with the current safety regulations. However, if not used or operated properly, the unit
may cause injury or death to persons, or serious damage to the equipment or surrounding objects.
The MODULEX EXT boiler is designed to be used in pumped hot water central heating systems.
Any other use of this appliance shall be considered improper, and AERCO declines any
responsibility for damages or injuries caused by the improper use of this equipment. In order to
use the equipment appropriately and safely according to its design, it is essential to carefully
follow the instructions in this manual.
1.2 Water Treatment
• It is vital to maintain the pH of boiler water between 6.5 and 8. Failure to do so could result in
severe damage to the boiler.
• The hardness of the main water supply influences the frequency with which the heat
exchanger must be cleaned.
• In hard water areas where the main water can exceed 15°f total hardness, a scale reducing
device is recommended. The choice of this device has to be made taking into consideration the
characteristics of the water.
• In order to improve the resistance to lime scale it is recommended that the domestic hot water
temperature be as near as possible to the temperature required for end use.
• AERCO recommends inspecting the state of cleanliness of the domestic hot water heat
exchanger at the end of the first year and subsequently, on the basis of the lime scale found,
this period can be extended to two years after the initial inspection.
1.3 Information to Be Made Available To The User
Go through the information in this manual with the owner/operator and make sure that he or she is
familiar with all necessary operating instructions, in particular:
• These instructions shall be made available to the end user, together with any other literature
regarding this appliance. It is highly recommended that the user keep these documents in a
safe and convenient place in order to always have them at hand for future reference.
• It is imperative that a proper venting and exhaust system be implemented with this unit. Refer
to the AERCO Venting Application Guide (GF-115-V).
• It is absolutely forbidden to make any alterations to the boiler not in keeping with the
manufacturers recommendations and instructions.
• It is critical to check the system’s water pressure and ensure it is at the correct pressure.
• For optimal operation of time and temperature controls, thermostats, heating controls and
radiators, refer to separate E8 Controller User Manual (GF-115-C).
• It is obligatory to carry out comprehensive maintenance services annually with a combustion
analysis every two years (in compliance with national and local laws).
• If the appliance is sold or transferred to another owner, or if the present user moves from the
installation site and leaves the appliance installed, ensure that the manual stays with the boiler
so that it can be consulted by the new owner and/or installer.

MODULEX EXT 321, 481, 641, 802, 962, 1123 BOILERS
Installation, Operation & Maintenance Manual
Page 8of 146 AERCO International, Inc. •100 Oritani Dr. •Blauvelt, NY 10913 OMM-0087_0F
07/13/15 Phone: [phone] GF-143
Failure to follow the instructions indicated in this manual, which is supplied with the boiler,
could cause injury to persons, animals or damage to property. The manufacturer shall not
be held liable for any such injury and/or damage.
1.4 Safety Warnings
WARNING!
• Children must be supervised so they do not play on, around, or
with the appliance.
• The installation, adjustment, and servicing of this appliance
must be carried out by a competent person and installed in
accordance with the current standards and regulations. Failure
to correctly install this appliance could cause injury to persons,
animals or damage to property. The manufacturer shall not be
held liable for any injury and/or damage.
• Servicing or repairs of the appliance must be carried out by
AERCO authorized service technicians; AERCO recommends
drawing up a service contract. Incomplete, inappropriate, or
irregular servicing could compromise the safe operation of the
appliance, and could cause injury to persons, animals or
damage to property for which AERCO shall not be held liable.
1.5 Modifications To Parts Connected To The Appliance
Do not carry out any modifications to the following parts:
• The boiler
• To the gas, air, water supply pipes and electrical power
• To the flue pipe, safety relief valve and its drainage pipe
• To the constructive components which influence the appliance’s safe operation
WARNING!
When tightening or loosening the screw pipe connections, use only
properly sized wrenches. The improper use of inadequate
equipment can cause damage (for example, water or gas leakages)
to the equipment.

MODULEX EXT 321, 481, 641, 802, 962, 1123 BOILERS
Installation, Operation & Maintenance Manual
OMM-0087_0F AERCO International, Inc. •100 Oritani Dr. •Blauvelt, NY 10913 Page 9of 146
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1.6 For Appliances Operating With Propane Gas
Before installing the appliance, ensure that the gas tank has been purged. For correct
instructions on purging the tank, contact the liquid gas supplier or a competent person who is
legally authorized to provide such information. If the tank has not been correctly purged,
problems may occur during ignition. If this happens contact the liquid gas tank’s supplier.
WARNING!
Do not store or use gasoline or other flammable vapors
or liquids in the vicinity of this or any other appliance.
WHAT TO DO IF YOU SMELL GAS:
• Do not try to light any appliance.
• Do not touch any electrical switch.
• Do not use any phone in the building.
• Immediately call your gas supplier from a neighbor’s
phone. Follow the gas supplier’s instructions.
• If you cannot contact your gas supplier, call the fire
department.
WARNING!
The boiler must be installed in such way as to avoid, under the
foreseen operation conditions, the freezing of the water and to
prevent the control devices from being exposed to temperatures
lower than 5°F (15°C) or higher than 104°F (40°C). The boiler must
be protected against environmental variations with:
• The insulation of the hydraulic pipelines and the condensate
drain.
• The adoption of specific antifreeze products in the Cold/Hot
water installation.

MODULEX EXT 321, 481, 641, 802, 962, 1123 BOILERS
Installation, Operation & Maintenance Manual
Page 10 of 146 AERCO International, Inc. •100 Oritani Dr. •Blauvelt, NY 10913 OMM-0087_0F
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1.7 Data Plate
A sample Data Plate for a MODULEX EXT boiler is shown in the left figure below. A sample of the
Data Packaging label is shown in the right image below.
Figure 1-1: MODULEX EXT Data Plate (L) and Data Packing Label (R)
Each unit is fitted with a data plate, which may be consulted for the details on gas type, power
source and venting classification.

MODULEX EXT 321, 481, 641, 802, 962, 1123 BOILERS
Installation, Operation & Maintenance Manual
OMM-0087_0F AERCO International, Inc. •100 Oritani Dr. •Blauvelt, NY 10913 Page 11 of 146
GF-143 Phone: [phone]/15
1.8 Operational Requirements
General Requirements 1.8.1
The following instructions MUST be followed:
• The boiler must only be used for its designated purpose as described in these Installation
Instructions.
• Each unit is fitted with a data plate. Consult the details on this plate to verify whether the boiler
is compliant with its intended location, e.g.: gas type, power source and venting classification.
• Only use the boiler with the accessories and spare parts listed.
• Other combinations of accessories and products must only be used if they are specifically
designed for the intended application and do not affect the system performance or the safety
requirements.
• Maintenance and repairs must only be performed by trained professionals.
• Installation of a condensing gas boiler must be approved per all federal and local government
codes, regulations, and laws.
• Operation of a condensing gas boiler must use a vent system that has been specifically
designed and approved for this type of boiler.
• Note that local permission and approval for the vent system and condensate water connection
to a public sewage system may be required.
Regulatory Requirements 1.8.2
You must also conform to any rules, regulations, or laws concerning the following:
• Local building codes regarding the installation.
• Local building codes concerning the air intake and outlet systems and the vent connection.
• Regulations for the power supply connection.
• Technical rules laid down by the gas utility company concerning the connection of the gas
connection to the local gas mains.
• Instructions and standards concerning the safety equipment for the water/space heating
system.
• Installation instructions for building heating systems.
• The boiler must be located in an area where leakage of the boiler or connections will not result
in damage to the area adjacent to the boiler or to lower floors of the structure. When such
locations cannot be avoided, it is recommended that a suitable drain pan be installed under
the boiler.
• Do not restrict or seal any air intake or outlet openings.
• If you find any defects, you must inform the owner, in writing, of the system defect and the
associated hazard.

MODULEX EXT 321, 481, 641, 802, 962, 1123 BOILERS
Installation, Operation & Maintenance Manual
Page 12 of 146 AERCO International, Inc. •100 Oritani Dr. •Blauvelt, NY 10913 OMM-0087_0F
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WARNING!
Should overheating occur, or the gas supply fail to shut off, do not
turn off or disconnect the electrical supply to the pump. Instead,
shut off the gas supply at a location external to the boiler.
Water Quality Requirements 1.8.3
NOTE
For additional information concerning water quality and treatment,
refer to AERCO technical documents Glycol Directive and AERCO
Piping Application Guide (GF-136-P).
Unsuitable heating system water can cause the formation of scale or sludge, which affects system
efficiency. It can also cause corrosion and reduce life of the heat exchanger.
• You must follow guidelines for boiler water quality.
• Thoroughly flush the system prior to filling.
• Follow the cleaning instructions.
• Never use water to fill the heating system that has been treated by reverse osmosis,
deionization, or distilled water in order to soften the water.
• Do not use inhibitors or other additives unless approved by AERCO for that purpose.
• When frost protection of the heating system is desired, only use AERCO-approved
antifreezes. The allowed maximum concentration is 50%.
• When using oxygen-permeable pipes, e. g. for under floor heating systems, you must
separate the system from the boiler using plate heat exchangers.
• Close the valves of the boiler while flushing the system, do not introduce any system cleaner
into the boiler loop. Flush system thoroughly to remove all system cleaner before filling boiler.
Approved antifreeze (maximum concentration of 50%):
• Rhomar RhoGard Mutli-Metal (AL safe)
• Noble Noburst AL
Approved system cleaners:
• Noble Noburst Hydronic System Cleaner
• Fernox F3 Cleaner
• Rhomar Hydro-Solv 9100
The system cleaners from NoBurst, Rhomar, and Fernox are NOT to be used in the boiler itself.
The boiler must be closed off (valves closed) from the rest of the system or not connected while
the cleaners are in the system. The system should then be drained and then thoroughly flushed
with clean water to remove all the system cleaner.
Approved inhibitors:
• Rhomar Pro-tek 922
• Noble Noburst AL inhibitor
• AERCO/Sentinel products. See list in GF-136-P, section 2.3 - System Flushing,
Treatment, and Cleansing.

MODULEX EXT 321, 481, 641, 802, 962, 1123 BOILERS
Installation, Operation & Maintenance Manual
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GF-143 Phone: [phone]/15
1.9 Tools, Materials, And Additional Equipment
For the installation and maintenance of the boiler you will need:
•
Standard tools for space heating, gas and water fitting
•
Manometer that is capable of reading both positive and negative pressures
•
Combustion analyzer
•
Digital multimeter
•
pH digital meter
•
Metric Allen wrenches
•
Metric socket wrenches
1.10 Disposal
•
Dispose of the boiler packaging in an environmentally sound manner.
•
Dispose of components of the heating system (e.g. boiler or control device), that must be
replaced in an environmentally responsible manner.
1.11 General Warnings
Using the Operation and Maintenance Manual 1.11.1
This instruction manual is an integral and indispensable part of the product and must be
retained by the person in charge of the appliance. Please read the instructions contained in this
manual carefully as they provide important information regarding the safe installation, use and
servicing of this appliance. Keep this manual in a safe place for future reference.
Installation and Servicing Personnel 1.11.2
Installation and servicing must be carried out in accordance with the regulations in force
according to the manufacturer’s instructions and by legally competent authorized persons. By
definition, a competent person is a person who has a specific technical qualification in the field
of components for central heating systems for domestic use, domestic hot water production, and
servicing. This person must have the qualifications legitimized by the current laws and
regulations in force.
Inappropriate, incomplete, or irregular servicing could compromise the safe operation of the
appliance, and could cause injury to persons, animals or damage to property. The manufacturer
shall not be held liable for any such injury and/or damage.
Any repairs must be carried out by AERCO authorized technicians and using only original spare
parts. Non-observance of the above requirement may jeopardize the safety of the appliance and
void any warranties.
In the event of failure and/or faulty functioning of the appliance, switch off the boiler. Do not
attempt to make any repairs, but instead contact qualified technicians.
To guarantee the efficiency and correct functioning of the appliance it is required that the boiler be
serviced annually by a qualified person.
Installation Materials 1.11.3
The installations for the domestic hot water production MUST be built, in their entirety, with
materials (taps, pipes, fittings, etc.) approved for drinkable water.

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Preparing Boiler for Servicing 1.11.4
Before carrying out any cleaning or servicing turn off the electrical supply to the boiler by means
of the ON/OFF switch and/or by means of the appropriate shutdown devices.
Returning a Boiler to Service 1.11.5
Before putting a boiler, which has been unused for a length of time, back into service, rinse the
entire domestic hot water system, allowing the water to flow an appropriate amount of time in
order to circulate throughout the entire system.
Change in Ownership 1.11.6
If the appliance is sold or transferred to another owner, or if the present user moves from the
installation site and leaves the appliance installed, ensure that the manual stays with the
appliance so that it can be consulted by the new owner and/or installer.
1.12 Operational Limits of the Boiler
• Max. boiler temperature: 180° F
• Max Allowable Working Temperature ASME: 200 °F
• Max. Allowable Working Pressure ASME: 92 psi

MODULEX EXT 321, 481, 641, 802, 962, 1123 BOILERS
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CHAPTER 2: TECHNICAL FEATURES AND DIMENSIONS
2.1 Modulex EXT Technical Features
• Compact, gas fired, Low NOx, condensing boiler.
• Comprised of one sectional boiler body, suitable as a single boiler or in a cascaded group.
• May be installed in either an inside or outside location.
• Low internal water volume.
• Fast response to load variations.
• Flue exhaust outlet positionable on three sides.
• Manifold delivery and return (reversible).
• Made up of two or more heating elements (2 to 7), cast aluminum / silicon / magnesium.
• Full range of modulation by variable speed blowers and premix burners.
• Each heating element monitors its own water temperature, and will individually shutdown
if flow is interrupted, without affecting the other burner sections.
• One gas supply line (reversible).
• Individual modules capable of between 46 and 160.5 kBTU/hr.
These boilers are designed for use with category IV venting.
The boiler is supplied complete with all the safety and control devices in accordance with all
current regulations, and its technical and functional features comply with the regulations
prescribed by: ANSI Z21.13 / CSA 4.9 - Gas-fired low pressure steam and hot water boilers.
Temperature Control Devices: 2.1.1
• Local NTC sensor (each heating
element)
• Limit thermostat room (each heating
element)
• Flow NTC sensor (General)
• Return NTC sensor (General)
• Safety thermostat approved (manual
reset)
• Flow sensor BCM
Control Panel (E8) Includes: 2.1.2
• ON-OFF switch
• Temperature control / Boiler operation
• Fuses
• High limit sensors
• Air pressure fans
• Condensate level sensor
• Air pressure switch (anti-obstruction)
Other Features Include: 2.1.3
• NTC heat sensors for global temperature control on the flow and return.
• 0-10V output to control variable speed primary pump.
• Integral insulation with hypoallergenic synthetic wool.
•
Premix fiber mesh modulating burner (premixes into the fan with automatic diaphragm
backflow separation from the combustion chamber).

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•
Less than 49 dBA of noise at maximum power.
•
Heating operation: instantaneous power microprocessor control, with preset parameters for
comparison between temperature (or calculated from the external temperature regulation)
and global temperature flow.
•
Operation modes:
o Ability to control power to the individual heating elements for any calibration with or
without confidential code access.
o Production of A.C.S. (Active Cooling System) by NTC sensor of priorities for control by
boiler feed pump or by three-way diverter valve controller.
•
E8 electronic controller included.
•
BCM (Boiler Communication Manager) included.
•
Ability to control power of the individual heating elements.
•
Control of heat demand: constant or remote setpoint.
•
Monitoring of operating status and temperature.
•
Reporting of alarms.
•
Setting of parameters.
•
Emergency operation prevents the boiler from shutting down as a result of the interruption
of communication with a control system or any remote control unit.
•
Alarm management.
•
Alarm reset input.
•
Warning alarm relay.
•
Stainless steel condensate collector tank with siphon, drain trap, and smoke chamber.
•
Easily removable stainless steel panels painted for outdoor installation.
•
Built-in air vent
2.2 General Boiler Operation
The boiler may be operated from the E8 controller or alternatively from a BCM (Boiler Cascade
Manager).
The boiler management logic provides the maximum number of simultaneously operating heating
elements in order to maximize heat production and overall efficiency. Burner efficiency and a high
heat exchange between surfaces contribute to the reliable and efficient output power. The various
components are designed to work together so that operating time is shared equally among the
components, thus reducing maintenance and labor costs.
The hot water moved by the pump is pushed to the return of the primary flow of the hydraulic
separator. From here a second pump will distribute the hot water to the various destinations. The
cooled return water is drawn by the pump through the hydraulic separator to resume the cycle via
the boiler.
WARNING!
If installing to an outdoor location where freezing temperatures may
occur, it is necessary to install devices and/or materials to prevent
any freezing in the condensate drain and the Flow and Return
manifolds. Failure to do so may cause serious damage to the
equipment.

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2.3 Dimensional Drawings
Figure 2-1: MODULEX EXT Dimensional Drawings (Side Views)
On Modulex EXT models 321,
642 and 962 the flue terminal
ends inside the casing

MODULEX EXT 321, 481, 641, 802, 962, 1123 BOILERS
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Figure 2-2: MODULEX EXT Dimensional Drawings (Top View)
Table 2-1: MODULEX EXT Dimensions and Sizes
Model
321
481
641
802
962
1123
Dimensions:
No. of Modules
2
3
4
5
6
7
Height (Open) - inches/mm 52.1‘‘
1323
52.1‘‘
1323
52.1‘‘
1323
52.1‘‘
1323
52.1‘‘
1323
52.1‘‘
1323
Height (Closed) - inches/mm 45.3‘‘
1150
45.3‘‘
1150
45.3‘‘
1150
45.3‘‘
1150
45.3‘‘
1150
45.3‘‘
1150
Width ‘’A’’ - inches/mm 30.0‘‘
764
30.0‘‘
764
40.6‘‘
1032
40.6‘‘
1032
51.2‘‘
1300
51.2‘‘
1300
Width ‘’B’’ - inches/mm 27.8‘‘
707
27.8‘‘
707
38.4‘‘
975
38.4‘‘
975
48.9‘‘
1243
48.9‘‘
1243
Depth ‘’D’’ - inches/mm 30.3‘‘
770
30.3‘‘
770
30.3‘‘
770
30.3‘‘
770
30.3‘‘
770
30.3‘‘
770
Depth ‘’E’’ - inches/mm 27.7‘‘
704
27.7‘‘
704
27.7‘‘
704
27.7‘‘
704
27.7‘‘
704
27.7‘‘
704
Connections:
Gas - inches/mm 2‘‘
60.3
2‘‘
60.3
2‘‘
60.3
2‘‘
60.3
2‘‘
60.3
2‘‘
60.3
M C/H System Flow
- inches/mm
2½‘‘
76.1
2½‘‘
76.1
2½‘‘
76.1
2½‘‘
76.1
2½‘‘
76.1
2½‘‘
76.1
R C/H System Return
- inches/mm
2½‘‘
76.1
2½‘‘
76.1
2½‘‘
76.1
2½‘‘
76.1
2½‘‘
76.1
2½‘‘
76.1
Vent Connection ‘’C’’
- inches/mm
5.9‘‘
150
5.9‘‘
150
5.9‘‘
150
5.9‘‘
150
7.8‘‘
200
7.8‘‘
200
Condensate drain diameter
- inches/mm
1.57‘‘
40
1.57‘‘
40
1.57‘‘
40
1.57‘‘
40
1.57‘‘
40
1.57‘‘
40

MODULEX EXT 321, 481, 641, 802, 962, 1123 BOILERS
Installation, Operation & Maintenance Manual
OMM-0087_0F AERCO International, Inc. •100 Oritani Dr. •Blauvelt, NY 10913 Page 19 of 146
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Figure 2-3a: MODULEX EXT Main Components (Left Side View)

MODULEX EXT 321, 481, 641, 802, 962, 1123 BOILERS
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Figure 2-3b: MODULEX EXT Main Components (Right Side View)
• Exhaust and condensate evacuation connections: are on the RIGHT
HAND side (supply condition), but may be moved to the RIGHT HAND or
REAR positions.
• Air intake connection: located on the LEFT HAND side.
• Cold/Hot flow connection: on the RIGHT HAND side (supply condition), but
may be moved to the LEFT HAND position.
• Cold/Hot return connection: on the RIGHT HAND side (supply condition) ,
but may be moved to the LEFT HAND position.
• Gas connection: on the RIGHT HAND side (supply condition) , but may be
moved to the LEFT HAND position.