Control system for burner

A control system for a burner having at least one of an alarm and a combustion reducing device which is actuated in response to an abnormality detecting signal indicating an abnormal oxygen concentration, said control system comprising:

• an oxygen sensor adapted to react with oxygen gas to generate an electric signal depending upon an oxygen concentration in a room in which the burner is placed;
• oxygen concentration detecting means responsive to the electric signal supplied from said oxygen sensor for generating a detected oxygen concentration value;
• first comparing means or comparing said detected oxygen concentration value with an oxygen concentration reference value;
• reference value storing means for storing an initial reference value and said detected oxygen concentration value and inputting the oxygen concentration reference value to said first comparing means, said reference value storing means including means to initially input said initial reference value as the oxygen concentration reference value inputted to said first comparing means, and means to thereafter input said detected oxygen concentration value as the oxygen concentration reference value inputted to said first comparing means when said first comparing means detects that said detected oxygen concentration value is larger than the oxygen concentration reference value previously inputted to said first comparing means;
• and,
• second comparing means for comparing a deviation between said detected oxygen concentration value and the oxygen concentration reference value with an abnormality judging reference value, and for generating said abnormality detecting signal when said deviation is larger than said abnormality judging reference value and said first comparing means detects that said detected oxygen concentration value is smaller than the oxygen concentration reference value.