KWK zębiec kocioł

*Zdjęcie poglądowe


Suitable for every building

The all-purpose KWK type boiler is a heating unit with the upper combustion of solid fuels. It is especially popular in private homes, but it is also installed in commercial spaces and individual shops. It is designed to burn such fuels as wood, hard coal, and coke.

Easy to use

Thanks to the unfailing upper-combustion design, every kind of fuel will be burnt almost completely. Fuel catches fire quickly and easily – it is enough to strike one match on the grate and fire will spread rapidly over the fuel. To ensure maximum efficiency of operation, we recommend fitting an automatic draught regulator. Also, the KWK boiler is fitted with a movable grate which can be easily emptied of ash.

Heat efficiency reaching 82%

The KWK from ZGM ZĘBIEC SA features a large combustion chamber enabling the burning of both hard coal and sizeable pieces of wood. The larger chamber can receive a bigger charge at one loading. The fuel charge burns evenly, ensuring a constant temperature in the heating medium. Simultaneously, with a view to enhancing heat transfer, the KWK boiler contains one extra path for the flue gas (the so-called water pocket) as well as a fixed water grate.

Only proven and durable materials used

KWK boilers are made only using proven and durable materials ensuring long service life. The use of certified boiler plates of 6 mm in thickness and an insulation mantle made of steel cassettes that are lined with mineral wool has a radical impact on the reliability of the design.

Option of automatic operation

The boiler is designed to accept a PID algorithm control module, which guarantees high accuracy of parameter control and reduces the user’s involvement to a minimum. However, the boiler is also the perfect choice for periods without electricity, using the natural air draught. Temperature can be adjusted using an air throttle located in the ash pan door, or an automatic regulator (the so-called draught regulator).

Large combustion chamber.

Designed for the self-assembly of the control kit, which is available as an option at an extra charge..

Combustion is controlled by means of an automatic draught regulator* or manually (*as an option at extra charge).

High combustion efficiency, up to 82%.

Certified boiler plates P265GH.

Szybkie i skuteczne odpopielanie dzięki ruchomemu rusztowi żeliwnemu.

60-month warranty for the leak-tightness of the water jacket.

24-month warranty for service life and efficient operation.

węgiel i koks opałowy
drewno paliwo
Hard coal Hard coal + coke Wood


By means of a screw adjusting the position of the flap in the lowest door


By means of a draught regulator

Instrukcja obsługi – Seria KWK KWK 12 – etykieta energetyczna KWK 16 – etykieta energetyczna
KWK 25 – etykieta energetyczna    

kwk zębiec

BOILER Height Width Depth A B C Flue Burning chamber Charging hole E
D height width depth width height
KWK 12 1014 320 650 253 886 1058 Ø 130 230 214 376 146 199 381
KWK 16 1025 382 686 253 878 1070 Ø 170 290 276 376 212 167 447
KWK 25 1140 506 752 280 1001 1185 170X170 290 400 397 317 197 570
Lp Detailed data Jedn. miary KWK 12 KWK 16 KWK 25
1 Rated thermal output kW 12 16 25
2 Standard fuel hard coal
3 Charge capacity of the burning chamber dm3 19 30 47
4 Boiler water capacity dm3 30 35 58
5 Max. water temperature °C 95 95 95
6 Min. required draught Pa 22 24 25
7 Min. chimney height m 5 5 5
8 Max. operating pressure bar 1,5 1,5 1,5
9 Min. chimney cross-section area cm ´ cm

Æ cm


Æ 14

20 x 14

Æ 18

20 x 14

Æ 20

10 Flue diameter mm Æ130 Æ170 170×170
11 Heat efficiency with standard fuel at rated power % do 82 do 82 do 82
12 Net weight kg 157 185 285
13 Overall dimensions height


depth (incl. flue)













ZĘBIEC boilers Thermal output Heated floor area [m2], based on the heat transfer coefficient of the walls (insulation)
U 1 [W/m2K] U ~ 0,7 [W/m2K] U ~ 0,5 [W/m2K] U ~ 0,3 [W/m2K]
no insulation ~5cm styrofoam ~8cm styrofoam ~10cm styrofoam
KWK 12 12 105 120 140 185
KWK 16 16 135 160 190 245
KWK 25 25 215 250 295 385

Draught regulator

A draught regulator in solid-fuel boilers is a thermostatically operated device for controlling the water temperature in the boiler.
The thermostatic head of the regulator monitors the water temperature in the boiler and via levers and a chain actuates a flap to increase or reduce the airflow into the hearth.


ST-81zPID controller

The ST-81zPID controller continuously regulates the induced air inflow and the central heating and utility water pumps.
It is fitted with boiler temperature and exhaust gas sensors. It is made from high quality materials, which are resistant to high and low temperatures.