AER Modulex 303 User manual

Instruction
No.
GF-115H
AERCO INTERNATIONAL, Inc., Northvale, New Jersey, 07647 USA
Installation, Operation
& Maintenance Instructions
Gas Fired
Boiler Systems
Modular, Condensing, Hot Water Boilers
Models: 303, 454, 606, 757, 909, 1060
Printed in U.S.A. 7/17/08

Telephone Support
Direct to AERCO Technical
Support
(8 to 5 pm EST, Mon. – Fri.)
1-800- 526-0288
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 this material.
AERCO International, Inc.
159 Paris Avenue
Northvale, NJ 07647-0128
www.aerco.com
© AERCO International, Inc., 2008

INSTALLATION, OPERATION & MAINTENANCE
i
TABLE OF CONTENTS
Chapter/Paragraph Page
SAFETY SYMBOLS AND WARNINGS iii
IMPORTANT iii
FOR YOUR SAFETY v
1GENERAL DESCRIPTION 1-1
1.1 TECHNICAL FEATURES 1-1
1.2 CODES AND STANDARDS APPROVALS 1-2
1.3 INSTALLATION FLEXIBILITY 1-2
1.4 DIMENSIONS 1-3
1.5 TECHNICAL DATA 1-5
1.6 MODULEX SIDE VIEW SHOWING MAIN COMPONENTS 1-6
1.7 BOILER FREEZE PROTECTION 1-7
2 INSTRUCTIONS FOR INSTALLERS 2-1
2.1 INTRODUCTION 2-1
2.2 INSTALLATION INSTRUCTIONS 2-1
2.2.1 UNPACKING THE BOILER 2-1
2.2.2 LOCATING THE BOILER 2-3
2.2.3 PAD HEIGHT FOR BOILER 2-3
2.2.4 BOILER CONNECTIONS 2-4
2.3 BOILER DATA PLATE 2-8
3GENERAL INFORMATION FOR THE VENTING SYSTEM 3-1
3.1 GAS VENT CATEGORIES 3-1
3.2 VENT PIPE CONNECTIONS 3-1
3.3 INSTALLATION & SIZING 3-1
3.4 REMOVAL OF EXISTING BOILER FROM COMMON VENTING
SYSTEM
3-2
4 PIPING 4-1
4.1 MAKEUP WATER QUALITY 4-1
4.2 MAXIMUM ALLOWABLE WORKING PRESSURE 4-1
4.3 BOILER LOOP DESIGN GUIDELINES 4-1
4.4 CSD-1 MANIFOLD ASSEMBLY 4-1
4.5 CONNECTING SUPPLY AND RETURN PIPING 4-1
4.6 SYSTEM FILLING AND DRAINING 4-2
4.7 NOTES ON CONDENSATE DRAIN 4-2

INSTALLATION, OPERATION & MAINTENANCE
ii
TABLE OF CONTENTS - Continued
Chapter/Paragraph Page
4.8 GAS MAINS AND CONNECTION 4-3
5 ELECTRICAL 5-1
5.1 ELECTRICAL CONNECTIONS 5-1
5.2 D.H.W. STORAGE TANK 5-2
5.3 ENABLE/DISABLE 5-2
5.4 INSTALLATION OF SENSORS 5-2
6 BOILER OPERATION 6-1
6.1 GENERAL DESCRIPTION AND OPERATION 6-1
6.2 MODULATION THEORY 6-1
6.3 IGNITION SEQUENCE 6-2
6.4 MODES OF OPERATION 6-2
6.4.1 INDOOR/OUTDOOR RESET 6-2
6.4.2 0 TO 10 VOLT REMOTE SET-POINT 6-3
6.4.3 CONSTANT SET-POINT 6-3
6.4.4 BOILER OPERATION IN CASE OF TROUBLESHOOTING
(MANUAL MODE)
6-3
6.5 MODULEX BOILER INITIAL STARTUP 6-3
6.5.1 TOOLS & INSTRUMENTION REQUIRED FOR COMBUSTION
CALIBRATION
6-4
6.5.2 INSTALLATION OF SUPPLY GAS MANOMETER 6-4
6.5.3 PREPARING THE FLUE FOR USE WITH THE COMBUSTION
ANALYZER
6-5
6.5.4 COMBUSTION CALIBRATION 6-6
6.6 UNIT REASSEMBLY 6-8
7 MAINTENANCE 7-1
7.1 MAIN FEATURES 7-1
APPENDIX A TEMPERATURE SENSOR RESISTANCE CHART A-1
APPENDIX B MODULEX PARTS LIST B-1

INSTALLATION, OPERATION & MAINTENANCE
iii
SAFETY SYMBOLS
The following defined symbols are used throughout this manual to notify the reader
of potential hazards of varying risk levels.
INDICATES AN IMMINENTLY HAZARDOUS SITUATION, WHICH IF NOT AVOIDED,
WILL RESULT IN DEATH OR SERIOUS INJURY.
INDICATES A POTENTIALLY HAZARDOUS SITUATION, WHICH IF NOT
AVOIDED, COULD RESULT IN DEATH OR SERIOUS INJURY.
INDICATES A POTENTIAL HAZARDOUS SITUATION, WHICH IF NOT AVOIDED,
MAY RESULT IN MINOR OR MODERATE INJURY. IT MAY ALSO BE USED TO
ALERT AGAINST UNSAFE PRACTICES.
READ ALL INSTRUCTIONS BEFORE INSTALLING.
The following WARNINGS appear here and in one or more Chapters of
this manual.
•KEEP THE UNIT AREA CLEAR AND FREE FROM ALL COMBUSTIBLE MATERIALS AND
FLAMMABLE VAPORS OR LIQUIDS.
•NEVER USE MATCHES, CANDLES, FLAMES OR OTHER SOURCES OF IGNITION TO CHECK
FOR GAS LEAKS.
•DO NOT ATTEMPT TO DRY FIRE THE BOILER. STARTING THE UNIT WITHOUT A FULL
WATER LEVEL CAN SERIOUSLY DAMAGE THE UNIT AND MAY RESULT IN INJURY TO
PERSONNEL OR PROPERTY DAMAGE. THIS SITUATION WILL VOID ANY WARRANTY.
•ELECTRICAL VOLTAGES IN THIS SYSTEM MAY INCLUDE 120 AND 24 VOLTS AC. IT MUST
BE SERVICED BY TECHNICALLY COMPETENT SERVICE TECHNICIANS.
•ELECTRICAL POWER MUST BE REMOVED PRIOR TO PERFORMING WIRE REMOVAL OR
OTHER TEST PROCEDURES THAT CAN RESULT IN ELECTRICAL SHOCK.
•TO AVOID PERSONAL INJURY, OBSERVE THE FOLLOWING WARNINGS:
•DISCONNECT THE AC SUPPLY BY TURNING OFF THE SERVICE SWITCH AND AC SUPPLY
CIRCUIT BREAKER
•SHUT OFF THE GAS SUPPLY AT THE MANUAL SHUT-OFF VALVE
•PROVIDED WITH THE UNIT
•ALLOW THE UNIT TO COOL TO A SAFE TEMPERATURE TO PREVENT
•SEVERE BURNS.

INSTALLATION, OPERATION & MAINTENANCE
iv
WARNINGS CONTINUED
•This INSTRUCTION MANUAL is an integral and indispensable part of the product. It must be
given to the user by the installers and must be kept in a safe place for future reference. In the
event that the boiler is transferred or sold, the manual must accompany the equipment.
•This boiler must be used only for the purposes for which it has been designed. Any other use
shall be considered incorrect and dangerous, thereby voiding the warranty
•The boiler must be installed in compliance with applicable laws and standards and according to
the manufacturer’s instructions given in this manual. Incorrect installation may cause injury to
personnel and/or damage to property. The manufacturer shall not be held liable for any such injury
and/or damage.
•Damage and/or injury caused by incorrect installation or use, or failure to observe the
manufacturer’s instructions shall relieve AERCO from any and all contractual and extra
contractual liability.
•DO NOT obstruct the air suction to the boiler room and/or heat dissipation devices in any other
room.
•Keep the packaging out of the reach of children as it may represent a choking and suffocation
hazard.
•Non-observance of the above requirement may jeopardize the safety of the boilers and expose
people, animals and property to danger.
CAUTIONS appear here and in one or more Chapters of this
manual.
•CAUTION, THE IGNITER MAY BE HOT. USE CARE TO AVOID SERIOUS BURNS
•Caution must be observed to prevent damage to the AERCO Modulex Boiler or associated
equipment. Failure to observe precautions may also void the Boiler warranty.
•Prior to installing the boiler, check to ensure that the technical data corresponds to
requirements for its intended use in the system.
•Check that the boiler is intact and that it has not been damaged during transport and handling. Do
not install equipment, which is evidently damaged and/or faulty.
•Only original accessories must be used for all boilers supplied with options or kits (including
electrical ones).
•Dispose of the packaging with care, as all the materials can be recycled. The packaging must
therefore be sent to specific waste management sites.
•In the event of failure and/or faulty functioning, switch off the boiler. Do not attempt to make
repairs: contact qualified technicians. Original parts must be used for all repairs to the boiler.
•In the event of long periods of inactivity of the boiler, disconnect it from the power mains and close
the gas valve. (In this case, the boiler’s electronic anti-freeze function will not be operative.)
Should there be a risk of freezing, add anti-freeze: it is not advisable to empty the system as
this may result in damage; use specific “aluminum-friendly”, neutral pH anti-freeze products
suitable for multi-metal heating systems.
•To guarantee efficiency and correct functioning of the equipment it is legally binding to
service the boilers once a year according to the schedule indicated in the relative
section of this manual.

INSTALLATION, OPERATION & MAINTENANCE
- v -
FOR YOUR SAFETY
For boilers that use gaseous fuel, what to do if you smell gas.
•Do not try to light any appliance.
•Do not touch any electric switch; do not use any phone in your building.
•Immediately call your gas supplier from a neighbor’s phone. Follow the
gas supplier’s instructions.
•If you cannot reach your gas supplier, call the fire department.
NEVER USE FLAMES TO DETECT GAS LEAKS.
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.
Carefully read the warranty conditions and clauses on the warranty certificate
attached to the boiler.
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

INSTALLATION, OPERATION & MAINTENANCE
vi
Extracted Information From 248 CMR 5.08 (2) – Continued
a. In the event that the side wall horizontally vented gas fueled equipment is installed in
a crawl space or an attic, the hard wired carbon monoxide detector with alarm and
battery back-up may be installed on the next adjacent floor level.
b. In the event that the requirements of this subdivision can not be met at the time of
completion of installation, the owner shall have a period of thirty (30) days to comply with
the above requirements; provided, however, that during said thirty (30) day period, a
battery operated carbon monoxide detector with an alarm shall be installed.
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.
(b) EXEMPTIONS: The following equipment is exempt from 248 CMR 5.08(2)(a)1 through 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)]

INSTALLATION, OPERATION & MAINTENANCE
1-1
1 GENERAL DESCRIPTION
IMPORTANT
Each AERCO Modulex Boiler is shipped as either a Natural Gas Only Boiler OR
a Propane Gas Only Boiler. It Is Not a Dual-Fuel Boiler. Ensure that the correct
fuel and fuel pressure are used when operating the equipment.
1.1 – TECHNICAL FEATURES
Modulex is a compact, modular, gas fired, Low NOx, condensing boiler. The boiler body, is comprised
of sections of cast aluminum/magnesium/silicon alloy. The boiler is designed to recover the sensible
and the latent heat of the combustion gases, thereby allowing it to attain a thermal efficiency of 92% as
tested by the Hydronics Institute, a Division of GAMA. These cast aluminum sections make up modules
referred to as the heat modules. Each module can deliver an output between a maximum of 152 MBH
and a minimum of 45 MBH and are composed of a pre mix combustion chamber, metallic mesh radiant
burner, modulating fan with control pressure switch, gas valve, ignition device, flame detection, NTC
sensor for local temperature control and a safety thermostat.
The heat modules are housed in a single enclosure and are connected to a single exhaust manifold.
These modules are independent of each and are sequentially staged, known as cascading, to take
advantage of higher efficiencies. Each heat module has its own printed circuit (PC) board that controls
and monitors combustion as well as the temperature of each heat module providing operational safety.
The entire boiler is controlled by a single microprocessor. This microprocessor is responsible for the
staging and modulation of the heat modules, monitoring supply and return water temperatures as well
as heating and domestic hot water (DHW) zones. Other features include:
•The heating load is shared with as many boiler modules as possible running at a minimum
output to ensure the maximum efficiency at partial load operation.
•Access to all testing/programming parameters of each module: operation test, operation time,
boiler freeze protection from 45°F (7°C), pump’s anti seize program.
•Lead-lag burner operation based on burner operating hours. The boiler module with the least
burner operating hours is the first to start and the burner with the most operating hours is the
first to stop.
•D.H.W. production by a priority sensor, with control capability of a dedicated pump or a 3-way
diverting valve for storage tank temperature control.
•A service mode for manual operation of individual heat modules capability for troubleshooting
or combustion calibration
•Diagnostics including relay and sensor testing.
Reliability is improved by the modular design of the Modulex since each heat module is independent of
the other, having its own ignition and combustion safeguard system. If one of the boiler’s heat modules
stops functioning, the remaining module(s) continue to operate.
The Modulex boiler can be comprised of from 2 to 7 modules and 3 to 8 cast aluminum sections. The
input to each heat module is 151.5 MBTU/Hr. The smallest Modulex 303, comprised of two heat
modules, has a combined total input of 303,000 BTU/Hr (2 x 151.5 = 303 MBTU) while the largest, the
1060 comprised of 7 heat modules has a total input of 1060 MBTU’s (See Table 1-1).
For one Modulex 303 boiler consisting of two modules, the output modulates from 15% to 100%. For a
Modulex 1060 boiler consisting of seven modules, the output modulates from 4.3% and 100%. If a
system comprised of two boilers is installed, then the modulation range for each boiler increases to 7.5%
to 100% for the Modulex 303 and 2.2% to 100% for the Modulex 1060.

INSTALLATION, OPERATION & MAINTENANCE
1-2
1.2 - CODE AND STANDARDS APPROVALS
MODULEX has been reviewed for compliance with the applicable sections of the following North
American Standards:
Z21.13: GAS FIRED LOW PRESSURE STEAM AND HOT WATER BOILERS
ASME SECTION IV: BOILER AND PRESSURE VESSEL CODE RULES FOR CONSTRUCTION
OF HEATING BOILERS
BTS 2000: TESTING STANDARD METHOD TO DETERMINE EFFICIENCY OF
COMMERCIAL SPACE HEATING BOILERS
SCAQMD Rule
1146.2:
NOx EMISSIONS FROM WATER HEATERS AND SMALL BOILERS
CSD-1-2004: CONTROLS AND SAFETY DEVICES FOR AUTOMATICALLY FIRED
BOILERS
Table 1-1. – Modulex Boiler Output Range, Turn-Down Ratio & Condensate Production
Output Range MBH1(KW) Condensate Production [gph (l/h)]
Heat
Modules Model Min. Max.
Turn Down
Ratio Min. Max.
2 303 41(12) 279 (82) 6:1 1.3 (5) 3.4 (13)
3 454 41(12) 418 (122) 10:1 1.9 (7.3) 5.3 (20)
4 606 41(12) 558 (163) 13:1 2.7 (10.1) 7.1 (27)
5 757 41(12) 696 (204) 16:1 3.3 (12.6) 9.0 (34)
6 909 41(12) 835 (245) 20:1 4.0 (15.1) 10.6 (40)
7 1060 41(12) 975 (286) 23:1 4.6 (17.6) 12.4 (47)
1MBH = 1000 Btu/hr
1.3 INSTALLATION FLEXIBILITY
The Modulex boiler allows for installation flexibility, i.e. it is suitable to be connected with the water
supply and return and the gas connections on the Right Hand (R.H.) side (standard delivery condition)
or on the Left Hand (L.H.) side. This is accomplished by reversing the gas and water manifolds utilizing
the instructions supplied with the boiler. The same is true for the vent pipe connection, which at the
installation, can be moved from the R.H. side (standard delivery condition) to the L.H. side or to the rear
of the boiler. The installation flexibility features include the following:
•Modulex can be installed in a multiple boiler system by the combination of two or more boilers.
•Gas connecting pipes, supply/return water pipes can be arranged for any connection (by either
the left or right hand side of the unit, the unit is shipped with all connections on the right hand
side as viewed from the front of the unit).
•Vent pipe, adjustable on the right, the left and behind the heating system.

INSTALLATION, OPERATION & MAINTENANCE
1-3
1.4 DIMENSIONS AND WEIGHTS
The dimensions and weights for each Modulex Model are shown in sheets 1 and 2 of Figure 1-1.
Figure 1-1. Modulex Dimensions and Weights (Sheet 1 of 2)

INSTALLATION, OPERATION & MA
1-4
INTENANCE
Figure 1-1. Modulex Dimensions and Weights (Sheet 2 of 2)

INSTALLATION, OPERATION & MAINTENANCE
1-5
1.5 - TECHNICAL DATA (THE NAME PLATE IS PLACED UNDER THE FRONT JACKET NEXT TO THE
CONTROL PANEL.)
Model Number Min Input Max Input Max Output* Net IBR Rating
MLX-303 45,500 303,000 260,000-279,000 237,000
MLX-454 45,500 454,000 390,000-418,000 355,000
MLX-606 45,500 606,000 521,000-558,000 474,000
MLX-757 45,500 757,000 651,000-696,000 592,000
MLX-909 45,500 909,000 781,000-835,000 710,000
MLX-1060 45,500 1,060,000 912,000-975,000 829,000
DIMENSIONS:
Model Number Height Width Depth Dry Weight
MLX-303 42” (1067 mm) 28” (711 mm) 27” (686 mm) 405 lbs. (183.7 kg)
MLX-454 42” (1067 mm) 28” (711 mm 27” (686 mm) 484 lbs. (219.6 kg)
MLX-606 42” (1067 mm) 33” (838 mm) 27” (686 mm) 575 lbs. (260.8 kg)
MLX-757 42” (1067 mm) 38” (965 mm) 27” (686 mm) 673 lbs. (305.2 kg)
MLX-909 42” (1067 mm) 44” (112 mm) 27” (686 mm) 765 lbs. (346.8 kg)
MLX-1060 42” (1067 mm) 49” (1245 mm) 27” (686 mm) 869 lbs. (394.0 kg)
SPECIFICATIONS:
Model Number MLX-303 MLX-454 MLX-606 MLX-757 MLX-909 MLX-1060
Boiler Category IV IV IV IV IV IV
Type of Gas Natural Gas
(MLX-303H)
or Propane
(MLX-303HP)
Natural Gas
(MLX-454H)
or Propane
(MLX-454HP)
Natural Gas
(MLX-606H)
or Propane
(MLX-606HP)
Natural Gas
(MLX-757HB)
or Propane
(MLX-757HP)
Natural Gas
(MLX-909H)
or Propane
(MLX-909HP)
Natural Gas
(MLX-1060H)
or Propane
(MLX-1060HP)
Gas Connections (NPT) 1.5” 1.5” 1.5” 1.5” 1.5” 1.5”
Max. Gas Pressure 14” W.C.
(34.8 mbar)
14” W.C.
(34.8 mbar)
14” W.C.
(34.8 mbar)
14” W.C.
(34.8 mbar)
14” W.C.
(34.8 mbar)
14” W.C.
(34.8 mbar)
Optimal Gas Pressure 7” W.C.
(17.4 mbar)
7” W.C.
(17.4 mbar)
7” W.C.
(17.4 mbar)
7” W.C.
(17.4 mbar)
7” W.C.
(17.4 mbar)
7” W.C.
(17.4 mbar)
Min. Gas Pressure 4”
(10 mbar)
4”
(10 mbar)
4”
(10 mbar)
4”
(10 mbar)
4”
(10 mbar)
4”
(10 mbar)
Max. Allowed Working
Pressure
92 psi
(634 kPa)
92 psi
(634 kPa)
92 psi
(634 kPa)
92 psi
(634 kPa)
92 psi
(634 kPa)
92 psi
(634 kPa)
Electrical Req:
120V 15 Amp. Max.
1.2 FLA 1.8 FLA 2.4 FLA 3.0 FLA 3.6 FLA 4.2 FLA
Water Connections
(NPT)
2-1/2” 2-1/2” 2-1/2” 2-1/2” 2-1/2” 2-1/2”
Min. Water Flow (GPM) 11 17 22 28 38 39
Max. Water Flow (GPM) 28 42 55 70 84 98
Water Pressure Drop
@ Max. Flow (Ft. of
Head)
10.5 10.6 11.6 12.6 13.7 16.1

INSTALLATION, OPERATION & MAINTENANCE
1-6
SPECIFICATIONS: (continued)
Model Number MLX-303 MLX-454 MLX-606 MLX-757 MLX-909 MLX-1060
Water Pressure Drop @
Max. Flow
5 psi
(34.5 kPa)
6 psi
(41.4 kPa)
9 psi
(62.1 kPa)
10 psi
(68.9 kPa)
13 psi
(89.6 kPa)
15 psi
(103.4 kPa)
Water Volume: Gallons 2.8 3.8 4.9 5.9 6.9 8.0
Water Volume: Liters 10.4 14.4 18.4 22.3 26.3 30.2
Thermal Modules 2 3 4 5 6 7
Turn-Down Ratio 6:1 10:1 13:1 16:1 20:1 23:1
Vent Size 4” (102 mm) 4” (102 mm) 4” (102 mm) 6” (152mm) 6” (152mm) 6” (152mm)
Vent Materials (per local
code)
Can support PVC, ABS, CPVC, or AL29-4C venting materials.
Temperature Control
Range
All units can be applied to deliver 50°F to 185°F (10°C to 85°C) supply water.
Maximum Noise Level All units deliver <50 dBA when operating at or below full fire.
NOx Emissions
Certification
All units have been certified by SCAQMD and TCEQ for <30 ppm NOx.
Standard Listings &
Approvals
All units have been certified by CSA.
1.6 MODULEX SIDE VIEW SHOWING MAIN COMPONENTS
Figure 1-2 on the following page illustrates the Main Components included in each Modulex Boiler
Model. In addition, an exploded view parts list drawing is included in Appendix B.

INSTALLATION, OPERATION & MAINTENANCE
1-7
FAN
GAS VALVE
BURNER
COVER
IGNITION
FLAME
DETECTOR
LOCAL NTC
SENSOR
H.L.
THERMOSTAT
BURNER
FILLING-UP
ELBOW
GAS PIPE
AIR INTAKE
CONNECTION
GLOBAL FLOW
NTC TEMPERATURE
SENSOR
HOT WATER
OUTLET (SUPPLY)
1/4" CONNECTION
WITH PLUG
GLOBAL RETURN
NTC TEMPERATURE
SENSOR
COLD WATER INLET
(RETURN)
WATER DRAIN
VALVE
CONDENSATE
DRAIN TRAP
1" [25 mm]
BOILER
FRAME
ALUMINUM/
SILICON HEAT
EXCHANGER
AUTOMATIC
AIR VENT
CONDENSATE
COLLECTION
TRAY MANIFOLD
5.9" [150 mm]
4"
[100 mm]
Figure 1-2.
Modulex
1.7 BOILER FREEZE PROTECTION
e to less than 44.6°F (7°C), the system pump will start.
NOTE
If glycol is used as antifreeze in the boile flow preventer must be installed in the
Main Components
Should the boiler water outlet temperature decreas
Should temperature decrease to less than 37.4°F (3°C), all heat modules will start at minimum output until
the return temperature reaches 50°F (10°C). Such a protection device is exclusively for the boiler. For the
protection of the whole system, a second freeze protection thermostat is necessary to switch on the
heating system pump.
r, a back
make-up/fill line.

INSTALLATION, OPERATION & MAINTENANCE
2-1
INSTRUCTIONS FOR INSTALLERS
2.1 INTRODUCTION
The Modulex Boiler is intended to be installed as a Category IV vent installation and must be installed
in compliance with all applicable laws and regulations including the ones below. See section 3.1 for
Category descriptions.
Before boiler installation, complete all of the following
instructions:
The installation must conform to the requirements of the authority having jurisdiction or, in the absence
of such requirements, to one of the following:
•United States - Installation must conform to the requirements of the National Fuel Gas Code,
ANSI Z223.1 Installation Codes.
•Canada - Installation must conform to the requirements of CAN/CGA B149 Installation Codes.
Where required by the authority having jurisdiction, the installation must conform to the Standard for
Controls and Safety Devices for Automatically Fired Boilers, ANSI/ASME CSD-1.
NOTES:
•Installers must follow local regulations with respect to installation of Carbon
Monoxide (CO) Detectors. Also, follow the maintenance recommendations in this
manual.
•FOR MASSACHUSETTS INSTALLATIONS: The boiler must be installed by a
plumber or gas fitter licensed within the Commonwealth of Massachusetts.
Also, for installations in buildings used for residential purposes, if a side-wall vent
termination is less than 7 feet above grade, an NFPA 720 compliant, ANSI/UL 2034
listed and IAS certified carbon monoxide detector must be installed on the floor level
where the boiler is installed and on each level of the building served by the boiler.
2.2 INSTALLATION INSTRUCTIONS
The following paragraphs in this Section provide the instructions to unpack and install the Modulex Boiler.
2.2.1 Unpacking the Boiler
The Modulex Boiler is delivered assembled and protected by a plastic bag inside a rugged cardboard
box, which is fixed on a pallet (see Figure 2-1). The pallet allows the boiler to be handled by a forklift or
pallet jack. The boiler, with the packaging, can fit through a doorway of 32 in. (81 cm), whereas, without
packaging, it can fit through a doorway of 28 in. (71 cm). To unpack the Modulex, remove both straps
and then the cardboard box from above. Check to ensure that the product is intact.
2
The packing elements (cardboard box, straps, plastic bags, etc…)
must not be left in children’s hands since they may be dangerous.

INSTALLATION, OPERATION & MAINTENANCE
2-2
Packed inside the boiler packing you will find:
•Painted steel panels:
•The front one connected to the back panel by a shrink wrap film
•The right hand side panel connected to the left hand panel by shrink wrap
On the front of the boiler:
•Flue collector, with exhaust connector screwed to the pallet: 6 inch for models 303 to 606 and 8
inch for models 757 to 1060. Use these items only when the specified flue pipe size is increased
to 6” (for models 303 to 606) and 8” (for models 757 to 1060). Otherwise, use the exhaust
connector “shipped in the separate carton” described below (4” for models 303 to 606, 6” for
models 757 to 1060).
•A plastic bag containing 3 gaskets (1 rectangular for condensate tray and flue collector, 1 square
for exhaust connector.
•Three (3) surface-mount strap-on sensors.
•Screws necessary for accessory installation.
•Piping for 1 ½” condensate drain, including one tee and two 90 degree elbows.
On the back of the boiler:
•Plastic condensate drainpipe, 38.5 inches (1meter) long, placed under the casing rear panel.
•Outside air sensor with 49 feet, 2.5 inches (15 m) cable.
•Manual Gas Shutoff Valve.
Shipped in a separate carton are the following:
•Accessory kit that includes a CSD-1 installation kit for Models 303 through 606 and Models 754
through 1060 as follows:
Kit P/N 29073: For Models 303-606 with 50 psig Relief Valve
Kit P/N 29074: For Models 707-1060 with 50 psig Relief Valve
Kit P/N 29075: For Models 303-606 with 90 psig Relief Valve
Kit P/N 29076: For Models 707-1060 with 90 psig Relief Valve
See the packing list shipped in this manual package for a complete listing of accessories. See
paragraph 4.4 for more information about the CSD 1- kits.
Figure 2-1.
Packaged Modulex Boiler

INSTALLATION, OPERATION & MAINTENANCE
2-3
2.2.2 Locating the Boiler
The boiler should be located on a level, solid area or base as near to the outside wall as possible and
centrally located to the space heating distribution system. Special attention must be given to local regulations
and codes about boiler rooms and particularly to the maintaining of minimum clearances and empty space
around the boiler. The installation must be in compliance with all recent regulations and laws about boiler
rooms, installations of heating and hot water systems, ventilation, boiler venting systems capable of
evacuating the flue gases of condensing boilers and any other applicable requirement.
The minimum clearance dimensions for service access, required by AERCO, are listed below (Figure 2-2)
and on the boiler Data Plate shown in Figure 2-7. Local building codes may require more clearance and
take precedence.
Minimum clearances required:
Sides 24" (510 mm)
Front 24" (510 mm)
Rear 24" (510 mm)
Top 24" (510 mm)
Figure 2-2
Boiler Clearances (Top View)
NOTE: All gas piping, water piping and electrical conduit or cable must be arranged so that
they do not interfere with the removal of any cover, or inhibit service or maintenance of the
unit.
The boiler MUST NOT be installed on carpeting
2.2.3 Pad Height for Boiler
To properly drain and service the boiler’s condensate system, attention must be given to installation
requirements regarding the mounting height of the boiler as well as installation clearances for the removal
of the condensate collector baffle.
The boiler should be mounted on a flat and sufficiently strong base with the same dimensions as the boiler
(see Figure 1-1) and at least 4 inches (100mm) high (see Figure 4-1 in paragraph 4.7), to allow for
assembly of the condensate drain trap. An alternative to this base may be a 4 inch (100mm) deep well next
to the boiler to house the condensate siphon.
The condensate collector baffle (see Section 7) can be fixed, from the Right Hand (R.H) or Left Hand (L.H.)
side of the condensate tray. If no modification has been made, the boiler must have its R.H. side
accessible, with the vent connection fitted on the R.H or L.H. side. However, if the flue collector terminal,
with the exhaust connector, is left to of the R.H. side and if, from this same side, the baffle has to be
removed, and then the exhaust connector must have the possibility to be also removed. If it is preferred,
the baffle can be moved in order to have its mounting screw on the opposite side, regardless the position of
the flue collector chamber terminal.

INSTALLATION, OPERATION & MAINTENANCE
2-4
2.2.4 Boiler Connections
Upon delivery, the Modulex Boiler has all the connections on its R.H. side (Figure
2-3). Note that the R.H. orientation is the right hand side when viewed facing the front of the boiler. These
connections include: water supply and return, gas, combustion air intake and flue collector outlet. The
locations of the air intake and/or the flue collector outlet can be changed on site by removing knock-outs on
the boiler right, left or back side panels. To attach the exhaust connector to the flue collector, use the
screws and the gaskets supplied inside the plastic bag and use a cross-tip (Phillips) screwdriver at least 12
in. (300 mm) long.
Figure 2-3.
Boiler Connections
Water supply and return and gas connections can also be moved to the boiler’s L.H. side by inverting the
flow (supply)/return manifold on the left side using the following procedure:
1. Remove the front, side and rear panels from the boiler.
2. For reversal of the water flow (supply) and return manifolds from the R.H. to the L.H. side, remove
the small plates securing the flow (supply) and return global temperature sensors (Figure 2-4).