3.5 Permitted fuels
❒ Burn natural, seasoned, hard or soft firewood or wood-only manufactured wood
bricks in this appliance only, length between 18“ (46 cm) and maximum 21“ (52
cm)
Chemically treated or painted wood is unsuitable as fuel. The S3 Turbo boiler is de‐
signed for burning fire wood only. Wood briquettes or manufactured pure wood logs
can also be used as fuel provided they have a minimum cross section of 2.5 sq in (16
cm²). The fuel loading chamber can be filled to the top. Excessively small and com‐
pact pieces of wood or wood pellets are not suitable. Coal cannot be used as it de‐
stroys the combustion chamber!
The S3 Turbo is made to burn natural forest wood. Both hardwood and softwood are
suitable, but oak should not be burned as the only source of wood for long periods be‐
cause of its high acid content.
For effective gasification, the wood must be dry, i.e. moisture content 15-20%. Please
follow the instructions included with the moisture meter provided to correctly determine
wood moisture content. In addition to increasing the likelihood of generating creosote
in the boiler, burning wet wood uses a substantial amount of the wood energy to evap‐
orate the water present in the wood, reducing the available energy for heat. Using
non-approved fuels will result in lower efficiency, higher emissions and may cause
boiler components to fail prematurely and/or operate incorrectly.
The wood will dry out most quickly if it is cut into the appropriate length and split into
pieces 4 – 5“ (10 – 12 cm) thick. The best length is 21“ (52 cm) for the S3 Turbo boiler.
The wood is best stored in the open air under cover. Wood will dry most quickly if it is
carefully stacked alternatively lengthwise and crosswise so that air can penetrate into
the stack. Ideally the wood should be stored for at least one and a half years (two
summer seasons). Do not burn small pieces of wood or wood chips in the boiler as
they can block the combustion slot. Also, it can be difficult to control the combustion
process with small wood pieces and chips.
3.6 Non-permitted fuels
DANGER
Non-permitted fuels
Burning non-permitted fuels increases cleaning requirements and leads to a build-up
of aggressive sedimentation and condensation, which can result in damage to the
boiler and void the warranty! Using non-standard fuels can result in severe combus‐
tion malfunctions.
Only use the fuels specified in the section "Permitted Uses" in these operating in‐
structions!
❒ Do not burn corn, grain, coal, fuel coke, garbage or other residual materials,
painted or treated wood, bark, gasoline, diesel, fuel oil, naphtha, engine oil, drain
oil or other flammable liquids, or any other organic or inappropriate materials!
❒ Do not store fuel or other combustible material within marked installation clearan‐
ces. Keep away from boiler while it is in operation!
❒ Do not use chemicals, gasoline, gasoline-type lantern fuel, kerosene, charcoal
lighter fuel or similar liquids, or any other combustible fluids to start or rekindle the
fire in this boiler.
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Description of the boiler
Permitted fuels
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Froling GesmbH | A-4710 Grieskirchen, Industriestraße 12 | www.froeling.com
