Mendota DXV-60 Installation & Operating Instructions Manual page 18

VERTICAL THROUGH-THE-ROOF VENTING
B - 1
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 (2" above horizontal vents).
IMPORTANT: REFER TO DRAWINGS ON PAGES 10 & 11 WHILE FOLLOWING THESE INSTRUCTIONS.
The DXV-60 Fireplace must be installed by a qualified Mendota approved service person.
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 12" x 12" 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 roof line. 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 pipe and
elbow connections are in their fully twist-lock position and are leak-proof. Maintain 1" airspace clearances to combus-
tibles (2" above horizontal runs). Be sure 2000º sealant is used on the inner pipe joints of all adjustable (telescoping)
pipe sections.
5. Cut a 12" x 12" 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 ne-
cessary 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 roof line 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 45º elbows instead of 90º elbows. The 45º elbow offers less restriction to the flow of
flue gases and intake air. If a 90º elbow is necessary there must be a minimum of a one foot pipe section rise
from the 90º elbow to the vent cap or to the next offset. A maximum of three (3) 90ºelbows are allowed per in-
stallation.
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 roof line.
7. 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 firestop 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.
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.
17