Monessen Hearth HDV500NV/PV - Manual (Page 19)

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HDV Series Direct Vent Gas Fireplace VeNtING INStAllAtIoN
W
ARNING
When installing the appliance as a rear vent unit, the 90°, 45° transition elbow
attached 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.
• The maximum number of 90° elbows per side wall
installation is three (3). Figure 20
• 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 21
FP1176
max 90 bends
Figure 20 -
Maximum Three (3) 90° Elbows
Per Installation
3 x 90°
Elbows
3 x 90°
Elbows
FP1176
Max 20"
Max 20"
36"
(914 mm)
Max.
36"
(914 mm)
Max.
FP1177
max horizontal run
Figure 21 -
Maximum Horizontal Run with No Rise
FP1177
• If a 90° elbow is used in the horizontal vent run (level
height maintained) the horizontal vent length is reduced
by 36" (914 mm) (Fig. 1 A and B) This does not apply if
the 90° elbows are used to increase or redirect a vertical
rise. Figure 22
Example: According to the vent graph (page 17) the maxi-
mum horizontal vent length in a system with a 7.5' vertical
rise is 20’ (6 m) and if a 90° elbow is required in the hori-
zontal vent it must be reduced to 17' (5.2 m).
In Figures 22 and 24, Dimension A plus B must not be
greater than 17' (5. m).
A: 10’
B: 7’
7’6”
FP1959
max run w/elbows
Figure 22 -
Maximum Vent Run with Elbows
Horizontal 90° Elbow = 3' Reduction
FP1959
A + B = 17' Maximum
A B
7’6”
90°
FP2413
horz run reduct
Figure 23 -
Horizontal Run Reduction
FP466