| 摘要 |
PURPOSE:To contrive energy saving by a method wherein a heater circuit is controlled by the AND signal of a water temperature detecting signal and a combustion tube temperature detecting signal as well as the OR signal of the combustion tube temperature detecting signal while a flip-flop circuit is set by the NOT signal of the combustion tube temperature detecting signal to operate a protect circuit. CONSTITUTION:In a high-temperature thermistor system 9, the output signal D of a comparator 10 becomes ''H'' and is supplied to an AND gate 18 when the temperature of a combustion tube is low. On the other hand, the output signal B of the comparator 12 becomes ''H'' in a hot-water temperature thermistor system 11 and is supplied to the AND gate 18 when water temperature is low. Accordingly, the output signal F of the AND gate 18 becomes ''H'' also the the heater circuit 21 is driven through an OR gate 17. When the temperature of the combustion tube has arrived to a predetermined temperature and the output signal d of the comparator 10 has become ''L'', the flip-flop circuit 20 is set through an inverter 19. Then, a set output I becomes ''H'' and the protect circuit 22 is operated. |
