Monessen Hearth LEXINGTON LX32DV - Manual (Page 22)

22 51D0528
LX Series Direct Vent Gas Fireplace VeNtING INStALLAtIoN
side. This prevents loose insulation from falling into the
required clearance space. Figure 30. Otherwise, install
firestop below the framed hole. The firestop should be
installed with no less than three nails per side. Figure
35.
FP1969
firestop w room above
Figure 30 -
If area above is a room, install firestop above framed
hole as shown
Firestop
Nails
FP1969
9
1 /
2
"
9
1
/
2
"
FP1970
firestop no room
Figure 31 -
If area above is not a room, install firestop below
framed hole as shown
Nails
Firestop
FP1970
2. Assemble the desired lengths of pipe and elbows nec-
essary to reach from the burner system flue up through
the firestop. Be sure pipe and elbow connections are
fully twist-locked. Page 17, Figure 16
3. Cut a hole in the roof using the locating hole as a center
point. (Cover any exposed open vent pipes before cut-
ting hole in roof). The 9Z\x" x 9Z\x" (241 x 241 mm) hole
must be measured on the horizontal. Actual length may
be larger depending on the pitch of the roof. There must
be a 1" minimum clearance from the vent pipe to com-
bustible materials. (Insulation should be considered a
combustible material) Frame the opening as shown on
Page 17, Figure 15.
4. Connect a section of pipe and extend up through the
hole.
Note: If an offset is needed to avoid obstructions, you
must support the vent pipe every three (3) feet. Use wall
straps for this purpose. Refer to Figures 27 & 29. Whenever
possible, use 45° elbows instead of 90° elbows. The 45°
elbow offers less restriction to the flow of the flue gases
and intake air.
5. Place the flashing over the pipe section(s) extending
through the roof. Secure the base of the flashing to
the roof and framing with roofing nails. Be sure roofing
material overlaps the top edge of the flashing. There
must be a 1" clearance from the vent pipe to combustible
materials.
6. Continue to add pipe sections until the height of the vent
cap meets the minimum requirements below.
Note: You must increase vent height for steep roof
pitches. Nearby trees, adjoining roof lines, steep pitched
roofs, and other similar factors may cause poor draft or
down-drafting in high winds. Increasing the vent height
may solve this problem.
Note: If the vent pipe passes through any occupied areas
above the first floor, including storage spaces and closets,
you must enclose pipe. You may frame and sheetrock the
enclosure with standard construction material. Make sure
to meet the minimum allowable clearances to combustibles.
Do not fill any of the required clearance spaces with
insulation.
2 ft.
Min.
2 ft. Min.
X
12
H*
FP1971
Min chimney clearance
Termination
Vent
Storm
Collar
Flashing
Lowest
Discharge
Opening
Concentric
Vent Pipe
1” Minimum Clearance to
Combustibles
FP1971
Horizontal Overhang
Figure 32 -
Minimum Chimney
Clearance
Roof pitch h (feet)
Flat to 6/12 1.0
Over 6/12 to 7/12 1.25
Over 7/12 to 8/12 1.5
Over 8/12 to 9/12 2.0
Over 9/12 to 10/12 2.5
Over 10/12 to 11/12 3.25
Over 11/12 to 12/12 4.0
*H - Minimum height from roof to
lowest discharge opening of vent