PURPOSE: To detect the abnormal temperature rise of a warm-air heater and improve the property of safety of the same by a method wherein the combustion of fuel in a combustion unit is stopped when the temperature of an operating unit has exceeded a reference temperature corresponding to a reference temperature signal.
CONSTITUTION: When usual heating operation is started, a microcomputer 17 reads a panel temperature detecting signal, outputted by a panel temperature sensor 16 which has detected the temperature near an operation panel 14, through an A/D converter and compares the temperature near the operation panel with a reference panel temperature. When the temperature near the operation panel 14 is higher than the reference panel temperature, the microcmputer 17 stops the operation of a fuel pump 8 to stop the supply of fuel to a burner and intercepts the power to an electric heater 21 to stop the heating of the fuel evaporating unit of the burner and stop combustion. By this method, the abnormal temperature rise of a control substrate, into which LSI and the like for controlling are incorporated and which is arranged near the operation panel, can be prevented.
OKADA HIDEO
NUMAO MASANOBU
