Lennox Hearth MPD-35 Series Indoor Fireplace User Manual


 
13
NOTE: DIAGRAMS & ILLUSTRATIONS NOT TO SCALE.
Figure 22
Figure 23
Figure 25
Figure 24
If the vent system extends more than 5' (1.5 m)
above the roof flashing, stabilizers may be nec-
essary. 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.
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 5 ft. (1.52 m) along horizontal/
inclined vent runs using conventional
plumbers tape.
See page 16, Figure 31.
It is
very important that the horizontal/inclined
run be maintained in a straight (no dips) and
recommended to be in a slightly elevated
plane, in a direction away from the fireplace
of 1/4" rise per foot (20 mm per meter) which is
ideal, though rise per foot run ratios that are
smaller are acceptable all the way down to at or
near level. Use a carpenters 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.
Figure 21
One method of support is by utilizing field
provided support straps (conventional
plumber's tape). Secure the plumber's tape
to the framing members with nails or screws.
Loop 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. Refer to
Figure 20.
F. Change vent direction to horizontal/in-
clined run - At transition from or to a horizon-
tal/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. See
Figure 21
.
K. Install the vertical termination - The final
step involves installation of the SV4.5CGV-1
Vertical Termination. Extend the vent sec-
tions to the height as shown in the "Vertical
vent termination section" on page 5. The
SV4.5CGV-1 Vertical Termination
(Figure 25)
can be installed 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 align-
ment 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 termination down until it fully en-
gages, then twist the termination clockwise
running the dimples down and along the
incline channels until they are seated at the
end of the channels.
I. Install the roof flashing - Extend 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 23
). Nail along pe-
rimeter 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 24.
Loosen the
storm collar screw. Slide collar down until it
meets the top of the flashing. Tighten the
adjusting screw. Apply non-combustible caulk-
ing or mastic around the circumference of the
joint to provide a water tight seal.
SV4.5E90
(90
° Elbow)
8-1/8"
(206 mm)
Swivel Joint
(360
°
swivel)
4-13/16"
(122 mm)
SV4.5E45
(45° Elbow)
Swivel Joint
(360
°
swivel)
C
D
Storm
Collar
H. Frame roof opening - Identify location for
vent at the roof. Cut and/or frame opening per
Roof Framing Chart and
Figure 22
.
Framing Dimensions for Roof
Pitch C D
0/12 10-1/2 in. 10-1/2 in.
(267 mm) (267 mm)
6/12 10-1/2 in. 12 in.
(267 mm) (305 mm)
12/12 10-1/2 in. 17-3/4 in.
(267 mm) (451 mm)