507651-01
Issue 1907
Page 15 of 32
MINIMUM LENGTH = AS SHORT AS PRACTICAL.
FOR MAXIMUM LENGTH SEE NOTE TO LEFT
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
VENT
CONNECTOR
NOTE- Refer to provided venting
tables for installations.
FURNACE
OTHER
APPLIANCE
Figure 17.
Common Venting Using Tile-Lined Interior Masonry Chimney and Combined Vent Connector
10. The vent pipe should be as short as possible with
the least number of elbows and angles required to
complete the job. Route the vent connector to the vent
using the shortest possible route.
11. A vent connector shall be supported without any dips
or sags and shall slope a minimum of 1/4 inch (6.4
mm) per linear foot (305 mm) of connector, back
toward the appliance.
12. Vent connectors shall be firmly attached to the furnace
flue collar by self drilling 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
screws or other approved means.
13. When the vent connector used for Category I
appliances must be located in or pass through a crawl
space, attic or other areas which may be cold, that
portion of the vent connector shall be constructed
of listed doublewall type B vent material or material
having equivalent insulation qualities.
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 (2223.1).
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 not
meet these requirements, it must be resized.