JP2841605B

PURPOSE:To prevent a high temperature to affect influence of a bath-preparation temperature to human body as being scalding by detecting hot water temperature from an additional burning circulation circuit, determining an abnormal temperature during circulation for predetermined time of additional burning, and determining a target temperature after the predetermined temperature. CONSTITUTION:Detecting temperature of temperature reading means 29 is compared with an abnormal temperature 32 by comparing means 30 in an additional burning operation, and additional burning signal 30a and a circulation signal 30b are sent to next stage. Circulation circuit control means 34 sets a circulation circuit 15 to an 'opening' state according to the signal 30b by a switching valve 16 to perform an additional burning operation, operates a pump 17, and circulates hot water in a bathtub 21 through the circuit 15. Additional burning control means 33 starts additional burning by burning means 35 including a solenoid valve 25, a gas control valve 26 according to an 'ON' signal of the signal 30a. Then, when predetermined time is elapsed by timer means 31, the signal 30b to be determined by the means 30 becomes an 'OFF' signal at a target temperature 33 or higher or an 'ON' signal at less than the temperature 33. Similarly, additional burning is controlled.