29
Dutchwest Seneca
2006063
Single Venting
Your stove requires a dedicated flue. Do not connect the
stove to a flue used by any other appliance. Chimney
draft is a natural form of energy and follows the path of
least resistance. If the stove is vented to a flue that also
serves an open fireplace or another appliance, the draft
will also pull air in through those avenues. The additional
air flow will lower flue temperatures, reduce draft
strength and promote creosote development; overall
stove performance will suffer. The effect is similar to that
of a vacuum cleaner with a hole in the hose. In some
extreme instances, the other appliance can even impose
a negative draft and result in a dangerous draft reversal.
Fuel
Even the best stove installation will not perform well with
poor fuel. If available, always use hardwood that has
been air-dried ("seasoned") 12-18 months. Softwood
burns more rapidly than hardwood and has a high pitch
content conducive to creosote production. Decayed
wood of any type has little heat value and should not be
used.
All unseasoned (‘green’) wood has a high moisture
content. Much of its heat value will be used to evaporate
moisture before the wood can burn. This significantly
reduces not only the amount of energy available to warm
your home, but also the intensity of the fire and tempera-
ture of the exhaust gas. Incomplete combustion and cool
flue temperatures promote creosote formation and weak
draft.
You can judge the moisture content of wood by its
appearance and weight or use a commercially available
moisture meter for an exact measurement. Unseasoned
wood will be a third heavier than dry wood. Also, look for
cracks ("checking") in the ends of the log that result from
contraction as the wood dries. The longer and wider the
cracks are, the dryer the wood is.
Purchase your fuel from a reputable dealer.
Creosote
Creosote is a by-product of low-temperature stove
operation, weak draft, or both. It is a tar that results
when unburned gases condense inside the flue system
at temperatures below 290
°
F. Creosote is volatile and
can generate a chimney fire. All of the installation
characteristics that adversely affect chimney draft also
promote creosote condensation. Consequently, you can
minimize creosote accumulation with an effective
chimney design and the use of operational techniques
that encourage good draft and complete combustion.
Inspect your chimney frequently and clean it whenever
accumulation exceeds 1/4".
Backpuffing
Backpuffing is a condition that results when the draft is
too weak to pull flue gases out of the chimney system as
fast as the fire generates them. Volatile gases build up
within the firebox until reaching a density and tempera-
ture at which they ignite. With this ignition, you may hear
a muffled popping sound and see a bit of smoke forced
out of the stove.
This condition is most likely to occur in the Spring or Fall
when moderate outdoor temperatures and low intensity
fires produce weak draft. If your stove back-puffs, open
up the damper to let the smoke rise to the flue more
quickly. Also, open the air inlets to induce a livelier fire
and speed airflow through the stove. Avoid large loads of
firewood at one time. You should always see lively,
dancing flames in the firebox; a lazy, smoky fire is
inefficient and will promote draft problems.
Draft Testing
An easy way to determine whether your chimney draft is
strong enough is to close the stove damper, wait a few
minutes to let the airflow stabilize, and then test whether
you can vary the strength of the fire by swinging the air
control open and closed. Results here are not instant;
you may need to wait a few minutes for a change in the
air control setting to have an effect on the fire. If there is
no change, the draft is not yet strong enough to let you
close the damper. You will need to open it for a while
longer and manage the fire with the air inlet until the
draft strengthens. Keep a record of your operating habits
and relate them to their effects on the stove’s function.
You’ll be rewarded with safe and efficient performance.
Negative Pressure
Good draft also depends on a sufficient supply of air to
the stove. The chimney can’t pull in more air than is
available to it. Sluggish draft can be caused by a house
that is tight enough to prevent the ready flow of air to the
stove, or by competition between the stove and other
appliances that vent indoor air to the outside; i.e.,
exhaust fans for range hoods, clothes dryers, bathroom
fans, etc. If the chimney draws well when all such
equipment is turned off (or sealed, in the case of fire-
places and/or other stoves), you need to be attentive in
timing the use of the other appliances. If you need to
crack a nearby window or door to enable the chimney to
pull well, you should install an outside-air intake to bring
combustion air into the room.
Conclusion
Woodburning is more an art than a science. Art includes
technique; and since installations, homes, and fuel vary,
the stove operator must also vary technique, (mostly
timing), to achieve satisfying results. Over time, you will
become familiar with the features of your particular
installation; you will be able to identify cause and effect
in a variety of seasonal circumstances, and adapt your
operating habits to changing conditions.