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4. Installing Roof Flashing or Site-produced
Chase Top. Position roof flashing (or construct a
chase and chase top) and secure in place with nails.
Continue to add vent sections through the roof open-
ing, maintaining at least a one inch air space clear-
ance. Major building codes specify a minimum vent
(chimney) height above the roof top depending on roof
pitch. See Figures 10 and 11. The Termination Cap
must be at least 2 feet from a vertical wall and 2 feet
below a horizontal overhang. Note that for steep roof
pitches, the vent height must be increased.
These vent system heights are necessary in the inter-
est of safety and do not ensure draft-free operation.
Trees, buildings, adjoining roof lines, adverse wind
conditions, etc., may create a need for a taller vent
system should down drafting occur.
5. Termination Cap. Twist lock the Vent Cap.
Vent (Chimney) Height
Roof Pitch
Flat to 6/12 ...........................................1.0
6/12 to 7/12 ..........................................1.25
Over 7/12 to 8/12..................................1.5
Over 8/12 to 9/12..................................2.0
Over 9/12 to 10/12................................2.5
Over 10/12 to 11/12..............................3.25
Over 11/12 to 12/12..............................4.0
Over 12/12 to 14/12..............................5.0
Over 14/12 to 16/12..............................6.0
Over 16/12 to 18/12..............................7.0
Over 18/12 to 20/12..............................7.5
Over 20/12 to 21/12..............................8.0
Vent (Chimney) Height
12-99
Figure 10
H (Min.) Ft.
Figure 11
R-CAST SERIES WALL FURNACE
WHEN VENT SECTIONS EXCEEDING 3
FEET IN LENGTH ARE INSTALLED
BETWEEN AN OFFSET/RETURN, STRUC-
TURAL SUPPORT MUST BE PROVIDED TO
REDUCE OFF-CENTER LOADING AND
PREVENT VENT SECTIONS FROM
SEPARATING AT THE VENT JOINTS.
C. Existing Masonry Chimney.
Installation Requirements:
This installation is subject to local jurisdiction.
Some codes may require the use of another liner
for intake air. If so, the 4" aluminum liner should
be inside a 6" UL 181 listed liner.
This heater can be vented through an existing
Masonry Chimney but the chimney must be lined with
one UL 1777 listed 4" aluminum flexible gas vent
liner for exhaust. The existing flue will be used to
supply the air intake to the galvanized steel flue sys-
tem. See Figure 12. Before installing the liner
system, the chimney passageway should be
cleaned and examined to verify it is unobstructed
and in good structural condition.
Figure 12 - Adaptation to Masonry Chimney
14
WARNING!
30750B
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