53D9041
23
B36LA & B36RA Woodburning Fireplaces
COMBUSTION AIR ASSEMBLY
Model OAC4 Combustion Air Assembly
1. Remove the cover cap from the 4” outlet opening location on the left or right outside surface of the fireplace. DO NOT
REMOVE THE COVER IF THE OUTSIDE AIR WILL NOT BE CONNECTED.
2. Fasten the 4” starting collar over the hole on the left or right side of the fireplace with the four (4) sheet metal screws
provided.
Figure 24
3. Cut a 6” diameter opening for model OAC4 in the outside wall covering where the model OAC4 outside grille is to be
located.
Figure 26
4. Select and cut a piece of duct of sufficient length to attach to the fireplace and protrude at least 3” beyond the face of
the wall to which the OAC4 inlet air box assembly will be attached. The duct may be cut with a standard pocket knife.
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.
5. If the duct is the insulated type, push the insulation back from one end of the duct approximately 2”.
Figure 27
6. Slip the exposed end of the duct over the flange tube of the fireplace.
7. Place the duct clamp around the exposed end of the aluminum duct.
8. Slip the band through the housing, then pull the band tight around the duct.
9. Snap the band locking screw down and tighten it with a screwdriver or nutdriver.
Figure 27
10.Nail or screw the combustion air assembly to the surface of the wall.
NOTE:
If the wall covering is brick or stone, use appropriate masonry fasteners. Mount the combustion air assembly
with “TOP” up to prevent rain from entering the assembly. Be sure the 6” diameter opening around the air duct is sealed
with insulating material to prevent cold air from entering through the wall. If it is necessary to splice the duct, a model
403 duct connector should be installed as described in Figure 26.
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Step 1
Attach outside air starting collar to
left or right side of fireplace with four
(4) sheet metal screws provided.
Attach Outside Air Starting Col-
lar to Fireplace
FP2173
Figure 25
Step 2
Attach outside air duct to starting
collar with duct clamp.
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Figure 26
6” Dia.
Hole
Clamp
Nail Holes
FP1904
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
Figure 27
FP1906
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Approximately
2”
Duct Connector
Insulation
Duct Clamp
FP1907
Figure 28
Combustion Air Assy. Model OAC4
Installation of the Model 403 Duct Connector
1. Push the insulation back approximately 2” from the end of each
duct.
2. Slip each duct over the duct connector until an equal length of the
connector extends into each duct.
3. Place a duct clamp over the end of each duct and tighten it down
snugly.
4. Push the insulation back into place and over the duct clamp.
