Pacific Energy DESIGN-D Installation And Operating Instructions Manual - page 4
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STEP.D1 090709-16
Creosote
Formation and Need for Removal
When wood is burned slowly, it produces tar and other or-
ganic vapours, which combine with expelled moisture to form
creosote. The creosote vapours condense in the relatively
cool chimney flue of a slow burning fire. As a result, creo-
sote residue accumulates on the flue lining. When ignited,
this creosote makes an extremely hot fire. The chimney
connector and chimney should be inspected periodically (at
least once every two months) during the heating season to
determine if a creosote buildup has occurred. If creosote
has accumulated (3 mm. or more), it should be removed to
reduce the risk of a chimney fire.
1. Highest smoke densities occur when a large amount of
wood is added to a bed of hot coals and the air inlet is
closed. The heated wood generates smoke, but without
ample air, the smoke cannot burn. Smoke-free, clean
burning requires small fuel loads, two or three logs at
a time or 1/4 to 1/2 of fuel load and leaving the air inlet
relatively wide open, especially during the first 10 to 30
minutes after each loading, when most of the smoke
generating reactions are occurring. After 30 minutes or
so, the air inlet can be turned down substantially without
excessive smoke generation. Wood coals create very
little creosote-producing smoke.
2. The cooler the surface over which the wood smoke is
passing, the more creosote will be condensed. Wet or
green wood contributes significantly to creosote forma-
tion as the excess moisture that is boiled off cools the
fire, making it difficult for the tars and gases to ignite,
thus creating dense smoke and poor combustion. This
moisture-laden smoke cools the chimney, compound-
ing the problem by offering the smoke the ideal place to
condense.
In summary, a certain amount of creosote is inevitable
and must be lived with. Regular inspection and clean-
ing is the solution. The use of dry, seasoned wood and
ample combustion air will help to minimize the buildup.
Chimney Fires
The result of excessive creosote buildup is a chimney fire.
Chimney fires are dangerous. Chimney inside temperatures
can exceed 2000° F. This causes much higher than normal
temperatures in the chimney and on its exterior surfaces.
Thus ignition of nearby or touching combustible material is
more likely during a chimney fire. Proper clearances are
critical during such a fire.
Chimney fires are easy to detect; they usually involve one
or more of the following:
-Flames and sparks shooting out of the top of the chim-
ney
-A roaring sound
-Vibration of the chimney
In Case of a Chimney Fire
1. Prepare to evacuate to ensure everyone's safety. Have
a well understood plan of action for evacuation. Have a
place outside where everyone is to meet.
2. Close air inlet on stove.
3. Call local fire department. Have a fire extinguisher handy.
Contact your local municipal or provincial fire authority
for further information on how to handle a chimney fire.
It is most important that you have a clearly understood
plan on how to handle a chimney fire.
4. After the chimney fire is out, the chimney must be cleaned
and checked for stress and cracks before starting another
fire. Also check combustibles around the chimney and
the roof.
- The services of a competent or certified installer, (certified
by the Wood Energy Technical Training program (WETT) -
in Canada, Hearth Education Foundation (HEARTH) - in
U.S.A.,) are strongly recommended.
Avoiding a Chimney Fire
There are two ways to avoid chimney fires:
1. Do not let creosote build up to a point where a chimney
fire is possible.
2. Do not have fires in the heater that may ignite chimney
fires. These are hot fires, such as when burning household
trash, cardboard, Christmas tree limbs, or even ordinary
fuel wood; (e.g.. with a full load on a hot bed of coals and
with the air inlet excessively open.)
3. The Chimney connector pipe should be disconnected
from stove to clean and inspect the chimney. Only if
this is not possible should you remove baffle assembly