Clinker build up is one of the most common faults that biomass boiler owners suffer with. Clinker is formed when there is a high build-up of ash on the grate inside the boiler. This excess in ash may be there due to the poor quality of fuel which is being used in the biomass boiler or due to the boiler not being cleaned out on a regular basis, as is advised by manufacturers and which is part of all standard biomass boiler maintenance regimes.
This ash will then cause a restriction on the movement of air across the combustion area, causing temperatures on the grate to increase which then lead to sintering. Sintering is where the ash is heated at such a high temperature that it begins to melt and then will solidify into slag named clinker. The clinker gets stuck very easily in the grate of the boiler and is extremely difficult to remove.
Clinker once formed will initially reduce the efficiency of your boiler which directly impacts the economic return from your system. Left for a prolonged period of time the build-up can lead to more serious issues developing with the operational side of your boiler, such as disabling the burner and collecting fuel on grates. The clinker is also prone to causing safety issues with the flue as discharge channels can rapidly become clogged. On top of all of this clinker will then begin to reduce the effective lifetime of your biomass boiler, meaning that your equipment may not provide the economic return that you were initially promised.
There are two main ways to avoid the build of clinker in your biomass boiler. The first is to adopt a strict maintenance regime where you regularly clean out the inside of the boiler and remove any ash that may have built up. We recommend that the boiler is cleaned every 80 – 160 hours’ worth of operational time in order to avoid any build up of ash. The second way to avoid clinker build up is by buying good quality fuel for your boiler as poor quality fuel creates more ash which directly impacts the formation of clinker. We offer more advice about fuel quality here.