Vermont Castings Defiant Flexburn 1975 Owner's Manual page 12

Surface Thermometer is a Valuable Guide to Operation
An optional surface thermometer tells you when to adjust
the air control, and when to refuel, Figure 2.8.
Figure 2.8 - Take temperature readings with a thermometer located
in the middle of the griddle.
For example, when the thermometer registers at least
450°F (230°C) on the stove top after start-up you know the
stove is hot enough and it may be time to close the damper
if a sufficient ember bed has also been established. Note
that the stove will warm up much sooner than the chimney,
though; a warm chimney is the key to easy, effective stove
operation. When thermometer readings drop below 350°F.
(175°C) it's time to adjust the air control for a higher burn
rate or to reload the stove. A temperature reading over
650°F. (340°C) is a sign to reduce the air supply to slow the
burn rate.
Use the following temperature ranges as a guide:
• Readings in the 350°-500°F. (175°-260°C) range indicate
low to medium heat output.
• 500°-600°F. (260°-315°C) readings indicate medium
heat output.
• Readings of 600°-650°F. (315-340°C) indicate high
heat output. Operating your Defian
continuously at griddle temperatures higher than 650° F
(340°C) may damage the cast iron or enamel finish.
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.
Too much draft may cause excessive temperatures in the
Defian ® Flexburn 1975, and could even damage the stove.
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On the other hand, too little draft can cause backpuffing into
the room and/or the "plugging" of the chimney.
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 or low heat output.
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Vermont Castings • Defiant Flexburn 1975 Owner's Manual_R1 • 2021 - ___ • 08/21
In some newer homes that are well-insulated and weather-
tight, poor draft may result from an insufficient air supply
in the house. In such instances, an open window near the
stove on the windward side of the house can provide the
combustion air supply needed.
Another option for getting more combustion air to the stove
is to duct air directly from outside to the stove. In some
areas provisions for outside combustion air are required in
all new construction.
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 adjustment range outlined
in these directions.
8390-035C