Mendota ML39 Assembly, Installation And Operating Instructions page 62

Vertical Through-The Roof Venting
The maximum vertical run of vent pipe is 40 ft. from the top of the fireplace. The fireplace will support a run of a maximum of
40 ft. Maintain 1" air space clearances on all sides of vents (3" above horizontal runs).
If an offset is required directly on top of the fireplace, two 45
create a horizontal offset then to run upwards vertically. Doing so will continue to allow the use of the 51 feet maximum
vertical run.
Follow these steps to install venting
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 relocate the
fireplace or to offset, to avoid cutting load bearing members.
2. Cut and frame a 10" x 10" opening in the ceiling centered on the hole drilled in Step 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 and the vertical rise in the attic or second story and allow sufficient vent height above roofline. For
two story installations, fire stops are required at each floor level. If an offset is needed in the attic, additional pipe and
elbows 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 are sealed and are leak-proof.
Maintain 1" airspace clearances to combustibles (2" above horizontal runs). Cut a 10" x 10" 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 roofline.
Galvanized pipe and elbows may be utilized in the attic, as well as above the roofline. The galvanized finish is desirable
above the roofline due to its higher corrosive resistance.
5. 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.
6. 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.
7. Continue to add pipe sections until the pipe and the vent cap meet the minimum building code requirements, as
outlined in No. 8 on the following page.
8. 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 10" x 10" inside dimensions as described in step No. 5.
9. 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.
Height "*H" from roof surface to the top of vent cap can be determined as follows:
Complete installation with storm collar and vent cap.
85-03-01136
o
elbows may be connected directly to the top of this fireplace to
"H" DIMENSION
ROOF PITCH FEET
FLAT to 6/12 2
7/12 to 9/12 2
10/12 to 12/12 4
13/12 to 16/12 6
17/12 to 21/12 8
ML39
METERS
.6
.6
1.2
1.8
2.4
Page 62