19
B-1
VERTICAL THROUGH-THE-ROOF VENTING
The maximum vertical run of vent pipe is 36ft. from the top of the fireplace. The fireplace will support a run of
a maximum of 36 ft. Maintain 1" air space clearances on all sides of vents (2" above horizontal runs).
The DXV-35 Fireplace must be installed by a qualified Mendota approved serviceperson.
1.
Place the fireplace in its desired location. Drop a plum bob from the ceiling to the position of the fireplace flue exit.
Mark the location where the vent will penetrate the ceiling. Drill a small hole at this point. Next, drop a plum bob
from the roof to the hole previously drilled in the ceiling. Mark and drill the spot where the vent will penetrate the
roof. Determine if ceiling joists, roof rafters or other framing will obstruct the venting system. You may wish to re-
locate the fireplace or to offset, to avoid cutting load bearing members.
2.
Cut and frame a 9" x 9" opening in the ceiling centered on the hole drilled in No. 1.
3.
To determine the length of the vent pipe required, measure the distance from the fireplace flue outlet to the ceiling, the
ceiling thickness, the vertical rise in the attic or second story and allow sufficient vent height above roofline. For two
story installations, firestops are required at each floor level. If an offset is needed in the attic, additional pipe and el-
bows will be required.
4.
Assemble the desired lengths of vent pipe and elbows to reach from the fireplace flue outlet. Ensure that all vent pipe
and elbow connections are in their fully twist-lock position and that inner pipe joints (DuraVent only) are sealed and
are leak-proof. Maintain 1" airspace clearances to combustibles (2" above horizontal runs).Cut a 9" x 9" opening in
the roof, centered in the small drilled hole placed in the roof in No. 1. The opening should be a sufficient size to meet
all clearance requirements. Continue to assemble lengths of pipe and elbows necessary to reach up through the roof-
line. Galvanized pipe and elbows may be utilized in the attic, as well as above the roof line. The galvanized finish is
desirable above the roofline due to its higher corrosive resistance.
a)
If an offset is necessary, it is important to support the vent pipe every 3 ft. to avoid excessive stress on the elbows and
possible separation. Wall straps are available for this purpose.
b)
Whenever possible, use 45
º
elbows instead of 90
º
elbows. The 45
º
elbow offers less restriction to the flow of flue
gases and intake air. If a 90
º
elbow is necessary there must be a minimum of one pipe section rise from the 90
º
elbow
to the vent cap or to the next offset. A maximum of three 90
º
elbows are allowed per installation.
5. Slip the flashing over the pipe sections protruding through the roof. Secure the base of the flashing to the roof with
roofing nails and seal flashing to roof. Ensure the roofing material overlaps the top edge of the flashing. Verify you
have at least the minimum clearance to combustibles at the roofline.
6. Continue to add pipe sections until the pipe and the vent cap meet the minimum building code requirements, as out-
lined in No. 8 on the following page.
a)
For multi-story vertical installation, a ceiling fire stop is required at the second floor and any subsequent floors. The
opening should be framed to 9" x 9" inside dimensions as described in step No. 5.
b)
Any occupied areas above the first floor, including closets and storage spaces, which the vertical vent passes through,
must be enclosed. The enclosure may be framed and sheet rocked with standard construction materials, however, be
sure to maintain minimum allowable clearances between the outside of the vent pipe and the combustible surfaces of the
enclosure.
IMPORTANT: REFER TO DRAWINGS ON PAGES1215 WHILE FOLLOWING THESE INSTRUCTIONS
.
