Pyroflex FFU

Underfeed firing system 180 to 850 kW

The underfeed firing system with double grate is specially suited for burning fuels such as scraps from wood processing (chipboard and MDF) and sawmill scraps. The resting fire bed results in low pollutant emissions even with fluctuating and proble­matic fuels.

Underfeed firing system FFU

State-of-the-art, highly robust firing technology

Logging and sawmill scraps
Saw shavings
Planing shavings

Minimal life cycle costs together with robust and reliable system engineering. MAWERA places the utmost importance on durability and a long lifespan for our systems.

Design and function

The complete insulation of the entire boiler system as well as the elaborate wall structure of the firing system guarantees minimal thermal radiation from the combustion chamber and high system efficiency.

The double grate design (outer and inner grate) is optimised for the fuel. The fuel is fully combusted by the outer grate of the firing system. The upper and lower air flows can be regulated separately. The fuel can be fed into the combustion chamber from the rear, right or left. The system supports fully modulated operation from 25 to 100%.

Robust quality

Solid steel construction and the use of high-quality refractory material guarantee reliable system availa­bility for many years. Thanks to frequency-controlled screws, drives and flue gas recir­cu­lation, we can guarantee minimal power consumption in all load states of the system.

Design and output ratings

Type Output range*
FFU 180 RIA 45 to 180 kW
FFU 220 RIA 55 to 220 kW
FFU 280 RIA 70 to 280 kW
FFU 350 RIA 87 to 350 kW
FFU 440 RIA 110 to 440 kW
FFU 550 RIA 137 to 550 kW
FFU 700 RIA 175 to 700 kW
FFU 850 RIA 212 to 850 kW

*Depending on fuel and water content

Pyroflex FFU

Model FFU 180 RIA FFU 220 RIA FFU 280 RIA FFU 350 RIA FFU 440 RIA FFU 550 RIA FFU 700 RIA FFU 850 RIA
Rated thermal output 180 220 280 350 440 550 700 850 kW
Length 2288 2288 2916 2916 2990 2990 2990 3730 mm
Width 1180 1180 1280 1280 1380 1380 1600 1700 mm
Height 2134 2134 2330 2330 2552 2763 2943 3105 mm
Operating weight 3464 3440 5325 5275 6606 8060 9425 13192 kg
Water volume 730 730 1075 1075 1546 1860 1925 3412 litres
Sectional drawing FFU
  1. 3-pass boiler (4.0 bar – higher pressure ratings on request)
  2. Safety heat exchanger (integrated into boiler)
  3. Combustion chamber with firing depression
  4. Injection of lower air
  5. Injection of upper air
  6. Injection of flue gas recir­cu­lation (optional)
  7. Automatic combustion chamber ash removal (optional)
  8. Fuel infeed right, left or rear
  9. Firebox door
  10. Pneumatic boiler cleaning (optional)

Profit from these benefits:

  • Minimal power consumption thanks to frequency-controlled screws and drives
  • Low pollutant emissions due to the resting fire bed even with MDF and chipboard
  • High efficiency of up to 92%
  • 3-pass flame tube-flue tube boiler with flue gas tempe­ra­tures below 190 °C at full load
  • Minimal operating actions required
  • Complete combustion of all fuels thanks to highly insulated, fully ceramic-lined combustion chamber and optimally designed combustion air injection
  • Integrated emergency heat exchanger for rapid control as per DIN 4751 Part 2
  • Sliding load regulation from 25 to 100% of the rated heat output in compliance with the emissions values


Example instal­lation

Carpentry workshop (solid wood floors and profile boards)

Firing system: Pyroflex FFU
Output: 440 kW
Fuel: Saw shavings, planing shavings and dust mixed with chips

Anlagenbeispiel FFU
  1. Fuel storage in a silo
  2. Fuel discharge with a pendulum screw
  3. Fuel transport with screw system
  4. Firing system: Pyroflex FFU
  5. Ash removal from the combustion chamber into 240 l container
  6. Coarse dust separation with multi­cy­clone separator
  7. Fine dust separation with electro­static filter

Areas of appli­cation

Wood industry

Local and district heating

Public developers