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For more information, visit www.desatech.com
The hearth extension must be made of non-combustible,
inorganic material having an effective thermal conductivity
“K” of 0.84 BTU IN/FT.HR.F (or less) at 1 inch thick.
Thermal conductivity “K” of materials can be obtained from
the manufacturer of the non-combustible material. The
minimum required thickness for any material could be
obtained by the following formula:
K factor at 1 inch = thickness required
0.84
For example, if the material selected has a K factor of 0.25,
such as a glass fiber, the following formula would apply:
0.25 = 0.30 thickness required
0.84
If the hearth extension is to be covered, use non-combustible
material such as tile, slate, brick, concrete, metal, glass,
marble, stone etc. Provide a means to prevent the hearth
extension from shifting and seal the gap between the fireplace
frame and hearth extension with a non-combustible material
(see figure 4).
OPTIONAL OUTSIDE AIR KIT (MODELS AK4 OR
AK4F):
The outside air kit must be installed during the rough framing
of the fireplace due to the nature of its location. Outside
combustion air can be accessed through an exterior wall
(Model AK4) or a vented crawl space (Model AK4F). See
figure 5 and Accessories on page 11.
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 children. The
maximum height of air inlet above platform of fireplace is 3 ft.
below the termination flue gas outlet.
For further details on the installation of the outside air kit,
please refer to the instructions included with the air kit. For
operating instructions please refer to your owner’s manual.
The outside air handle is located at the left-hand side of the
fireplace refractory (see figure 6, Model V(I)36NCR shown).
To close, pull down; to open, push up. Always open the
mechanism when starting a fire to provide adequate outside
combustion air. Close the mechanism when not in use to
prevent cold air from entering the room.
GAS LINE INSTALLATION (OPTIONAL):
Gas line hook up should be done by your supplier or a
qualified service person.
NOTE:
Before you proceed, make sure your gas supply is
turned off.
WARNING:
HEARTH EXTENSION IS TO BE
INSTALLED ONLY AS DESCRIBED.
Figure 5 AIR KIT INSTALLATION
CAUTION:
AIR DUCTS MUST NOT TERMINATE
IN ATTIC SPACE OR GARAGE.
Figure 4 HEARTH EXTENSIONS
Figure 6 AIR KIT DAMPER ROD
f i r e - p a r t s . c o m
