Block-Off Plate Installation - Lopi Answer Owner's Manual

I
NSERT
P 18
AGE
B -O P
LOCK FF LATE
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.
1. 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 the illustration
below). 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.
2. 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.
3. With the template in place, mark the location that is centered in the fireplace and 9 1/4" back
from the fireplace opening. 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.
4. 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.
5. 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).
6. Insulate the block-off plate using high-temperature fiberglass insulation (KaowoolÒ or
equivalent) and furnace cement (allow the cement to dry for at least 24 hours before burning).
7. 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.
The center of
the flue is 9
1/4" back from
the fireplace
opening.
I
NSTALLATION
I
NSTALLATION
Damper
B
C A
Firebox
(C .)
ONT
2" Flanges
(for attaching
the block-off
plate)
The center of the flue is 9 1/4" back from
the fireplace opening (6 1/4" in diameter).
Block-Off Plate Template
Measurement
"A"
Measurement "B"
Measurement
"C"