- 20 -
The maximum horizontal vent run is 20 feet (6100mm)
when the vertical vent rise is 7.5 feet (2286mm). Fig. 43
Fig. 43
VERTICAL SIDEWALL INSTALLATIONS
Since it is very important that the venting system
maintain its balance between the combustion air intake
and the flue gas exhaust, certain limitations as to vent
configurations apply and must be strictly adhered to.
The graph showing the relationship between vertical and
horizontal side wall venting will help to determine the
various vent lengths allowable. Fig. 47.
Minimum clearance between vent pipes and
combustible materials is one (1") inch (25
mm) on top, bottom and sides unless
otherwise noted.
When vent termination exits through
foundation less than 20" below siding outcrop,
the vent pipe must flush up with the siding. A
7DVSS must also be used.
It is always best to locate the fireplace in such a way that
minimizes the number of offsets and horizontal vent
length.
The horizontal vent run refers to the total
length of vent pipe from the flue collar of the
fireplace to the face of the outer wall.
Horizontal plane means no vertical rise
exists on this portion of the vent assembly.
For some installations, it may be desirable to
have some amount of the horizontal vent run
immediately after the fireplace. A vertical
rise must be used but can be located any-
where in the vent system, to meet the perim-
eters identified in the venting graph.
SIDE VIEW
MAXIMUM
20 ft. (6100mm)
90" (2286mm)
VERTICAL
DIMENSION
7.5 ft. MINIMUM
WHEN HORIZONTAL
RUN IS 20 ft.
7TDVRT90
ELBOW
,
,
,
15 ft.
(4572mm)
48"
(1220mm)
12"
(305mm)
VERTICAL SIDEWALL APPLICATIONS
The maximum number of 90 degree elbows per side wall
installation is four (4), (includes 7TDVRT90 off back of unit)
The maximum number of 45 degree elbows permitted per
side wall installation is two (2). These elbows can be
installed in either the vertical or horizontal run.
When one 90
o
elbow is installed directly onto another off
the back of the fireplace the maximum horizontal vent
length is 36" (914mm). Fig. 44.
SIDE VIEW
MAXIMUM
3' (914mm)
7TDVRT90
ELBOW
,
,
,
Fig. 44
For each 45 degree elbow installed in the
horizontal run (while maintaining a constant
horizontal plane), the length of the horizontal
run MUST be reduced by 18" (457mm). This
does not apply if the 45 degree elbows are
installed on the vertical part of the vent
system.
If a 90 degree elbow is used in the horizontal
vent run (level height maintained) the maxi-
mum horizontal vent length is reduced by 36
inches. Fig. 45. This does not apply if the 90
degree elbows are used to increase or redi-
rect a vertical rise.
Example: According to the vent chart the maximum
horizontal vent length is 20 ft.when the vertical height is 7.5
ft. from fireplace base height. If one 90 degree elbow is
required in the horizontal vent it must be reduced to 17 ft.
