METHOD FOR SENSING OXYGEN DEFICIENCY FOR GAS WATER HEATER

PROBLEM TO BE SOLVED: To sense when an incomplete combustion that an oxygen is deficient occurs by providing a combustion temperature sensor for measuring a combustion temperature of a gas combustor, and sensing an oxygen deficiency state by a falling speed of the combustion temperature of the combustor. SOLUTION: A gas proportional valve 13 and a main solenoid valve 14 are provided at gas piping 12 for supplying gas to a gas burner 10. A burner sensor (combustion temperature sensor) 17 such as a thermistor or the like for directly sensing a combustion temperature by a thermal conduction due to a contact with a burning flame is provided at a gas burning position of the burner 10, and the combustion temperature of the burner 10 is measured more accurately than that of a flame rod or the like. An oxygen deficiency deciding unit 21 provided in a controller 19 reads a measured value (burner sensor temperature) of the sensor 17 each time a predetermined time is elapsed, calculates a falling speed of the combustion temperature of the burner 10 from the burner sensor temperature, and monitors the oxygen deficient state based on the result.