Masport P36-3 Gas Inbuilt
17
INSTALLATION
Offset Chart
7) Ensure flue is vertical and secure the base
of the flashing to the roof with roofing rails,
slide storm collar over the pipe section and
seal with a mastic.
8) Install the vertical termination cap.
Note: Any closets or storage spaces,
which the flue passes through
must be enclosed.
Diagram 3
Diagram 1
Diagram 2
Note: Apply sealant "Mill-Pac" to inner
pipe and high temperature sili-
cone sealant to outer pipe.
VERTICAL
TERMINATION
1) Maintain the 1-1/2" clearances
(air spaces) to combustibles
when passing through ceilings,
walls, roofs, enclosures, attic
rafter, or other nearby com-
bustible surfaces. Do not pack
air spaces with insulation.
Check pages 14-15 for the max-
imum vertical rise of the flueing
system and the maximum hor-
izontal offset limitations.
2) Set the gas appliance in
its desired location. Drop
a plumb bob down from
the ceiling to the position
of the appliance flue exit,
and mark the location
where the flue will penetrate the ceiling.
Drill a small hole at his point. Next, drop a
plumb bob from the roof to the hole previ-
ously drilled in the ceiling, and mark the spot
where the flue will penetrate the roof.
Determine if ceiling joists, roof rafters or
other framing will obstruct the flueing sys-
tem. You may wish to relocate the appli-
ance or to offset, as shown in Diagram 2 to
avoid cutting load bearing members.
3) A Firestop spacer must be installed in the
floor or ceiling of every level. To install the
Firestop spacer in a flat ceiling or wall, cut
a 10 inch square hole. Frame the hole as
shown in Diagram 3 and install the firestop.
4) Assemble the desired lengths of pipe and
elbows. Ensure that all pipes and elbow
connections are in the fully twist-locked
position and sealed.
5) Cut a hole in the roof centered on the small
drilled hole placed in the roof in Step 2. The
hole should be of sufficient size to meet the
minimum requirements for clearance to com-
bustibles of 1-1/2". Slip the flashing under
the shingles (shingles should overlap half
the flashing) as per Diagram 4.
Diagram 4: The upper half of the flashing is
installed under the roofing material and not
nailed down until the chimney is installed.
This allows for small adjustments.
6) Continue to assemble pipe lengths.
Note: If an offset is necessary in the attic
to avoid obstructions, it is impor-
tant to support the flue pipe every
3 feet, to avoid excessive stress
on the elbows, and possible sep-
aration. Wall straps are available
for this purpose (Diagram 2).
Galvanized pipe is desirable above the roof-
line due to its higher corrosion resistance.
Continue to add pipe sections through the
flashing until the height of the flue cap meets
the minimum height requirements specified in
Diagram 5 or local codes. Note that for steep
roof pitches, the vertical height must be
increased. A poor draft, or down drafting
can result from high wind conditions near big
trees or adjoining roof lines, in these cases,
increasing the flue height may solve the
problem.
