Biomass Boiler - The effects of poor fuel

Freshly harvested wood contains a naturally high amount of water, between 65-90% depending on the species. Seasoned wood must be used in the Attack boiler due to achieve high efficiency. Many wood fuel suppliers may consider their wood to be seasoned, however often their wood may be seasoned incorrectly and have a high moisture content, resulting in inefficient burning and possible damage to the boiler. Common problems and the long term effects of using poor fuel are listed below.


  • Low output temperature due to moisture burn off from the fuel cooling the inside of the boiler.
  • Fuel will not carbonise, gasification will not occur.
  • Unseasoned timber will produce gases and tars that will corrode the inside of the boiler. Reducing the life of the boiler.
  • Poor combustion will create excessive tar and soot, affecting the flue and the performance of the heat exchanger.
  • We recommend the use and mixing of both hard woods and softwoods during the burning season.
  • Briquettes can only be used to a maximum of 10% of the hopper volume, or lighting the boiler only.

Moisture meters are a convenient way to give you an accurate reading from wood sourced from suppliers or to monitor wood that you may have harvested yourself. Moisture meters are available from the sales team.

Please note- Use of manufactured timber: MDF, Plywood, Chipboard or wood with paints, varnish or wax applied is strictly prohibited due to the harmful materials contained. Any use of these materials will damage the boiler and void your warranty.

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