Vermont Casting DBT36 - Manual (Page 12)

DBT33/DBT36/DBT39 -12- 10002789/0
V
ERTICAL
S
IDEWALL
A
PPLICATIONS
Since it is very important that the venting system
maintain its balance between the combustion air
intake and the ue gas exhaust, certain limita-
tions as to vent congurations apply and must
be strictly adhered to.
The Vent Graph showing the relationship between vertical and
horizontal side wall venting will help to determine the various
dimensions allowable.
Minimum clearance between vent pipes and
combustible materials is one 1"(25mm) on top,
bottom and sides unless otherwise noted.
When vent termination exits through foundations less than 20"
below siding outcrop, the vent pipe must ush up with the
siding.
It is always best to locate the replace 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 ue collar of the replace to the face of the outer
wall.
Horizontal plane means no vertical rise exists on this portion
of the vent assembly.
• The maximum number of 90º elbows per side wall instal-
lation is three (3).
• If a 90º elbow is tted directly onto the replace ange
the maximum horizontal vent run before the termination
is 36" (914 mm).
• If a 90º elbow is used in the horizontal vent run (level
height maintained) the maximum horizontal vent length is
reduced by 36" (914 mm), (Fig. 20). This does not apply
if the 90º elbows are used to increase or redirect a vertical
rise (Fig. 21).
Example: According to the chart the maximum horizontal
vent length in a system with a 7.5' vertical rise is 20' (6 m)
and if a 90º elbow is required in the horizontal vent it must
be reduced to 17' (5.2 m).
In Fig. 20 Dimension A plus B must not be greater than
17' (5.2 m).
• The maximum number of 45º elbows permitted per side
wall installation is two (2). These elbows can be installed
in either the vertical or horizontal run.
• For each 45º elbow installed in the horizontal run, the
length of the horizontal run MUST be reduced by 18"
(45cm). This does not apply if the 45º elbows are
installed on the vertical part of the vent system.
• The maximum number of elbow degrees in a system is
270º (See Fig. 21).
Example: In Figure 21
Elbow 1 = 90º
Elbow 2 = 45º
Elbow 3 = 45º
Elbow 4 = 90º
Total angular variation = 270º
Fig. 18
Fig. 19
Fig. 20
Fig. 21