Heatilator • LM42 • Installers Manual • 4087-901 • Rev A • 04/14/16
20
6 ft (1.83 m) max.
unsupported chimney
above roof
20 ft (6.10 m) max.
pipe between an
offset & return
35 ft (10.7 m)
max. straight
unsupported
chimney height
14 ft (4.28 m) min. height/single offset-return
16.5 ft. (5.41 m) min. height/double offset-return
90 ft (27.4 m) max. height
56-5/8 in.
(1538 mm)
Effective
Height
Ceiling firestop
Figure 4.1 Chimney Requirements
NOTICE:
A maximum of two pairs of offsets and returns
may be used. Offsets may be used directly off the top of
the fireplace.
Minimum overall straight height
14 ft
4.28 m
Minimum height with single offset/
return
14 ft
4.28m
Double offset/return minimum height
16-1/2
ft
5.41 m
Maximum height
90 ft
27.43 m
Maximum chimney length between
an offset and return
20 ft
6.1 m
Maximum distance between chimney
stabilizers
35 ft
10.67 m
Maximum unsupported chimney
length between the offset and return
6 ft
1.83 m
Maximum unsupported chimney
height above the fireplace
35 ft
10.67 m
Maximum unsupported chimney
above roof
6 ft
1.83 m
Freestanding Unit (using (1) SL348)
8 ft
8in.
2.64 m
WARNING! Risk of Fire! You must maintain 2 in. (51 mm)
air space clearance to insulation and other combustible
materials around the chimney system.
NOTICE
: You must provide support for the pipe during
construction and check to be sure inadvertent loading has
not dislodged the chimney section from the fireplace or at
any chimney joint.
A. Chimney Requirements
Vertical distances are measured from the base of the
fireplace as shown in Figure 4.1.
• Minimum overall straight height is 8 ft 8 in. if the
fireplace is freestanding and a minimum of 10 ft from a
combustible structure. See Figure 3.2.
• Chimney must extend 2 ft. (.6m) above any portion of
the roof within 10 ft (3m) of the chimney. Refer to Figure
4.3.
4
Chimney and Termination Requirements
Table 4.2 Chimney Component Dimensions
Table 4.1 Chimney Requirements
Section 4
HEIGHT OF CHIMNEY COMPONENTS
in.
mm
Chimney Stabilizer
SL3
4-3/4
121
Offsets/Returns
SL315
13-3/8
340
SL330
15-1/2
394
Chimney Sections*
SL306
4-3/4
121
SL312
10-3/4
273
SL318
16-3/4
425
SL324
22-3/4
578
SL336
34-3/4
883
SL348
46-3/4
1187
* Dimensions reflect effective height.