12
Heatilator • MEL36, MEL42 Installation Manual • 4044-212 • Rev D • 01/06/15
B. 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. Secure offsets with screws ( not to exceed 1/2” / 13 mm in length) Secure returns with strapping.
Straight chimney sections may be secured with screws. Keep chimney sections from separating or twisting.
• Measure the shift needed to avoid the overhead obstruction. Refer to dimension A in Figure 4.2.
• Find the appropriate A dimension listed in Table 4.3. The B dimension coinciding with the A dimension measurement in
Table 4.3 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 4.2 Chimney Offset/Return
Table 4.3 Offset Dimensions
Example:
Your “A” dimension from Figure 4.2 is 14-1/2 in. (368
mm). Using Table 4.3, the dimension closest to, but not
less than 14-1/2 in. (368 mm) is 14-1/2 in. (368 mm) us-
ing a 30° offset/return.
You determine from the table that you need 34-1/8 in.
(867 mm) (Dimension “B”) between the offset and re-
turn.
The chimney component that best fits your application is
one SL324.
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.
