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SSCBL-RPBL-IOM (10-22) 149159-C
5 . Connect outside section of combustion air pipe to concentric adapter box (see
):
a . Determine length of combustion air pipe so that dimension X in
is equal to bracket length plus roof
thickness and plus anticipated snow depth . Ensure that length of combustion air pipe does not exceed 48
inches (1,219 mm) or does not extend
less than
18 inches (457 mm) above roof .
b . Secure inlet air pipe to collar of concentric adapter box using sheet metal screws . Seal joint and seam using
tape or sealant .
Figure 28. Combustion Air Pipe Installation
6 . Secure concentric adapter box to underside of roof (see
):
⚠ CAUTION ⚠
• If the roof is combustible, ensure that brackets are positioned to allow a 2-inch (51 mm) clearance
between the concentric adapter box and the roof.
• If any holes are made in the concentric adapter box in error, ensure that they are sealed.
a . Insert combustion air pipe through roof as shown in
b . Position concentric adapter box to match pipe runs and secure short angles of concentric adapter brackets
) to underside of roof using field-supplied hardware .
c . Install field-supplied flashing around combustion air pipe on roof outside .
