Enviro Venice - Manual (Page 19)

19
Installation
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If this unit is to be installed into a masonry fireplace or a zero-clearance fireplace with a direct connection
you must install a non-combustible seal-off device such as a block-off plate or damper adapter. By
installing a block-off plate you seal the chimney, ensuring that no smoke enters the home and sealing the
chimney to encourage draft. To construct a block-off plate follow the below steps.
1. Determine where the block-off plate will be installed; above the top of the firebox (it must be high
enough to easily install the connection pipe) but below the damper area. Look for a location that
A
B
C
D
Front of fireplace opening.
is level and in an area where the plate can be mounted
easily.
The measurement that will be needed are as followed (refer
to Figure 17 and 18):
A - The width at the front of the firebox at the height where
the block-off plate will be installed.
B - The width at the back of the firebox at the height where
the block-off plate will be installed.
C - Then depth of the block-off needed (the distance
between A and B).
D - The distance of the center of the flue to the front of the
fireplace opening. Refer to Step 3.
NOTE: In general masonry fireplaces have square fireboxes
while zero-clearance (metal) fireplaces have domed firebox
tops. Therefore zero-clearance block-off plates may be more
difficult to install. Insulation may be used around the edges
to simplify sealing the plate.
2. Create a cardboard template of the dimensions with 2” (51
cm) wide flanges on each side. These flanges 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. Continue on if the template fits correctly in
its planned location. If the template does not fit, make a
new template with the required corrections until it does fit
correctly.
3. With the template in place, mark the location for the center
of the flue pipe when the unit is in place. If installing a
1200-V the distance will be approximately 81⁄4” or 9 15 /
16
”
back from the fireplace opening. If installing a 1700-V the
distance will be approximately 123⁄4” or 14 7 /
16
” back from
the fireplace opening. Remove the template and cut a 61⁄4”
diameter hole centered on this mark.
4. Using the template make the block-off plate of 24 gauge or
thicker steel. Drill two (2) holes in each flange for mounting
the plate.
Figure 17: 3D of Dimensions needed from
the Fireplace.
Figure 18: Layout of the Block-Off Plate.