Northland Crown Royal 1000 Installation And Operation Instructions Manual - page 20
operaTIon
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Pristine series installation and oPeration Manual • 2011
Understanding the Gasification Process of
the Pristine Wood Furnace
Wood gasification is an amazingly clean burning and
efficient process! It is a process where much of the
solid fuel is converted to gases. These gases ignite
and burn along with the solid fuel. A large percentage
of wood is converted into gases. In order to burn these
gases there must be the right amount of air, as well as
temperatures of well over 1000ºF (538ºC). Gasification
is accomplished in the Pristine furnace because:
a) air flow is engineered to provide the correct amount
of under fire and over fire air. This setting is calibrated
for burning seasoned wood;
b) temperatures high enough to burn the gases are
reached in the insulated chamber below the firewood.
A key factor in the gasification process is the wood itself,
the type of wood, the moisture content, diameter, length
and placement in the firebox. The Pristine furnace is not
difficult to operate using seasoned wood and by using
the following guide it will also work well even when using
less than ideal wood.
The gases in the wood are released when the wood
surface is exposed to the fire. The more surface area of
a piece of wood that is exposed and the drier the wood
is, the faster the gases are released. Example: A small
DRY piece of burning firewood will release gases much
faster than a large WET piece of firewood.
Scenario 1: in the case of the small DRY piece of
firewood which has a lot of exposed surface area, the
gases are released rapidly and the fire burns very hot
but it is starving for air due to the high volume of gases.
This will eventually create smoke.
Scenario 2: in the case of the large piece of WET firewood
that, in proportion to its mass, has little surface area
and will release gases slowly. In this case there is too
much air. The air is now cooling the fire resulting in blue
smoke and very little heat.
Generally speaking, when burning extremely dry
firewood, pieces should be over 5” (12.7 cm) in
diameter. If using high moisture wood, use pieces that
are less than 5” (12.7 cm) in diameter. It is good to mix
the dry and wet wood when possible. When using the
recommended seasoned wood, where the moisture
content is between 19% and 25%, the diameter of the
wood is not that important.
Scenario 1 is also created when stirring a hot fire. Scenario
2 is also created when firewood is too short in relation to
the length of the firebox. Correct length of firewood for
the Pristine Series 1000 is 18” - 25” (45.7 cm - 63.5 cm).
Stack wood pieces side by side. If pieces are short,
place them end to end making one long piece. Firewood
should be centered front to back over the brick slots.
Scenario 2 is also created when wood bridges in the
firebox. This is often due to wood with high moisture
or lack of careful placement of the wood. Scenario 2
is also created when starting up a cold furnace. Only a
small amount of wood is burning with a lot of excess air.
identifying smoke Verses Condensation
Mostly the exhaust from the chimney will be clear. There
are times soon after loading the furnace when a gray
vapour may appear. This vapour disappears soon after
leaving the chimney. This vapour is moisture being
released from the wood. Smoke is more blue in colour
and will not disappear as quickly as the gray vapour. On a
cold winter day what looks like smoke may only be vapour.
loading Wood into the Firebox
1. The right time to add wood is when there still is a
good layer of charcoal or wood left, but not so much
that it is difficult to stir.
2. Using the ash rake, gently pull the charcoal away from
the back of the firebox. Stir the charcoal sufficiently
so that ash falls down through the brick slot. Always
ensure that the brick slots are not blocked by ash
build-up. Place wood into the firebox, DO NOT throw,
as this may damage the brick lining.
Correct:
The firebox should be loaded with
wood of proper length. This will
lengthen the burn time.
incorrect:
The firebox loosely filled with irreg-
ular pieces of wood will decrease
burn time and may cause unneces-
sary bridging.