CREOSOTE AND THE NEED FOR REMOVAL
When wood is burned slowly, it produces tar and other organic vapors, which combine with expelled moisture to form
creosote. The creosote vapors condense in the relatively cool chimney flue of a slow-burning fire. As a result, creosote
residue accumulates on the flue lining. When ignited this creosote makes an extremely hot fire.
The chimney connector and chimney should be inspected at least once every two months during the heating season to
determine if a creosote build-up has occurred.
If creosote a significant layer of creosote (1/8 inch, 3mm or more) has accumulated it should be removed to reduce the
risk of a chimney fire.
CAUTION: Increase the minimum fire only as much as necessary to reduce the formation of tars. Increasing the
minimum fire may cause overheating on warm days.
Establish a routine for the fuel, wood burner and firing technique. Check daily for creosote build-up until experience
shows you how often you need to clean to be safe. Be aware that the hotter the fire the less creosote is deposited, and
weekly cleaning may be necessary in mild weather even though monthly cleanings may be enough in the coldest
months. Contact your local municipal or provincial fire authority for information on how to handle a chimney fire. Have a
clearly understood plan to handle a chimney fire.
Creosote is caused from the condensation of the vapor that exists within the escaping smoke – drier wood is less likely
to form creosote. The density of the vapor is dependent upon the moisture content of the gases in the flue. The hotter
the escaping gases in the chimney, the less creosote formation you will have. A well-constructed chimney with smooth
liners and a flue that is well insulated from the colder air is best. Chimneys built with porous brick, or ones with loose
brick, or ones constructed with stovepipe are undesirable because the colder air condenses the escaping gases much
more rapidly than they are in a well-constructed chimney.
The formation of creosote could also be caused by a severe downdraft condition caused from taller objects surrounding
the chimney such as a hill, trees, other buildings, or chimneys of poor construction.
Under such conditions, the cold air drifts into and down the chimney, chilling the escaping vapor within the smoke below
the dew point and depositing this residue on the inside of the chimney walls.
It is important that you inspect the chimney connector and chimney flues more frequently than every 1 to 2 months until
you see what pattern of deposition is occurring.
WARNING: If wood with a high pitch content is used or the chimney is not properly constructed or insulated or if the
chimney connector is excessively long or has several elbows or turns, more frequent inspections must be made.
If creosote is a problem, the following may reduce it:
1. Dry wood.
2. More frequent refueling.
3. Avoid prolonged operation of the heater with the thermostat at its lowest setting.
4. Use logs as large as possible.
A CAUTION NOTE ABOUT CHIMNEY FIRES
If you suspect a chimney connector or flue fire, you should reduce all combustion air to a minimum.
Turn the heater thermostat knob to LOW. Make sure that the loading door (and the ash door on the NC100 and
NCM120 Classic heaters) is completely closed and secure. If necessary call you local fire department. Do not take
down the flue pipes until the fire has been completely extinguished.
When wood is burned slowly such as under low fire conditions, tars are formed in the flue products. These tars, in time,
are deposited on the inside of the flue and chimney pipe. With enough build-up these tars can ignite and cause a fire
inside the chimney until the burnout is complete. A listed chimney is sufficient to contain the fire, but distortion can
result. If such a burnout should occur, your chimney should be inspected immediately and any deformed, warped or
otherwise distorted parts replaced before further use.
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