Lennox LSS-35CN Installation Instructions Manual page 15

Where required, a telescopic vent section
(SV4.5LA) may be used to provide the installer
with an option in installing in tight and confined
spaces or where the vent run made up of fixed
length pieces develops a joint in a undesirable
location, or will not build up to the required
length. The SV4.5LA Telescopic Vent Section
has an effective length of from 1-1/2" (38 mm)
to 7-1/2" (191 mm). The SV4.5LA is fitted with
a locking inclined channel end (identical to a
normal vent section component) and a plain end
with 3 pilot holes. Slip the plain end over the
locking channel end of a standard SV4.5 vent
component the required distance and secure
with three screws.
Maintain a minimum 1" (25 mm) clearance to
combustible materials for all vertical elements.
Clearances for all horizontal elements are 3"
(76 mm) on top, 1" (25 mm) on sides and 1"
(25 mm) on the bottom.
A. Frame ceiling opening - Use a plumb line
from the ceiling above the appliance to locate
center of the vertical run. Cut and/or frame an
opening, 10-1/2" x 10-1/2" (267mm x 267mm)
inside dimensions, about this center mark
(Figure 19 ).
10-1/2" Min.
(267 mm)
10-1/2" Min.
(267 mm)
Figure 19
B. Attach vent components to appliance
- Secure Vent SV4.5 direct vent system compo-
nents are unitized concentric pipe components
featuring positive twist lock connections (see
Figure 20 ).
All of the appliances covered in this document
are fitted with collars having locking inclined
channels. The dimpled end of the vent com-
ponents fit over the appliance collar to create
the positive twist lock connection.
First Vent
Component
Align the dimple (four places)
with the opening of the locking
incline channel on appliance
collar. Twist vent component
clockwise to engage and seal.
Dimple
Locking
Incline Channel
Appliance collar
Vent / Appliance Collar
Connection
Figure 20
Arrow
Align the dimple (four places) of the
upper vent section with the opening of
the locking incline channel on the
lower vent section. Twist vent
component clockwise to engage and
seal until arrow and dimple align.
Dimple
Locking
Incline Channel
Connected
Vent Sections
Vent / Vent Section
Arrow
Connection
Figure 21
To attach a vent component to the appliance
collar, align the dimpled end over the collar,
adjusting the radial alignment until the four
locking dimples are aligned with the inlet of
the four inclined channels on the collar (refer to
Figure 20 ). Push the vent component against
the collar until it fully engages, then twist the
component clockwise, running the dimples
down and along the incline channels until they
seat at the end of the channels.
The unitized design of the Secure Vent com-
ponents will engage and seal both the inner
and outer pipe without the need for sealant or
screws. If desired, a #6 x 1/2" screw may be
used at the joint, but is not required as the pipe
will securely lock when twisted.
C. Attach vent components to each other -
Other vent sections may be added to the pre-
viously installed section in accordance with
the requirements of the vertical vent figures
and tables. To add another vent component
to a length of vent run, align the dimpled end
over the inclined channel end of the previously
installed section, adjusting the radial alignment
until the four locking dimples are aligned with
the inlets of the four incline channels of the
previous section.
NOTE: DIAGRAMS & ILLUSTRATIONS ARE NOT TO SCALE.
Push the vent component against the previous
section until it fully engages, then twist the
component clockwise running the dimples down
and along the incline channels until they seat at
the end of the channels. This seating position
is indicated by the alignment of the arrow and
dimple as shown in Figure 21.
D. Install firestop/spacer at ceiling - When
using Secure Vent, use SV4.5VF firestop/spacer
at ceiling joists; when using Secure Flex, use
SF4.5VF firestop/spacer. If there is living space
above the ceiling level, the firestop/spacer
must be installed on the bottom side of the
ceiling. If attic space is above the ceiling, the
firestop/spacer must be installed on the top side
of the joist. Route the vent sections through the
framed opening and secure the firestop/spacer
with 8d nails or other appropriate fasteners at
each corner.
Remember to maintain 1" (25 mm) clearance
to combustibles, framing members, and attic
Arrow
or ceiling insulation when running vertical
chimney sections.
E. Support the vertical vent run sections
-Support the vertical portion of the venting
system every 8 feet (2.4m) above the fireplace
vent outlet using 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 . See Figure 22.
Figure 22
Blocking
Support Straps
(Plumber's tape)
8 feet (2.4 m)
Maximum
15