HDG M300-400 (Wood Chip)

Proven technologies and clever innovations make the HDG M300-400 a "power cube".

Log wood
Wood chips
Power levels: 310 kW, 350 kW, 400 kW
  • Inside view of the boiler












    1 - PLC control
    2 - Lambda sensor
    3 - Special combustion chamber
    4 - Innovative stepping grate
    5 - Automatic cleaning system
    6 - Automatic ash removal
    7 - Primary and secondary air
    8 - Overfill protection
    9 - Relaxation zone
    10 - Combustion chamber temperature sensor
    11 - Walk-in access
  • Technical data





    Nominal thermal power (kW) 300 350 (375 in pellet mode) 400
    Minimum thermal power (kW) 90 105 (112.5 in pellet mode) 120
    Flue gas temperature at nominal thermal power (°C) 150 160 170
    Flue gas mass flow at nominal thermal power* (kg/s) 0.185 0.221/0.229 0.257/0.245
    Water capacity (l) 3060 3060 3060
    Maximum permissible operating pressure (bar) 3 3 3
    Flue draught requirement (Pa) 10 10 10
    Maximum flow temperature (°C) 95 95 95
    Flue gas pipe connection (mm) 300 300 300

    Dimensions and weight





    Height without attachments (mm) 2316 2316 2316
    Width without attachments (mm) 2570 2570 2570
    Depth without attachments (mm) 2012 2012 2012
    Weight (kg) 5910 5950 5980

    * In the case of two specifications, the first refers to wood chip operation, the second to pellet operation.

Technology makes the difference

Climate-friendly heat on a grand scale

The HDG M300-400 is the ideal heating system where a high heat demand meets the most exacting requirements when it comes to efficiency and reliability. It combines proven technologies in combustion and control engineering with clever convenience functions to create a sophisticated wood heating system with great performance. An efficiency of up to 94 percent speaks for itself.

This makes the HDG M300-400 a "power cube" for a wide range of applications – also ideal for setting up carbon neutral municipal heating networks.

Unique 3-zone control

The 3-zone control system with combustion chamber temperature sensor, lambda sensor and negative pressure control, used for the first time, sets new standards. This is because the regulation of the combustion air has the greatest influence on the efficiency and emissions of the wood heating system.

In addition, the stepping grate with two primary zones guarantees efficient part-load operation with precise modulation from 30 to 100 percent. And all this with a consistently high efficiency of up to 94 percent.

SPS Wirkungsgrad

Combustion chamber temperature sensor

The combustion chamber temperature sensor provides the information for controlling the amount of material, ignition and, above all, the primary air supply. This is needed for pre-drying and outgassing of the fuel and provides the main air for combustion.

Lambda sensor

The lambda sensor measures the residual oxygen following combustion and therefore determines the values for the secondary and tertiary air. Both are admixed with the combustion gases at different times and therefore guarantee extremely clean combustion with the highest levels of efficiency.

Flue gas fan with negative pressure control

The speed-controlled flue gas fan is controlled by a negative pressure control and ensures a constant negative pressure in the combustion chamber. Fluctuating fuel properties and unfavourable flue conditions are therefore effectively compensated.

Maximum efficiency and low emissions

The geometry of the combustion chamber was developed together with the Fraunhofer Institute. The core of this is the integrated centrifugal separator with downstream slowdown and depressurising zone. Due to a 180° deflection, dust is already separated in the combustion chamber. Furthermore, the combustion control takes control right from the start phase and therefore guarantees almost smoke-free combustion.

Forced-flow heat exchanger

The layered flow of the heat exchanger optimises the heat transfer and guarantees maximum levels of efficiency. All heat exchanger surfaces are cleaned fully automatically, whereby the maintenance effort is reduced to a minimum.

Extremely clean and quiet

In normal operation, the combustion of the HDG M300-400 runs at low volume and, thanks to the integrated central ash removal system with the new and unique lower grate ash removal system for the removal of combustion ash as well as the fully automatic cleaning of all heat exchanger surface areas, the heating system virtually cleans itself. In addition, numerous ash removal systems are available for all requirement profiles.

Video of the HDG M300-400 with Vario feeding system

Find out how easy it is to heat with the HDG and experience our flexible wood chip boilers as used by our customers.

Please to watch this YouTube video.
Please to watch this YouTube video.

Absolute control

PLC combustion technology and system control with HDG Control

For control, we rely on the combination of PLC control and the new HDG Control:

PLC combustion technology

  • Continuous determination of reference variables via combustion chamber temperature sensor and lambda sensor
  • Constant adjustment of the optimum air and fuel quantity
  • Capacity control according to strict specifications ("QM heating plants")
  • Open for extensions (Mod-Bus, etc.)
HDG Control Systemregler

HDG Control

  • Integration of external heat sources, solar thermal systems, accumulators, heating circuits, mains pumps, domestic hot water preparation, etc.
  • Control of cascade systems and local heating networks
  • On request: Full web access and app for iOS and Android

From the warehouse to the boiler

Flexible delivery system and feeding technology for every area of application

A sophisticated delivery and feeding system is crucial for the safe and reliable operation of an automatic wood heating system. With clever innovations, the new HDG Vario system sets standards here.

  • Cut-Connection: Huge transfer opening between the auger and the rotary feeder reliably prevents material blockages
  • 4-chamber rotary feeder: Combines absolute back burn protection with minimum component stress due to low friction surfaces
  • Stoker auger with dosing container: The fuel dosage via light barrier guarantees an even material supply and constant output even with different fill levels in the warehouse

In addition, with several delivery systems for wood chips (flexi blade delivery system, hinged arm delivery system, walking floor delivery system, etc.) and pellets (suction system, auger), solutions are also available for fuel transport for every application.

Out of the boiler – into the bin

The right ash removal solution for every area of application

Depending on the area of application, various ash containers can be used. We work together with you to plan an individual solution.

Entaschung M-Serie Transparent
  • 80 litre ash box: Ideal for pellet operation and in confined spaces
  • 230 litre ash box with Euro interface: Ideal for agricultural enterprises. Can be transported using the front loader.
  • 120 or 240 litre ash bin: Ideal if the ashes are disposed of by a disposal company.
  • 400 litre dump body: Large volume for industrial use. Can be transported using the forklift truck.
  • "We heat our poultry fattening farm with wood from our own forest. Independent of speculation and in harmony with nature."

    Ramelsberger family