BURNiT WBS 40, 40kW

Solid fuel boiler Burnit WBS 40 for central heating of premises up to 250m². Constructed for solid fuel burning - wood, wood briquettes class B and coal.

€1,307.00 €1,089.17
Availability: In stock

Steel boiler with natural air feed, controlled by a thermostatic draught regulator. Solid fuel boilers WBS range in nominal output from 20 to 110 kW to satisfy the heating demands of medium to large sized spaces. They are engineered for burning solid fuel - wood, wood briquettes class B and coal, and provide the option for fitting pellet, oil or gas-fired burners. 


The boiler body is manufactured from high quality steel with 5mm thickness for the combustion chamber and 3mm thickness for the water mantle. The combustion chamber has a large heat exchanging surface and low chamber impedance. Large firebox door ensures easy loading even of large chunks of wood.


To increase the heat exchange, the combustion chamber's surface is ribbed and designed for a three-pass flue gas flow. The mantle completely envelops the firebox for maximized usage of the heat. The boiler's body is insulated from the external conditions by 50mm thick high temperature resisting wool. This series uses a thermostatic draught regulator that opens or closes a flap on the lower door, depending on the amount of air needed for the burning process.

Safety devices

For a safe and reliable operation of the boiler, a number of safety devices are installed

- Thermostatic draught regulator;

- Removable metallic ash grate protects the heat exchanging pipes and the chamber base from the flame;

- Pressure relief valve 3 bar incl.in the delivery set;

- Safety heat evacuator: a tap-water filled line passes through the uppermost part of the boiler body. In case of overheating it is triggered open by a thermostatic valve (not included) to evacuate the heat off the boiler.


The central heating boiler can operate with natural untreated wood, but also with coal and compressed solid fuels such as briquettes. Maximum length of the wood logs is between 330mm and 500mm depending on the model. Fuel moisture should be 20% or lower.

In order to use the maximum caloricity of the fuel, the wood logs should be dried for a prolonged period of time. High moisture levels reduces caloricity and the output power of the boiler.


This series of boilers is manufactured for burning solid fuel, with the option of adaptation to a different kind of fuel. This is possible by mounting a pellet, gas or an oil burner on the lower door opening. A flange is also needed to mount the burner (optional).

Schematic of the main features of a WBS wood boiler



1. Temperature indicator
2. Housing
3. High efficiency thermal insulation
4. Safety heat evacuator
5. Three-pass flue gas flow
6. Mantle
7. Combustion chamber
8. Metal grate
9. Ash-and-soot container
10. Burner flange
11. Flue
12. Hot water outlet
13. Thermostatic regulator
14. Air intake flap

This appliance complies with EN 303-5.

More Information
Warranty 2 Years
Weight (kg) 310.0000
Country of Manufacture Bulgaria
Heat output (kW) 40
Approximate heating surface (m²/ft²) 140-250
Approximate heating capacity (m³) 675
Dimension Depth (mm) 930
Dimension Width (mm) 624
Dimension Height (mm) 1115
Construction material Steel
Mantle volume (L) 96
Insulation boiler high efficiency thermal wool
Insulation doors high efficiency thermal wool
Combustion chamber volume (L) 94
Combustion chamber impedance (Pa/mbar) 15/ 0.15
Combustion viewer Yes
Pellet burner No
Operating pressure (bar) 2.5
Operating temperature range (°C) 65-85
Maximum water temperature (°C) 95
Min. return water temperature (°C) 60
Recommended fuel wood,humidity 20%, wood briquettes ; coal
Fuel Type Wood, Briquettes, Coal
Maximum length of the firewood logs (mm) 400
Flue (mm) 180
Required chimney draught (Pa/mbar) 23/ 0.23
More Information
Flue cleaning opening O : 150/70 mm
Exhaust gas temperature (operation mode), °C <150
Exhaust Location Back side
Control panel No
Control of central heating pump No
Combustion forced ventilation No
Automatic cleaning system No
Thermostatic draught regulator Yes
Temperature indicator Yes
Certification CE
Cold water inlet A : R 1 1/4''/ 430 mm
Hot water outlet B : R 1 1/4'' / 1145 mm
Distance of hot water outlet J : 312 mm
Height of Hot Water Outlet B : 1145 mm
Cooling loop Yes
Safety line sleeve K : G 1/2'' / 1045 mm
Safety heat evacuator inlet/outlet E : R 1/2'' / 1045 mm
Air vent I: Yes
Air intake flap V: Yes
Height of Flue Pipe F : 905 mm
Height of Water Drain Valve Y : 205mm
Drain Y : G 1/2'' / 205 mm
Burner flange (optional) Z : 176 mm
Ash and soot container X : Yes
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