Napoleon Arlington GDS20N Installation And Operating Instructions Manual page 17

Simple venting configurations.
For vent configurations requiring more than one 45° and one 90° elbow, the following formulas apply:
Formula 1: H < 3V
T T
Formula 2: H + V < 40 feet
T T
Example 4:
V = 1 FT
1
V = 1.5 FT
2
V = V + V = 1 + 1.5 = 2.5 FT
T 1 2
H = 6 FT
1
H = 2 FT
2
H = H + H = 6 + 2 = 8 FT
R 1 2
H = .03 (one 45° + three 90° elbows - 135°)
O
= .03 (45 + 270 - 135°) = 5.4 FT
H = H + H = 8 + 5.4 = 13.4 FT
T R O
H + V = 13.4 + 2.5 = 15.9 FT
T T
Formula 1: H < 3V
T T
3V = 3 x 2.5 = 7.5 FT
T
13.4 > 7.5
Since this formula is not met, this vent configuration is unacceptable.
Formula 2: H + V < 40 FT
T T
15.9 < 40
Since only formula 2 is met, this vent configuration in unacceptable and a new fireplace location or vent configuration
will need to be established to satisfy both formulas.
Example 5:
V = 1.5 FT
1
V = 8 FT
2
V = V + V = 1.5 + 8 = 9.5 FT
T 1 2
H = 1 FT
1
H = 1 FT
2
H = 10.75 FT
3
H = H + H + H = 1 + 1 + 10.75 = 12.75 FT
R 1 2 3
H = .03 (three 90° elbows + two 45° elbows - 135°)
O
= .03 (270 + 90 - 135°) = 6.75 FT
H = H + H = 12.75 + 6.75 = 19.5 FT
T R O
H + V = 19.5 + 9.5 = 29 FT
T T
Formula 1: H < 3V
T T
3V = 3 x 9.5 = 28.5 FT
T
19.5 < 28.5
Formula 2: H + V < 40 FT
T T
29 < 40
Since both formulas are met, this vent configuration is acceptable.
(H ) > (V )
T T
See graph to determine the required vertical rise V
20
19
REQUIRED
VERTICAL
RISE IN
10
FEET V
T
3
0
5
HORIZONTAL VENT RUN PLUS OFFSET IN FEET H
The shaded area within the lines represents acceptable
45°
45°
H
1
required horizontal run H
10 15 20
values for H and V
T T
90°
H
1
V
90°
H
2
H
V
45°
1
90°
18.3_2A
17
for the
T
.
T
25 30
T
V
2
H
2
1
90°
90°
V
2
3
90°
W415-0496 / D / 11.05.10