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Option
Combustion air may be ducted directly to the boiler using
PVC, CPVC, or sealed single-wall galvanized ducting.
The resulting installation meets the requirements for a
direct-vent installation. See venting section for detailed
information.
1. Install combustion air duct to the Air Intake
Connection. See Figure 4 and Figure 10. Remove
and discard the outdoor cap, connect the collar from
the Truseal option kit. Connect ducting material to
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supplied). All ducting shall be self-supporting.
2. In cold climates, and to mitigate potential freeze-
up, Raypak highly recommends the installation of a
motorized sealed damper to prevent the circulation
of cold air through the boiler during non-operating
hours. The optional Motorized Combustion Air
Dampers D-37 meets these needs.
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practical point communicating with the outdoors.
The total cross-sectional area of these openings
shall be at least 1 square inch free air space per
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of all equipment in the room, when the opening is
communicating directly with the outdoors or through
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be at least 1 square inch of net free air space per
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of all equipment in the room, when the opening is
communicating with the outdoors through horizontal
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ventilation of the space is not a warrantable failure.
Motorized Combustion Air Dampers D-37 or
Louvers
When motorized dampers or louvers are used for
combustion air, they must be interlocked with each
appliance in the equipment room, to ensure proper
operation.
See Field Wiring Connection section of this manual for
proper wiring instructions, using Fan/Damper dry contacts
and external interlock.
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WARNING: When unit is installed in the freezing
climates using ducted combustion air, a motorized
damper must be used and must be interlocked with the
boiler per NFGC requirements.
CAUTION: All ducting must be self-supported.
Air Supply
U.S. Installations
All Air from Inside the Building
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permanent openings communicating directly with an
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combined volume of all spaces meets the criteria for a
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gas utilization equipment installed in the combined space
shall be considered in making this determination. Each
opening shall have a minimum free area of 1 square inch
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of the bottom of the enclosure. The minimum dimension
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direction.
All Air from Outdoors
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in accordance with one of the methods below. The
minimum dimension of air openings shall not be less than
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shall be of the same cross-sectional area as the net free
area of the openings to which they connect.
1. Two permanent openings, one commencing within
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provided. The openings shall communicate directly,
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attic) that freely communicate with the outdoors.
a. Where directly communicating with the outdoors
or where communicating to the outdoors through
vertical ducts, each opening shall have a
minimum free area of 1 square inch per 4,000
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all equipment in the enclosure.
b. Where communicating with the outdoors through
horizontal ducts, each opening shall have a
minimum free area of 1 square inch per 2,000
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all equipment in the enclosure.
2. One permanent opening, commencing within
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permitted where the equipment has clearances of
at least 1".4 mm) from the sides and back and
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opening shall directly communicate with the out-
doors or shall communicate through a vertical or
horizontal duct to the outdoors or spaces that freely
communicate with the outdoors, and shall have a
minimum free area of: