Watts Aerco Modulex EXT Series User guide

Modulex EXT Vent and Combustion Air Application Guide GF-136-V
TAG-0054-0F AERCO International, Inc. •100 Oritani Dr. •Blauvelt, NY 10913 Page 1of 28
GF-136-V Phone: [phone]/2017
Venting & Combustion Air Guide
Modulating Condensing Hot Water Boilers
Latest Update: 09/25/2017
TECHNICAL APPLICATION GUIDE
APPLIES TO THE FOLLOWING
LIGHT COMMERCIAL MODELS
•MLX EXT 321
•MLX EXT 450 / MLX EXT 481
•MLX EXT 600 / MLX EXT 641
•MLX EXT 800 / MLX EXT 802
•MLX EXT 962
•MLX EXT 1100 / MLX EXT 1123
COMMERCIAL MODELS
•MLX EXT 1500 / MLX EXT 1530
•MLX EXT 1912
•MLX EXT 2295 / MLX EXT 2300
•MLX EXT 2600 / MLX EXT 2677
•
MLX EXT 3000 / MLX EXT 3060

Modulex EXT Vent and Combustion Air Application Guide
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TABLE OF CONTENTS:
CHAPTER 1: CODES, SAFETY, AND VENTING SYSTEMS...............................................3
1.1. APPLICABLE FEDERAL CODES ...............................................................................3
1.2. GAS VENT CATAGORIES..........................................................................................4
1.3. CERTIFIED VENTING MATERIALS FOR FLUE PIPE SYSTEMS..............................4
1.3.1. OPTION 1: AL29-4C Stainless Steel.....................................................................5
1.3.2. OPTION 2: VP1738A Stainless Steel....................................................................5
1.3.3. OPTION 3: Polypropylene.....................................................................................5
1.3.4. OPTION 4: PVC/CPVC.........................................................................................5
1.4. FACTORY SUPPLIED INLET AND VENT COMPONENTS ........................................6
1.4.1. Exhaust Manifold Assembly (Supplied) .................................................................6
1.4.2. European-to-American Flue Adaptor (Supplied)....................................................6
1.4.3. Flue Exhaust Piping Starter Pieces.......................................................................7
1.4.4. Air Intake Connector (Supplied).............................................................................8
CHAPTER 2: COMBUSTION AIR SYSTEM.........................................................................9
2.1. COMBUSTION AIR REQUIREMENTS........................................................................9
2.2. COMBUSTION AIR PIPE SIZING.............................................................................12
2.3. COMMON COMBUSTION AIR PIPE SIZING............................................................13
CHAPTER 3: VENT SYSTEM.............................................................................................16
3.1. VENT INSTALLATION..............................................................................................16
3.2. INSTALLATION PROCEDURE FOR VENTING SYSTEM THROUGH WALLS.........22
3.3. INSTALLATION PROCEDURE FOR VERTICAL VENTING......................................24
3.4. VENT PIPING SIZE...................................................................................................25
3.5. COMMON VENT PIPING SIZE.................................................................................26

Modulex EXT Vent and Combustion Air Application Guide
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CHAPTER 1: CODES, SAFETY, AND VENTING SYSTEMS
1.1. APPLICABLE FEDERAL CODES
United States:
NFPA 54/ANSI
Z223.1:
National Fuel Gas Code
NFPA/ANSI 211:
Chimneys, Fireplaces, Vents and Solid Fuel Burning Appliances
Canada:
CAN1-B149.1:
Installation Codes for Gas-Burning Equipment
B149.2:
Installation Codes for Gas-Burning Equipment
The above listed codes contain information for gas vented appliances requiring Category II, III and
IV, vent sizing, location, air space clearances to combustibles and safe installation practices. The
gas vent installer must be familiar with the above codes, as well as Local Codes and Regulations.
WARNING!
All installations of boilers and venting should be done only by qualified venting systems personnel
and in accordance with the manufacturer’s recommendations. Installing or venting a boiler or any
other gas appliance with improper methods or materials may result in serious injury or death due to
fire or to asphyxiation from poisonous gases (carbon monoxide is odorless and invisible).
WARNING!
•For correct installation of vent system, read all of these instructions and refer to the vent pipe
manufacturer’s instructions.
•Failure to use the venting system described in this document will void the manufacturer’s
warranty and may result in rapid deterioration of the venting system, creating a potential health
hazard.
•Faulty vent installation can allow toxic fumes to be released into living areas. This may cause
serious bodily injury or property damage. Improper assembly may also affect vent performance.
•Install separate vents for forced exhaust appliances and natural draft appliances. A common
vent between natural draft and forced exhaust appliances may cause toxic gases to exhaust
through the natural draft appliance rather than to outside air. Breathing exhaust gases will
cause serious personal injury or death.

Modulex EXT Vent and Combustion Air Application Guide
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1.2. GAS VENT CATAGORIES
WARNING!
The Modulex boiler is approved for a Category IV vent configuration as well as for sealed
combustion installations. Make provisions for combustion and ventilation air in accordance with
Section 5.3, (Air for Combustion and Ventilation) of the National Fuel Gas Code - ANSI Z223.1, or
Sections 7.2, 7.3, or 7.4 of CAN/CGA B149, Installation Codes, or applicable provisions of the local
building codes.
Federal Codes have categorized gas appliances by the vented flue gas pressure and temperature:
•Category I, being a gas appliance that operates with a non-positive vent (or natural drafted vent)
connector with a flue gas pressure and temperature at least 140°F (60°C) above its dew point.
•Category II, being a gas appliance that operates with a non-positive vent (or natural drafted vent)
connector with a flue gas pressure and temperature less than 140°F (60°C) above its dew point.
•Category III, being a gas appliance that operates with a positive vent (fan forced vent) connector
with a flue gas pressure and temperature at least 140°F (60°C) above its dew point.
•Category IV, being a gas appliance that operates with a positive vent (fan forced vent) connector
with a flue gas pressure and temperature less than 140°F (60°C) above its dew point.
•Direct Vent, a gas appliance is constructed and installed so that all air for combustion is derived
directly from the outdoors and all flue gases are discharged to the outdoors.
1.3. CERTIFIED VENTING MATERIALS FOR FLUE PIPE SYSTEMS
Acceptable materials and manufacturers for flue vent pipe systems are listed below in Option #1 –
Option #4.
WARNING!
The Vent Pipe Systems below are used for venting gas burning Category IV appliances. Do not
use these vent pipe systems for venting appliances burning fuels such as wood, coal, oil or
kerosene.
Maintain clearances from combustible construction for boiler, vent connector, and steam and hot-
water pipes.
Do not use these vent pipe systems for incinerators of any kind.
Do not vent Modulex systems using the same vent piping as being used for either Benchmark or
KC boilers.

Modulex EXT Vent and Combustion Air Application Guide
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1.3.1. OPTION 1: AL29-4C Stainless Steel
•Security Chimneys International, Secure Seal, SS, SSD, and SSID (available through AERCO)
•Flex-L International Inc., StaR 34 Vent
•Heat-Fab Inc., Saf-T Vent
•Protech System Inc., Fas N Seal Vent
•Metal-Fab Inc., Corr/Guard Vent
•Z-Flex Z-Vent
1.3.2. OPTION 2: VP1738A Stainless Steel
•Van-Packer Company, Inc., Model CS Special Gas Vent
1.3.3. OPTION 3: Polypropylene
•DuraVent, Polypro Commercial (Available through AERCO)
•Centrotherm ECO Systems, InnoFlue Single Wall Commercial
1.3.4. OPTION 4: PVC/CPVC
Use Schedule 40 or thicker, Single-Wall, Uninsulated Pipes
When using Non-Metallic (Plastic) vent systems for Canadian installations, per CSA B149.1, use vent
systems that are certified to the Standard for Type BH Gas Venting Systems, ULC-S636. The plastic
components, primers and glues of the certified vent system must be from a single system
manufacturer and not inter-mixed with other manufacturers vent system parts.
PVC
•ASTM F891
•ASTM D2665
•ASTM D1785
•ASTM D2241
CPVC
•ASTM D2846
•ASTM F441
•ASTM F442

Modulex EXT Vent and Combustion Air Application Guide
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1.4. FACTORY SUPPLIED INLET AND VENT COMPONENTS
For installation flexibility, venting connectors are provided for left hand, right hand, and rear
connections. Basic drawings of the connection components and optional assemblies are shown in
Figures 1 through 4.
1.4.1. Exhaust Manifold Assembly (Supplied)
The exhaust manifold and necessary parts are supplied with the unit, and can be positioned on the
right, left, or rear of the unit. Two flue exhaust opening covers with gaskets are used to cover the
unused manifold openings. Assembly of the exhaust manifold is described in detail in Chapter 3. See
Figure 1 for image of the exhaust manifold parts.
Figure 1: Exhaust Manifold Components for Exhaust Outlet (Supplied)
1.4.2. European-to-American Flue Adaptor (Supplied)
The exhaust manifold supplied with the unit requires the use of an adaptor to connect to American
flue systems. This adaptor comes standard with the unit, and is pictured in Figure 2. Assembly of this
adaptor is described in detail in Chapter 3.
Figure 2: European-to-American Flue Adaptor (Supplied)
FOR EXT MODELS 1500 3060
FOR EXT MODELS 321 – 1123
EXHAUST
MANIFOLD
GASKET
MANIFOLD
ADAPTER GASKET
NUTS (6)
EXHAUST
MANIFOLD
GASKET
MANIFOLD
ADAPTER GASKET
NUTS (10)
FOR EXT MODELS 321 – 1123
FOR EXT MODELS 1500 – 3060

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1.4.3. Flue Exhaust Piping Starter Pieces
Table 1 lists the exhaust vent adaptors available for each Modulex EXT model. Instructions for
assembling the vent adaptors are in Chapter 3.
TABLE 1: EXT Vent Adaptors
BOILER MODELS DIAMETER MATERIAL KIT PART NUMBER
EXT
321, 450, 481 4”
Stainless Steel Contact vent manufacturer directly
Polypropylene
P/N 39006-1 (for Duravent PolyPro.
For other brands, contact manufacturer
directly.
PVC P/N 49051 (included)
EXT
600 – 1123 6”
Stainless Steel Contact vent manufacturer directly
Polypropylene
P/N 39006-2 (for Duravent PolyPro.
For other brands, contact manufacturer
directly.
PVC P/N 49050 (included)
EXT
1500, 1530, 1912 10” Stainless Contact vent manufacturer
Polypropylene Contact vent manufacturer
PVC 58115-1
EXT
2295 – 3060 12” Stainless Contact vent manufacturer
Polypropylene Contact vent manufacturer
PVC 58115-2
While the MLX EXT 1500 – 3060 are approved for use with PVC venting, this option can be
extremely heavy and expensive. AERCO strongly recommends Polypropylene or Stainless Steel
venting for these models.
FOR EXT MODELS 1500 – 3060 FOR EXT MODELS 321 – 1123
Figure 3: Flue Piping Starter Pieces
ADAPTER
CONNECTOR
BOLTS
WASHERS
WORM-DRIVEN
HOSE CLAMP
ADAPTER
GASKET

Modulex EXT Vent and Combustion Air Application Guide
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1.4.4. Air Intake Connector (Supplied)
Air is drawn into the EXT through the air inlet on the left side of the unit (Figure 4). A connector is
included installed and ready to use for connecting the appropriate air intake piping for EXT 321–
1123/450–1100. For EXT 1530–3060/1500–3000, the combustion air intake adapter is shipped loose.
This adapter is designed for spiral ducting only. For PVC ducting, order either P/N 58115-1 or 58115-
2 as per Table 1.
Figure 4: Air Intake Connection
NOTE:
See Chapter 3 for instructions for assembling the flue piping, including the exhaust manifold, Euro-to-
USA Adaptor, and Diameter Reduction Kits.
When using sealed combustion, observe the following requirements:
•Sealed combustion is only available on the left of the unit only.
•If using side-by-side minimum installation clearances, the center facing air inlet is not
available. See “Multi-Unit Installation Clearances (SD-A-968)” for further details.
Please note the following:
•EXT Models 321 – 1123 are set up for PVC inlet piping.
•EXT Models 1500 – 3060 come with an air intake adaptor for spiral ducting.
FOR EXT MODELS 321 – 1123
FOR EXT MODELS 1500 – 3060

Modulex EXT Vent and Combustion Air Application Guide
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CHAPTER 2: COMBUSTION AIR SYSTEM
WARNING!
Air openings to combustion area must not be obstructed. Using Table 2, air openings may be
specified so that adequate combustion air can be maintained.
2.1. COMBUSTION AIR REQUIREMENTS
WARNING!
•Non-Motorized louvers and grilles must be fixed in an open position.
•Minimum screens mesh size shall not be smaller than 1/4” (inch) mesh.
Table 2, below, shows the minimum required air openings in square inches (square centimeters) freely
communicating with the outdoors for boiler room combustion and ventilation air for each boiler. For
multiple boiler installations, sum the openings for the specific boiler sizes.
TABLE 2: Min. Required Air Openings Freely Communicating With the
Outdoors for Boiler Room Combustion & Ventilation Air
MODEL
TWO SEALED
COMBUSTION OR
VERTICAL DUCTS EACH
HAVING AN OPENING IN
SQ. IN. (SQ.CM) OF:
TWO HORIZONTAL
DUCTS EACH HAVING AN
OPENING IN SQUARE
INCHES OF:
SINGLE
PERMANENT
OPENING
EXT 321
80 in
2
(516 cm
2
) 161 in
2
(1039 cm
2
) 107 in
2
(690 cm
2
)
EXT 481/450
120 in
2
(774 cm
2
) 241 in
2
(1555 cm
2
) 160 in
2
(1032 cm
2
)
EXT 641/600
160 in
2
(1032 cm
2
) 321 in
2
(2071 cm
2
) 214 in
2
(1381 cm
2
)
EXT 802/800
201 in
2
(1297 cm
2
) 401 in
2
(2587 cm
2
) 267 in
2
(1723 cm
2
)
EXT 962
241 in
2
(1655 cm
2
) 481 in
2
(3103 cm
2
) 321 in
2
(2071 cm
2
)
EXT 1123/1100
281 in
2
(1813 cm
2
) 562 in
2
(3626 cm
2
) 374 in
2
(2413 cm
2
)
EXT 1530/1500 383 in
2
(2471 cm
2
) 765 in
2
(4935 cm
2
) 510 in
2
(3290 cm
2
)
EXT 1912 478 in
2
(3084 cm
2
) 956 in
2
(6168 cm
2
) 637 in
2
(4110 cm
2
)
EXT 2295/2300 574 in
2
(3703 cm
2
) 1148 in
2
(7406 cm
2
) 765 in
2
(4935 cm
2
)
EXT 2677/2600 669 in
2
(4316 cm
2
) 1339 in
2
(8639 cm
2
) 892 in
2
(5755 cm
2
)
EXT 3060/3000 765 in
2
(4936 cm
2
) 1530 in
2
(9871 cm
2
) 1020 in
2
(6581 cm
2
)
1. The combustion air must be free of chlorine, halogenated hydrocarbons or other chemicals that
can become hazardous when used in gas-fired equipment. Common sources of these
compounds are swimming pools, degreasing compounds, plastic processing, and refrigerants.
Whenever the environment contains these types of chemicals, combustion air MUST be
supplied from a clean area outdoors for the protection and longevity of the equipment and
warranty validation.
2. Ventilation of the boiler room must be adequate enough to provide sufficient air to properly
support combustion.

Modulex EXT Vent and Combustion Air Application Guide
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3. When combustion air is brought from outside the building and the boiler room is provided with
two permanent openings, one shall commence 12 inches from the top and the other shall
commence within 12 inches from the bottom of the room (see Figure 5). The openings shall
communicate directly, or by ducts, freely with the outdoors. One of the following methods must
be made to provide adequate air for ventilation and combustion.
Figure 5: Combustion-Air Makeup-Air Vent Locations
oWhen directly communicating with the outdoors, each opening shall have a minimum free area
of 1 square inch per 4,000 BTU per hour of total input rating of all equipment in the room.
oWhen communicating with the outdoors by means of vertical ducts, each opening shall have a
minimum free area of 1 square inch per 4,000 BTU per total input rating of all appliances in the
room.
oIf horizontal ducts are used, each opening and duct shall have a minimum free area of 1
square inch per 2,000 BTU per hour of total input rating of all appliances in the room.
4. When calculating free area using louvers and grilles, the required size of the openings for
combustion, ventilation, and dilution air shall be based on the total free area of each opening.
5. If the free area through a designed louver or grille is known, it shall be used in calculating the size
of the opening required to provide the free area specified.
6. If the louver and grille design free areas are not known, the following will be assumed for wooden
louvers a 25 percent free area, and for metal louvers and grilles a 75 percent free area opening.
12” (305 mm)
12” (305 mm)
MAKEUP AIR
MAKEUP AIR

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7. When terminating the combustion air through the roof:
a) Combustion air inlet must be 3 ft. below any vent outlet within 10 ft. See Figures 6 and 7.
b) Combustion air inlet must also face away from the vent outlet. See Figure 6.
Figure 6: Combustion Air Roof Termination Locations
8. All inlet air ducts must be sealed air tight.
9. When using sealed combustion, the combustion air inlet and vent outlet must be located on the
same surface (same wall, roof, etc.). See Figures 7. This is required so that equal pressure zones
are acting on both the air inlet and vent outlet. This makes the installation a balanced vent system,
which helps maintain stable combustion characteristics.
10. For outdoor installations, a downward facing 90° elbow should be added to the inlet air connection
and covered with a bird screen. See Figure 8.
Figure 7: Sealed Combustion Air Inlet and Vent Outlet Locations (Wall & Roof)

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Figure 8: Outdoor Installation Air Inlet and Vent Outlet Locations
11. For outdoor installations, an outdoor venting kit is available through AERCO. Please contact your
local representative for further details.
2.2. COMBUSTION AIR PIPE SIZING
The maximum length is the combined length of straight horizontal and vertical runs, and the
equivalent straight length of fittings. The required lengths for each boiler are shown in Table 3, below.
TABLE 3: Maximum Combustion Air Run Lengths
MODEL NO. PIPE
DIAM.
EQUIVALENT PIPE LENGTHS EXAMPLES MAXIMUM
LENGTH
EQUIVALENT
FT (M)
Sharp 90°
Elbow
Equiv. Ft (m)
Sweep 90°
Elbow
Equiv. Ft (m)
45° Elbow
Equiv. Ft (m)
EXT 321
EXT 481/450
EXT 641/600
4”
(102
mm)
10 ft.
(3.05 m) 5 ft. (1.5 m) 5 ft. (1.5 m) 100 ft. (30.5 m)
EXT 802/800
EXT 962
EXT 1123/1100
6”
(152
mm)
10 ft.
(3.05 m) N/A 5 ft. (1.5 m) 100 ft. (30.5 m)
EXT 1530/1500
EXT 1912
10”
(254
mm)
10 ft.
(3.05 m) N/A 5 ft. (1.5 m) 100 ft. (30.5 m)
EXT 2295/2300
EXT 2677/2600
EXT 3060/3000
12”
(305
mm)
10 ft.
(3.05 m) N/A 5 ft. (1.5 m) 100 ft. (30.5 m)
The maximum pressure drop of the vent is also 100 equivalent feet (30.5 m). See Section 3.4. Note
that this does NOT mean the allowed combined pressure drop between the vent and combustion air is
200 equivalent feet (61 m). That is, the vent cannot go above 100 equivalent feet (30.5 m), even if the
combustion air is less than 100 equivalent feet, and vice versa.
Bird Screen
Installed

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EXAMPLES:
1. A 40 foot length of combustion air pipe and 1 sharp 90° elbow plus two termination 90° elbows
add up to 40 ft. + 10 ft. + (2 x 10 ft.) = 70 equivalent ft. (21.3 m).
2. A 30 foot length of combustion air pipe and 2 sharp 90° elbows plus two termination 90°
elbows add up to 30 ft. + (2 x 10 ft.) + (2 x 10 ft.) = 70 equivalent ft. (21.3 m).
2.3. COMMON COMBUSTION AIR PIPE SIZING
Refer to Figures 9 and 10 for typical common combustion air inlet installation. The maximum length is
the sum of the equivalent straight length of horizontal runs, vertical runs, and fittings of the individual
combustion air connector and the common combustion air pipe. The required diameter lengths for a
given Modulex total BTU/hr. Input are shown in Table 4, below.
TABLE 4: Typical Common Combustion Air Run Lengths
TOTAL
BTU/HR
INPUT
(UP TO AND
INCLUDING)
COMMON
VENT
DIAMETER
EQUIVALENT COMMON VENT LENGTHS EXAMPLES MAXIMUM LENGTH

INDIVIDUAL
CONNECTOR
PLUS
COMMON VENT
EQUIVALENT FT (M)
Sharp 90°
Elbow
Equiv. Ft (m)
Sweep 90°
Elbow
Equiv. Ft (m)
45° Elbow
Equiv. Ft (m)
WYE or
Termination
Tee or
Vent
Cap
Equiv. Ft (m)
606,000 4”
(102 mm) 10 ft. (3.05 m) 5 ft. (1.5 m) 5 ft. (1.5 m) 5 ft. (1.5 m) 100 ft. (30.5 m)
1,284,000 6”
(152 mm) 10 ft. (3.05 m) N/A 5 ft.
(1.5 m) 5 ft. (1.5 m) 100 ft. (30.5 m)
2,407,500 8”
(203 mm) 10 ft. (3.05 m) N/A 5 ft.
(1.5 m) 5 ft. (1.5 m) 100 ft. (30.5 m)
3,825,000 10”
(254 mm) 10 ft. (3.05 m) N/A 5 ft.
(1.5 m) 5 ft. (1.5 m) 100 ft. (30.5 m)
5,355,000 12”
(305 mm) 10 ft. (3.05 m) N/A 5 ft.
(1.5 m) 5 ft. (1.5 m) 100 ft. (30.5 m)
6,885,000 14”
(358 mm) 10 ft. (3.05 m) N/A 5 ft.
(1.5 m) 5 ft. (1.5 m) 100 ft. (30.5 m)
9,180,000 16”
(407 mm) 10 ft. (3.05 m) N/A 5 ft.
(1.5 m) 5 ft. (1.5 m) 100 ft. (30.5 m)
The chart above shows equivalent pipe lengths of the fittings for the common combustion air pipe.
See section 2.2 for equivalent lengths for fittings for the individual boiler connector.
The maximum equivalent length shown is the sum of the equivalent length of the longest individual
connector plus the equivalent length of the common combustion air pipe. If the maximum equivalent
length exceeds 100 equivalent feet, contact your AERCO sales representative or AERCO
International for design assistance and approval.
It is important to use a WYE as a means to connect the individual combustion air pipe into the
common combustion air pipe. This will ensure the least amount of pressure drop. Do NOT use a
TEE, 90°, or 45° elbow.
The maximum pressure drop of the vent is also 100 equivalent feet (30.5 m). Note that this does
NOT mean that the allowed combined pressure drop between the vent and combustion air is 200
equivalent feet (61 m). That is, the vent cannot go above 100 equivalent feet (30.5 m), even if the
combustion air is less than 100 equivalent feet, and vice versa.

Modulex EXT Vent and Combustion Air Application Guide
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EXAMPLES:
The combustion air system of two EXT 1123/1100 (2 x 1,123,000 BTU/hr. = 2,246,000 BTU/hr.)
consists of 30 foot length of common combustion air pipe and 3 sharp 90° elbows. The termination
includes two (2) 90° elbows. Each individual combustion air connector consists of 10 ft. straight run
and one WYE.
Common Combustion air pipe: 30 ft. + (3 x 10ft) + (2 x 10ft) = 80 equivalent ft. (24.3 m)
Individual combustion air connector: 10 ft. + 5 ft. = 15 equivalent ft. (4.6 m)
Total Combustion air equivalent length: 80 ft. + 15 ft. = 95 (29.0 m)
95 equivalent ft. is LESS than 100 equivalent feet: OK to use 8” Common air intake piping and
6” individual connectors.
Figure 9: Typical Common Combustion Air Inlet installation Through Roof

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Figure 10: Typical Common Combustion Air Inlet installation Through Wall

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CHAPTER 3: VENT SYSTEM
Correct boiler venting is crucial for proper operation. Being a condensing boiler, combustion gases are
discharged at a very low temperature. It is therefore necessary for the venting system to be
impermeable to combustion products and condensate and to be made of corrosion resistant
materials. Typical Category IV venting and sealed combustion illustrations are shown in Figure 5
through 9. The various funnel joints shall be well sealed and/or equipped with suitable gaskets, in
order to avoid any condensate drain and/or air intake. Ensure that the boiler vent’s section and height
conform to national and local regulations (see Section 1.1 in this guide).
For boilers designed for connection to gas vents or chimneys, vent installations shall be in accordance
with Part 7, Venting of Equipment, of the National Fuel Gas Code, ANSI Z223.1, or Section 7, Venting
Systems and Air Supply for Appliances, of the CAN/CGA B149, Installation Codes, or applicable
provisions of the local building codes.
The vent system for the Modulex boilers must be installed in accordance with AERCO’s installation
CAUTION!
For Category IV Boilers, the vents must be installed to prevent accumulation of condensate, and
have means provided for drainage of condensate.
3.1. VENT INSTALLATION
•The boilers covered in this section are design-certified as Category IV for venting, only when
they are installed with manufacturer specified vent system components and installation
practices.
•Install supplied vent pipe starter piece at the boiler vent connector and work toward the vent or
rain cap. To attach the exhaust connector to the flue collector, use the screws and the gasket
supplied inside the plastic bag. Use a 14mm socket wrench with at least a 12 inche (300 mm)
extension. See Figures 11 and 12.
•Vent pipe fittings and connectors serving appliances vented by natural draft shall not be
connected into any portion of mechanical draft systems operating under positive pressure.
•Horizontal runs shall be sloping upwards not less than 1/4 inch per foot
(21 mm/m) from the boiler to the vent termination.
•Horizontal portions of the venting system shall be supported to prevent dips or sags where
condensate could collect.
•Rigidly support vent pipe every 5 feet and at the elbows. Plumber straps may be used.
•ALL vent pipe and fittings must be installed with appropriate air space clearances to
combustibles. These air space clearances apply to indoor or outdoor vents, whether they are
open, enclosed, horizontal or vertical or pass through floors, walls, roofs, or framed spaces.
The appropriate air space clearances should be observed between joists, studs, sub floors,
plywood, drywall, or plaster enclosures, insulated sheathing, rafters, roofing, and any other
combustible material. The minimum air space clearance also applies to electrical wires and
any kind of building insulation. For horizontal runs, keep 4 inch and 6 inch vent piping from
any contact with any combustible material, electric wires, and building materials.

Modulex EXT Vent and Combustion Air Application Guide
TAG-0054_0F AERCO International, Inc. •100 Oritani Dr. •Blauvelt, NY 10913 Page 17 of 28
GF-136–V Phone: [phone]/2017
Figure 11: Connection of Exhaust Manifold to Flue Exhaust Outlet (EXT 321 – 1123)
Figure 12: Connection of Exhaust Manifold to Flue Exhaust Outlet (EXT 1500 – 3060)
NOTE:
The gasket may seem large. It is intentionally designed to produce a tight fit.
EUROPEAN FLUE
EXHAUST MANIFOLD
(SUPPLIED)
FLUE ADAPTOR
GASKET (SUPPLIED)
NUTS (6)
(SUPPLIED)
EUROPEAN FLUE
EXHAUST MANIFOLD
(SUPPLIED)
FLUE
ADAPTOR
GASKET
(SUPPLIED)
NUTS (10)
(SUPPLIED)

Modulex EXT Vent and Combustion Air Application Guide
Page 18 of 28 AERCO International, Inc. •100 Oritani Dr. •Blauvelt, NY 10913 TAG-0054-0F
09/25/2017 Phone: [phone] GF-136-V
Figure 13: Assembly of USA Adaptor to European Flue Manifold (EXT 321 – 1123)
Figure 14: Assembly of USA Adaptor to European Flue Manifold (EXT 1500 – 3060)
EUROPEAN-TO-USA
FLUE EXHAUST
ADAPTER (SUPPLIED)
EUROPEAN FLUE
EXHAUST MANIFOLD
INSPECTION PORT
EUROPEAN FLUE
EXHAUST MANIFOLD
EUROPEAN-TO-USA
FLUE EXHAUST
ADAPTER (SUPPLIED)
GASKET FOR FLUE
ADAPTOR
GASKET FOR FLUE
ADAPTOR

Modulex EXT Vent and Combustion Air Application Guide
TAG-0054_0F AERCO International, Inc. •100 Oritani Dr. •Blauvelt, NY 10913 Page 19 of 28
GF-136–V Phone: [phone]/2017
Figure 15: Flue Piping Starter Piece Assembly (EXT 321 – 1123)
OPTIONAL FLUE PIPING
STARTER PIECE
EUROPEAN-TO-USA
FLUE ADAPTER
EUROPEAN
EXHAUST MANIFOLD
WORM-DRIVEN
HOSE-CLAMP
BOLT (4)
WASHER (4)
GASKET
ADAPTOR
CONNECTOR
(4” or 6”, PVC
or SS)

Modulex EXT Vent and Combustion Air Application Guide
Page 20 of 28 AERCO International, Inc. •100 Oritani Dr. •Blauvelt, NY 10913 TAG-0054-0F
09/25/2017 Phone: [phone] GF-136-V
Figure 16: Flue Piping Starter Piece Assembly (EXT 1500 –3060)
GASKET
EUROPEAN-TO-USA
FLUE ADAPTER
DIAMETER REDUCTION
ADAPTOR CONNECTOR
WORM-DRIVEN HOSE CLAMP
WASHERS (8 EACH)
SCREWS (8 EACH)
EUROPEAN
EXHAUST MANIFOLD
FLUE PIPING STARTER PIECE