DuraVent DuraTech 5-8 - Manual (Page 8)

8
3. Install Support Box: For installation into a
flat ceiling, there is the option of the Round
Support Box (Round or Square Trim Collar),
Flat Ceiling Support Box, Square Ceiling
Support Box, Reduced Clearance Support
Box, or the Combustion Air System (CAS)
Ceiling Support Box. 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 system. The Flat
Ceiling Support Box is primarily used for Oil
Appliances and comes unpainted.
For the Round support box, the trim mounts
flush to the ceiling with the bottom protruding
a min of 3” below the ceiling (Fig.7). For the
Square support box, the square face must
protrude a min of 2” below the ceiling (Fig.7).
Level the Support Box and secure it to the
framing using at least three 8-penny nails
per side (min. of 12 total). Alternatively, you
may use 1-1/2” #8 wood screws (min. of 12
total), instead of nails. After the Support Box
is mounted, secure the Trim Collar (round or
square) to the framing members using the (4)
1” long, round-head wood screws provided
Figure 9
Figure 8
REF FIG. 7 FOR MIN
DISTANCE BELOW
CEILING FOR
SUPPORT USED
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
(Fig.9). For installation into a cathedral ceiling,
you must use the Square Ceiling Support
Box or Reduced Clearance Support Box (or
the CAS Ceiling Support if installing the CAS
system) and the two-piece Trim. The bottom
of the square portion of the Support Box must
be a minimum of 2” lower (round portion is
then an additional 3” lower) than the finished
ceiling at the lowest side of the penetration
(Fig.9). Level the Support Box and secure it
to the framing using at least three (3) 8-penny
nails per side (minimum of 12 nails total), or a
minimum of (3) #8, 1-1/2” wood screws. Adjust
SQUARE SUPPORT BOX
WITH TRIM FRAME IN
PLACE
WOOD SCREWS ARE
REQUIRED
MINIMUM OF
2” BELOW
CEILING