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(G) 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
horizontal run H .
T
FIGURE 20
For vent configurations requiring more
than one 90° elbow, the following formulas
apply:
V E R T I C A L
RISE IN 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
* BGD36CF the fi rst 90° offset has a zero value and is shown in
the formula as - 90°
* BGD42CF the fi rst 45° and 90° offset has a zero value and
is shown in the formula as -45° and - 90° respectively or -135°
combined.
Formula 1: H
Formula 2: H
for the required
T
Example 1:
V = 3 ft
1
V = 8 ft
2
V = V
H
T
T
H = 2.5 ft
1
H = 2 ft
2
H = H
R
H = .03 (three 90° elbows - 90°) = .03(270° - 90°) = 5.4 ft
O
H = H
T
H + V
T
Formula 1:
Formula 2:
Since both formulas are met, this vent confi guration is ac-
ceptable.
ELBOW VENT LENGTH VALUES
feet
1° 0.03
15° 0.45
30° 0.9
45°* 1.35
90°* 2.7
< V
T T
+ V < 40 feet
T T
90°
90°
V
1
+ V = 3 + 8 = 11 ft
1 2
+ H = 2.5 + 2 = 4.5 ft
1 2
+ H = 4.5 + 5.4 = 9.9 ft
R O
= 9.9 + 11 = 20.9 ft
T
H < V
T T
9.9 < 11
H + V < 40 feet
T T
20.9 < 40
11
inches
0.5
6.0
11.0
16.0
32.0
H
2
V
2
90°
H
1
FIGURE 21
W415-0661 / C / 02.20.08