M&G DuraVent Combustion Air Systems - Manual (Page 6)

Fig 3
For Thru-the-Wall
installations using a
chase enclosure,
provide an access
door for cleaning.
Maintain at least 8"
clearance between
CAS Stove Pipe and
ceiling
6
THROUGH-THE-CEILING
INSTALLATIONS
Step 1. Determine the location of the CAS
Ceiling Support. The CAS Ceiling Support is
installed instead of a standard Support Box.
The CAS Ceiling Support can support up to
50-ft of DuraTech chimney or up to 70-ft of
chimney when the optional support straps are
used. The CAS Ceiling Support should be
located directly above the stove if possible to
facilitate the installation of the CAS Connector
Pipe. If possible, use a plumb bob to ensure
the center of the Ceiling Support will be directly
over the stove’s outlet. If the CAS Ceiling
Support is not aligned with the stove outlet,
elbows will be required for the offset.
Step 2. Install CAS Ceiling Support. Cut
and frame an opening for the CAS Ceiling
Support. Refer to Table 1 for proper framing
dimensions. Install the CAS Ceiling Support
into the framed opening, and ensure the
Ceiling Support is level. The square portion of
the Ceiling Support must be a minimum of 2”
below the finished ceiling (Fig 1, 2). Secure
the Ceiling Support with at least (2) 1-1/2”
wood screws per side; minimum of (8) wood
screws total.
For most installations, the CAS
Ceiling Support can be left at full height (does
not need to be cut down), and it can act as
an insulation shield for the attic space. If the
CAS Ceiling Support is being installed into a
cathedral ceiling, the box can often be installed
connected directly to the roof rafters, and then
folded over and nailed down or trimmed to be
flush with the roof (Fig 4).
Alternatively, the CAS Ceiling
Support can be installed in a chase enclosure
that is placed directly against the outside
of the Ceiling Support and extends up to
Figure 3
Figure 4
FOR THRU-
THE-WALL
INSTALLATIONS
USING A CHASE
ENCLOSURE,
PROVIDE AN
ACCESS DOOR
FOR CLEANING
MAINTAIN AT LEAST
8" CLEARANCE
BETWEEN CAS
STOVE PIPE AND
CEILING
CUT AND FOLD SIDES OF CEILING SUPPORT TO BE FLUSH WITH
ROOF. SECURE WITH NAILS OR SCREWS AS DESCRIBED.