Hearth and Home Technologies HST-42D owner manual Using Offsets/Returns, Example

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 Heat & Glo • HST-42D • 27177 • Rev AB • 11/08