Fine coal boilers

The KMK heating boilers with the underfeed stoker are fired with fine coal, with the heat output ranging between 80 and 700 kW. These boilers serve as the source of heat in the open-vented pumped central heating systems in municipal buildings, commercial and service pavilions, workshops and in particular, in glass houses and other structures intended for horticultural purposes.

The boilers are provided with the two-year manufacturer’s warranty and post-warranty service.

Characteristics of the KMK boiler:

  • thermal efficiency – 85%
  • made of long-life materials,
  • external thermal insulation,
  • adaptability of dimensions and parameters to customer requirements,
  • operation and maintenance adapted to the boiler house conditions,
  • modern controllers which allow the home control of the device.


KMK boilers are welded steel constructions made of high quality boiler plates with the thickness of 8 mm. The boiler insulation consists of a mineral wool layer with the thickness of 50 mm. The boiler is equipped with the underfeed stoker furnace.

The construction of the furnace in combination with the effectively operating control system guarantees high efficiency of fuel combustion. It has been obtained as a result of controlled fuel supply to the combustion zone by means of the underfeed feeder. The accurate mixing of the degassing products with the supplied air stream ensures the optimal course of the combustion process and the emission of pollution is at a very low level. Hot exhaust gases are directed to the highly efficient convection heat exchanger (the fire-tube or channel heat exchanger), where they are cooled down as a result of transfer of heat to the boiler water. This solution ensures the boiler operation with unlimited constant combustion time.

The operation of the boiler involves its single firing up, periodical fuel replenishment and ash space cleaning.



Specification Unit of measure KMK-250 KMK-400 KMK-600
Rated thermal output * kW 250 400 600
Minimum thermal output kW 70 110 150
Required chimney draught Pa 70 80 120
Maximum boiler water temperature °C 95
Maximum boiler water pressure MPa 0.2
Thermal efficiency % 86
Boiler heating surface m2 30 47 70
Boiler water capacity dm3 1100 1580 2200
Dimensions Height  – Hc ~1900 ~2250 ~2250
Width   – Bc mm ~1615 ~1740 ~1960
Length      – Lc ~3355 ~3560 ~3600
 10. Boiler weight kg 2900 4500 6000
 11. Basic fuel Hard coal, type 32.1, MI assortment, class 24/12
 12. Fuel consumption at nominal output** kg/h 45 70 100


* thermal output range at continuous operation of the fuel feeder and air fan.

** the data are indicative and are specified for the fuel’s calorific value amounting to 24000 kJ/kg and with the ash content in the fuel at the level of about 12%.