Napoleon BGD40-N Installation And Operating Instructions Manual page 15

Simple venting confi guration (only one 45° and 90°
elbow)
For vent confi gurations requiring more than one 45° elbow and 90° elbow, the following formulas
apply:
Formula 1: H < 4.2 V
T T
Formula 2: H + V < 24.75 feet
T T
Example:
= 4 FT
V
1
= 1.5 FT
V
2
= V + V = 4 FT + 1.5 FT = 5.5 FT
V
T 1 2
= 2 FT
H
1
= 1 FT
H
2
= 1 FT
H
3
= 1.5 FT
H
4
= H + H + H + H
H
R 1 2 3 4
= .03 (one 45° elbow + four 90° elbows - 135°) = .03 (405 - 135°) = 8.1 FT
H
O
= H + H = 5.5 + 8.1 = 13.6 FT
H
T R O
+ V = 13.6 + 5.5 = 19.1 FT
H
T T
Formula 1: H < 4.2 V
T
4.2 V
13.6 < 23.1
Formula 2: H + V
T T
19.1 < 24.75
Since both formulas are met, this vent confi guration is acceptable.
(H
= 2 + 1 + 1 + 1.5 = 5.5 FT
T
= 4.2 x 5.5 FT = 23.1 FT
T
< 24.75 FT
) > (V )
T T
See graph to determine the required vertical
rise V for the required horizontal run H
T
147"
REQUIRED
VERTICAL
RISE IN
INCHES V
T
57"
The shaded area within the lines represents
acceptable values for H
90°
V
1
150
100
50
0
5 10 15
12.5'
HORIZONTAL VENT RUN PLUS
OFFSET IN FEET H
and V
T
90°
90°
H
3
V
H
2
1
H
2
90°
45°
16.5_2
W415-0811 / D / 08.16.12
15
.
T
20
T
T
H
4