Venting installation – FMI S42 User Manual
Page 6

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6
Figure 6 - Lineal Gain
LINEAL GAIN
PART NO.
DESCRIPTION
GAIN
42"
Fireplace
44"
12-8DM
12-8HT
Pipe Section
10
5
/
8
"
18-8DM
18-8HT
Pipe Section
16
5
/
8
"
24-8DM
24-8HT
Pipe Section
23
5
/
8
"
36-8DM
36-8HT
Pipe Section
34
5
/
8
"
48-8DM
48-8HT
Pipe Section
46
5
/
8
"
RT-8DM Round Termination
6
7
/
8
"*
RTL-8DM Round Termination
7
3
/
4
"*
RTT-8DM Round Termination
with Slip Section
6
7
/
8
" to
23
1
/
8
"*
RTTL-8DM Round Termination
with Slip Section
8
1
/
2
" to
21
1
/
2
"*
ET-8DM
Square Chase-Top
12"*
ETO-8DM Square Chase-Top
with Mesh
12"*
ETL-8DM Square Chase-Top
with Slip Section
7" to 15"*
ETLO-8DM
Square Chase-Top
with Mesh & Slip
Section
12" to
25
1
/
2
"*
* The lineal gain for the terminations is mea-
sured to the flue gas outlet height.
Hemmed
End
8" Stainless
Inner Pipe
12
3
/
8
" Galvanized
Outer Pipe
ASSEMBLY AND INSTALLATION OF
DOUBLE WALL CHIMNEY SYSTEM
Each double wall chimney section consists of
a galvanized outer pipe, a stainless steel inner
flue pipe and a wire spacer. Pipe sections must
be assembled independently as the chimney
is installed. When connecting chimney directly
to fireplace, the inner flue pipe section must be
installed first with lanced side up. The outer
pipe section can then be installed over the flue
pipe section with hemmed end up. Press down
on each pipe section until lances securely
engage hem on fireplace starter. The wire will
assure the proper spacing between inner and
outer pipe sections.
VENTING INSTALLATION
OPTIONAL OUTSIDE AIR KIT
(MODEL AK4/AK4F)
The installation of an outside air kit should
be performed during the rough framing of
the fireplace due to the nature of it's location.
Outside combustion air is accessed through
a vented crawl space (AK4F) or through a
sidewall (AK4).
CAUTION: Combustion air
inlet ducts shall not terminate
in attic space.
Figure 5 - Outside Air Kit
Secure to Collars with Metal Tape,
Screws or Straps (Min. of 1/4" x 20"
in size)
Air Inlet
Location
Must Allow
For Bushes
or Snow
Vent Hood
Required for
Wall Installation
Air Inlet
Eyebrow
Vented Crawl Space
(Check Local Codes
Before Installing in a
Vented Crawl Space)
CHIMNEY PIPE
The FMI PRODUCTS, LLC chimney system
consists of 12", 18", 24", 36" and 48" snap-
lock, double-wall pipe segments, planned
for maximum adaptability to individual site
requirements. Actual lengths gained after fit-
ting overlaps must be taken into consideration
(lineal gain) and are given in the lineal gain
chart (see Figure 6). Lineal gain is the actual
measurable length of a part after two or more
parts are connected. For Canada, use chimney
parts designated "HT".
WARNING: The opening in
the collar around the chimney at
the top of the fireplace must not
be obstructed. Never use blown
insulation to fill the chimney
enclosure.