Vitoflex 300-FSR – wood combustion system with flat moving grate combustion

Take advantage of these benefits

  • Three-pass flame tube boiler or two-pass boiler with water wall with flue gas temperatures below 190 °C at full load
  • High efficiency of up to 92 %
  • Outputs: 850 to 13,000 kW
  • Minimal radiation losses thanks to complete insulation of the entire boiler system
  • Static firebed results in significantly lower emissions
  • Highly wear-resistant due to generously dimensioned grate area and water cooling of grate
  • Overlapping pre-tensioned grate rods ensure little fuel falls through the grate (continuous automatic ash removal)
  • Wood fuels up to M55
  • Integral backup heat exchanger for quick controllability to DIN 4751 part 2
  • Modulating load control from 25 to 100 % of rated output while adhering to emission levels
  • Staged combustion (low NOx combustion chamber)
  • Low loading of grate area reduces fuel costs

Vitoflex 300-FSR wood combustion system

The major benefits of flat moving grate combustion (type FSR) are the ability to use different fuels and a low dust concentration in the flue gas, due to the static fuel bed.

Low NOx reduction technology can be employed to best effect in flat moving grate combustion systems. The low NOx combustion chamber is equipped with primary-side features such as air staging to reduce NOx emissions.

Standard boilers are designed for a maximum flow temperature of 100 °C and a maximum permissible operating pressure of 6 bar.

Suitable wood fuels:

  • Forestry and sawmill wood remnants
  • Wood remnants from wood processing (chips and sawdust from planing, sawing and milling, dust)
  • Chipboard
  • MDF

Fuel moisture content

Moisture content M6 to M55

Fuel granulation

Version with screw conveyor feed up to P45S as per EN ISO 17225 and version with hydraulic feed up to P100 available on request


Product cross-section


850 to 13,000 kW
Annual hours in use
up to 6,000 hours
Chips, pieces of chipboard, pellets, residual forestry and sawmill wood, bark, chipboard, dust, waste wood from wood processing, residual wood from thinning
Fuel moisture content
10 - 55 %
Ash content
up to 6 %
Application range
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Local and district heating associations, combined heat and power generation, commercial nurseries, municipal and private property developers, recycling industry
Additional features
Low NOx combustion chamber, fully automatic ash removal, modulating load control from 25 % to 100 %, fuel supply via screw conveyors or water-cooled hydraulic feed, underfeed pushrod as standard, generous and very solid construction
Produktschnitt Holzheizkessel Vitoflex 300-FSR