Lennox SL280DFNV Installation Instructions Manual page 13

Common Venting Using Tile-Lined Interior Masonry Chimney and Combined Vent Connector
NOTE- Refer to provided venting tables
for installations.
Common Venting Using Metal-Lined Masonry Chimney
MAX. LENGTH
-- SEE NOTE 1
BELOW.
5 ft. (1.5 m)
MIN. LENGTH -- AS
minimum
SHORT AS PRACTICAL
VENT CONNECTOR
4 in. (102 mm)
minimum
OTHER
APPLIANCE
AIR FLOW
NOTE 1 - Refer to the provided venting tables for installations. Refer
to the capacity requirements shown in the provided venting tables.
FIGURE 17
Venting Using a Masonry Chimney
The following additional requirements apply when a lined
masonry chimney is used to vent this furnace.
A chimney with one or more sides exposed to the outside
of the structure is considered to be an exterior chimney.
An exterior masonry chimney that is not tile-lined must be
lined with B1 vent or a listed insulated flexible metal vent.
An exterior tile-lined chimney that is sealed and capped
may be lined with a listed uninsulated flexible metal vent.
If the existing chimney will not accommodate a listed met-
al liner, either the chimney must be rebuilt to accommo-
date one of these liners or an alternate approved venting
method must be found.
Insulation for the flexible vent pipe must be an encapsu-
lated fiberglass sleeve recommended by the flexible vent
pipe manufacturer. See figure 17.
MINIMUM LENGTH = AS SHORT AS PRACTICAL.
FOR MAXIMUM LENGTH SEE NOTE TO LEFT
OTHER
APPLIANCE
SEALED
EXTERIOR
CHIMNEY WITH
METAL
LINER
FURNACE
PERMANENTLY
SEALED FIREPLACE
OPENING
VENT
CONNECTOR
FURNACE
AIR FLOW
FIGURE 16
DO NOT insulate the space between the liner and
the chimney wall with puffed mica or any other loose
granular insulating material
SINGLE appliance venting of a fan-assisted furnace
into a tile-lined masonry chimney (interior or outside
wall) is PROHIBITED. The chimney must first be
lined with either type B1 vent or an insulated single
wall flexible vent lining system which has been
sized according to the provided venting tables and
the vent pipe manufacturer's instructions.
A fan-assisted furnace may be commonly vented into an
existing lined masonry chimney if the following conditions
are met:
• The chimney is currently serving at least one draft-
hood equipped appliance
• The vent connectors and chimney are sized accord-
ing to the provided venting tables.
If type B1 double-wall vent is used inside a chimney, no
other appliance can be vented into the chimney. The out-
er wall of type B1 vent pipe must not be exposed to flue
products.
A type B1 vent or masonry chimney liner shall terminate
above the roof surface with a listed cap or a listed roof as-
sembly according to the terms of their respective listings
and the vent manufacturer's instructions.
When inspection reveals that an existing chimney is not
safe for the intended purpose, it shall be rebuilt to conform
to nationally recognized standards, lined or relined with
suitable materials, or replaced with a gas vent or chimney
suitable for venting SL280DFNV series units. The chim-
ney passageway must be checked periodically to ensure
that it is clear and free of obstructions.
Do not install a manual damper, barometric draft regulator,
or flue restrictor between the furnace and the chimney.
Page 13
INTERIOR TILE-LINED
MASONRY CHIMNEY
NOTE - the chimney must be properly
sized per provided venting tables or
lined with listed metal lining system.
PERMANENTLY
SEALED FIREPLACE
OPENING
IMPORTANT