Installation Guide
7
CEILING SUPPORTED 
1. Place Appliance: Position the appliance 
according to the manufacturer’s instructions. 
The ue outlet collar should be placed 
between the rafters or joists above, if possible.   
2.  Frame Support Opening: Drop a plumb 
bob to the center of the appliance’s ue outlet 
and mark this center point on the ceiling. Refer 
to Table 2 for specic framing and clearance 
dimensions. Mark appropriate cutting lines 
around the center point. Cut a square hole in 
the ceiling for the Support Box. Frame a level, 
square opening centered over the hole which 
you have cut. (Figures 3 and 4).
Figure 3
Figure 4 Figure 5
3. Install Support Box: For installation into 
a at ceiling, there is the option of the Round 
Support Box, the Flat Ceiling Support Box, 
the Square Ceiling Support Box , Reduced 
Clearance Support Box , or the CAS Ceiling 
Support. The CAS Ceiling Support is only 
used when installing the CAS system. Refer 
to the DuraTech CAS Installation Instructions 
for directions on how to install the remainder 
of the Combustion Air System.. The Flat 
Ceiling Support Box is primarily used for 
Oil Appliances and comes unpainted. For 
the Square Ceiling Support Box, Reduced 
Clearance Support Box, and the CAS Ceiling 
MINIMUM OF 3 
INCHES BELOW 
FINISHED CEILING
18 INCHES 
MINIMUM FOR 
SINGLE WALL 
STOVEPIPE
ADJUSTABLE FLASHING
CHIMNEY SECTIONS
ATTIC INSULATION SHIELD
ROUND TRIM COLLAR
FRAMED OPENING
ROUND SUPPORT 
BOX
CHIMNEY CAP
STORM 
COLLAR
JOISTS & FRAMING
3 INCH MIN REQUIRED 
BELOW FINISHED CEILING
3 INCH MIN BELOW 
FINISHED CEILING
ROUND SUPPORT BOX WITH 
SQUARE TRIM COLLAR
ROUND SUPPORT BOX WITH 
ROUND TRIM COLLAR










