Majestic Appliances 360DVSR User Manual

18

Horizontal plane means no vertical rise exists on this 
portion of the vent assembly.

• 

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)

FP1436

Fig. 21  Maximum horizontal run w/no rise.

• 

If a 90° elbow is used in the horizontal vent run 
(level height maintained), the maximum horizontal 
vent length is reduced by 36” (914 mm). (Fig. 21) 
This does not apply if the 90° elbows are used to 
increase or redirect a vertical rise.

  Example:  According to the vent graph (Fig. 16), 

the   maximum horizontal vent length in a system 
with a 7¹⁄₂” (191mm) vertical rise  is 20 ft. (6.1m), but 
if a 90° is required in the horizontal vent, it must be 
reduced to 17 ft. (5.2m).

  NOTE: The sum of Dim. A and Dim. B must not be 

greater than 17 ft. (5.2m). (Fig. 22)

 

Elbow 1  =  90°

 

Elbow 2  =  45°

 

Elbow 3  =  45°

 

Elbow 4  =  90°

 Total angular variation =  270°

A

B

90

o

FP1437

Fig. 22  Horizontal run reduction.

A + B = 17’ 

(5.2m) Max.

7’6” (2.3m)

• 

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” (45 cm). This does not apply if 45° elbows are  
installed on the vertical part of the vent system.

• 

The maximum number of elbow degrees in a system 
is 270°. Example shown in Figure 23:

1
2
3
4

1
2
3
4

1 + 2 + 3 + 4 = 270°

FP1438

Fig. 23  Maximum elbow usage.

STEP 1
Locate and cut vent opening in the side wall. It may be 
necessary to first position the fireplace and measure to 
obtain the hole location. Depending on whether the wall 
is combustible or noncombustible, cut the opening to 
size per Figure 24.

 

Combustible walls:  Cut a rectangular hole measuring 
9³⁄₈” H x 9³⁄₈” W (240 x 240mm) through the exterior wall 
and frame. Frame in the opening per Figure 24.
Noncombustible walls:  Cut a round hole measuring 
7¹⁄₂” (190 mm) diameter through the exterior wall and 
frame. (Fig. 24) 
STEP 2
For combustible walls:  Measure wall thickness and 
cut zero clearance sleeve parts to proper length. Max. 
length is 12” (305mm). Assemble the sleeve and attach 
it to the firestop with #8 sheet metal screws (supplied). 
Install the firestop assembly. (Fig. 25)