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10− A vent connector shall be supported without any dips
or sags and shall slope a minimum of 1/4inch (6.4 mm)
per linear foot (305 mm) of connector, back toward the
appliance. See local and national installation codes for
support intervals and methods. National installation
code in the U.S.A is current edition of National fuel Gas
Code (ANSI−Z223.1/NFPA54). National installation
codes in Canada are current editions of CSA−B149
codes.
11− Vent connectors shall be firmly attached to furnace flue
collars by sheet metal screws or other approved
means, except vent connectors of listed Type B vent
material which shall be assembled according to the
manufacturer’s instructions. Joints between sections
of single wall connector piping shall be fastened by
sheet metal screws or other approved means.
12− When the vent connector used for Category I ap-
pliances must be located in or pass through a crawl
space or other areas which may be cold, that portion
of the vent connector shall be constructed of listed
double−wall Type B vent material or material having
equivalent insulation qualities.
13− All venting pipe passing through floors, walls, and ceil-
ings must be installed with the listed clearance to com-
bustible materials and be fire stopped according to
local codes. In absence of local codes, refer to NFGC
(Z223.1/NFPA54).
14− No portion of the venting system can extend into, or pass
through any circulation air duct or plenum.
15− 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.
16− 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 percent, the equivalent of one 90
elbow (0.90 x
maximum common vent capacity).
17− The common vent diameter must always be at least as
large as the largest vent connector diameter.
18− In no case, shall the vent connector be sized more than
two consecutive table size diameters over the size of
the flue collar outlet.
19− Do not install a manual damper, barometric draft regu-
lator or flue restrictor between the furnace and the
chimney.
20− When connecting this appliance to an existing dedicated
or common venting system, the venting system must be
inspected for signs of corrosion and general condition.
The sizing of the vent system must be reviewed and
must conform to these instructions and the provided
venting tables for the USA, and the appropriate venting
tables in the standards of CSA B149.1 of the Natural
Gas and Propane Installation Code for Canada. If the ex-
isting system is in conflict with these requirements, the
venting system must be resized.
