type B11 boiler definition
type B11 boiler means a fuel boiler space heater incorporating a draught diverter and possibly fitted with a clearance monitoring device that is intended to be connected to a natural draught flue that evacuates the residues of combustion to the outside of the room containing the fuel boiler space heater and that draws the combustion air directly from the room; a type B11 boiler is marketed as type B11 boiler only;