Lennox DAVE SIGNATURE SL280DFV Installation Instructions Manual page 15

14 - All venting pipe passing through floors, walls, and
ceilings must be installed with the listed clearance
to combustible materials and be fire stopped
according to local codes. In absence of local codes,
refer to NFGC (Z223.1).
15 - No portion of the venting system can extend into,
or pass through any circulation air duct or plenum.
16 - Vent connectors serving Category I appliances shall
not be connected to any portion of mechanical draft
systems operating under positive pressure such as
Category III or IV venting systems.
17 - If vent connectors are combined prior to entering
the common vent, the maximum common vent
capacity listed in the common venting tables must
be reduced by 10%, the equivalent of one 90° elbow
(0.90 x maximum common vent capacity).
18 - The common vent diameter must always be at least
as large as the largest vent connector diameter.
19 - In no case, shall the vent connector be sized more
than two consecutive table size diameters over the
size of the draft hood outlet or flue collar outlet.
20 - Do not install a manual damper, barometric draft
regulator or flue restrictor between the furnace and
the chimney.
21 - When connecting this appliance to an existing
dedicated or common venting system, you must
inspect the venting system's general condition
and look for signs of corrosion. The existing vent
pipe size must conform to these instructions and
the provided venting tables. If the existing venting
system does
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