Bricking-up of the heating walls courses 32 to ?Adjustment of burner level:first slide bricks in the burner level have to be installed and have to be fixed afterthat in order to avoid moving during ongoing bricking up.During bricking up the heating flue, mortar must not drop down to the burner level.In any case, the heating flues including the burner level and the air / gas flues inthe corbel area have to be carefully inspected and cleaned before continuing theupper part of the heating wall.