Heatilator • EL36/EL42 • 4044-132 Rev P • 02/07
18
B. Using Offsets/Returns
To bypass any overhead obstructions, the chimney may be
offset using an offset/return.
An offset and return may be attached together or a chimney
section(s) may be used between an offset and return.
Perform the following steps to determine the correct chim-
ney component combination for your particular installation:
• Measure how far the chimney needs to be shifted to enable
it to avoid the overhead obstacle. See Figure 5.3. Use
dimension “A” to determine chimney section required to
achieve the needed shift.
• After determining the offset dimension, refer to Table 5.2
and
fi
nd the “A” dimension closest to but not less than the
distance of shift needed for your installation.
• The “B” dimension that coincides with the “A” dimension
represents the required vertical clearance that is needed
to complete the offset and return.
• Read across the chart and
fi
nd the number of chimney
sections required and the model number of those particular
chimney parts.
• Whenever the chimney penetrates a
fl
oor/ceiling, a ceiling
fi
restop must be installed.
• The effective height of the
fi
replace assembly is measured
from the base of the
fi
replace to the top of the starter collar.
See Dimensions in Section 12.
Table 5.2
Fire Risk
• Draft will be restricted if offset/returns
greater than 30° are used.
WARNING
15-degree
30-degree
SL306 SL312 SL318 SL324 SL336 SL348
A
B
A
B
in.
mm
in.
mm
in.
mm
in.
mm
1-5/8
41
13-3/8 340
3-5/8
92
15-1/2
394
-
-
-
-
-
-
2-7/8
73
17-3/4 451
5-1/2
140
18-5/8
473
1
-
-
-
-
-
4-1/8
102
22-3/8 568
7-1/4
184
21-3/4
552
2
-
-
-
-
-
4-1/2
114
23-5/8 600
8-1/2
216
23-3/4
603
-
1
-
-
-
-
5-3/4
146
28-1/4 718
10-1/4
260
27
686
1
1
-
-
-
-
6
152
29-3/8 746
11-1/2
292
29
737
-
-
1
-
-
-
7-1/4
184
34
864
13-1/4
337
32-1/8
816
-
2
-
-
-
-
7-3/4
197
36-1/8 918
14-1/2
368
34-1/8
867
-
-
-
1
-
-
8-3/4
222
39-3/4 1010 16-1/4
413
37-3/8
949
1
-
-
1
-
-
10-3/8
264
45-5/8 1159 19-1/4
489
42-1/2 1080
-
-
2
-
-
-
10-5/8
270
46-3/4 1187 20-1/2
521
44-5/8 1133
-
-
-
-
1
-
11-7/8
302
51-3/8 1305 22-1/4
565
47-3/4 1213
1
-
-
-
1
-
13-1/2 243
57-1/4 1454 25-1/4
641
52-7/8 1343
-
-
-
2
-
-
13-3/4 349
58-3/8 1483 26-1/2
673
55
1397
-
-
-
-
-
1
15
381
63
1600 28-1/4
718
58-1/8 1476
1
-
-
-
-
1
16-1/2 419
68-3/4 1746 31-1/4
794
63-1/4 1607
-
1
-
-
-
1
18
457
74-5/8 1895 34-1/4
870
68-1/2 1740
-
-
1
-
-
1
19-5/8 498
80-3/8 2042 37-1/4
946
73-3/4 1873
-
-
-
1
-
1
20-5/8 524
84-1/8 2137 39-1/8
994
76-7/8 1953
1
-
-
1
-
1
22-3/4 578
91-7/8 2334 43-1/4 1099 84-1/8 2137
-
-
-
-
1
1
24
610
96-1/2 2451 45-1/8 1146 87-1/4 2216
1
-
-
-
1
1
25-7/8 657
103-1/2 2629 49-1/4 1251 94-1/2 2400
-
-
-
-
-
2
Proper assembly of air-cooled chimney parts result in an overlap at chimney joints of 1-1/4 in. (32 mm). Effective
length is built into this chart.
A
B
1-1/4 in. (32 mm)
OVERLAP
Figure 5.3 Chimney Offset/
Return
Example:
Your “A” dimension
from Figure 5.3 is 14 1/2 in.
(368 mm). Using Table 5.2
the dimension closest to, but
not less than 14 1/2 in. (368
mm) is 14 1/2 in. (368 mm)
using a 30° offset/return.
It is then determined from
the table that you would
need 34 1/8 in. (867 mm)
(Dimension “B”) between
the offset and return. The
chimney component that
best
fi
ts your application is
one SL324.