53D9025
23
OUTSIDE COMBUSTION AIR PRECAUTIONS & RECOMMENDATIONS
Outside Combustion Air Recommendations
(continued)
1. Extremely long runs and numerous turns in the duct leading from the fireplace to the combustion
air assembly should be avoided. These conditions will increase the resistance to the free flow of
air through the duct. Refer to Figures 1, 21, and 22 for methods of installing the outside air for
combustion assemblies.
2. The combustion air assembly should be located at an exterior location, which is not likely to be ac-
cidentally blocked in any manner. The assembly should be located above the snow line to prevent
blockage by snow accumulation.
3. The combustion air inlet assembly should never be mounted in a garage or storage area where
combustible fumes such as gasoline might be drawn into the fireplace.
4. Combustion air can be drawn form the crawl space under a house when an adequate supply of air
is provided by open ventilation.
5. Do not take combustion air from attic space or garage space.
Figure 22
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Screw
Nail
Holes
Screws
AK4 Inlet Air Vent
Duct
Extending
3” min.
6” Diameter Hole
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Outside Air Control Lever
(Lift to Open, Pull Down
to Close)
Installing Model 403 Duct Connector
1. Push insulation back approximately 2” from the end of each duct.
2. Slip each duct over duct connector until an equal length of connector extends into each duct.
3. Place duck clamp over the end of each duct. Tighten duct clamp down snuggly.
4. Push insulation back into place and over duct clamp.
1
2
3
2“
App.
FP1906
Duct connector
8/08
Loop Disengaged
Clamp Around
Duct
Slip Band
Through
Housing
Snap Screw
Down and
Tighten
Band
Screw
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Approximately
2”
Duct Connector
Insulation
Duct Clamp
