Fröling S1, S3 & S4 Turbo Log Firewood Boilers (15-60kW)

s4 log boilerOverview

Froling has been working with environmentally friendly, CO2-neutral heat from wood for almost 5 decades. Much of the currently accepted technology originated with us. Our experienced engineers have set themselves high targets for the S4 Turbo firewood boiler, and they have implemented them:

  • Optimal combustion for emissions and efficiency
  • Robust combustion chamber with long service life
  • Expanded automatic functions (e.g. automatic heat up)
  • User-friendly cleaning and ash removal
  • Modular control technology with bus system

A Design with Unique Benefits

  1. Top quality heat insulation.
  2. Generous cleaning openings for easy cleaning from the front.
  3. New bus control design with Lambdatronic S 3200 micro-processor control.
  4. Carbonisation gas extraction system for “smoke-free” reloading.
  5. Hot cladding for efficient combustion without a build-up of tar.
  6. Large fuel loading chamber for pieces of wood up to half a metre in length enables long reloading intervals.
  7. Automatic heat up with special air ducts for fast heat up (optional: automatic ignition device).
  8. New combustion chamber shape for the lowest emissions through a long combustion zone.


Introducing the new S1 Turbo Firewood Boiler

Froling’s new firewood boiler (15 – 20 kW) combines all the features of a state-of-the-art biomass combustion system. The speed-regulated induced draught fan ensures constant high quality combustion and the carbonisation gas extraction system prevents flue gas from escapin, even when topping up. The new S1 Turbo stands out for its high efficiency and long refilling intervals, combined with low emissions and low energy consumption.

The new air duct concept in Froling’s S1 Turbo firewood boiler automatically regulates the heating air, primary air and secondary air with a single actuator. Thanks to the special air ducts for heating up, the fuel loading chamber door can be closed very soon afer lighting. Heating with firewood can be that convenient!

s4ignitionUnique automatic heat up


  • Load the boiler, light the fuel, close the door and that’s it.
  • No smoke is produced in the boiler room.
  • Automatic ignition device (optional)

If you like ease of operation, you will love the automatic ignition device. Heating with firewood can be so easy!


s4smokeSpecial carbonisation gas extraction


  • No smoke escapes during reloading.
  • The boiler room stays clean



s4wosSerial efficiency optimisation system (WOS)


  • High efficiency
  • Easy cleaning from outside
  • Low energy consumption



For Technical Specifications and Further Information:

Download S4 Turbo PDF Brochure

Download S3 Turbo PDF Brochure


Video – Froling S4 – How It Works

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