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Fireplace Insert Installation (for qualified installers only) 21
© Travis Industries 100-01166 4040907
Block-Off Plate Installation
Whenever this appliance is installed with a direct connection a block-off plate, or other non-combustible
seal-off device (e.g. damper adapter), will need to be installed. This device is used to seal the chimney,
insuring no smoke enters the home and providing the chimney system with a seal to promote draft. The
directions below detail the steps for construction and installation of a block-off plate.
• Determine a location for the block-off plate at the top of the firebox below the damper area (make it
high enough to allow installation of the connection pipe). The location should be level and in an area
where it can be mounted easily. Measure the width at the rear ("A") and front ("B") of the firebox at
the height where the block-off plate will be installed (see Figure 20). Then measure the depth of the
location where the block-off plate will be installed ("C").
NOTE: Most masonry fireplaces have square fireboxes while certain zero-clearance (metal) fireplaces
often have domed firebox tops. This makes zero-clearance block-off plates more difficult to install.
To simplify the procedure, insulation may be used to seal the rounded edges.
• Make a cardboard template of the measurements, but add a 2" flange to each side. This flange will
be used to mount the block-off plate to the inside of the firebox. Bend the flanges downwards on the
template and place it inside the fireplace. If the template fits correctly in its planned location, go to the
next step. If it does not, make a new template with the appropriate corrections until it fits correctly.
• With the template in place, mark the location of the flue (see “Dimensions” on page 6). This location
approximates the center of the flue when the insert is in place (a slight offset may occur based upon
insert and block-off plate placement). Remove the template and cut a 6 1/4" diameter hole centered
on this mark.
• Make the block-off plate of 24 gage or thicker steel to match the template. Drill two holes in each
flange for mounting the plate.
• Mount the block-off plate using masonry screws.
NOTE: Use sheet metal screws on zero-clearance (metal) fireplaces (screws need only be long
enough to penetrate the first layer of metal).
• Insulate the block-off plate using high-temperature fiberglass insulation (Kaowool® or equivalent) and
furnace cement (allow the cement to dry for at least 24 hours before burning).
• After placing the appliance and installing the pipe through the block-off plate, use high-temperature
fiberglass insulation and furnace cement to seal any cracks between the pipe and block-off plate.
Firebox
A
C
B
See the
dimensions to
determine the
location of the
center of the
flue.
Damper
Measurement
"A"
Measurement "B"
2" Flanges
(for attaching
the block-off
plate)
Measurement
"C"
See the dimensions to determine the location of
the center of the flue.
Block-Off Plate Template
Figure 20