Installing The Chimney System - Lennox Hearth Products Magna-Fire LS43ST Installation Instructions Manual

Step 4. Two sets of nailing tabs have been
provided. One set of four is to accommodate
⁵⁄₈" drywall and the other set is for ¹⁄₂" drywall.
To insert the unit into prepared framing, bend
the four nailing flanges adjacent to one of the
fireplace faces completely over 180 degrees
until they are flush with the cabinet. Bend the
remaining nailing flanges adjacent to the op-
posite face out 90 degrees ( see Figure 18 ).
Slide the unit through the framed opening with
the face adjacent to the flanges bent fully over
180 degrees, inserted first.
Slide the unit into the prepared framing until the
unit is centered between the walls. Fold the
nailing tabs back against the framing, level the
unit with shims as necessary and secure the
fireplace to the side frame members with 8d
nails or screws as appropriate.
Figure 18
Note: The nailing tabs are exempt from the
fireplace clearances described on the fireplace
clearance label.

INSTALLING THE CHIMNEY SYSTEM

Step 1. Check flue damper for proper opera-
tion. To open, pull handle down and release.
Damper will open automatically. To close, push
handle up. The damper should lock into the
closed position.
Note: The damper is set to one opening, but
may be switched if necessary.
Step 2. Using standard construction framing
techniques, construct opening for chimney route
up through the ceiling(s) and roof or through an
outside chase.
Framing must maintain adequate minimum air
space clearance at all times.
CAUTION: ALLOW MINIMUM 2" (51 MM)
CHIMNEY AIR SPACE TO COMBUSTIBLE
FRAMING MEMBERS THROUGHOUT VERTI-
CAL OR OFFSET CHIMNEY INSTALLATION.
ALSO MAINTAIN AIR SPACE ON TOP OF THE
FIREPLACE AS DEFINED BY THE SPACERS
AND STANDOFFS.
A minimum 2" (51 mm) air space must be
reserved for all materials extending for any
continuous length surrounding the chimney.
See Figures 26 and 27 and charts "Framing
Dimensions for Ceiling and Roof" on page 10,
which specify minimum ceiling and roof di-
mensions.
For new construction, to determine chimney
center line, use plumb line from roof or ceiling
Framing
above fireplace to center of flue collar on
Stud
fireplace.
For remodeling, plumb to center of flue collar
from ceiling above, drive nail through ceiling
Nailing
from below to mark position, then mark and
Flange
cut to passage from above ceiling (around
nail) ( Figure 19 ). Then plumb from ceiling or
roof level directly above hole which has just
been completed.
Figure 19
NOTE: DIAGRAMS & ILLUSTRATIONS NOT TO SCALE.
Step 3. Position appropriate firestop spacer at
ceiling and nail temporarily with two (2) 8d
nails. Use flat firestop spacer, Model F10FS-2,
if chimney penetrates ceiling vertically. If chim-
ney penetrates ceiling at 30° angle (offset
chimney), use Model F10FS30-2. Nailed, one
each on opposite sides to hold firestop spacer
in position. Nail permanently, using at least
two (2) more 8d nails, after chimney sections
have been assembled through the firestop
spacer and after any necessary adjustments
have been made. Firestop spacer must be
secured by at least four (4) 8d nails when
completely installed.
Note: If there is a room above ceiling level,
firestop spacer must be installed on the bottom
side of the ceiling. If an attic is above ceiling
level, firestop spacer must be installed on top
side of ceiling joist (Figures 20 and 21).
Figure 20
Plumb Line
Figure 21
Step 4. Note: Chimney sections are con-
structed with a unique locking tab design
which ensures an immediate, tight assembly
between sections. Plan your chimney require-
ments carefully before assembly as chimney
is difficult to disassemble after installation. If
disassembled, the tabs might become dam-
aged. Be certain tabs are properly formed to
ensure tabs engage properly.
Room Above
Firestop Spacer
Attic Above
Firestop Spacer
9