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The offset and return elbows may be attached
together, or a section or sections of chimney
may be used between, but do not exceed 20'
(6.1 m) in total length between elbows (Figure
35). If sections of pipe exceed 10' (3 m) between
elbows, a chimney stabilizer must be used at
the midpoint. The stabilizer support straps
must be attached under tension (in shear) to
structural framing members above. When two
sets of offset elbows are used, the maximum
combined length of chimney used between
elbows cannot exceed 20' (6.1 m) (Figures 35
through 37). example: If C
C
cannot exceed 10' (3 m).
2
If an offset exceeds 6' in length, each chimney
joint beyond the first 6' of offset to the return
elbow, must be secured by a No. 8 x 1/2" sheet
mental screw located at the underside of the
joint (Figure 38).
chimney
section
6'
Figure 38
A 1/8" (3 mm) diameter hole must be drilled in
the chimney joint using a 1/8" (3 mm) diameter
drill. Hole should be drilled in center of joint
overlap (Figure 39). Be sure to drill only through
the outer chimney casting. Do not puncture
the inner flue.
underside of chimney
Figure 39
16
Maximum offset of the chimney system is 30°.
Two offset elbows must not be assembled to
form a 60° offset. However, two sets of offset
and return elbows may be used on a single flue
system, provided the total height of the system
exceeds 25' (7.6 m).
Return elbow support straps must be securely
attached under tension (in shear) to structural
framing members above.
offseT calculaTIons
= 10' (3m) then
1
1. Use Offset Chart to determine amount of
horizontal offset (A) and height (B) for various
chimney sections.
. Use "Height of Chimney Only" column to
determine combinations of pipe used above
return elbow to achieve desired heights. Ref-
erence Components Effective Height Chart in
Figure elevation chart section.
3. Use Elevation Chart as job estimator only.
Add necessary firestop spacers and stabilizers
Joints
as required. Firestop spacers must be used as
shown in Figures 20 and 21 and stabilizers as
shown in Figure 27.
4'
InsTallInG offseTs
First, review Offset Elevation Chart (Table 3)
no. 8 x ¹⁄₂" sms
and Figure 34 on Page 14.
step 1. Determine the offset distance where
chimney is to pass through the first ceiling-
dimension "A." To find this point on your
ceiling, first determine the center point for a
vertical chimney following the instructions for
vertical installation.
Measure height to the ceiling from the top of
fireplace-dimension "B." Use Offset Elevation
Chart to find dimension "A." Mark point where
you will drive your nail to show the center point
for your offset ceiling cut.
step . Proceed by using the Straight Up In-
stallation Instructions for cutting and framing
ceiling and roof openings.
Note: See "Framing and Dimension" Chart for
the sizes of the ceiling and roof openings. The
size of the roof opening varies with the degree
of pitch of the roof.
NOTE: DIAGRAMS & ILLUSTRATIONS ARE NOT TO SCALE.
offseT elbow assembly
Offset elbows install the same as chimney
sections. First, snap the inner section INTO
the preceding inner section of flue. Check con-
nection by pulling up slightly to ensure a tight
fit. Next, the outer sections snap locks OVER
the preceding outer section of chimney. Again,
check outer section by pulling up slightly to
ensure proper connection is made.
reTurn elbow assembly
Return elbows install the same way as round
terminations and stabilizers:
step 1. Hold return elbow over top of last
chimney section.
step . Center inner slip section into inner flue
pipe-slip down.
step 3. Center outer locking section over outer
chimney pipe-push down until locking
joint has firmly engaged.
step 4. Pull up slightly on return elbow to
ensure locking joint has firmly en-
gaged.
step 5. Secure support straps to framing
members by nailing under tension in
sheer (Figure 40).
return elbow
Figure 40
Note: The return elbow assembly performs the
same function as a stabilizer. Consider this when
determining the need for a stabilizer.
Note: Do not apply excessive pressure to any
subsequent chimney section following return
elbow assembly when installing. Ensure subse-
quent chimney sections are securely attached
by testing as noted above.
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