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If the existing chimney will not accommodate a listed meta
liner, either the chimney must be rebuilt to accommodate
one of these liners or an alternate approved venting
method must be found.
Insulation for the flexible vent pipe must be an encapsulated
fiberglass sleeve recommended by the flexible vent pipe
manufacturer. See Figure 17.
NOTE 1: Refer to the provided venting tables for installations.
Refer to the capacity requirements shown in the provided venting
tables.
Figure 17. Common Venting Using Metal-Lined
Masonry Chimney
DO NOT insulate the space between the liner and the
chimney wall with puffed mica or any other loose granular
insulating material.
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 drafthood
equipped appliance.
NOTE- Refer to provided venting tables
for installations.
508145-01G / 31-5000660
MINIMUM LENGTH = AS SHORT AS PRACTICAL.
FOR MAXIMUM LENGTH SEE NOTE TO LEFT
OTHER
APPLIANCE
Figure 18. Common Venting Using Metal-Lined Masonry Chimney
•
The vent connectors and chimney are sized according
to the provided venting tables.
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.
If type B1 double wall vent is used inside a chimney, no
other appliance can be vented into the chimney. The outer
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 assembly 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. The chimney 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.
Never connect a Category I appliance to a chimney that is
servicing a solid-fuel appliance. If a fireplace chimney flue
is used to vent this appliance, the fireplace opening must
be permanently sealed.
A type B1 or listed chimney lining system that passes
through an unused masonry chimney flue is not considered
to be exposed to the outdoors.
VENT
CONNECTOR
FURNACE
AIR FLOW
Issue 2220
IMPORTANT
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
Page 13 of 38
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