6
GENERAL INFORMATION
Woodchuck furnaces represent the ultimate in solid
fuel and dual fuel heating appliances. From the mas
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sive model 4000 to the economy model 526, each unit
is designed to be attractive, durable and efficient while
providing the safety and comfort you and your family
deserve.
HIGH QUALITY CONSTRUCTION
Constructed of high grade, heavy gauge, hot rolled
steel plate, the firebox is continuously welded for an
airtight seal and structural strength. The heavy duty
cast iron doors are equipped with a positive latching
device for your safety. The loading door has a
two-step safety latch. The large cast iron grates pro
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vide for durability and help promote efficient combus
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tion of the fuel. The firebox is lined with heavy duty
firebrick and is done so without any retainers to warp
or burn out. These features together with high quality
electrical components provide the safety, efficiency
and total control possible only in a Woodchuck. Total
control means that you can better avoid overheating
the unit and developing excessive and unsafe temper-
atures.
Woodchuck furnaces are subjected to the most strin-
gent test criteria applicable by an independent third
party testing laboratory and listed/labeled as having
met or exceeded those standards. Finally, any ma-
chine, even this Woodchuck, is only as safe as the
person operating it. This is why we have compiled this
comprehensive manual to assist you in operating your
Woodchuck properly and safely. Please read and fol
-
low all instructions.
EFFICIENCY
The total efficiency of a unit is broken down into com
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bustion efficiency and transfer efficiency. We know
that when woodburning, 20% of it burns as fixed car
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bon. The other 80% is in the gaseous state as it burns.
Therefore, to obtain efficient combustion of the wood it
is necessary to introduce 20% of the oxygen “under”
the fire to promote combustion of the solid material
and 80% “over” the fire where it can readily react with
the gaseous material. Coal burns just the opposite of
wood. 80% of it burns as fixed carbon and 20% burns
in the gaseous state. Therefore, before a furnace can
burn coal or wood efficiently, it must provide the 80/20
ratio of combustion air and allow the operator to re
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verse the ratio depending on the fuel being used.
Combustion air must be warm when it enters the fire
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box to further promote complete combustion. Your
Woodchuck furnace provides all these features and
more. Here is how: when combustion air enters a
Woodchuck furnace it enters into a “draft
channel." Here it comes into contact with the hot fire
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box front and is warmed before entering the firebox.
The draft channel is equipped with adjustable orifices
which provide for the 80/20 distribution of the combus
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tion air. A lever on the front of Models 2900/4000 al
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lows for quick and easy adjustment of these orifices to
correspond to the fuel being used. As the air enters
the firebox it strikes a deflector which creates a turbu
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lence and causes the oxygen to mix thoroughly with
the gases for complete combustion.
Finally, Woodchuck Model 2900/4000 furnaces are de
-
signed to accept a catalytic combustor. This device will
cause the small amount of unburned fuel to ignite be
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fore entering the secondary heat exchanger. The ben
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efits of all this are threefold:
A.) You obtain very high combustion efficiencies,
meaning you use less fuel.
B.) You reduce the amount of unburned fuel that can
collect in your chimney as creosote and hence reduce
the hazard of a chimney fire.
C.) You virtually eliminate pollution of the air we all
breathe.
Transfer efficiency refers to how effectively we transfer
the heat generated inside the firebox to the rooms we
want to heat. Insufficient blower capacity will result in
poor transfer allowing the unused heat to escape up
the chimney. This is why we utilize a blower with such
large air handling capacity. The large surface area of
the firebox and secondary heat exchanger provide for
efficient transfer.
COMFORT
Comfort and efficiency are closely related. The more
efficient the heating system is, the more comfortable
you and your family are. Not only are the Woodchuck
furnaces efficient, they can actually increase the effi
-
ciency of your home.
On a furnace with a conventional single speed
blower, the speed of the blower is a compromise be
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tween comfort and efficiency. If the blower has a
large enough capacity to heat the home in the cold
-
est weather it will cycle rapidly in milder weather so
the system air is not as warm. If this air is moved too
rapidly it can actually feel cool. Air that is moving at
3 ft. per second will feel 4° cooler than stationary air
at the same temperature. If the blower capacity is