Draft Management - Vermont Castings 1920 Installation & Operating Manual

Safety Tips:
Conveniently locate a "Class A" fire extinguisher to contend
with small fires. Be sure the fire extinguisher works and
is clearly visible. All occupants of the house should know
where it is, and how it operates. Have heavy stove gloves
available near the stove. Have special safety accessories
(e.g., Child Guard Screen) available for use if small children
will be in the home.
In the event of a stove pipe or chimney fire....
• Evacuate the house immediately
• Notify the fire department
• If the fire isn't too threatening, closing down the stove
tight, (primary air, all doors) will help to smother the fire.
• Inspect your stove, stove pipe and chimney for any
damage caused by the fire and correct any damage
before using your stove again.
DO NOT USE CHEMICALS OR FLUIDS TO START THE
FIRE. DO NOT BURN GARBAGE OR FLAMMABLE
FLUIDS SUCH AS GASOLINE, NAPTHA, OR ENGINE
OIL. Also, never use gasoline-type lantern fuel,
kerosene, charcoal lighter fluid, or similar liquids to
start or "freshen up" a fire. Keep all such liquids well
away from the Aspen while it is in use.
Caution: the Aspen will be hot while in operation.
Keep children, clothing and furniture away. Contact
may cause skin burns.
DO NOT OVERFIRE THIS HEATER. Overfiring may
cause a house fire, or can result in permanent damage
to the stove. If any part of the stove glows, you are
overfiring.
!
This wood heater has a manufactured-set minimum low
burn rate that must not be altered. It is against federal
regulations to alter this setting or otherwise operate this
wood heater in a manner inconsistent with operating
instructions in this manual.
C. Draft Management:
Your stove is only one part of a system that includes the
chimney, the operator, the fuel and the home. The other parts
of the system will affect how well the stove works. When there
is a good match between all the parts, the stove works well.
Save These Instructions
WARNING
Vermont Castings • Aspen 1920 Owner's Manual_R32 • 08/17
Wood stove operation depends on natural (unforced) draft.
Natural draft occurs when exhaust gas is hotter (and therefore
lighter) than the outdoor air at the top of the chimney. The
greater the temperature difference, the stronger the draft.
As the hot exhaust gas rises out of the chimney it generates
suction that draws air into the stove for combustion. A slow,
lazy fire with the stove's air inlets fully open indicates a weak
draft. A brisk fire, supported only by air entering the stove
through the normal inlets, indicates a good draft. The inlets
are passive; they regulate how much air can enter the stove,
but they do not move air into it.
The efficiency of a modern woodburning appliance, (in which
the amount of air available for combustion is regulated),
depends on the chimney to keep exhaust gases warm all
the way outdoors. The characteristics of your chimney -
whether it is steel or masonry, interior or exterior, matched
or mismatched to the stove collar - determine how quickly
it will warm up and how well it will sustain the optimum
temperatures necessary to maintain strong draft and efficient
combustion. Here follows a description of various flue system
characteristics and related effects on stove performance.
Masonry Chimney:
Although masonry is the traditional material used for chimney
construction, it can have distinct performance disadvantages
when used to vent a controlled-combustion woodstove.
Masonry forms an effective 'heat sink' - that is, it absorbs
and holds heat for long periods of time. The large mass,
however, may take a long time to become hot enough to
sustain a strong draft. The larger the chimney (in total mass),
the longer it will take to warm up. Cold masonry will actually
cool exhaust gases enough to diminish draft strength. This
problem is compounded if the chimney is located outside the
home or if the chimney flue has a cross-sectional size larger
than the stove outlet.
Steel Chimney:
Most factory-made 'Class A' steel chimneys have a layer of
insulation around the inner flue. This insulation keeps the
smoke warm and protects the surrounding structure from the
high flue temperatures. Because the insulation is less dense
than masonry, the inner steel liner warms up more quickly
than a masonry chimney. Although steel chimneys are not
as attractive as their masonry counterparts, they are very
durable and generally outperform masonry.
Inside/Outside Location:
Because the chimney's function is to keep the smoke warm,
it is best to locate it inside the house. This location uses the
house as insulation for the flue and allows some radiant heat
release from the flue into the home. Since an interior chimney
does not continuously lose its heat to the outdoors, it takes
less heat from the stove to get it warm and keep it warm.
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