Watts Aerco Modulex EXT Series User manual

Modulex EXT Commercial Series Boilers User Manual
OMM-0095_0H AERCO International, Inc. •100 Oritani Dr. •Blauvelt, NY 10913 Page 1of 144
GF-139 Phone: [phone]/2017
GF-139
INSTALLATION, OPERATION & MAINTENANCE
Modulating and Condensing Boilers
Latest Update: 09/15/2017
APPLIES TO MODELS:
•MLX EXT 1530 / MLX EXT 1500
•MLX EXT 1912
•MLX EXT 2295 / MLX EXT 2300
•MLX EXT 2677 / MLX EXT 2600
•MLX EXT 3060 / MLX EXT 3000
USER MANUAL

Modulex EXT Commercial Series Boilers User Manual
Page 2of 144 AERCO International, Inc. •100 Oritani Dr. •Blauvelt, NY 10913 OMM-0095_0H
09/15/2017 Phone: [phone] GF-139
Table of Contents:
CHAPTER 1: SAFETY PRECAUTIONS.....................................................................................................7
CHAPTER 2: GENERAL INFORMATION ................................................................................................11
2.1 CORRECT USE OF THE APPLIANCE .....................................................................................................................11
2.2 WATER TREATMENT ..........................................................................................................................................11
2.3 INFORMATION TO BE MADE AVAILABLE TO THE USER .....................................................................................11
2.4 SAFETY WARNINGS ............................................................................................................................................12
2.5 MODIFICATIONS TO PARTS CONNECTED TO THE APPLIANCE ...........................................................................12
2.6 FOR APPLIANCES OPERATING WITH PROPANE GAS..........................................................................................13
2.7 DATA PLATE .......................................................................................................................................................14
2.8 OPERATIONAL REQUIREMENTS .........................................................................................................................15
2.8.1 General Requirements............................................................................................................................15
2.8.2 Regulatory Requirements .......................................................................................................................15
2.8.3 Water Quality Requirements ..................................................................................................................16
2.9 TOOLS, MATERIALS, AND ADDITIONAL EQUIPMENT.........................................................................................17
2.10 DISPOSAL OF PACKAGING AND PARTS ............................................................................................................17
2.11 GENERAL WARNINGS.......................................................................................................................................17
2.11.1 Using the Operation and Maintenance Manual ...................................................................................17
2.11.2 Installation and Servicing Personnel.....................................................................................................17
2.11.3 Installation Materials ............................................................................................................................17
2.11.4 Preparing Boiler for Servicing ...............................................................................................................18
2.11.5 Returning a Boiler to Service ................................................................................................................18
2.11.6 Change in Ownership............................................................................................................................18
2.12 OPERATIONAL LIMITS OF THE BOILER .............................................................................................................18
CHAPTER 3: TECHNICAL FEATURES & DIMENSIONS........................................................................19
3.1 MODULEX EXT COMMERCIAL TECHNICAL FEATURES........................................................................................19
3.1.1 Temperature Control Devices:................................................................................................................19
3.1.2 Control Panel (E8) Includes:....................................................................................................................19
3.1.3 Other Features Include: ..........................................................................................................................19
3.2 GENERAL BOILER OPERATION ...........................................................................................................................20
3.3 DIMENSIONAL DRAWINGS.................................................................................................................................21
3.4 PERFORMANCE DATA ........................................................................................................................................24
CHAPTER 4: INSTALLATION INSTRUCTIONS......................................................................................25
4.1 INSTALLATION WARNINGS AND REQUIREMENTS .............................................................................................25
4.1.1 Appropriate Use of the Boiler.................................................................................................................25
4.1.2 Prerequisite System Flushing..................................................................................................................25
4.1.3 Installation Personnel Qualifications ......................................................................................................25
4.1.4 Carbon Monoxide Detector Installation .................................................................................................25
4.1.5 Installation Conformity Requirements ...................................................................................................25
4.2 CODE AND STANDARDS APPROVALS .................................................................................................................26
4.3 PACKAGING........................................................................................................................................................26
4.4 TRANSPORTING AND SECURING THE BOILER SAFELY........................................................................................27
4.5 UNPACKING THE BOILER....................................................................................................................................27
4.6 BOILER PACKAGE CONTENTS .............................................................................................................................28
4.7 BOILER LOCATION IN A BOILER ROOM ..............................................................................................................29
4.7.1 Boiler Room Safety Concerns .................................................................................................................29
4.7.2 Products to Avoid in the Boiler Room.....................................................................................................30
4.8 RECOMMENDED CLEARANCES FOR SERVICING.................................................................................................30
4.9 GAS CONNECTION GENERAL INFORMATION.....................................................................................................31
4.9.1 Natural Gas Connections ........................................................................................................................32

Modulex EXT Commercial Series Boilers User Manual
OMM-0095_0H AERCO International, Inc. •100 Oritani Dr. •Blauvelt, NY 10913 Page 3of 144
GF-139 Phone: [phone]/2017
Natural Gas Piping Sizes.......................................................................................................................324.9.1.1
Natural Gas Piping Connections ..........................................................................................................324.9.1.2
Natural Gas Supply Pressure Requirements ........................................................................................324.9.1.3
4.9.2 Propane Gas Connections.......................................................................................................................32
Propane Gas Piping Sizes .....................................................................................................................324.9.2.1
Propane Gas Piping Connections.........................................................................................................324.9.2.2
Propane Gas Supply Pressure Requirements.......................................................................................324.9.2.3
4.10 FLOW AND RETURN PIPE CONNECTIONS ........................................................................................................33
4.11 PRESSURE RELIEF VALVE ..................................................................................................................................33
4.12 CSD-1 MANIFOLD ASSEMBLY (SUPPLIED) ........................................................................................................34
4.13 DETERMINATION OF PRIMARY BOILER PUMP OR BOILER SYSTEM PUMP ......................................................35
4.14 CONDENSATE PIPING AND DRAIN ...................................................................................................................36
4.15 WATER TREATMENT ........................................................................................................................................38
4.16 IMPORTANT INSTALLATION WARNINGS..........................................................................................................38
4.16.1 Oxygen Levels in the System Water Warning.......................................................................................38
4.16.2 Antifreeze Compatibility Warning ........................................................................................................38
4.16.3 Lime Scale and Corrosive Water Damage Warning ..............................................................................39
4.16.4 Connection to Refrigeration System Warning ......................................................................................39
4.17 OPTIONAL AIR INTAKE CONNECTION ..............................................................................................................39
4.18 FLUE MANIFOLD INSTALLATION ......................................................................................................................39
4.19 FLUE EXHAUST PIPING TO VENT ......................................................................................................................41
4.20 VENT STARTER PIECES .....................................................................................................................................42
4.21 COMBUSTION AIR AND VENTILATION OPENINGS ...........................................................................................43
4.21.1 Insufficient Ventilation and Combustion Air.........................................................................................43
4.21.2 Room Air Combustion...........................................................................................................................44
4.21.3 Sealed Combustion ...............................................................................................................................44
4.22 INSTALLATION OF THE EXHAUST AND AIR INTAKE SYSTEM ............................................................................45
4.22.1 Important Factors for Terminal Orientation and Location ...................................................................45
4.22.2 Minimum and Maximum Wall Thickness..............................................................................................46
4.23 VENT PIPE SIZING.............................................................................................................................................46
4.24 ELECTRICAL CONNECTIONS .............................................................................................................................48
4.24.1 Regulations in Force .............................................................................................................................48
4.24.2 Mains Electrical Supply Connection (120 V – 60 Hz) ............................................................................48
4.24.3 Service Relay Requirement ...................................................................................................................49
4.24.4 Electrical Requirements ........................................................................................................................49
4.25 FUNCTIONAL WIRING DIAGRAM .....................................................................................................................53
4.26 LADDER DIAGRAMS .........................................................................................................................................55
4.27 GENERAL LADDER DIAGRAM ...........................................................................................................................56
4.28 E8 CONTROLLER AND BCM TERMINAL ASSIGNMENTS....................................................................................56
4.29 INSTALLATION EXAMPLES................................................................................................................................59
4.30 STARTING UP: FILLING AND DE-AERATING THE BOILER ..................................................................................61
4.30.1 Necessary Precautions for Safety .........................................................................................................61
4.30.2 Supply Voltage, Gas Pressure, and Water pressure..............................................................................61
4.31 FILLING THE SYSTEM........................................................................................................................................61
4.31.1 Necessary Precautions While Filling the System ..................................................................................61
4.31.2 Filling Locations and Preparation..........................................................................................................62
4.32 TESTING THE IGNITION SAFETY SHUT-OFF DEVICE..........................................................................................64
4.33 BURNER CALIBRATION.....................................................................................................................................65
4.33.1 Installing the Gas Analyzer Probe .........................................................................................................65
4.33.2 Maximum Output Calibration...............................................................................................................66
4.33.3 Minimum Output Calibration ...............................................................................................................67
4.33.4 Final Check and Ignition Failure Adjustment Procedure.......................................................................67
4.34 SWEEPER MODE (MANUAL CONTROL)............................................................................................................70
4.35 HIGH ALTITUDE ADJUSTMENT .........................................................................................................................71
4.36 HIGH ALTITUDE CONVERSION LABEL...............................................................................................................72
4.37 CONVERSION FROM NATURAL GAS TO PROPANE GAS ...................................................................................73

Modulex EXT Commercial Series Boilers User Manual
Page 4of 144 AERCO International, Inc. •100 Oritani Dr. •Blauvelt, NY 10913 OMM-0095_0H
09/15/2017 Phone: [phone] GF-139
4.38 CONTROLS AND EMERGENCY FUNCTIONS ......................................................................................................74
4.39 INITIAL BOILER IGNITION .................................................................................................................................75
4.39.1 Preliminary Checks................................................................................................................................75
CHAPTER 5: E8 CONTROLLER AND BCM MODULES.........................................................................77
5.1 E8 CONTROLLER.................................................................................................................................................77
5.1.1 E8 Controller Features and Functions.....................................................................................................77
5.1.2 E8 Display Functions ...............................................................................................................................78
5.1.3 E8 HEATING Mode Selection ..................................................................................................................79
5.1.4 E8 MENU Mode Operation (Door Open) ................................................................................................80
5.1.5 E8 MENU Navigation and Parameter Settings........................................................................................81
5.1.6 E8 Parameter Navigation, Selection, and Setting ...................................................................................82
5.2 BCM (BOILER COMMUNICATION MODULE) ......................................................................................................83
5.2.1 BCM Features and Functions ..................................................................................................................83
5.2.2 BCM Description .....................................................................................................................................83
CHAPTER 6: OPERATION OF THE E8 CONTROLLER .........................................................................87
6.1 INSTALLATION MENU: INITIALIZING THE E8 CONTROLLER................................................................................88
6.2 QUICK START INSTRUCTIONS.............................................................................................................................89
6.2.1 Setting Maximum and Minimum Flow Temperature .............................................................................89
6.2.2 Setting Room Temperature and Outdoor Compensation ......................................................................90
6.2.3 Setting Heating Programs and Pumps ....................................................................................................91
6.3 MENU AND SUB-MENU DESCRIPTIONS .............................................................................................................92
6.3.1 Menus (Top Level): .................................................................................................................................92
6.3.2 Sub-Menus:.............................................................................................................................................92
6.4 GENERAL MENU.................................................................................................................................................93
6.5 SERVICE MENU...................................................................................................................................................95
6.6 DISPLAY MENU...................................................................................................................................................97
6.7 USER MENU .......................................................................................................................................................99
6.8 TIME PROGRAM MENU ...................................................................................................................................101
6.9 EXPERT MENU..................................................................................................................................................102
6.10 OTHER POSSIBLE SETTINGS............................................................................................................................106
6.10.1 Settings for Heating Circuit 1/2 ..........................................................................................................106
Heating Adjustment With Constant Flow Temp ...............................................................................1066.10.1.1
Temperature Settings For Heating Circuits......................................................................................1066.10.1.2
A Second DHW Storage Tank ...........................................................................................................1076.10.1.3
Temperature Setting For Second DHW Storage Tank......................................................................1076.10.1.4
Swimming Pool ................................................................................................................................1076.10.1.5
Swimming Pool Temperature Setting ..............................................................................................1076.10.1.6
Screed Dry Program (For Floor Heating Installation).......................................................................1076.10.1.7
Temperature Setting For Screed Program.......................................................................................1076.10.1.8
Signal 0 – 10 V.................................................................................................................................1076.10.1.9
Slope And Temperature Setting with 0 – 10 V Signal ...................................................................1076.10.1.10
6.10.2 Setting of DHW Circuit........................................................................................................................108
Operation of Pumps In Parallel........................................................................................................1086.10.2.1
Use of a DHW Storage Tank Thermostat (On/Off)...........................................................................1086.10.2.2
Antilegion.........................................................................................................................................1086.10.2.3
Setting for Solar Panel Use ..............................................................................................................1086.10.2.4
6.11 ACCESS CODE SETTING ..................................................................................................................................108
CHAPTER 7: TROUBLESHOOTING......................................................................................................109
7.1 E8 CONTROLLER FAULT CODES........................................................................................................................109
7.1.1 E8 Controller Fault Codes .....................................................................................................................111
7.1.2 BCM (Boiler Communications Module) Fault Codes.............................................................................115
7.1.3 BMM (Burner Management Module) Fault Codes ...............................................................................116

Modulex EXT Commercial Series Boilers User Manual
OMM-0095_0H AERCO International, Inc. •100 Oritani Dr. •Blauvelt, NY 10913 Page 5of 144
GF-139 Phone: [phone]/2017
CHAPTER 8: MAINTENANCE SCHEDULE...........................................................................................119
8.1 INSTRUCTIONS FOR INSPECTION AND MAINTENANCE ...................................................................................120
8.2 PERIODIC EXAMINATION OF VENTING SYSTEM ..............................................................................................120
8.3 PROPER PROCEDURE FOR CLEANING EXHAUST FLUE .....................................................................................120
8.3.1 Cleaning the Condensate Drain Line.....................................................................................................121
8.4 CHECKING CSD-1 MANIFOLD FLOW SWITCH...................................................................................................121
8.5 VISUAL INSPECTION OF THE FLAME ................................................................................................................122
8.5.1 FLAME COLOR:......................................................................................................................................122
8.6 PROPER REASSEMBLY AND RESEALING OF THE VENT-AIR INTAKE SYSTEM ....................................................122
8.7 PRESSURE SWITCH HOSES AND CONNECTIONS ..............................................................................................123
8.8 BURNER / HEAT EXCHANGER CLEANING PROCEDURE ....................................................................................124
8.9 HEAT AND RETURN SENSOR RESISTANCE VALUES ..........................................................................................124
8.10 UNIT DISASSEMBLY........................................................................................................................................125
8.11 CLEANING THE BURNER MODULE .................................................................................................................131
8.12 CLEANING THE HEAT EXCHANGER.................................................................................................................131
8.12.1 Mechanical Cleaning of the Heat Exchanger ......................................................................................132
8.12.2 Cleaning the Heat Exchanger with Cleaning Solution.........................................................................133
8.12.3 Repeat Cleaning ..................................................................................................................................134
8.13 REASSEMBLY OF THE BURNER MODULES......................................................................................................134
8.14 FINAL PROCEDURES AFTER MAINTENANCE...................................................................................................135
8.15 MAINTENANCE KIT PART NUMBER................................................................................................................136
8.16 ACCESSORY KIT PART NUMBER .....................................................................................................................137
CHAPTER 9: SPARE PARTS DRAWING AND LISTS..........................................................................139

Modulex EXT Commercial Series Boilers User Manual
Page 6of 144 AERCO International, Inc. •100 Oritani Dr. •Blauvelt, NY 10913 OMM-0095_0H
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Modulex EXT Light Commercial Series Boilers User Manual
CHAPTER 1: Safety Precautions
OMM-0095_0H AERCO International, Inc. •100 Oritani Dr. •Blauvelt, NY 10913 Page 7of 144
GF-139 Phone: [phone]/2017
CHAPTER 1: SAFETY PRECAUTIONS
The following defined symbols are used throughout this manual to notify the reader of potential
hazards of varying risk levels.
DANGER!
Indicates an imminently hazardous situation, which if not avoided, WILL result in death or
serious injury.
WARNING!
Indicates a potentially hazardous situation, which if not avoided, MAY result in death or
serious injury.
CAUTION!
Indicates a potential hazardous situation, which if not avoided, COULD result in minor or
moderate injury. Also may caution against unsafe practices.
Note that all hazard notifications and notes are presented enclosed in a rectangle with filleted
(round) corners, as shown below, in order to differentiate them from the main text.
It is of utmost importance to observe all CAUTIONS and WARNINGS presented in this manual to avoid
injury, death, and damage to the equipment. Failure to properly heed safety warnings and cautions may
result in the voiding of applicable warranties.
WARNING!
Never use flames to detect gas leaks!
What to do if you smell gas:
•Do NOT try to light or turn on any appliance.
•Do NOT touch any electric switch or open switched doors.
•Do NOT use any phone or intercom device in your building.
•Do NOT touch metal doorknobs or any grounded device or surface without using insulated
gloves or other insulated material if you suspect static charge buildup.
•Immediately call your gas supplier from a neighbor’s phone or, if you are outside, your cell
phone. Follow the gas supplier’s instructions.
•If you cannot reach your gas supplier, call the fire department.
WARNING!
This boiler has been built for installation in the country indicated on the technical data plate.
Installation in any other country may be a source of danger for people, animals and
property.
NOTE:
Carefully read the warranty conditions and clauses on the warranty certificate attached to the
boiler.

Modulex EXT Light Commercial Series Boilers User Manual
CHAPTER 1: Safety Precautions
Page 8of 144 AERCO International, Inc. •100 Oritani Dr. •Blauvelt, NY 10913 OMM-0095_0H
09/15/2017 Phone: [phone] GF-139
Important – For Massachusetts Installations
Boiler Installations within the Commonwealth of Massachusetts must conform to the following
requirements:
•Boiler must be installed by a plumber or a gas fitter who is licensed within the Commonwealth of
Massachusetts.
•Prior to unit operation, the complete gas train and all connections must be leak tested using a non-
corrosive soap.
•If a glycol solution is used as anti-freeze protection, a backflow preventer must be installed
upstream of the Fill/Makeup Valve.
•The vent termination must be located a minimum of 4 feet above grade level.
•If side-wall venting is used, the installation must conform to the following requirements extracted
from 248 CMR 5.08 (2):
A. For all side wall horizontally vented gas fueled equipment installed in every dwelling, building or
structure used in whole or in part for residential purposes, including those owned or operated by
the Commonwealth and where the side wall exhaust vent termination is less than seven (7) feet
above finished grade in the area of the venting, including but not limited to decks and porches,
the following requirements shall be satisfied:
1. INSTALLATION OF CARBON MONOXIDE DETECTORS.At the time of installation of the
side wall horizontal vented gas fueled equipment, the installing plumber or gasfitter shall
observe that a hard wired carbon monoxide detector with an alarm and battery back-up is
installed on the floor level where the gas equipment is to be installed. In addition, the
installing plumber or gasfitter shall observe that a battery operated or hard wired carbon
monoxide detector with an alarm is installed on each additional level of the dwelling, building
or structure served by the side wall horizontal vented gas fueled equipment. It shall be the
responsibility of the property owner to secure the services of qualified licensed professionals
for the installation of hard wired carbon monoxide detectors
a) In the event that the side wall horizontally vented gas fueled equipment is installed in a
crawl space or an attic, the hard wired carbon monoxide detector with alarm and battery
back-up may be installed on the next adjacent floor level.
b) In the event that the requirements of this subdivision can not be met at the time of
completion of installation, the owner shall have a period of thirty (30) days to comply with
the above requirements; provided, however, that during said thirty (30) day period, a
battery operated carbon monoxide detector with an alarm shall be installed.
2. APPROVED CARBON MONOXIDE DETECTORS. Each carbon monoxide detector as
required in accordance with the above provisions shall comply with NFPA 720 and be
ANSI/UL 2034 listed and IAS certified.
3. SIGNAGE.A metal or plastic identification plate shall be permanently mounted to the exterior
of the building at a minimum height of eight (8) feet above grade directly in line with the
exhaust vent terminal for the horizontally vented gas fueled heating appliance or equipment.
The sign shall read, in print size no less than one-half (1/2) inch in size, "GAS VENT
DIRECTLY BELOW. KEEP CLEAR OF ALL OBSTRUCTIONS".
4. INSPECTION.The state or local gas inspector of the side wall horizontally vented gas fueled
equipment shall not approve the installation unless, upon inspection, the inspector observes
carbon monoxide detectors and signage installed in accordance with the provisions of 248
CMR 5.08(2)(a)1 through 4.
(Continued on Next Page)

Modulex EXT Light Commercial Series Boilers User Manual
CHAPTER 1: Safety Precautions
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GF-139 Phone: [phone]/2017
Important - For Massachusetts Installations
(Continued from Previous Page)
B. EXEMPTIONS:The following equipment is exempt from 248 CMR 5.08(2)(a)1 to 4:
1. The equipment listed in Chapter 10 entitled "Equipment Not Required To Be Vented" in the
most current edition of NFPA 54 as adopted by the Board; and
2. Product Approved side wall horizontally vented gas fueled equipment installed in a room or
structure separate from the dwelling, building or structure used in whole or in part for
residential purposes.
C. MANUFACTURER REQUIREMENTS - GAS EQUIPMENT VENTING SYSTEM PROVIDED:
When the manufacturer of Product Approved side wall horizontally vented gas equipment
provides a venting system design or venting system components with the equipment, the
instructions provided by the manufacturer for installation of the equipment and the venting system
shall include:
1. Detailed instructions for the installation of the venting system design or the venting system
components; and
2. A complete parts list for the venting system design or venting system.
D. MANUFACTURER REQUIREMENTS - GAS EQUIPMENT VENTING SYSTEM NOT
PROVIDED: When the manufacturer of a Product Approved side wall horizontally vented gas
fueled equipment does not provide the parts for venting the flue gases, but identifies "special
venting systems", the following requirements shall be satisfied by the manufacturer:
1. The identification of each "special venting system" shall include the listing of either the
website, phone number or manufacturer’s address where the venting system installation
instructions can be obtained; and
2. The "special venting systems" shall be Product Approved by the Board, and the
instructions provided with the system shall include a parts list and detailed installation
instructions.
E. A copy of all installation instructions for the Product Approved side wall horizontally vented gas
fueled equipment, all venting instructions, all parts lists for venting instructions, and/or all venting
design instructions shall remain with the appliance or equipment at the completion of the
installation.
[End of Extracted Information From 248 CMR 5.08 (2)]

Modulex EXT Light Commercial Series Boilers User Manual
CHAPTER 1: Safety Precautions
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Modulex EXT Commercial Series Boilers User Manual
CHAPTER 2: General Information
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GF-139 Phone: [phone]/2017
CHAPTER 2: GENERAL INFORMATION
2.1 CORRECT USE OF THE APPLIANCE
The MODULEX EXT Commercial boiler has been designed utilizing the latest heating
technologies and in compliance with 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 Commercial 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.
2.2 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.
•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.
2.3 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-136-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-136-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 Commercial Series Boilers User Manual
CHAPTER 2: General Information
Page 12 of 144 AERCO International, Inc. •100 Oritani Dr. •Blauvelt, NY 10913 OMM-0095_0H
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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.
2.4 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.
2.5 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 Commercial Series Boilers User Manual
CHAPTER 2: General Information
OMM-0095_0H AERCO International, Inc. •100 Oritani Dr. •Blauvelt, NY 10913 Page 13 of 144
GF-139 Phone: [phone]/2017
2.6 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:
• Donot 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 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 Commercial Series Boilers User Manual
CHAPTER 2: General Information
Page 14 of 144 AERCO International, Inc. •100 Oritani Dr. •Blauvelt, NY 10913 OMM-0095_0H
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2.7 DATA PLATE
A sample Data Plate for a MODULEX EXT Commercial boiler is shown in the left figure below.
A sample of the Data Packaging label is shown in the right image below.
Figure 2-1: MODULEX EXT Commercial 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 Commercial Series Boilers User Manual
CHAPTER 2: General Information
OMM-0095_0H AERCO International, Inc. •100 Oritani Dr. •Blauvelt, NY 10913 Page 15 of 144
GF-139 Phone: [phone]/2017
2.8 OPERATIONAL REQUIREMENTS
2.8.1 General Requirements
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.
2.8.2 Regulatory Requirements
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 Commercial Series Boilers User Manual
CHAPTER 2: General Information
Page 16 of 144 AERCO International, Inc. •100 Oritani Dr. •Blauvelt, NY 10913 OMM-0095_0H
09/15/2017 Phone: [phone] GF-139
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.
2.8.3 Water Quality Requirements
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%):
•Sentinel X500 (available from AERCO)
•Rhomar RhoGard Mutli-Metal (AL safe)
•Noble Noburst AL
Approved system cleaners:
•Sentinel X300 (available from AERCO)
•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:
• Sentinel X100 (available from AERCO)
• Rhomar Pro-tek 922
• Noble Noburst AL inhibitor
• Intercool NFP-AA
• Cryo-tek 100/Al

Modulex EXT Commercial Series Boilers User Manual
CHAPTER 2: General Information
OMM-0095_0H AERCO International, Inc. •100 Oritani Dr. •Blauvelt, NY 10913 Page 17 of 144
GF-139 Phone: [phone]/2017
2.9 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
2.10 DISPOSAL OF PACKAGING AND PARTS
•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.
2.11 GENERAL WARNINGS
2.11.1 Using the Operation and Maintenance Manual
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.
2.11.2 Installation and Servicing Personnel
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.
2.11.3 Installation Materials
The installations for the domestic hot water production MUST be built, in their entirety, with
materials (taps, pipes, fittings, etc.) approved for drinkable water.

Modulex EXT Commercial Series Boilers User Manual
CHAPTER 2: General Information
Page 18 of 144 AERCO International, Inc. •100 Oritani Dr. •Blauvelt, NY 10913 OMM-0095_0H
09/15/2017 Phone: [phone] GF-139
2.11.4 Preparing Boiler for Servicing
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.
2.11.5 Returning a Boiler to Service
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.
2.11.6 Change in Ownership
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.
2.12 OPERATIONAL LIMITS OF THE BOILER
•Max. boiler temperature: 180° F (80° C)
•Max Allowable Working Temperature ASME: 200 °F
•Max. Allowable Working Pressure ASME: 92 psi

Modulex EXT Commercial Series Boilers User Manual
CHAPTER 3: Technical Features & Dimensions
OMM-0095_0H AERCO International, Inc. •100 Oritani Dr. •Blauvelt, NY 10913 Page 19 of 144
GF-139 Phone: [phone]/2017
CHAPTER 3: TECHNICAL FEATURES & DIMENSIONS
3.1 MODULEX EXT COMMERCIAL 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.
• Made up of four or more heating elements (4 to 8), 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.
• Individual modules capable of between 83 and 382.5 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.
3.1.1 Temperature Control Devices:
• Local NTC sensor (each heating element)
• Limit thermostat (each heating element)
• Flow NTC sensor (General)
• Return NTC sensor (General)
• Safety thermostat approved (manual
reset)
• Flow sensor BCM
3.1.2 Control Panel (E8) Includes:
• ON-OFF switch
• Temperature control / Boiler operation
• Fuses
• High limit sensors
• Air pressure fans
• Condensate level sensor
• Air pressure switch (anti-obstruction)
3.1.3 Other Features Include:
• NTC heat sensors for global temperature control on the flow and return.
• 0-10 V 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).
•Less than 49 dBA of noise at maximum power.

Modulex EXT Commercial Series Boilers User Manual
CHAPTER 3: Technical Features & Dimensions
Page 20 of 144 AERCO International, Inc. •100 Oritani Dr. •Blauvelt, NY 10913 OMM-0095_0H
09/15/2017 Phone: [phone] GF-139
•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:
oAbility to control power to the individual heating elements for any calibration with or
without confidential code access.
oProduction 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 Module) 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
3.2 GENERAL BOILER OPERATION
The boiler may be operated from the E8 controller or alternatively from a BCM (Boiler Cascade
Manager). The boiler management logic automatically fires 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.