14
Heatilator • ST42A Installation Manual • 4012-051 • Rev C • 10/03/13
G. Outside Air Kit
When you install the outside air kit, Hearth & Home
Technologies recommends you utilize the shortest duct
run to optimize the performance of the outside air kit. The
outside air inlet hood should be positioned in a manner
that will not allow snow, leaves, etc. to block the inlet. In
some installations the air duct may need to be run verti-
cally. In such an installation, a 3 ft (914 mm) height differ-
ence must be maintained from the top of the uppermost
chimney section to the outside air inlet hood.
Refer to Figures 3.8 and 3.9 when placing the outside air
inlet hood.
AK17 Installation
• Remove the cover plate from the side of the fireplace and
replace it with outside air plate assembly using existing
screws.
• Mark and cut out a 4 1/2 in. (114 mm) diameter hole in
the building side for air entry. This hole should allow for
some framing (two sides) so the outside air inlet hood
may be nailed into position, flush with building’s outside.
• Secure flexible duct (not supplied) to the plate assembly.
• Feed duct through hole to the outside, fasten to the
outside air inlet hood.
• Fasten outside air inlet hood assembly to the structure
with screws.
• Seal between the wall and the pipe with silicone to
prevent moisture penetration and air leaks.
• Seal between the outside air inlet hood and the house
with silicone to prevent air infiltration.
CAUTION! Risk of Cuts/Abrasions.
Wear protective
gloves and safety glasses during installation. Sheet metal
edges are sharp.
CAUTION!
Risk of Fire or Asphyxiation!
DO
NOT draw outside combustion air from wall,
floor or ceiling cavity, or enclosed spaces such
as an attic or garage.
•
DO NOT place outside air inlet hood close to
exhaust vents or chimneys. Fumes or odor
could be drawn into the room through the
fireplace.
• Locate outside air inlet hood to prevent
blockage from leaves, snow/ice, or other
debris. Blockages could cause combustion
air starvation.
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3 ft min. from
top of uppermost
chimney section
to air inlet.
Figure 3.8 Outside Air Inlet Locations
Outlet placed
higher than 3 ft
below the
termination cap
Attic space
Garage or
combustible
liquids storage
Outlet blocked by
snow, leaves, etc.
Clear area
outside
house or in
ventilated
crawl space
YES
NO
NO
NO
NO
Factory-built
fireplace
• Use UL181 Class 0 or Class 1 rigid or flexible ducting.
• Install with short run or mainly straight duct, except small
dip for cold air trap which will help prevent flow of cold air.
• Secure flex duct with metal tape, screws or wire ties.
Figure 3.9 Outside Air Installation
Note:
Chimney air kit and
11-10 in./279-254 mm
adapter are not shown,
but are required in Canada.
