26
Table 8.2
B. Using Offsets/Returns
• Use an offset/return to bypass overhead obstructions.
• An offset and return can be used as a single entity or separated by chimney section(s).
WARNING! Risk of Fire! DO NOT use offset/returns greater than 30°. Chimney draft will be restricted and could cause
overheating and fire.
• Measure the shift needed to avoid the overhead obstruction. Refer to dimension A in Figure 8.3.
• Find the appropriate A dimension listed in Table 8.2.
• The B dimension coinciding with the A dimension measurement in Table 8.2 represents the required vertical clearance
needed to complete the offset/return.
• Read across the chart to find the number of chimney sections/model numbers needed between the offset and return.
A
B
1-1/4 in. (32 mm)
OVERLAP
Figure 8.3 Chimney Offset/Return
Heat & Glo • RUTHERFORD-42 • 4059-309 Rev L • 5/11
A
B
SL1106 SL1112 SL1118 SL1136 SL1148
in.
mm
in.
mm
4 7/8
124
17 7/8
454
-
-
-
-
-
7 1/4
184
22
559
1
-
-
-
-
9 3/4
248
26 1/8
664
2
-
-
-
-
10 1/4
260
27 1/4
692
-
1
-
-
-
12 3/4
324
31 3/8
797
1
1
-
-
-
13 1/4
337
32 3/8
822
-
-
1
-
-
15 3/4
400
36 5/8
930
-
2
-
-
-
18 1/8
460
40 3/4
1035
1
2
-
-
-
18 3/4
476
41 3/4
1060
-
1
1
-
-
21 3/4
552
47
1194
-
-
2
-
-
22 1/4
565
4 8
1219
-
-
-
1
-
24 3/4
629
52 1/8
1324
1
-
-
1
-
27 3/4
705
57 3/8
1457
-
1
-
1
-
28 1/4
718
58 3/8
1483
-
-
-
-
1
30 3/4
781
62 1/2
1588
1
-
-
-
1
33 3/4
857
67 3/4
1721
-
1
-
-
1
36 3/4
933
73
1854
-
-
1
-
1
39 3/4
1010
78 1/8
1984
-
-
-
2
-
41 1/8
1045
82 3/8
2092
1
-
-
2
-
45 3/4
1162
88 1/2
2248
-
-
-
1
1
48 1/8
1222
92 3/4
2356
1
-
-
1
1
51 3/4
1314
98 7/8
2511
-
-
-
-
2
Proper assembly of air cooled chimney parts results in an overlap of chimney joints
of 1-1/4 in. (32 mm). Effective length is built into this table.
Example:
Your “A” dimension from Figure 8.3 is 14 1/2 in. (368
mm). Using Table 8.2 the dimension closest to, but not
less than 14 1/2 in. (368 mm) is 15 3/4 in. (400 mm) using
a 30° offset/return.
You determined from the table that you would need
36 5/8 in. (930 mm) (Dimension “B”) between the offset
and return.
The chimney component that best fits your application is
two SL1112s.