Definitions; Elbow Vent Lengths; Horizontal Termination - Napoleon The Bayfield GDS25N Installation And Operating Instructions Manual

2.4

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 (Hr) and offsets (Ho) in feet
T
H - combined horizontal vent lengths in feet
R
H - offset factor: .03 (total degrees of offset - 135°*) in feet
O
V - combined vertical vent lengths in feet
T
2.5

ELBOw vENT LENgThS

FEET INCHES
1° 0.03
15° 0.45
30° 0.9
45° 1.35
90°* 2.7
* The first 45° and 90°offset has a zero value and is shown in the formula as -45° and - 90° respectively or
-135° when combined.
2.6

hOrIzONTAL TErmINATION

Simple venting configuration (only one 45° and 90° elbow)
90°
fIGure 2.6a
For vent configurations requiring more than one 45° and 90° elbow, the following formulas apply:
Formula 1: H < V
T
Formula 2: H + V
T
Example 1:
V = 8 FT
1
V = V = 8FT
T 1
H = 2.5 FT
1
H = 2 FT
2
H = H + H = 2.5 + 2 = 4.5 FT
R 1 2
H = .03 (one 45° elbow + two 90° elbows - 135°) = .03 (225° - 135°) = 2.7 FT
O
H = H + H = 4.5 + 5.4 = 9.9 FT
T R O
H + V = 4.5 + 2.7 = 7.2 FT
T T
Formula 1:
Formula 2:
Since both formulas are met, this vent configuration is acceptable.
0.5
6.0
11.0
16.0
32.0
45°
T
< 40 feet
T
H < V
T T
7.2 < 8
H + V < 40 FT
T T
15.2 < 40
(H ) < (V )
T T
See graph to determine the required vertical rise V
40
39
30
REQUIRED
VERTICAL
20
RISE IN
FEET V
T
10
0
2.5
HORIZONTAL VENT RUN PLUS OFFSET IN FEET H
The shaded area within the lines represents acceptable
required horizontal run H .
T
5 7.5 10 12.5 15
values for H and V
T T
90°
fIGure 2.6b
V
1
45°
H
1
90°
TP - ELbOW VENT LENGTHS_45
TP - HORIZONTAL TERMINATION_45
W415-0547 / D / 11.14.08
11
for the
T
17.5 20
T
H
2
TP - DEFINITIONS_45