Napoleon BGD36CFNTR Installation And Operating Instructions Manual page 11

DEFINITIONS
for the following symbols used in the venting calculations
and examples are:
> - greater than
> - equal to or greater than
< - less than
< - equal to or less than
H - total of both horizontal vent lengths (H
T
(H ) in feet
O
H - combined horizontal vent lengths in feet
R
H - offset factor: .03(total degrees of offset - 90°*) in
O
feet
V - combined vertical vent lengths in feet
T
BGD36CF TOP EXIT / HORIZONTAL TERMINATION
when (H ) < (V )
T T
Simple venting confi guration (only one 90° elbow)
See graph to determine the required vertical rise V
required horizontal run H
FIGURE 20
For vent confi gurations requiring more than one 90° elbow,
the following formulas apply:
VERTICAL
R I S E I N
FEET
V
T
HORIZONTAL VENT RUN PLUS OFFSET IN FEET
The shaded area within the lines represents acceptable
values for H and V
T T
) and offsets
R
.
T
.
ELBOW VENT LENGTH VALUES
1°
15°
30°
45°
90°*
* the fi rst 90° offset has a zero value and is shown in the
formula as -90°
Formula 1: H
Formula 2: H
for the
T
Example 1:
V = 3 ft
1
V = 8 ft
2
V = V + V
T 1
H = 2.5 ft
1
H = 2 ft
2
H = H + H
R 1
H = .03(three 90° elbows - 90°) = .03(270° - 90°) = 5.4
O
ft
H = H + H
T R
H
T
H + V = 9.9 + 11 = 20.9 ft
T T
Formula 1: H
9.9 < 11
Formula 2: H
20.9 < 40
Since both formulas are met, this vent confi guration is
acceptable.
feet
0.03
0.45
0.9
1.35
2.7
< V
T T
+ V < 40 feet
T T
90°
V
2
H
1
90°
V
1
= 3 + 8 = 11 ft
2
= 2.5 + 2 = 4.5 ft
2
= 4.5 + 5.4 = 9.9 ft
O
< V
T T
+ V < 40 feet
T T
W415-0566 / D / 08.30.07
11
inches
0.5
6.0
11.0
16.0
32.0
H
2
90°
FIGURE 21