Method and apparatus for controlling fuel-to-air ratio of the combustible gas supply of a radiant burner

In a heating appliance employing a surface combustion or radiant burner that burns a combustible gas comprised of a mixture of gaseous fuel and combustion air and that emits radiation while burning said combustible gas, having means for supplying said gaseous fuel to said radiant burner at one or more flow rates and having means for supplying said combustion air to said radiant burner at a variable flow rate, a method of setting the proportion of said gaseous fuel to said combustion air in said combustible gas to a desired proportion comprising the steps of:

• determining a reference intensity, said reference intensity being the intensity of radiation emitted by said radiant burner when said radiant burner is burning a reference combustible gas, said reference combustible gas being a combustible gas having a proportion of gaseous fuel to combustion air that is equal to said desired proportion;
• setting said gaseous fuel supply means at a given flow rate;
• sensing the intensity of radiation emitted by said radiant burner while said radiant burner is burning said combustible gas;
• and
• controlling said combustion air supply means so as to reach and maintain a flow of combustion air that will produce a resultant combustible gas having such a proportion of gaseous fuel to combustion air that, when said radiant burner burns said resultant combustible gas, said radiant burner will emit radiation at an intensity equal to said reference intensity.