18
Alpine SE42 Direct Vent Gas Fireplace
FLEX VENTING
INCORRECT
CORRECT
24"
2"
12"
Flex vent may be used in a number of basic installations to simplify the
installation process.
It must be noted that the use of flex vent increases
the height of the ceiling (as shown in the illustration below right) by
6”. It also needs to be noted that all firestopping practices must be
adhered to with flex venting also.
It is recommended that a high temperature sealant such as Mill Pac or Dap
High Heat Mortar be used to seal the center flex liner to the appliance vent
nipple as well as the vent nipple on the termination cap. Aluminum tape
or silicone is recommended to seal the outer flex liner to the appliance and
to the vent termination. All four points of connection should be fastened
with a band clamp.
As noted in the venting chart below, there must be a minimum of 1’ of
vertical rise before the transition into the horizontal . 1’ of vertical rise
will provide a maximum of 2’ horizontal run, which will accomplish
most exterior wall applications. 2’ of vertical rise will accommodate up to
3’ of horizontal run, which is the maximum horizontal run allowable with
flex vent. Only one 90° transition may be used with the flex vent taking it
from the vertical to the horizontal. Offsetting in the horizontal plane is not
allowed.
INSTALLING FLEX VENT
Horizontal Venting With One 90 Degree Elbow
Vertical
Horizontal
1
FT
2
FT
2
FT
3
FT
3-8
FT
3
FT
NOTE: Horizontal piping must maintain 1/4” rise per foot.
Piping Clearances
Vertical Pipe
1 1/2” to Combustibles
Horizontal Pipe
2” To Combustibles—Top
1” To Combustibles—Sides
There are spacers Provided to maintain the orientation between the
two liners. The spacers need to be utilized at the beginning and the
end of a 90° transition and also at 12” intervals during the horizontal
run of the flex vent.
( see below)
The maximum horizontal run may be 3’ with a minimum vertical rise of
3’ as shown in the chart below. A maximum vertical run of 8’ may be
utilized. If your vertical run is greater than 3’ you may incorporate up to
two bends into the vertical run. The bends must not exceed 45°.
