18
CHIMNEY DRAFT
The chimney is critical to the proper operation of the stove. It is the chimney that creates draft; THE STOVE DOES NOT
AND CANNOT CREATE DRAFT. The chimney provides two vital functions for proper stove operation. First, it is the pas-
sage to exhaust smoke and hot gases created in the combustion process. Secondly, it supplies the draft (or pressure) to
bring oxygen to the
fi
re to sustain combustion. Draft is the natural movement of air or gases through a chimney. Chimney
draft comes from the natural tendency for hot (less dense) air to rise. As the hot air rises within the chimney it creates a
lower pressure at the bottom of the chimney to which the stove is connected. The higher pressure air outside the stove
then rushes into the stove where the lower air pressure level exists, thus bringing oxygen to the
fi
re. This constant
fl
ow of
air is referred to as the draft. Many factors or combination of factors can act together to build or impede the draft. Without
the correct amount of draft, the stove will not operate properly. If there is excessive draft, an unsafe condition will arise
with too much air being drawn into the stove and creating an excessively hot
fi
re. This could cause over
fi
ring which runs
the risk of igniting structural elements around the stove and chimney. The most common experience is that of insuf
fi
cient
draft. Under insuf
fi
cient draft conditions, the
fi
re will be starved for oxygen, improper or incomplete combustion occurs
resulting in smoke spillage into the area around the stove. A
fi
re that is starved for oxygen will not burn well. Such a
fi
re
will produce excessive smoke that will cool and condense in the chimney creating creosote. Excessive amounts of creo-
sote buildup can ignite causing a chimney
fi
re with the possibility of structural elements igniting as well. Correct any draft
related issues before using the stove. The following are some possible causes of insuf
fi
cient draft. Please note that one or
more factors may play a role in a draft issue and certain factors may change over time as conditions vary.
1. Atmospheric Pressure and Air Supply
Atmospheric pressure that affects the draft may occur from outside the structure, inside the structure, or both. High
pressure weather (clear and cold) usually produces a better chimney draft than low pressure (overcast and damp)
conditions. Negative pressure can be created inside a home by appliances that expel air from within such as bath-
room vents, range hoods, clothes dryers, and forced air furnaces. Do not allow such appliances to overcome the
natural draft. Note that newer homes tend to be built more tightly allowing less make up air to seep freely in. Negative
pressure may be overcome by opening a nearby door or window. In extreme conditions of negative draft, the air
fl
ow in
the chimney will reverse direction. This is known as “down drafting.”
2. Environmental
Factors
Wind or air de
fl
ecting off external objects such as the roof, neighboring structures, trees, or hills. These can cause a
pressure change in the air surrounding the chimney.
3. Chimney
Temperature
The temperature of the chimney is an important factor in how well it drafts. Warm chimneys draft better than cold
chimneys. This is based upon the principle that hot air rises while cold air sinks. Hot gases going up a cold chimney
will cool rapidly. Warm the chimney by allowing a hot
fi
re to burn for the
fi
rst
fi
fteen to thirty minutes after starting
the
fi
re. Be careful not to over
fi
re the stove. If any part of the stove or chimney starts to glow, you are over
fi
ring the
WARNING: IN CASE OF CHIMNEY FIRE:
(1) CLOSE ALL AIR INLET CONTROL(S)
(2) GET OUT OF THE HOUSE
(3) CALL THE FIRE DEPARTMENT
SERVICE HINTS
fi
re. As a result, creosote residue accumulates on the
fl
ue lining. When ignited this creosote makes an extremely hot
fi
re.
The chimney connector and chimney should be inspected at least once every two months during the heating season to
determine if a creosote buildup has occurred.
If creosote has accumulated (3mm or more) it should be removed to reduce the risk of a chimney
fi
re.
ASH DISPOSAL
Whenever ashes get 3 to 4 inches deep in your
fi
rebox or ash pan, and when the
fi
re has burned down and cooled, re-
move excess ashes. Leave an ash bed approximately 1 inch deep on the
fi
rebox bottom to help maintain a hot charcoal
bed.
Ashes should be placed in a metal container with a tight-
fi
tting lid. The closed container of ashes should be placed on a
noncombustible
fl
oor or on the ground, away from all combustible materials, pending
fi
nal disposal. The ashes should be
retained in the closed container until all cinders have thoroughly cooled.
SMOKE AND CO MONITORS
Burning wood naturally produces smoke and carbon monoxide(CO) emissions. CO is a poisonous gas when exposed to
elevated concentrations for extended periods of time. While the modern combustion systems in heaters drastically reduce
the amount of CO emitted out the chimney, exposure to the gases in closed or con
fi
ned areas can be dangerous. Make
sure you stove gaskets and chimney joints are in good working order and sealing properly to ensure unintended expo-
sure. It is recommended that you use both smoke and CO monitors in areas having the potential to generate CO.
