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1. Using Offsets and Returns
a.
To bypass any overhead obstructions, the chimney may be offset using a 15° or a 30° offset/return. Perform the following steps
to determine the correct chimney component combination for your particular installation.
b.
An offset and return may be attached together or a chimney section(s) may be used between an offset and return.
1)
Measure how far the chimney needs to be shifted to enable it to avoid the overhead obstacle. See Figure 11A, dimension
"A" to determine chimney sections required to achieve the needed shift.
2)
After determining the offset dimension, refer to Table 1 and find the "A" dimension closest to but not less than the
distance of shift needed for your installation.
3)
The "B" dimension that coincides with the "A" dimension represents the required vertical clearance that is needed
to complete the offset and return.
4)
Read across the chart and find the number of chimney sections required and the model number of those particular
chimney parts.
5)
Whenever the chimney penetrates a floor/ceiling, a firestop spacer must be installed.
6)
The effective height of the fireplace assembly is measured from the base of fireplace to top of starter collar.
Do not combine offsets to create an offset greater than 30° from vertical.This
may create a fire hazard since the natural draft may be restricted.
Table 1
15°
A
B
A
1-5/8"
13-3/8"
3-7/8"
2-7/8"
17-3/4"
6-1/4"
-
-
8-5/8"
4-1/2"
23-5/8"
9-1/4"
-
-
11-5/8"
6"
29-3/8"
12-1/4"
7-1/4"
34"
14-5/8"
-
-
15-1/4"
-
-
17-5/8"
-
-
20-5/8"
10-5/8"
46-3/4"
21-1/4"
11-7/8"
51-3/8"
23-5/8"
-
-
26-5/8"
13-3/4"
58-3/8"
27-1/4"
15"
63"
29-5/8"
16-1/2"
68-3/4"
32-5/8"
18"
74-5/8"
35-5/8"
-
-
38-5/8"
-
-
41"
22-3/4"
91-7/8"
44-5/8"
24"
96-1/2"
47"
25"
103-1/2"
50-5/8"
Proper assembly of air cooled chimney parts result in an overlap at
*
chimney joints of 1-1/4". Effective length is built into this chart.
4-03
WARNING!
Offset Chart*
30°
SL306
SL312 SL318 SL324 SL336
B
14-1/2"
-
-
18-5/8"
1
-
22-3/4"
2
-
23-3/4"
-
1
27-7/8"
1
1
29"
-
-
33"
-
2
34-1/8"
-
-
38-1/4"
1
-
43-1/2"
-
-
44-5/8"
-
-
48-3/8"
1
-
53-7/8"
-
-
55-3/4"
-
-
59"
1
-
64-1/4"
-
1
69-1/2"
-
-
74-5/8"
-
-
78-3/4"
1
-
85"
-
-
89-1/8"
1
-
95-1/2"
-
-
SL348
-
-
-
--
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-
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--
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--
-
-
-
--
-
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--
1
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--
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--
2
1
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--
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1
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--
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1
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1
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2
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1
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1
1
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1
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1
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1
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1
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1
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1
1
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1
1
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2
11
Constitution
EPA Certified Fireplace
A
B
1-1/4" OVERLAP
Figure 11A - Chimney Offset/
Return
Example: Your "A" dimension
from Figure 11A is 14-1/2".
Using Table 1 the dimension
closest to, but not less than
14-1/2" is 14-5//8" using a 30°
offset/return. It is then deter-
mined from the table that you
would need 33" (Dimension
"B") between the offset and
return. The chimney com-
ponents that best fit your
application are two SL312s.
480-1091
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