Operating instructions


75D0004
MLDV Series Gas Fireplace
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• Two sets of 45°elbows offsets may be used within the
vertical sections. From 0 to a maximum of 8' (.5 m) of
vent pipe can be used between elbows. Figure 31
• Determine the roof pitch and use the appropriate starter
kit for offset installation.
• The maximum angular variation allowed in the system
is 70°. Figure 31
• For the minimum height of the vent above the highest
point of penetration through the roof refer to Page 5,
Figure 35.
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1. Determine the route your vertical venting will take. If
ceiling joist, roof rafters or other framing will obstruct
the venting system, consider an offset. Refer to Figure
32 to avoid cutting load bearing members.
 Pay special attention to these installation instructions
for required clearances (air space) to combustibles when
passing through ceilings, walls, roofs, enclosures, attic
rafters, etc. Do not pack air spaces with insulation. Also
note maximum vertical rise of the venting system and any
maximum horizontal offset limitations. Offsets must fall
within the parameters shown on Page 17, Figure 13.
FP1969
offset w/ wallstrap
Figure 32 -
Offset with Wall Strap and 45° Elbows
Roof
Flashing
Wall Strap
45° Elbows
Ceiling Firstop
FP1669
1
2
3
4
1
2
3
4
FP1179
max bends
Figure 31 -
Maximum Elbow Usage
Example: Elbow 1 = 90°
Elbow  = 45°
Elbow 3 = 45°
Elbow 4 = 90°
Total Angular Variation = 70°
FP1179
. Set replace in desired location. Drop a plumb line down
from the ceiling to the position of the ue exit. Mark the
center point where the vent will penetrate the ceiling.
Drill a small locating hole at this point.
Drop a plumb line from the inside of the roof to the locat-
ing hole in the ceiling. Mark the center point where the
vent will penetrate the roof. Drill a small locating hole
at this point.
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1. Cut a 10Z\x" (67 mm) square hole in the ceiling using
the locating hole as a center point The opening should
be framed to 10Z\x" x 10Z\x" (67 x 67 mm) inside
dimensions as shown in Figure 33 using framing lumber
the same size as the ceiling joist. If the area above the
ceiling is an insulated ceiling or a room, nail restop
from the top side. This prevents loose insulation from
falling into the required clearance space. Figure 34.