A gas burner apparatus for discharging a mixture of fuel gas and air into a furnace, wherein the mixture is burned in the presence of flue gas while producing a low content of nitrous oxides comprising: a plenum including a housing for attachment to said furnace, said housing including: an upper end attached to said furnace, said upper end having an air outlet disposed therein; a lower end opposing said upper end; and a sidewall connecting said upper end and said lower end together, wherein at least one of said sidewall and said lower end has an air inlet disposed therein; a burner tile having a central opening therein for receiving air from said air outlet of said housing, said burner tile including: a bottom end attached to said upper end of said housing over said air outlet; a top end opposing said bottom end, said top end including a discharge outlet; and a wall connecting said bottom end to said top end and surrounding said central opening, said wall extending into said furnace and having an interior surface and an exterior surface, primary fuel gas injection means connected to a source of fuel gas and operably associated with said burner apparatus for injecting primary fuel gas into said central opening of said burner tile; and secondary fuel gas injection means connected to a source of fuel gas and operably associated with said burner apparatus for injecting secondary stage fuel gas from outside of said burner tile to a point adjacent to said discharge outlet of said burner tile; wherein said interior surface of said wall including an internal Coanda surface bulging into the central opening and/or said exterior surface of said wall including an external Coanda surface bulging outwardly from the external surface and the secondary fuel gas injection means inject fuel gas on or adjacent said external Coanda surface; wherein a gas tip is used as the secondary fuel gas injection means, said gas tip comprising: a gas barrel connected to a source of fuel gas; a gas deflector attached to said gas barrel; and a fuel gas outlet disposed between said gas barrel and said gas deflector, said gas deflector having an exterior surface that includes a Coanda surface positioned with respect to said fuel gas outlet such that fuel gas discharged from said fuel gas outlet follows the path of said Coanda surface. a plenum including a housing for attachment to said furnace, said housing including: an upper end attached to said furnace, said upper end having an air outlet disposed therein; a lower end opposing said upper end; and a sidewall connecting said upper end and said lower end together, an upper end attached to said furnace, said upper end having an air outlet disposed therein; a lower end opposing said upper end; and a sidewall connecting said upper end and said lower end together, wherein at least one of said sidewall and said lower end has an air inlet disposed therein; a burner tile having a central opening therein for receiving air from said air outlet of said housing, said burner tile including: a bottom end attached to said upper end of said housing over said air outlet; a top end opposing said bottom end, said top end including a discharge outlet; and a wall connecting said bottom end to said top end and surrounding said central opening, said wall extending into said furnace and having an interior surface and an exterior surface, a bottom end attached to said upper end of said housing over said air outlet; a top end opposing said bottom end, said top end including a discharge outlet; and a wall connecting said bottom end to said top end and surrounding said central opening, said wall extending into said furnace and having an interior surface and an exterior surface, primary fuel gas injection means connected to a source of fuel gas and operably associated with said burner apparatus for injecting primary fuel gas into said central opening of said burner tile; and secondary fuel gas injection means connected to a source of fuel gas and operably associated with said burner apparatus for injecting secondary stage fuel gas from outside of said burner tile to a point adjacent to said discharge outlet of said burner tile; wherein said interior surface of said wall including an internal Coanda surface bulging into the central opening and/or said exterior surface of said wall including an external Coanda surface bulging outwardly from the external surface and the secondary fuel gas injection means inject fuel gas on or adjacent said external Coanda surface; wherein a gas tip is used as the secondary fuel gas injection means, said gas tip comprising: a gas barrel connected to a source of fuel gas; a gas deflector attached to said gas barrel; and a fuel gas outlet disposed between said gas barrel and said gas deflector, said gas deflector having an exterior surface that includes a Coanda surface positioned with respect to said fuel gas outlet such that fuel gas discharged from said fuel gas outlet follows the path of said Coanda surface. a gas barrel connected to a source of fuel gas; a gas deflector attached to said gas barrel; and a fuel gas outlet disposed between said gas barrel and said gas deflector, said gas deflector having an exterior surface that includes a Coanda surface positioned with respect to said fuel gas outlet such that fuel gas discharged from said fuel gas outlet follows the path of said Coanda surface.