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Date: 8-4-2010
Revision: 0
Form: 2396
specified. Where the louver and grille design
and free area are not know, it shall be assumed
that wood louvers have a 25 percent free area,
and met louvers and grilles have 75 percent free
area. Non-motorized louvers and grilles shall be
fixed in the open position.
Screens
Minimum Screen Mesh Size:
Screens shall not be smaller than 1/4 “ mesh.
Motorized Louvers:
Motorized louvers shall be interlocked with the
appliance so they are proven in the full open
position prior to main burner ignition and during
main burner operation. Means shall be provided
to prevent the main burner from igniting should
the louver fail to opening during burner startup
and to shut down the main burner if the louver
close during burner operation.
Combustion Air Ducts
Combustion air ducts shall comply with the
following:
Ducts shall be constructed of galvanized steel or
a material having equivalent corrosion
resistance, strength and rigidity.
Ducts shall terminate in an unobstructed space,
allowing free movement of combustion air to the
appliances.
Ducts shall serve a single space.
Ducts shall not serve both upper and lower
combustion air openings where both such
openings are used. The separation between
ducts serving the upper and lower combustion
air openings shall be maintained to the source of
combustion air.
Ducts shall not be screened where terminating
in an attic space.
Horizontal upper combustion air ducts shall not
slope downward toward the source of
combustion air.
For informational purposes, there are several
codes that address the amount of air and/or size
of the opening(s) in walls for combustion air.
NFPA 54, National Fuel Gas Code (ANSI
Z223.1)
ASME CSD-1, Controls and Safety Devices for
Automatically Fired Boilers
ASME Section VI, Recommended Rules for
Care and Operation of Heating Boilers
BOCA, National Mechanical Code
WARNING:
Do not locate air intakes where
petroleum distillates, CFC’s,
detergents, volatile vapors or any
other chemicals are present. Severe
boiler corrosion and failure will result.
1.7 FLUE GAS VENTING SYSTEM
Triple-Flex boilers are Category IV appliances
that vent with a positive exhaust vent pressure
and with a temperature that is likely to cause
condensation. Any venting system used with
the Triple-Flex boiler must comply with the
requirements for Special Gas Vents per UL
Category Code (CCN) DGSH, which are UL
Listed per UL 1738 or UL Category Code
DGSH7, which are cUL Listed (Canada) per UL
1738.
WARNING:
The Triple-Flex boiler is NOT certified
for use with other types of venting
excepting Special Gas Vents. Use of
any other types of venting may cause
vent failure resulting in serious injury
or death.
1.7.1 DESIGN & INSTALLATION
6
A qualified venting professional experienced in
venting system designs should design the boiler
vent system. The vent size must be NO LESS
THAN 8” IN DIAMETER and sized such that the
pressure drop between the boiler and the point
of discharge does not exceed 0.20” WC. While
the vent must be UL Listed Special Gas Vent
per Category Code DGSH or DGSH7 for
Canada, Bryan Steam, LLC recommends the
use of venting components fabricated from
AL29-4C® material. The vent installation must
be in strict compliance with the vent
manufacturers requirements. Clearances to
combustible materials and supporting
requirements, per the vent manufacturers
installation instructions, must be maintained.