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
OVERLAP
Figure 8.3 Chimney Offset/Return
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.
Table 8.2
| A |
| B |
|
|
|
|
| ||
in. |
| mm | in. |
| mm | SL1106 | SL1112 | SL1118 | SL1136 | SL1148 |
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
26 | Heatilator • Birmingham BIR42 • |
