www.desatech.com
55511E
6
FireBox inSTALLATion
Continued
VenTing inSTALLATion
OPTIONAL OUTSIDE AIR KIT
The installation of an outside air kit should be per-
formed during the rough framing of the firebox due
to the nature of it’s location. Outside combustion air
is accessed through and exterior wall or a vented
crawl space (see Figure 12, page 7).
CAUTION: Air inlet ducts
must not terminate in attic
space.
The maximum height for the
air vent can not exceed 3 feet
below the flue gas outlet of the
termination.
Avoid installing outside air eyebrow in areas
where inlet opening may be blocked by snow,
bushes or other obstacles. It should also be
located beyond the reach of small children.
For further details on installation of outside air
kit, please refer to instructions included with
air kit. For operating instructions, please refer
to your owner's manual.
8" Max.
“K” Factor
.84
1
1
/
2
" Typ.
1
1
/
2
" Typ.
Noncombustible
Hearth
Extension
“Z” Type Ember
Protector
Noncombustible
Hearth Extension
Ember Protector
Figure 11 - Raised Hearth Extension
Figure 9 - Nailing Flanges
Nailing
Flanges
Prepared
Framing
Nails or
Screws
1/2" (1.27 cm)
Minimum to
Combustibles
HEARTH ExTENSION
A hearth extension projecting a minimum of
16" in front of and a minimum of 8" beyond
each side of the firebox opening is required to
protect combustible floor construction in front
of firebox (see Figure 10). Fabricate a hearth
extension using a material which meets the
following specifications: a layer of noncom
-
bustible, inorganic material having a thermal
conductivity of K=0.84 BTU IN/FT, HR. F (or
less) at 1" thick. For example, if the material
selected has a K factor of 0.25, such as glass
fiber, the following formula would apply:
0.25 x 1.0" = 0.30" thickness required
0.84
NONCOMBUSTIBLE
HEARTH EXTENSION
52
1
/
2
" MIN.
(133.3cm)
36
1
/
2
" MIN.
(92.7cm)
8" MIN.
(20.3cm)
16" MIN.
(40.6cm)
Figure 10 - Hearth Extension
Thermal conductivity "K" of materials can be
obtained from manufacturer or supplier of
noncombustible material.
If hearth extension is to be raised, a “Z” type
ember protector must be used (see Figure 7,
page 5, and Figure 11)
