Conversion of a coal or oil boiler to pellet. How to burn pellet in a coal boiler?

Heating with pellet is an environmentally friendly and economical alternative to coal and oil.

The simplest and at the same time the cheapest way to switch to pellet heating is to install a pellet burner in an already existing boiler, e.g. a coal boiler. 

Conversion of a coal boiler to pellet – where to start?

If you want to install a pellet burner in a coal boiler, you should first consult a chimney sweep. It is worth remembering that in such modernization the European standard EN 15270 is of key importance. Some chimney sweeps previously had doubts about such a burner replacement, but now, if the pellet burner complies with the mentioned standard, conversion of the boiler to pellet is possible.

Other important aspects are the requirements regarding the boiler and the chimney. It should be checked whether the following requirements are met:

• During boiler operation, the chimney draft must be at least 15 Pa.
• The chimney must be resistant to soot fire. It may be necessary to use a heat-resistant steel liner.
• The distance from the ember of the pellet burner to the nearest surface/wall of the boiler should be at least 25 cm (30–40 cm for the Domna 22 kW burner).

Choosing a pellet burner for modernization of a coal boiler

Before starting modernization works, you should ask yourself which burner will be best suited for a coal boiler. There is a wide range of pellet burners on the market with different power, construction and level of advancement. When choosing the right model, it is worth considering the following issues:

• Does the burner comply with the EN 15270 standard (due to approval)?
• Does the burner fit the existing boiler opening?
• Is the flame directed forward and not too long (will it fit easily in the existing combustion chamber)?
• Does the burner operate in modulation mode? Operation in modulation mode may result in an increased amount of ash remaining after combustion in the burner.
• Does it have appropriate protection against flame backfire?
• What controller is the burner equipped with?

When choosing a pellet burner, attention should be paid to whether it is easy to operate, modern and self-cleaning. All DOMNA burners from TechnoMaszBud meet these conditions, have an intuitive Plum controller and are additionally equipped with a feeder, which significantly facilitates boiler operation.

The pellet burner is selected depending on the boiler power. Assuming that the boiler power is 20 kW, the best choice is the pellet burner DOMNA EKO-22 with a maximum power of 25 kW. It is a fully automatic chamotte burner that tolerates various types of pellet, including low-quality ones. TechnoMaszBud additionally offers an aesthetic DOMNA ZP-450 pellet hopper with a capacity of 450 liters, which allows the burner to be supplied with pellet for up to 7 days.

How to install a pellet burner in a coal boiler

To install a new pellet burner in a coal boiler, the following steps should be taken:

• Remove the old burner.
• Check the opening of the old retort burner or ash pan for the new pellet burner in terms of dimensions. If the opening is too small, it should be enlarged.
• Check the position of existing bolts and screws. If necessary, drill new holes or make an appropriate mounting frame.
• Tighten the burner and mounting frame. The connection must be perfectly sealed, e.g. with sealing rope!
• Connect electrical wires and the controller.
• Connect the burner to the pellet auger, and the auger to the hopper supplying the burner with pellet.
• Install a draft regulator in the flue pipe or in the chimney collar.
• If necessary, install a return temperature regulator.

Summary

Installing a pellet burner in a coal or oil boiler allows modernization of the central heating installation with relatively low financial outlays. It is a great alternative to purchasing a new pellet boiler. Modern DOMNA burners are perfect for boiler modernization, which are available in power ranges from 22 to 350 kW and ensure automatic boiler operation, increasing user comfort and safety. Converting a coal boiler to a pellet boiler is the right choice, both economically and ecologically.