The insert becomes a masonry heater

Converting an insert into a masonry heater

Same chimney flue, same firewood... but not the same heat!

Updating the hearth of this 1980s detached house by replacing the original insert with a modern, made-to-measure masonry heater!

For this we used a cast-iron firebox , the Brunner HKD, specially designed for building heat-storage heaters, which we coupled to a thermal mass built with a modular heat-storage system.

As an option, we installed for the first time on this type of appliance an automatic closing damper at the end of the flue circuit. It is controlled by the Brunner combustion management system, the EAS. In addition to the air inlet damper, which regulates and closes the heater without any user intervention, adding the end-of-circuit damper gains 10% to 15% in heat release by eliminating the losses caused by air movement in the flue.

Start of work: laying the insulation after demolishing the existing installation

Installing the combustion control system

Fitting the first elements of the heat-storage train

Detail of the connection to the outdoor combustion air supply

Inserting the temperature probe for the EAS

Connecting the HKD firebox to the KMS heat store

Detail of the door contact switch that drives the combustion control

Overall view, core finished and working, cladding being fitted

Detail of the end-of-circuit control damper – the flue is painted black so it cannot be seen through the future warm-air grille when it is in the open position

Detail of the 2 mm high-temperature stainless steel connection

The end damper motor recessed behind the insulation in one of the openings left by the old warm-air distribution grilles.

Detail of the bench, with 45° angles echoing the design of the house.

General view of the masonry heater with cladding finished, before rendering.

Final view of the masonry heater in place with its superb stone-veneer cladding.