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3.
It is recommended a minimum of 26 gauge galvanized
flue pipe be used. Use of single-wall vent pipe for the vent
connector is permissible only in conditioned space.
Use
Doublewall Type B vent pipe through unconditioned
space such as attics and crawl spaces.
The vent
material used should be in accordance with the National
Fuel Gas Code, ANSI Z223.1/NFPA 54 (latest edition) or
the CSA B149.1, Natural Gas and Propane Installation
Codes and local codes. Fan-assisted combustion system
Category I furnaces shall not be vented into single wall
metal vents.
4.
The vent connector must have an upward slope
toward the chimney on all horizontal runs of at least
1/4" per foot of horizontal run and should be sup-
ported by a sheet metal strap. The vent pipe connec-
tion must be secured to the induced draft blower
outlet. A single screw is sufficient.
5.
All vents passing through floors, ceilings, and walls must
be firestopped according to the requirements of the
National Fuel Gas Code (see Figure 11).
Figure 11
Vent Through Ceiling
Vent Through Floor
Vent Through Wall
6.
The furnace shall be connected to a factory-built
chimney or vent complying with a recognized stan-
dard, or a masonry or concrete chimney lined with a
lining material acceptable to the authority with jurisdic-
tion.
Venting into an unlined chimney or a single
wall metal vent is prohibited in all cases. A lined
chimney may be used if a draft hood equipped
appliance, such as a water heater, is connected to
the same flue (see Figures 12 and 13).
7.
Extend the vent connector into the chimney so that it
is flush with the inside of the flue liner. Seal the joint
between the pipe and the liner.
8.
Masonry chimneys serving fireplaces cannot be used
for venting purposes unless the fireplace opening is
permanently sealed.
9.
A vent connector serving this appliance must not be
connected into any portion of mechanical draft
systems operating under positive pressure.
10. The vent pipe must not be connected to a chimney
flue serving a solid fuel appliance.
11. A manual damper, barometric draft regulator, or flue
restrictor must not be installed between the furnace
and the chimney.
12. Where local experience indicates that condensate
may be a problem, the vent shall be constructed to
prevent condensation from entering the combustion
blower. Provision shall be made to drain off the
condensate (see Figures 12 and 13).
13. All unused chimney openings should be closed.
14. All vent pipe run through unconditioned areas or
outside shall be constructed of factory-built chimney
sections (see Figure 13).
15. Multistory venting is allowed as permitted by the
National Fuel Gas Code or local codes.
16. Install all vents in accordance with the vent
manufacturer’s instructions. For unlisted material,
install in accordance with the National Fuel Gas Code.
17. Vent terminals must be installed in accordance with
the vent terminals listing or in accordance with the
National Fuel Gas Code, ANSI Z223.1/NFPA 54
(latest edition) or the CSA B149.1, Natural Gas and
Propane Installation Codes, and local codes.
Vertical Venting (Using Optional Outside Fresh Air for
Combustion)
Consult local codes for any requirements relating to a
fresh air inlet to the furnace. In the absence of local codes
