Flues are an integral part of your biomass boiler installation and the maintenance of them should not be overlooked. Ignoring the maintenance needs of your flue will lead to a build-up of soot and residue, which in turn could result in harmful gases in the plant room and even flue fires.
HETAS recommend that your boiler flue should be cleaned out at least twice a year as a minimum, normally at the start and end of heating season. However like any servicing on biomass boilers, the main consideration should be the boiler hours run. If the boiler has high operational hours then flue maintenance should take place on a more regular basis. Additionally, consideration of the fuel type should be given. Higher water content wood-chip fuels will create more ash than a wood-pellet fuel and therefore will require more maintenance.
During your boilers operation there will gradually be a build-up of soot inside the flue, reducing the cross-sectional area of the flue which in turn restricts the flow of flue gases. The severity of build-up depends on the operational hours and type of fuel used. It impacts on the boiler performance and carries the risk of flue gas spillage back into the boiler room. Flue gases contain high concentrations of carbon monoxide (CO), which can lead to a high risk of CO poisoning if they are not able to freely disperse through the flue.
In extreme circumstances where the flue is severely restricted or blocked, there could be a build-up of explosive gas mixtures and these can then become ignited and lead to an explosion within the flue.
Another consequence of poor quality fuel is the potential of a tar like substance within the flue. This would normally burn off incrementally but combined with soot build-up can ignite and cause a chimney fire.
All the above issues can occur if due consideration is not given to the flue. However a good design, installation and maintenance program will dramatically reduce any risks.
It is important to have your flue cleaned by a professional and qualified sweep who is able to give it a thorough clean and remove any build-up of soot and residue to avoid any of the previously mentioned issues. At TES we carry this out as part of our maintenance contracts.
If you have any concerns over your biomass boiler flue please contact us on 01483 603090.