Intertherm BM36HC Installation Instructions Manual page 9

Outer Pipe Of
Chimney Thimble Cathedral
Ceiling
14" Min.
Use Thimble FM8-AT1
For All Ceiling Pitches
From Flat To 3/12 Pitch.
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 locking tabs engage properly.
The FireCraft Technologies' FTF8 chimney sys-
tem is a two piece chimney, which snap to-
gether from the fireplace up. Start with the
inner flue section with the lanced end up, snap
lock it in to the matching collar on top of the
fireplace. At all subsequent joints, the upper
flue section fits into the preceding flue section.
Each piece snaps together by means of locking
tabs (9 locking tabs per joint). Check each
piece by pulling up slightly from the top to
ensure proper engagement before installing
the next section. If the flue has been installed
correctly, it will not separate when you test it.
Also, the inner flue joint where each section is
joined should be tight and flat without gaps
( Figure 22 ).
Figure 22
Outer pipe section installs in just the opposite
way; the lanced end goes down and each new
section goes OVER the outside of the previous
section installed ( Figure 23 ).
Figure 23
Note: Assemble one component of chimney at
a time (inner section first, then outer section
last) before proceeding with the next complete
section.
Continue to assemble the chimney up through
framed opening. Assemble just enough to
penetrate the roof flashing openings ( Figure
24 ). Maintain 1" minimum air space to insula-
tion and building materials and always check
each chimney joint (inner and outer) to ensure
proper engagement. Check vertical alignment
of chimney so that it projects from the roof in
true vertical position.
Figure 24
FireCraft chimney sections do not need to be
screwed together. Additional reinforcement is
not necessary except in certain offset condi-
tions (refer to page 13, Figure 35 ).
Step 5. The height of vertical chimney pipe
supported only by the fireplace must not ex-
ceed 30'. Chimney heights above 30' must be
supported by a Model FTF8-S4 stabilizer in-
stalled at 30' intervals.
Note: The Model FTF8-S4 adds 3" net effective
height to the total chimney system.
NOTE: DIAGRAMS & ILLUSTRATIONS NOT TO SCALE.
Install the Model FTF8-S4 stabilizer by fitting
inner section down into respective section of
proceeding flue pipe and locking outer stabilizer
section into place over the outer chimney pipe.
Position for proper clearance through framed
opening and nail straps securely (under tension
in "shear") into place on framing. Use 8d nails.
Attach successive lengths of chimney pipe
directly to stabilizer using same techniques as
Locking described in Step 4 ( Figure 25 ).
Tabs
(Lances)
Figure 25
Note: Do not apply excessive pressure to any
subsequent chimney sections following the
stabilizer when installing. Ensure each subse-
quent chimney section is securely attached by
testing as noted in Step 4.
Step 6. Select the proper FireCraft roof flash-
ing based on pitch of roof. Use chart below for
selection:
Roof Pitch
Flat to 6/12
6/12 to 12/12
Next, slide roof flashing over extended chimney
section that previously has been installed above
the roof opening in Step 4. Slide flashing all the
way down until the flashing base rests flat on
the roof ( Figure 26 ). Again, check the vertical
position of the chimney and the 2" minimum air
space to combustibles.
FTF8 Chimney
FTF8 Flashing
Figure 26
FTF8-S4 Stabilizer
Model
F8F6
F8F12
9