Vermont Castings Montpelier Medium Insert Owner's Manual page 6

Be aware that a chimney originally designed for fireplace use
may perform differently when used to vent an air-controlled
appliance such as your Montpelier Medium Insert - even if
the flue is less than 3 times larger than the flue collar. For
example, a chimney on an outside wall may not heat up
enough to sustain an adequate draft. Such a flue can often
be improved if it is relined to reduce its size and/or insulated
to keep it warmer.
• A positive flue connection must be made between the
Insert and the first masonry tile or prefabricated metal
chimney section. A positive flue connection consists of
a plate that seals or replaces the fireplace damper and
a section of chimney connector that passes through the
plate into the chimney.
• The chimney connector must be a minimum equivalent to
a 6" (152 mm) diameter opening and must be 24 gauge or
heavier stainless steel. The connector must extend four
(4) feet measured from the collar of the insert.
Chimney Connection systems are available from a variety
of manufacturers. Your Vermont Castings dealer can
recommend a system that will best meet the requirements
of your particular installation.
Sealing Requirements / U.S.
• The chimney must be sealed off from room air, either by
a plate at the damper level or by sealing the fireplace
opening.
• Unused openings to the flue must be sealed with masonry
to the thickness of the chimney wall. Openings sealed
with pie plates or wallpaper are a hazard. In the event of
a chimney fire, flames and smoke may be forced from the
openings.
Canada
In Canada (CAN/CSA-B365-M91, Section 5), if installed
in a masonry fireplace:
• This fireplace insert must be installed with a continuous
chimney liner of 6" (152 mm) diameter extending from the
fireplace insert to the top of the chimney. The chimney
liner must conform to the Class 3 requirements of CAN/
ULC-S635, Standard for Lining Systems for Existing
Masonry or Factory-Built Chimneys and Vents, or CAN/
ULC-S640, Standard for Lining Systems for New Masonry
Chimneys.
• The opening of the fireplace around the insert must be
sealed to prevent room air passing to the fireplace cavity.
• Existing air-circulation chambers in a fireplace with a steel
liner may not be blocked.
• Provision must be made for removal of the insert to clean
the chimney flue.
• The existing fireplace damper (if any) should be locked
in the open position.
6 Vermont Castings • Montpelier Medium Insert Installation & Operating Manual_R26 • 05/19
• A permanent metal warning label must be affixed to the
back of the fireplace stating the fireplace may have been
altered to accommodate the insert, and may be unsafe to
use as a conventional fireplace. (A Fireplace Modification
Tag is included in the hardware bag inside the Montpelier
Medium Insert.)
Minimum Fireplace Dimensions
The Montpelier Medium Insert will fit most fireplaces. To
confirm that it will fit yours, measure the lintel depth, plus the
height, width, and depth of your fireplace and hearth. Compare
them to the measurements in the accompanying chart. If
you choose to install a new hearth over an existing fireplace
hearth, be sure to take its thickness into consideration when
measuring both front and back height of the fireplace and
clearances to any existing trims and mantels.
The unit can be installed virtually flush with the fireplace
opening or it can extend 3" (76 mm) onto the hearth using the
optional 3" Hearth Extension Kit. Figure 3 gives minimum and
maximum dimensions for fireplaces which will accommodate
the Montpelier Medium Insert in the flush mount configuration
and using the optional extension kit.
NOTE: The clearance between the Montpelier Medium Insert
and the mantel, top trim and side trim cannot be reduced by
installing shields.
Another requirement to consider is the clearance for movable
items such as tables, bookcases, rugs, furnishings, and your
woodbox. All combustible materials of this type should be
a minimum of 48" (1220 mm) from the front surface of the
Montpelier Medium Insert. Be sure that family members are
aware of this requirement as well, so they too will keep objects
a safe distance from the Montpelier Medium Insert.
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