Heating components


Maintenance burner and boiler

Maintenance and cleaning of the burner Atmos A25

The system for burning wooden pellets is designed in such a way to require minimum maintenance.

The necessary degree of maintenance directly depends on the set power of the burner and quality of used pellets.

CAUTION - Before starting repair or maintenance work during which you will handle the burner always turn off the power supply with the main switch of the boiler or disconnect to supply cable of the burner with the connector! 

Regular removal of ashes:

Burning of wooden pellets leaves approximately 1 to 2 % of ashes. In practice you will gradually find out how often the burner should be cleaned depending on the set power, intensity of heating and quality of used fuel.

Before the start of cleaning you must first shut down the burner and let the fuel burn out, best by reducing the temperature on the control thermostat or by turning off the burner switch on the boiler panel. The common interval of cleaning the burner mouth and boiler varies in the range of 7 to 30 days (after burning of 300 to 1000 kg of high-quality pellets). You should remove ashes from the burner mouth by removing the combustion chamber from the burner mouth and knocking it out. Then remove ashes from the combustion space of the boiler and clean the heat exchanger of the boiler (tube plate) as described in the boiler manual.

CAUTION - Always put ashes in a closed vessel. During the removal of ashes and cleaning of the combustion chamber use means of personal protection (gloves and protective goggles). 

Annual maintenance

  • At least once a year you must perform a complete check, maintenance and inspection of the burner during which the burner must be removed from the boiler.
  • During this maintenance remove and wipe the photocell that senses the flame.
  • Thoroughly clean the space under the combustion chamber of the burner and behind the ignition spiral. Disassemble the inlet pipe through which pellets fall to the burner and clean it.
  • Dismount the covering metal sheet of the burner mouth attached with one screw and clean the space under it where pellets fall and burn (scrape off dust and deposits). Clean the opening through which the photocell sees the flame.
  • Knock dust out of the flexible supply hose and visually check whether it is not perforated. In such a case repair it or replace. On that occasion check the worm of the external conveyor by inspecting it from the bottom where pellets fall into the flexible hose. Check whether is it not strangled by some objects, e.g. wound strings, a piece of wood, etc. that are sometimes found in pellets.
  • Then, assemble and seat everything in the boiler. Tighten all the connections.

Heating system maintenance including boilers Atmos DC15EP, DC18SP, DC25SP, DC32SP

Inspect at least once every 2 weeks. If necessary, refill the system with water. If the boilers are out of operation during wintertime, a risk of water freezing in the system arises. Therefore, we recommend letting all the water out from the system or fill it with an anti-freeze.

In other situations, only let water out if necessary and keep without water for as little time as possible. After the heating season is over, clean the boiler thoroughly and replace damaged parts.

Do not leave parts replacement for the last moment; prepare your boiler for the heating season as early as Spring

Use and inspections

Boiler operators must always follow the operation and maintenance instructions. Interventions into boilers that could endanger the health of the operators or other persons in the vicinity are prohibited. Boilers may only be operated by a person that is more than 18 years old, that has been acquainted with the instructions and operation of the equipment and that complies with the requirements of § 14 of the Directive no. 24/1984 Coll. The boiler operation needed increased attention to safety in terms of potential burns from hot boiler parts and systems. You must never leave unattended children near boiler that is in operation. During the operation of solid fuel boilers it is prohibited to use any flammable liquids for lighting the fire and it is also prohibited to increase the nominal output of the boiler during operation (overheating).

You must not put flammable objects on the boiler and near the fuel feeding and ash pan openings and ash must be stored in non-flammable containers with a lid. When handling fuel and ash, wear protective equipment (gloves, dust mask).

Boilers in operation must be under occasional supervision of the operator. The user may only carry out repair consisting in simple replacement of a spare part (e.g. a sealing cord, etc.). During the operation check the doors and cleaning openings for tightness and always tighten them properly. The user must not alter the structure and electric installation of boilers. The boiler must always be cleaned properly and in time so that free passage of all the ways can be guaranteed. Cleaning doors must always be properly closed.


Most of you already have some experience in using wood or wooden briquettes for heating either in boilers or fireplaces. These fuels are widely available at reasonably good prices. A new product, not yet known by all, is the so-called pellets, which are produced in a similar way as wooden briquettes by high-pressure pressing of waste wood (dry sawdust and chips) without any binder. Only pellets made of soft bark-less wood, i.e. "white pellets" which ensure trouble free and reliable operation of the boiler are considered quality pellets. At present, however, some producers add biological binding agents in order to increase solidity of the pellets for pneumatic transport. These pellets can be burned, but the amount of ash and poorly burned butts increases.

Pellets can be produced by the same way from hard wood or wood with bark so called dark pellets but these can cake in the burning chamber and can cause problems. Burners produced by our company can burn these pellets, but the firing chamber must be cleaned at least once per day. When burning high-quality pellets without binding agents or bark, the firing chamber should be cleaned once every seven or thirty days.

The most frequently used pellet size is with a diameter of 6 and 8 and a length of 5 to 25 mm. The heating value is approximately the same as for wooden briquettes, ranging from 14 to 19 MJ/kg.