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

1-1/4 in. (32 mm)

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 14 1/2 in. (368 mm) using a 30° offset/return.

You determine from the table that you need 34 1/8 in. (867 mm) (Dimension “B”) between the offset and return.

The chimney component that best fits your applica- tion is one SL324.

Table 8.2

 

 

15-degree

 

 

 

 

 

 

 

 

 

 

30-degree

 

 

 

A

 

B

 

 

 

 

 

 

 

A

 

B

Offset

Height

 

 

 

 

 

 

Offset

Height

in.

 

mm

in.

 

mm

SL306

SL312

SL318

SL324

SL336

SL348

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

1

-

-

-

-

-

5-1/2

 

140

18-5/8

 

473

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

4-1/8

 

102

22-3/8

 

568

2

-

-

-

-

-

7-1/4

 

184

21-3/4

 

552

4-1/2

 

114

23-5/8

 

600

-

1

-

-

-

-

8-1/2

 

216

23-3/4

 

603

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

5-3/4

 

146

28-1/4

 

718

1

1

-

-

-

-

10-1/4

 

260

27

 

686

6

 

152

29-3/8

 

746

-

-

1

-

-

-

11-1/2

 

292

29

 

737

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

7-1/4

 

184

34

 

864

-

2

-

-

-

-

13-1/4

 

337

32-1/8

 

816

7-3/4

 

197

36-1/8

 

918

-

-

-

1

-

-

14-1/2

 

368

34-1/8

 

867

8-3/4

 

222

39-3/4

 

1010

1

-

-

1

-

-

16-1/4

 

413

37-3/8

 

949

10-3/8

 

264

45-5/8

 

1159

-

-

2

-

-

-

19-1/4

 

489

42-1/2

 

1080

10-5/8

 

270

46-3/4

 

1187

-

-

-

-

1

-

20-1/2

 

521

44-5/8

 

1133

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

11-7/8

 

302

51-3/8

 

1305

1

-

-

-

1

-

22-1/4

 

565

47-3/4

 

1213

13-1/2

 

243

57-1/4

 

1454

-

-

-

2

-

-

25-1/4

 

641

52-7/8

 

1343

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

13-3/4

 

349

58-3/8

 

1483

-

-

-

-

-

1

26-1/2

 

673

55

 

1397

15

 

381

63

 

1600

1

-

-

-

-

1

28-1/4

 

718

58-1/8

 

1476

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

16-1/2

 

419

68-3/4

 

1746

-

1

-

-

-

1

31-1/4

 

794

63-1/4

 

1607

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

18

 

457

74-5/8

 

1895

-

-

1

-

-

1

34-1/4

 

870

68-1/2

 

1740

19-5/8

 

498

80-3/8

 

2042

-

-

-

1

-

1

37-1/4

 

946

73-3/4

 

1873

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

20-5/8

 

524

84-1/8

 

2137

1

-

-

1

-

1

39-1/8

 

994

76-7/8

 

1953

22-3/4

 

578

91-7/8

 

2334

-

-

-

-

1

1

43-1/4

 

1099

84-1/8

 

2137

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

24

 

610

96-1/2

 

2451

1

-

-

-

1

1

45-1/8

 

1146

87-1/4

 

2216

25-7/8

 

657

103-1/2

 

2629

-

-

-

-

-

2

49-1/4

 

1251

94-1/2

 

2400

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.

26

Heatilator • SC60 • 32838 • Rev Y • 11/08 WIP

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Hearth and Home Technologies SC60 owner manual Using Offsets/Returns, Example