Heatmor 200X - Wood as Fuel: Types and Moisture Content

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Our experience indicates that piece diameters of 6 to 8 inches or less are preferable. Larg-
er pieces (up to 10 inch diameter) will perform well as long as they are properly seasoned.
Fortunately, the combustion process will “see” a mix so that larger/smaller and damper/drier
wood combinations can still provide a good result.
Learn to load the furnace to most appropriately match the heat demand. Warmer outdoor
temperatures indicate a need for smaller loads and smaller pieces of wood, thereby match-
ing demand to supply and resulting in higher efciencies. Being aware of your individual
“Types of Wood” will aid in your decisions.
How does a re burn out?
When the temperature of the water has reached its high limit (185 degrees Fahrenheit), the
combustion air blower(s) shut off. At this point, the re “banks”. When the air combustion
blower(s) turn back on, there may not be enough coals to restart the re. You will then need
to restart the re. If this situation occurs, you may want to transfer to your standard system
for better efciency.
A new unit will require the establishment of “bed of coals” which will aid in re-establishing
proper combustion. This may take a few burn cycles.
Please refer to the “Outdoor Wood Furnace Best Burn Practices” located on the
inside front cover of this manual.
NOTE: To obtain the high efciencies that the X Series is designed for, please follow these
guide lines:
The moisture content of wood is very important. Trying to burn “wet” wood is wasteful and
not recommended. When you burn “wet” wood, the moisture must be driven out of the
wood before it burns, so there is heat wasted on driving out this moisture.
One cord of Oak has roughly 26.5 Million BTUs of Energy in it.
If you burn this cord of oak when it has 23% Moisture Content you will get roughly 20.4MB-
TUs of energy. If you burn this cord of Oak when it has 40% Moisture Content you will get
roughly 15.37MBTUs of energy.
This means that roughly for every 5 cords of wood you burn at 40% Moisture Content
you will waste 1 cord just because the wood was not dry. HEATMOR™ is dedicated to
helping you burn your wood cleaner, and more efciently! We recommend burning wood
with a moisture content range of 17-25% in this furnace.
Types of Wood
There are different types of wood, classied by species, hard or soft, old or new, dry or
damp, even larger or smaller. All will burn satisfactorily as long as the proper moisture
content and heat load combinations are observed. Therefore, knowing your heat load
demands and our fuel supply characteristics is very important.
Wood as a Fuel
Wood as a fuel contains more moisture than most heating fuels. Therefore, proper
management of the process is more important. Heat is required to evaporate the moisture
from the fuel. Once moisture is evaporated, proper control of the remainder of the
combustion process is also required. At about 600 degrees Fahrenheit the wood will gasify.
At this point the fuel/air mixture is fuel rich. With proper “secondary air” introduction the fuel/
air mixture will