18 Harman Oakwood
3-90-08327R26_03/14
VENTING
Existing Masonry Chimneys
If you plan on using an existing masonry chimney, have it
thoroughly inspected and cleaned. Any faults which make
the chimney unsafe and unusable must be repaired prior to
use. These can include improper height, structural defects,
blockages, inadequate clearance to combustibles, unsealed
openings into other rooms of the house, signs of creosote or
smoke leakage, a loose or absent clean-out door, or absence
of a liner.
DO NOT CONNECT TO ANY AIR DISTRIBUTION
DUCT OR SYSTEM
Venting to a Masonry Chimney
When connecting to a masonry chimney, several provisions
are standard. First, whether the chimney connector is vented
to the chimney through a thimble or a breech pipe, neither
must pass beyond the inner surface of the chimney liner,
and both must be rmly cemented in place with refractory
cement. (A thimble is a masonry pipe which is inserted
through the chimney wall, and is frequently the preferred
method; a breech pipe is a piece of steel pipe used the same
way.) In Canada, a breech pipe has ridges or protrusions to
lock it rmly into the refractory cement. In either case, the
chimney connector vents to the chimney through the thimble
or breech pipe.
Using a thimble, the connector slides completely inside the
masonry to the inner edge of the ue liner, and may be easily
removed for chimney and connector inspection. A breech
pipe must extend at least 2" (50 mm) into the room, so the
connector can be attached with sheet metal screws.
Venting to a Masonry Fireplace Chimney
In some situations, a code compliant chimney originally used
for a masonry replace may be used to install your Oakwood.
In addition to the requirements found in the previous
paragraphs, it is important to be aware that all clearances
must be met, including those from the chimney connector to
combustibles — 18" (360 mm) to sides and 18" (450 mm)
to ceiling. Do not forget to include oor protection in your
plans. (See Clearances and Floor Protection in this section.)
Since many replaces have exposed wooden mantels and
trim, pay special attention to the clearances necessary to
these materials.
If your replace chimney is behind a combustible wall, you
must use an approved wall pass-through system to gain
access to the masonry chimney. The chimney connector
must enter the chimney at a place where it is lined, and
the replace must be made inoperable. For example, you
might remove the damper, replacing it with a secure, airtight,
noncombustible seal, like a steel plate (removable for
inspection); this also satises the requirement that no room air
must be allowed to enter the chimney. Kaowool, mineral wool
or equivalent non-combustible insulation may be installed on
top of the plate to help minimize condensation. (Install a rain
cap on the top of the chimney).
Installing to a Prefabricated Chimney
When venting your Oakwood using a prefabricated chimney,
be sure to contact local building code authorities, and to
follow the manufacturer’s instructions exactly. Use only
the manufacturer’s parts; do not use makeshift installation
techniques. All prefabricated chimneys must be tested to
either the U.S. or Canadian high-temperature standards, UL
103 or ULC-629.
Chimney
Connector
Clay thimble, reaching
just to the inside of the
chimney liner
Mechanical fasteners
(minimum 3) but not at the
bottom of the connector
Chimney liner
inner edges
High-temperature
sealant used to cement
the clay thimble
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