Napoleon BGD36CFGN - Page 18

18
W415-0661 / 12.07.07
BGD42CF VERTICAL TERMINATION
when (H
T
) > (V
T
)
Simple venting confi gurations
HORIZONTAL VENT RUN PLUS OFFSET
IN FEET
H
T
The shaded area within the lines represents acceptable values
for H
T
and V
T
.
For vent confi gurations requiring more than one 45º and one 90°
elbow the following formulas apply:
Formula 1: HT < 3VT
Formula 2: HT + VT < 40 feet
Example 4:
V
1
= 1 ft
V
2
= 1.5 ft
V
T
= V
1
+ V
2
= 1 + 1.5 = 2.5 ft
H
1
= 6 ft
H
2
= 2 ft
H
R
= H
1
+ H
2
= 6 + 2 = 8 ft
H
O
= .03 (one 45° elbow + three 90° elbows - 135°)
= .03 (45 + 90 + 90 +90 - 135) = 5.4 ft
H
T
= H
R
+ H
O
= 8 + 5.4 = 13.4 ft
H
T
+ V
T
= 13.4 + 2.5 = 15.9 ft
Formula 1: H
T
< V
T
3V
T
= 3 x 2.5 = 7.5 ft
13.4 < 7.5
Since this formula is not met, this vent confi guration is unac-
ceptable.
Formula 2: H
T
+ V
T
< 40 feet
15.9 < 40
Since only formula 2 is met, this vent confi guration is unac-
ceptable and a new fi replace location or vent confi guration will
need to be established to satisfy both formulas.
Example 5:
See graph to determine the required vertical rise V
T
for the required
horizontal run H
T
.
90°
90°
90°
H
1
V
1
V
2
45°
H
2
90°
90°
90°
H
1
V
1
V
2
45°
H
2
H
3
V
1
= 1.5 ft
V
2
= 8 ft
V
T
= V
1
+ V
2
= 1.5 + 8 = 9.5 ft
H
1
= 1 ft
H
2
= 1 ft
H
R
= H
1
+ H
2
+ H
3
= 1 + 1 + 10.75 = 12.75 ft
H
O
= .03 (two 45° elbows + three 90° elbows - 135°)
= .03 (45 + 45 + 90 + 90 +90 - 135) = 6.75 ft
H
T
= H
R
+ H
O
= 12.75 + 6.75 = 19.5 ft
H
T
+ V
T
= 19.5 + 4.5 = 24 ft
Formula 1: H
T
< V
T
3V
T
= 3 x 2.5 = 7.5 ft
13.4 < 7.5
Formula 2: H
T
+ V
T
< 40 feet
24 < 40
Since both formulas are met, this vent confi guration is ac-
ceptable.
FIGURE 40
FIGURE 41
FIGURE 42
45°
MAXIMUM
VERTICAL
RISE IN
FEET
V
T
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