Vermont Casting DVRTSB - Manual (Page 15)

15
Vermont Castings, Majestic Products DVRTSB
10003848
Minimum clearance between vent pipes
and combustible materials is one 1”
(25mm) on top, bottom and sides unless
otherwise noted.
When the vent termination exits through foundations
less than 20” (508mm) below siding outcrop, the vent
pipe must flush up with the siding.
It is always best to locate the fireplace in such a way
that minimizes the number of offsets and horizontal
vent 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.
When installing the appliance as a rear
vent unit the 90
°
Transition Elbow at-
tached directly to the rear of the unit is
not included in the following criteria and
calculations, and unless specifically
mentioned should be ignored when
calculating venting layouts.
FP1381
Fig. 19 Maximum number of 90· elbows per sidewall.
• The maximum number of 90
°
elbows per side wall
installation is three (3).
• If a 90
°
elbow is fitted directly on top of the fireplace
flange, the maximum horizontal vent run before the
termination or a vertical rise is 36” (914mm).
Max. 20"
(508mm)
Max. 36"
(914mm)
FP1381
Fig. 20 Maximum horizontal vent run.
• If a 90
°
elbow is used in the horizontal vent run
(level height maintained) the maximum horizontal
vent length is reduced by 36” (914mm). (Fig. 21)
This does not apply if the 90
°
elbows are used to
increase or redirect a vertical rise. (Fig. 21)
Example: According to the chart the maximum horizon-
tal vent length in a system with a 7.5’ vertical rise is 20’
(6m) and if a 90
°
is required in the horizontal vent it
must be reduced to 17’ (5.2m).
Dimension A plus B must not be greater than 17’
(5.2m). (Fig. 21)
• The maximum number of 45
°
elbows permitted per
side wall installation is two (2). These elbows can be
installed in either the vertical or horizontal run.
• For each 45
°
elbow installed in the horizontal run,
the length of the horizontal run MUST be reduced by
18” (45cm). This does not apply if the 45
°
elbows
are installed in the vertical part of the vent system.
• The maximum number of elbow degrees in a system
is 270
°
. (Fig. 22)
Example: In Fig. 22
Elbow 1 = 90
°
Elbow 2 = 45
°
Elbow 3 = 45
°
Elbow 4 = 90
°
Total Angular Variation = 270
°
7’6"
(2286mm)
A B
A + B = 17’ Max.
(5.2m)
90 °
FP1382
Fig. 21 Maximum vent run with elbows.
1
2
3
4
1 + 2 + 3 + 4 = 270 o
1
2
3
4
FP1383
Fig. 22 Maximum number of elbows allowed.