Osburn 900 Installation and Operation Manual
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4.4.6.4
Maximum Burn Cycle Times
The burn cycle time is the period between loading wood on a coal bed and the consumption of
that wood back to a coal bed of the same size. The flaming phase of the fire lasts for roughly the
first half of the burn cycle and the second half is the coal bed phase during which there is little or
no flame. The length of burn you can expect from your wood fire, including both the flaming and
coal bed phases, will be affected by a number of things, such as:
•
firebox size,
•
the amount of wood loaded,
•
the species of wood you burn,
•
the wood moisture content,
•
the size of the space to be heated,
•
the climate zone you live in, and
•
the time of year.
The table below provides a very general indication of the maximum burn cycle times you are likely
to experience, based on firebox volume.
FIREBOX VOLUME
MAXIMUM
BURN TIME
< 0.042 cubic meter
3 to 5 hours
0.042 m
3
to 0.056 m
3
5 to 6 hours
0.056 m
3
to 0.071 m
3
6 to 8 hours
0.071 m
3
to 0.085 m
3
8 to 9 hours
> 0.085 m
3
9 to 10 hours
Long burn times are not necessarily an indication of efficient wood fire operation. When you are
home during the day and able to tend the fire, it is preferable to build a smaller fire that might
provide three or four hours of heating than to fully load the firebox for a much longer burn.
Shorter burn cycles make it easier to match the heat output of the wood fire to the heat demand
of the space.
