13
61D1013
BUF Vent-Free Fireboxes
COMBUSTION AIR
W
ARNING
DO NOT remove the cover if the outside
air will not be connected.
The use of outside air for combustion is optional unless
required by building codes. It is only necessary to supply
outside combustion air to one side of the fireplace. Use the
model AK4 combustion air kit.
MODEL Ak-4 COMBUSTION AIR ASSEMBLY
1. Remove the cover plate from the 4" outlet opening loca-
tion on the left or right outside of the fireplace.
2. Place the insulation ring between the AK-4 starting collar
and fireplace wall.
3. Place the starting collar (4") into the hole on the side
of fireplace. Fasten it in place with the four sheet metal
screws provided.
Figures 15 and 16
NOTE: The air starting collar extends through the
fireplace outer wrap. When the air starting collar
is securely attached, it will form a seal against the
fireplace wall.
FP1900
OA start collar
8/08
Figure 15 -
Attach Outside Air Starting Collar and Insulation
Ring to Left Side of Fireplace
Insulation
Ring
AK-4 Starting
Collar
Sheet Meal
Screws
Left Side of
Fireplace
Shorter End
of Air Starting
Collar
4. Attach outside duct to starting collar with duct clamp or
screws.
Figure 16
5. Cut a 6-inch diameter opening for model AK-4 in the
outside wall covering where the outside vent is to be
located.
Figure 17
6. Select and cut a piece of duct long enough to attach to
the fireplace and stick out at least 3" beyond the face of
the wall to which the AK-4 inlet air vent will be attached.
Cut duct with a standard pocket knife.
Figure 16
FP2700
OA duct
Screws
Air Starting
Collar
Duct
Left Side of
Fireplace
FP2700
Figure 16 -
Attach Outside Duct to Starting Collar
FP1904
AK4 install
8/08
6"
Diameter
Hole
Duct
Extending
3" Min.
Screws
Nail
Hole
Screws
AK-4 Inlet
Air Vent
Figure 17 -
Combustion Air Assembly for Model
AK-4
FP1904
W
ARNING
Use Fp-4 U duct for maximum efficiency
and safety. Do not use a combustible duct.
Always use UL Listed Class 0 or 1 duct
material.
