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12 31072 Rev G 08/04
MHC36 AND MHR36 INSTALLATION INSTRUCTIONS
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.
1. Using Offsets and Returns
a. To bypass any overhead obstructions, the chimney may be offset using a 15-deg (SL315) or 30-deg (SL330)
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 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 fireplace to top of starter
collar. See Figure 6.
Example: Your “A” dimension from Figure 7 is 14½”. Using
Table 1 the dimension closest to, but not less than 14½” is
14
5
/8” using a 30° offset/return. It is then determined from the
table that you would need 33” (Dimension “B”) between the
offset and return. The chimney components that best fit your
application are two SL312s.
Figure 7 - Chimney Offset/Return
* Proper assembly of air cooled chimney parts result in an overlap at chimney joints
of 1-1/4 in. Effective length is built into this chart.
Table 1 Offset Chart*
15° 30°
SL306 SL312 SL31 8 SL324 SL336 SL348ABA B
1-5/8 in. 13-3/8 in. 3-7/8 in. 14-1/2 in. - - - - - -
2-7/8 in. 17-3/4 in. 6-1/4 in. 18-5/8 in. 1 - - - - -
4-1/8 in. 22-3/8 in. 8-5/8 in. 22-3/4 in. 2 - - - - -
4-1/2 in. 23-5/8 in. 9-1/4 in. 23-3/4 in. - 1 - - - -
5-3/4 in. 28-1/4 in. 11-5/8 in. 27-7/8 in. 1 1 - - - -
6 in. 29-3/8 in. 12-1/4 in. 29 in. - - 1 - - -
7-1/4 in. 34 in. 14-5/8 in. 33 in. - 2 - - - -
7-3/4 in. 36-1/8 in. 15-1/4 in. 34-1/8 in. - - - 1 - -
8-3/4 in. 39-3/4 in. 17-5/8 in. 38-1/4 in. 1 - - 1 - -