Lennox Montebello MDLX40IN Installation Instructions Manual page 15

LENNOX HEARTH PRODUCTS • MONTEBELLO
One method of support is by utilizing field pro-
vided support straps (conventional plumber's
tape). Secure the plumber's tape to the framing
members with nails or screws. Strap the tape
around the vent, securing the ends of the tape
to the framing. If desired, sheet metal screws
#6 x 1/2" length may be used to secure the
support straps to the vent pipe. See Figure 18
on Page 14.
F. Change vent direction to horizontal/inclined
run - At transition from or to a horizontal/inclined
run, install the SV8 E45 and SV8 E90 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 direc-
tion of the next vent run element. Twist elbow
sections in a clockwise direction only so as
to avoid the possibility of unlocking any of
the previously connected vent sections. See
Figure 17 on Page 14 and Figure 19.
6"
(153mm)
Swivel Joint Swivel Joint
(360° swivel) (360° swivel)
SV8E45 SV8E90
(45° Elbow) (90° Elbow)
Figure 19
G. Continue installation of horizontal/inclined
sections - Continue with the installation of the
straight vent sections in horizontal/inclined run
as described in Step C. Install support straps
every 3 ft (914 mm) along horizontal/inclined
vent runs using conventional plumber's tape.
See Page 17, Figure 26. 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" per
foot (20 mm per meter) horizontal, in a direction
away from the fireplace. The 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 clear-
ances to combustibles: 1" (25 mm) at all sides
for all vertical runs; and 3" (76 mm) at the
top, 1" (25 mm) at sides, and 1" (25 mm) at
the bottom for all horizontal/inclined runs.
H. Frame roof opening - Identify location for
vent at the roof. Cut and/or frame opening per
Roof Framing Chart (Figure 20).
DLX DIRECT VENT GAS FIREPLACES (MDLX40/45) • INSTALLATION INSTRUCTIONS
®
Framing Dimensions for Roof
Inches (millimeters)
Pitch
0/12
6/12
12/12
Figure 20 - Roof Framing
I. Install the roof flashing - Extend the vent
10"
sections through the roof structure. Install the
(254mm)
roof flashing over the vent section and posi-
tion such that the vent column rises vertically
(use carpenters level) (Figure 21). Nail along
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.
J. Install the storm collar - Install the storm
collar, supplied with the flashing, over the vent/
flashing joint (see Figure 21). 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.
Flashing
Figure 21
NOTE: DIAGRAMS & ILLUSTRATIONS ARE NOT TO SCALE.
C
D
C D
13" 13"
(330 mm) (330 mm)
13" 15-1/2"
(330 mm) (394 mm)
13" 20-1/2"
(330 mm) (541 mm)
Storm
Storm
Collar
Collar
K. Install the vertical termination - The final
step involves installation of the Vertical Termina-
tion. Extend the vent sections to the height as
shown in the "Vertical vent termination section"
on Page 6. The SV8VTR Vertical Termination
(Figure 22) can be installed in the exact same
fashion as any other Secure Vent
the termination over the end of the previously
installed section, adjusting the radial alignment
until the four locking dimples of the termination
are aligned with the inlets of the four incline
channels of the last vent section. Push the ter-
mination down until it fully engages, then twist
the termination clockwise running the dimples
down and along the incline channels until they
seat at the end of the channels.
Figure 22
If the vent system extends more than 5 feet (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 sup-
port on multiple joint configurations.
section. Align
®
15