26988-3-1012
Page 18
To Use the vent Graph (Figure 29)
1. Determine the height of the center of the horizontal
vent pipe. Using this dimension on the Sidewall
Vent Graph, locate the point it intersects with the
slanted graph line.
2. From the point of this intersection, draw a vertical
line to the bottom of the graph.
3. Select the indicated dimension, and position the
unit in accordance with same.
EXAMPLE A:
If the vertical dimension from the floor of the unit is
12 feet, 4 inches, the horizontal run to the outer wall
flange must not exceed 12 feet, 3 inches.
EXAMPLE B:
If the vertical dimension from the floor of the unit is
6 feet, 9 inches the horizontal run to the outer wall
flange must not exceed 6 feet, 6 inches.
SPECIAL NOTE:
For each 45 degree elbow installed
in the horizontal run, the length of the horizontal
run MUST be reduced by 18" (457 mm). This does
not apply if the 45 degree elbows are installed on
the vertical part of the vent system. Reduce 3' for
every 90° elbow.
Example:
According to the chart the maximum
horizontal vent length is 20' and if two 45 degree
elbows are required in the horizontal vent it must
be reduced to 17'.
The maximum number of 45 degree elbows permitted
per side wall installation is two (2). These elbows can
be installed in either the vertical or horizontal run.
Figure 29
Acceptable vertical and horizontal vent run.
Unacceptable vertical and horizontal vent run.
Note: When rear venting unit, adjust air shutter from 1/16" open to between 1/8"
and 3/16" for NAT gas.
Adjust air shutter from 1/4" open to between 5/16" and 3/8" for LP gas.
Venting Graph (Dimensions in Feet)
VERTICAL
DIMENSION
FROM
THE
BOTT
OM
OF
THE
UNIT
T
O
THE
CENTER
OF
THE
FLUE
OUTLET
WITH
VERTICAL
OR
HORIZONT
AL
TERMINA
TION
CAPS
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
HORIZONTAL RUN
REAR EXIT - VERTICAL AND HORIZONTAL TERMINATION
(DIMENSIONS IN FEET)
REAR HORIZONTAL
VENT CONNECTION
B
A
vENTING FIREPLACE - REAR
Note: When rear venting unit, adjust air shutter
from 1/16" open up to between 1/8" and 3/16"
for NAT gas.
Adjust air shutter from 1/4" open to between
5/16" and 3/8" for LP gas.
