![background image](http://html.mh-extra.com/html/desa/hd18na/hd18na_owners-operation-and-installation-manual_2485984010.webp)
www.desatech.com
123168-01C
10
Minimum
Noncombustible
Material
Minimum
Noncombustible
Material Height
Distances to
Underside of
Mantel
Top of
Fireplace
Opening
Underside
of Mantel
Shelf
Mantel Shelf
12"
(
A
)
18" 20"
22"
24"
All
minimum
distances
are in
inches
2
1
/
2
"
6"
8"
10"
INSTALLATION
Continued
If Using Mantel
You must have noncombustible material(s)
above the fireplace opening. Noncombustible
materials (such as slate, marble, tile, etc.) must
be at least 1/2" thick. With sheet metal, you
must have noncombustible material behind it.
Noncombustible material must extend at least
12" up. See Figures 5 and 6 and Figure 7 on
page 11 for minimum clearances.
MANTEL CLEARANCES
In addition to meeting noncombustible mate-
rial clearances, you must also meet required
clearances between fireplace opening and
mantel shelf. If you do not meet the clearances
listed below, you will need a hood.
Determining Minimum Mantel Clearance
If you meet minimum clearance between
mantel shelf and top of fireplace opening, a
hood is not required (see Figure 6).
Figure 6 - Minimum Mantel Clearances
Without Using Hood
MINIMUM NONCOMBUSTIBLE
MATERIAL CLEARANCES
If Not Using Mantel
Note: If using a mantel, proceed to If Using
Mantel. If not using a mantel, follow the infor-
mation below.
You must have noncombustible material(s)
above the fireplace opening. Noncombustible
materials (such as slate, marble, tile, etc.)
must be at least 1/2" thick. With sheet metal,
you must have noncombustible material be-
hind it. Noncombustible material must extend
at least 12" up (for all models). See Figure 5
for minimum clearances.
Heat Resistant
Material
(A)
Figure 5 - Heat Resistant Material (Slate,
Marble, Tile, etc.) Above Fireplace
Noncombustible
Material Distance (A)
Requirements for Safe
Installation
12" or more
Noncombustible mate-
rial OK.
Between 8"
and 12"
2 4 " M o d e l s : I n s t a l l
fireplace hood acces-
sory (GA6050, GA6052,
GA6053, see
Accesso-
ries
, page 27).
18" Model: Noncombus
-
tible material OK.
Less than 8"
Noncombustible material
must be extended to at
least 8". See
Between
8" and 12"
, above. If you
cannot extend material,
you must operate heater
with flue damper open and
damper clamp installed.