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New version
with external storage hopper. The smallest pellet boiler in Poland!

First in Poland automatic burner output modulation with 2nd Generation Fuzzy Logic controller reduces fuel consumption by up to 20% and improves energy efficiency.
Ecodesign 2020 A+ Energy Class 5 Class
A1 Pellets A1 Pellets/Oat
A1 Pellets A1 Pellets/Oat
This device is subsidised in these countries:

Poland Slovakia Bulgaria
Mini Bio B NE
10 kW 20 kW
Mini Bio B NE See product
  • Passive house Passive house
  • Single-family house Single-family house
  • Multi-family house Multi-family house
  • Small farm Small farm

Mini Bio B NE with external storage hopper combines a compact size boiler with a large 295 l storage hopper. Automatic burner output modulation with 2nd Generation Fuzzy Logic controller reduces fuel consumption by up to 20% and improves energy efficiency. Even greater fuel efficiency with ceramic burner and heat exchanger components.



High quality steel and the highest quality components guarantee many years of failure free operation. All new models are thoroughly tested for many months before marketing. All our boilers are individually tested for durability at min. 4 bar - a feature hardly ever found elsewhere.


Remote access to the heating system data, configuration of parameters through our website at from any device with internet browser.



We maintain an extensive service network. Over 200 qualified service engineers provide warranty and post-warranty services in Poland and abroad.



Even the best boiler isn’t enough. We offer complete boiler room and heating system solutions. We offer advanced solutions including pellet storage, pneumatic fuel feeding, cascade automation, weather compensated CH system control, DHW and buffer tank control, return protection, fuel and ash sensors, heat pump, solar panel and gas boiler control.

Tests and certificates

Our boilers are tested by an accredited testing facility - a member of the international Association of Accreditation..


The test results show that KOSTRZEWA products meet the emission requirements laid down in the Ecodesign Directive and guarantee user safety.


All boiler types undergo over 20 different tests including:


  • Boiler pressure test at 4 bar
  • Energy-efficiency and emission tests at 10%, 11% and 13% fuel oxygenation
  • Energy consumption test in operation and standby mode
  • Operational test in a closed loop system without auxiliary safety devices
    Our boilers are included in the list of devices qualifying for a subsidy in many EU countries.


compact, silent and energy-efficient.


automatic burner start-up, automatic burner modulation with 2nd Generation Fuzzy Logic, flame control with a photocell, low thermal inertia during start-up and shutdown, low power input, burner temperature control for highest safety, three-stage start-up to prevent gas explosions, AUTOSTART after power loss - the current settings are stored, separate primary and secondary air ducts for reduced CO emission (emission levels similar to gas and oil burners), automatic cleaning function - automatic slag removal from the grate (not available in the gravity fed models), oats - burner design allows use of oats as a fuel, ceramic insert - reduced emission and higher efficiency.



Galvanized and machine manufactured pellet storage hoppers are used as intermediate stores. The storage hoppers can be refilled manually or automatically from another store using our Pellets Vacuum system. With different capacities available, the boiler can be installed anywhere in the boiler room and the operation time between manual refills can be extended. All boilers include a 295 l storage hopper as standard (up to 192 kg of pellet at 650 kg/m3 bulk density). Storage hoppers up to 1,460 l are also available.



A virtually maintenance-free pneumatic device feeding pellet at a large distance from the storage area directly to the boiler including multiple sensors for a fully automatic operation.  If MINIMUM level is detected in the buffer tank, it is immediately refilled to the MAXIMUM level. The device can also be timer programmed, i.e. the buffer tank will be refilled to the MAXIMUM level at a pre-set date and time.



Platinum Bio controller controls not only the boiler but also central heating system and domestic hot water. Adjustable blower power with 2nd Generation Fuzzy Logic controller.


Fuel feeding from the storage hopper, automatic feeder, ash removal, burner feeder, pressure blower, igniter, CH pump, DHW pump, mixing valve (optional) and heating element - igniter.

Mini Bio B NE
Object power selection
Boiler power Heating surface
m2 m3
10 kW 50-200 125-500
20 kW 100-300 250-750
Surface is provided at ceiling height of 2.5 m.
10 kW 20 kW
Flue draught mbar 0,15-0,20 0,15-0,20
Water capacity l 47 90
Maximum working pressure bar 2 2
Test pressure bar 4 4
Flue gas temperature at rated output °C no data* 111,2
Flue gas mass flow at minimum output °C no data* 74,8
Flue gas mass flow at rated output kg/s no data* 0,01158
Flue gas mass flow at minimum output kg/s no data* 0,00514
Flue connector diameter mm 127 159
Flow resistance at 10 K mbar no data* 21,8
Flow resistance at 20 K mbar no ata* 6,1
Rated heat output kW 10 20
Heat output range kW no data* 6-20
Efficiency at rated output % no data* 92,8
Efficiency at minimum output % no data* 91
Boiler class as per EN 303-5 5 5
Combustion time at rated output
(fuel calorific value: 17,280 kJ/kg)
h no data* 53
Temperature controller settings range °C 50-80 50-80
Minimum water return temperature °C 45 45
Fuel type Class Sawdust granulate (pellet made according to EN ISO 17225-2 class A1)
Test fuel used in the certification procedure - A1.
Also compatible with A2, B class pellet.
Storage hopper capacity l 295 295
Hopper dimensions mm 550x550 560x560
Power supply V / Hz / A 230 / 50 / 2 230 / 50 / 2
Power input at rated output W no data* 112
Power input at minimum output W no data* 33
Power input in STANDBY mode W 2 2
Maximum power input W 492 492
Maximum noise level dB 52 52

PELLET is a processed waste timber compressed under high pressure without use of any bonding agents.


PELLET CLASSES TO PN-EN ISO 17225-2:2014-07:

A1 - ash content ≤0.7% Premium quality product

A2 - ash content ≤1.2%

B - ash content ≤2%


PELLET - eco-friendly, high-energy clean fuel!

Ceramics is everywhere - the combustion chamber, the heat exchanger and the burner are coated with advanced ceramics to improve the combustion process and efficiency and to reduce the emission. During operation, the ceramics heats up to over 1,000°C to improve the biomass combustion efficiency.


Flue gas vortex generators retain energy inside the boiler.


Conrtoller - User Manual 1.91 MB
295 l tank installation manual 2.05 MB

Informacje zawarte na stronie internetowej nie stanowią oferty w rozumieniu art. 66 Kodeksu Cywilnego z dn. 23.04.1964 r. Księga pierwsza, Tytuł IV, Dział II.