Monessen Hearth DIRECT VENT MLDV500 - Manual (Page 24)

4 75D0004
MLDV Series Gas Fireplace VENTING INSTALLATION
INSTALLATION FOR VERTICAL TERMINATION
1. Determine the route your vertical venting will take. If ceiling joist,
roof rafters or other framing will obstruct the venting system, con-
sider an offset. Refer to Figure 32 to avoid cutting load bearing
members.
NOTE: 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.
. Set fireplace in desired location. Drop a plumb line down from the
ceiling to the position of the flue 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 locating hole
in the ceiling. Mark the center point where the vent will penetrate
the roof. Drill a small locating hole at this point.
FLAT CEILING INSTALLATION
1. Cut a 10 Z\x " (67 mm) square hole in the ceiling using the locating
hole as a center point The opening should be framed to 10 Z\x " x
10 Z\x " (67 x 67 mm) inside dimensions as shown in Figure 34
using framing lumber the same size as the ceiling joist. If the area
above the ceiling is an insulated ceiling or a room, nail firestop
from the top side. This prevents loose insulation from falling into
the required clearance space. Figure 34. Otherwise, install firestop
below the framed hole. The firestop should be installed with no
less than three (3) nails per side. Figure 34.
. Assemble the desired lengths of pipe and elbows necessary to
reach from the burner system flue up through the firestop. Be sure
pipe and elbow connections are fully twist-locked. Page 18, Figure
15.
3. Cut a hole in the roof using the locating hole as a center point.
(Cover any exposed open vent pipes before cutting hole in roof).
The 10
Z\x " x 10 Z\x " (67 x 67 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 combustible materials. (Insulation should be considered
a combustible material). Frame the opening as shown on Page
18, Figure 16.
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 Page 6, Figure 3. 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.
FP1969
offset w/ wallstrap
Figure 32 -
Offset with Wall Strap and 45° Elbows
Roof
Flashing
Wall Strap
45° Elbows
Ceiling Firstop
FP1669
FP1969
firestop w room above
Figure 33 -
If Area Above is a Room, Install Firestop
above Framed Hole as Shown
Firestop
Nails
FP1969
10
1 /
2
" 10
1
/
2
"
FP1970
firestop no room
Figure 34 -
If Area Above is Not a Room, Install Firestop
above Framed Hole as Shown
Nails
Firestop
FP1970