11
5797 344 - 01
Vitoflex 300-UF Installation & Operating
Wood Fuel Requirements
Allowed fuels
- Forest wood and plantation wood (complete untreated trees and trunk wood):
Mature wood from trunks and branches, untreated, chopped to chips
- Compressed wood, pellets conforming to standards, as per CAN/CSA-B366.1-M91, size P1, P2, P4.
Untreated wood with limited bark content, compressed by machine and calibrated
Fuel
Minimal Diameter
Maximal Diameter
P1 - Pellets Small
---
e
in. (10 mm)
P2 - Pellets Medium
e
in. (10 mm)
c
in. (20 mm)
P4 - Briquettes (Pellets Large)
c
in. (20 mm)
2
b
in. (60 mm)
CAUTION
Chips have to pass through a 1 in. (25 mm) sieve,
additionally, a fraction of max. 5% of the fuel with a
cross-section of max.
c
in.² (500 mm²) up to a length
of max. 6
a
in. (160 mm) can be tolerated.
The Vitoflex 300-UF is only suitable for burning fuels
listed in this section. A prerequisite for approval is of
a fuel by Viessmann is the approval for the fuel by the
responsible public authorities.
Warranty claims for Viessmann Biomass boilers are
excluded if the following fuel conditions are not met.
- Wood with an increased proportion of bark, tree cuttings from roadside trees (untreated):
Wood remnants from the forestry and sawmill industries or from landscape conservation (likelihood of elevated ash content).
- Remnants from derived timber products:
Usually a mixture of untreated and treated wood in the form of shavings from processing machinery and chips from
choppers.
- Used wood:
This is untreated wood that has been used prior to its energetic utilization (e.g. pallets). It is reduced in size by
shredders for thermal utilization. The metal parts have to be removed by magnetic separators.
General Information
If different fuels are used, Viessmann will not assume any
liability for the functioning or service life of the boiler plant.
Refer to the “Warranty” section in the General Terms and
Conditions of Delivery.
- Burn wood only
- Do not use chemicals or fluids to start fire.
- Do not burn garbage, gasoline, naphtha, engine oil,
or other inappropriate materials.
IMPORTANT
Size of briquettes:
- Fraction of one-offs. max. 5% with cross-section of max.
c
in.
2
(500 mm
2
) up to a length of max. 6
a
in. (160 mm).
- Frayed surface by chopping tools (shredders) or slow-running choppers.
- Briquettes, diameter max. 2
e
in. (60 mm).
Consequences of overstepping particle size:
- Increased maintenance because of a substantially higher risk of malfunction
- Shortened service life of the conveyor augers and drives
Size of Wood Chips as per CAN/CSA-B366.1-M91, Grade C7
Total mass 100%
G 30 Fine
G 50 Medium
Coarse percentage max. 20%
Max. cross-section in.
2
(cm
2
)
b
(3)
c
(5)
Max. length in. (cm)
3
g
(8.5)
4
c
(12)
Coarse sieve nominal mesh width in. (mm)
f
(16)
1
a
(31.5)
Main percentage 60 to 100%
Medium sieve nominal mesh width in. (mm)
d
(2.8)
a
(5.6)
Percentage of fines
(incl. ultrafine content) max. 20%
Fine sieve nominal mesh width in. (mm)
1
/
25
(1)
1
/
25
(1)
