Majestic 300DVBNV7 Installation And Operation Instructions Manual page 18

DVB7 Series Direct Vent Gas Fireplace
When installing the appliance as a rear vent unit, the
90° or 45° transition elbow attached directly to the
rear of the unit is Not INCluDeD in the following cri-
teria and calculations, and unless specifically men-
tioned should be ignored when calculating venting
layouts.
• The maximum number of 90° elbows per side wall in-
stallation is three (3). Figure 22
• If a 90° elbow is fitted directly on top of the fireplace
flange the maximum horizontal vent run before the ter-
mination or a vertical rise is 36" (914 mm). Figure 23
• If a 90° elbow is used in the horizontal vent run (level
height maintained) the horizontal vent length is re-
duced by 36" (914 mm). Figures 23 & 24. This does
not apply if the 90° elbows are used to increase or
redirect a vertical rise. Figure 22
3 x 90°
Elbows
Figure 22 -
Maximum three (3) 90° elbows per installation
36"
(914 mm)
Max.
FP1176
max 90 bends
Figure 23 -
Maximum horizontal run with no rise
example: According to the vent graph (Page 14) the
maximum horizontal vent length in a system with a 7Z\x'
(.3 m) rise is 0' (6 m) and if a 90° elbow is required in
the horizontal vent it must be reduced to 17' (5. m).
In Figures 25 & 26, dimension A plus B must not be great-
er than 17' (5.m)
• The maximum number of 45° elbows permitted per in-
stallation is six (6). These elbows can be installed in
either the vertical or horizontal run.
Max 20"
• For each 45° elbow installed in the horizontal run, the
length of the horizontal run MUST be reduced by 18"
(457 mm). This does not apply if the 45° elbows are
installed on the vertical part of the vent system.
18
3 x 90°
Elbows
FP1176
36"
(914 mm)
Max.
FP1177
• The maximum number of elbow degrees in a system is
70°. Figure 26
Example: Elbow 1 = 90°
Elbow  = 45°
Elbow 3 = 45°
Elbow 4 = 90°
Total angular variation = 70°
A
Figure 24 -
Horizontal Run
Reduction
FP1177
A
10'
(3 m)
7'6"
(.3 m)
Figure 25 -
Maximum Vent Run with Elbows
V584-01
1+ 2 + 3 + 4 = 270°
V584-201
1
Horizontal Run
2
2/99 djt
3
4
Figure 26 -
Maximum Elbow Usage
VeNtING INStAllAtIoN
B
A + B = 17' (Max.)
(5.2m)
7'6"
(2.3m)
B
7'
(.1 m)
1
2
3
4
54D7051
FP1180