1.Using Offsets and Returns
a.To bypass any overhead obstructions, the chimney may be offset using a
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 7, 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 the fireplace to the top of starter collar. See Figure 6.
WARNING!
Do not combine offsets to create an offset greater than 30 deg from verti- cal. This may create a fire hazard since the natural draft may be restricted.
Table 1 |
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| Offset Chart* |
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| A |
| B | A | B | SL306 | SL312 | SL318 | SL324 |
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| - | - | - | - | ||||
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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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| 6 in. |
| 29 in. | - | - | 1 | - | ||
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| 34 in. | 33 in. | - | 2 | - | - | ||
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| - | - | - | 1 | ||||
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| 1 | - | - | 1 | ||||
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| - | - | 2 | - | |||||
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| - | - | - | - | |||||
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| - | - | - | 2 | |||||
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| - | - | - | - | |||||
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| 15 in. |
| 63 in. | 59 in. | 1 | - | - | - | |
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| - | 1 | - | - | |||||
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| 18 in. |
| - | - | 1 | - | |||
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| - | - | - | 1 | |||||
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| 41 in. | 1 | - | - | 1 | ||||
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| 85 in. | - | - | - | - | ||||
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| 24 in. |
| 47 in. | 1 | - | - | - | ||
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| - | - | - | - | |||||
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Figure 7 - Chimney Offset/
Return
Example: Your “A” dimension from Figure 7 is 14-1/2 in. Using Table 1 the dimension closest to, but not less than 14-1/2 in. is 14-5/8 in. using a 30-deg offset/return. It is then determined from the table that you would need 33 in. (Dimension “B”) between the offset and return. The chimney components that best fit your application are two SL312s.
08/04 | 26022 Rev i | 13 |
