When the owners of this poorly insulated property were planning the construction of a two-storey detached garage and workshop, they reserved some space for a new plant room. This gave them the opportunity to replace their aging gas-fired boiler with a modern, efficient biomass boiler. By installing a dual fuel boiler they are able to burn self-sourced logs, whilst at the same time taking advantage of the convenience of burning wood pellets.


We installed a 22kW Froling SP Dual log and pellet boiler and a 1250 litre accumulator tank in the plant room. This tank is connected via a 25m Microflex heat main to a plate heat exchanger inside the house. The secondary side of the heat exchanger supplies heat to the existing radiator system and DHW storage cylinder.


A 500L Pellet Cube rectangular store, loaded using bagged pellets, is also housed within the plant room. Pellets are transferred pneumatically from this store to the boiler’s day hopper. If logs have been loaded into the combustion chamber, when the accumulator tank temperature has dropped to its set point the boiler will automatically light them using the pellets. If no logs are loaded then the boiler will detect this and will heat the accumulator tanks using pellets instead.