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20
Vermont Castings Defiant
Use the Air Control Settings
that Work Best for You
No single air control setting will fit every situation.
Each installation will differ depending on the quality of
the fuel, the amount of heat desired, and how long you
wish the fire to burn; outdoor air temperature and
pressure also affect draft.
The control setting also depends on your particular
installation’s “draft,” or the force that moves air from
the stove up through the chimney. Draft is affected by
such things as the length, type, and location of the
chimney, local geography, nearby obstructions, and
other factors. See pages 24 for details on how the
installation affects performance.
Too much draft may cause excessive temperatures
in the Defiant, and could even damage the combustor.
On the other hand, too little draft can cause
backpuffing into the room and/or the “plugging” of the
chimney or combustor.
How do you know if your draft is excessively high
or low? Symptoms of too much draft include an
uncontrollable burn or a glowing-red stove part. Signs
of weak draft are smoke leaking into the room through
the stove or chimney connector joints, low heat, and
dirty glass.
In some newer homes that are well-insulated and
weather-tight, poor draft may result from insufficient air
in the house. In such instances, an open window near
the stove on the windward side of the house will
provide the fresh air needed.
Another option for getting more combustion air to
the stove is to duct air directly from the outside to the
stove. In some areas provisions for outside combus-
tion air are required in all new construction.
With an optional outside air adapter, No. 1904,
your Defiant will accept a duct to deliver outside air for
combustion.
When first using the stove, keep track of the air
control settings. You will quickly find that a specific
setting will give you a fixed amount of heat. It may take
a week or two to determine the amount of heat and the
length of burn you should expect from various settings.
Most installations do not require a large amount of
combustion air, especially if adequate draft is available.
Do not for any reason attempt to increase the firing
of your heater by altering the air control adjust-
ment range outlined in these directions.
Use the following air control settings as a starting
point to help determine the best settings for your
installation. Each is described as a fraction of the total
distance the lever may be moved from right to left.
Defiant Control Settings
(see Fig. 21, page 15)
Burn Rate Primary Air Control
Low From far right to 1/3 the distance
to left
Medium From 1/3 to 2/3 the distance
to left
High From 2/3 the distance
to left, to far left
High-Efficiency Wood Burning
with Catalytic Combustion
A Defiant leaves the factory with the combustor
installed.
In the United States, it is against the law to operate
this wood heater in a manner inconsistent with operat-
ing instructions in this manual, or if the catalytic
combustor is deactivated or removed. The components
of the catalytic combustion system in your Defiant work
together to produce optimum conditions for secondary
combustion.
When the damper is closed, smoke travels through
the catalytic element, which causes ignition of smoke
at temperatures of 500-600° F (260-315˚C), half the
temperature normally required for unaided secondary
combustion.
The catalytic element is a ceramic “honeycomb”
coated with the catalytic material. The element is
located in the secondary combustion chamber, molded
from a special high-temperature insulating refractory
material. The chamber provides the correct environ-
ment necessary for secondary combustion of the fuel
(smoke).
Closing the damper exposes the smoke to the
combustor. If the combustor is at least 600˚F (315˚C),
it will begin to burn the smoke.
Closing the stove damper may also reduce the
draft, so to avoid putting out the fire or deactivating the
combustor, close the damper only when a fire is well-
established and the chimney is thoroughly warmed.
When starting a fire, wait until the fire is well estab-
lished and there is an ember bed of at least 3-4 inches
before closing the damper.
Never kindle a fire with colored paper or paper that
has colored ink or a glossy surface, and never burn
treated wood, garbage, solvents, or trash. All of these
may poison the catalyst and prevent it from operating
properly. Never burn cardboard or loose paper except
for kindling purposes. Never burn coal; doing so can
produce soot or large flakes of char or fly ash that can
coat the combustor and cause smoke to spill into the
room. Coal smoke also can poison the catalyst so that
it won’t operate properly.