By swapping their old oil boiler for a dual fuel biomass boiler the owners of this large (345m2), listed and poorly insulated rural property are able to heat their home predominantly with their own logs whilst retaining the convenience of automatic ignition provided by wood pellets.


We installed a 40kW Froling SP Dual log and pellet boiler in an outbuilding supplying heat to a 3000 litre accumulator tank via a backflow circuit. The accumulator connects to the existing heating and hot water system in the house via a short buried heat main. The connection between the accumulator and the vented system in the house is indirect via a plate heat exchanger.


Bagged pellets are loaded manually into a 500 litre pellet hopper and transferred pneumatically to the boiler. 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 use pellets instead.