Lennox Merit MLDVT-35NM-FB Installation Instructions Manual page 15

LENNOX HEARTH PRODUCTS • MERIT
6. Change vent direction to horizontal/
inclined run—At transition from or
to a horizontal/inclined run, install
the SV4.5E45 and SV4.5E90 elbows
in the same manner as the straight
vent sections. The elbows feature
a twist section to allow them to be
routed about the center axis of their
initial collar section to align with the
required direction of the next vent run
element. Twist elbow sections in a
clockwise direction only so as to avoid
the possiblity of unlocking any of the
previously connected vent sections
(Figure 15).
Figure 17: Vent Elbows
4 13/16 in.
(122 mm)
Swivel Joint
Swivel Joint
°
(360 swivel)
°
(360 swivel)
SV4.5E45
SV4.5E90
°
(45 Elbow)
(90
7. Continue installation of horizontal/
inclined sections—Continue with the
installation of the straight vent sections
in horizontal/inclined run as described
on Page 14. Install support straps
every 5 ft (1.52 m) along horizontal/
inclined vent runs using conventional
plumber's tape.
It is very important that the horizontal/
inclined run be maintained in a straight
(no dips), slightly elevated plane. The
recommended incline is approximately
1/4 in. per foot (20 mm per meter)
horizontal, in a direction away from
the fireplace. Rise per foot run ratios
that are smaller are acceptable all the
way down to at or near level. Use a
carpenter's level to measure from a
constant surface and adjust the support
straps as necessary.
It is important to maintain the required
clearances to combustibles:
• 1 in. (25 mm) at all sides for all
vertical runs; and
• 3 in. (76 mm) at the top,
• 1 in. (25 mm) at sides, and
• 1 in. (25 mm) at the bottom for all
horizontal/inclined runs.
8. Frame roof opening—Identify location
for vent at the roof. Cut and/or frame
opening (Table 16).
SERIES DIRECT-VENT GAS FIREPLACES • MLDVT-30/35/40/45 • INSTALLATION INSTRUCTIONS
®
Table 16: Framing Dimensions for Roof
Pitch
0/12
6/12
12/12
8 1/8 in.
9. Install the roof flashing—Extend
(206 mm)
the vent sections through the roof
structure. Install the roof flashing over
the vent section and position such that
the vent column rises vertically (use
carpenters level) (Figure 18 ). Nail along
°
Elbow)
perimeter to secure flashing or adjust
roofing to overlap the flashing edges
at top and sides only and trim where
necessary. Seal the top and both sides
of the flashing with waterproof caulking.
Figure 18: Installing the Roof Flashing
10. Install the storm collar—Install the
storm collar, supplied with the flashing,
over the vent/flashing joint (Figure 18).
Loosen the storm collar screw. Slide
collar down until it meets the top of the
flashing. Tighten the adjusting screw.
Apply non-combustible caulking or
mastic around the circumference of the
joint to provide a water tight seal.
11. Install the vertical termination—The
final step involves installation of the
SV4.5CGV-1 vertical termination.
Extend the vent sections to the height
as shown in Vertical Vent Termination
Clearances on Page 6. The
SV4.5CGV-1 vertical termination
(Figure 19) installs in the exact same
fashion as any other Secure Vent
section. Align the termination over the
end of the previously installed section,
adjusting the radial alignment until the
four locking dimples of the termination
DIAGRAMS & ILLUSTRATIONS ARE NOT TO SCALE.
C
D
C D
10 1/2 in. 10 1/2 in.
(267 mm) (267 mm)
10 1/2 in. 12 in.
(267 mm) (305 mm)
10 1/2 in. 17 3/4 in.
(267 mm) (451 mm)
and Storm Collar
Storm
Collar
®
are aligned with the inlets of the four
incline channels of the last vent section.
Push the termination down until it fully
engages, then twist the termination
clockwise running the dimples down
and along the incline channels until they
are seated at the end of the channels.
Figure 19: SV4.5CGV-1 Vertical
Termination
NOTE: If the vent system extends
more than 5 ft (1.5 m) above the roof
flashing, stabilizers may be necessary.
Additional screws may be used at
section joints for added stability. Guide
wires may be attached to the joint for
additional support on multiple joint
configurations.
15