| 摘要 |
PURPOSE:To effectively stop a no-water burning and to safely protect a heat exchanger and the like by detecting the operation of a temperature detector attached to the exchanger, storing the number of operations of the detector, and providing means for displaying it if it becomes a predetermined number or more and stopping the combustion of a burner. CONSTITUTION:If first no-water burning occurs, a temperature detector 5 operates to open a contact so that the voltage of the clock terminal 16 of a counter IC 15 alters from low to high and lights a first display lamp 26 through a memory circuit 25. On the other hand, a high voltage is also applied to a relay coil 19 though a diode 28, a relay contact 19b is opened from its closure, and a solenoid valve 3 is closed to extinguish a burner 2. In case of second no-water burning, the same operation as that in the first place is conducted. ln case of third no-water burning, a voltage is also applied to the coil 21a of a relay 21, and a contact 21b is opened from its closure. Thus, even if the contact of the detector 5 is closed, the clock terminal 16 of the IC 16 remains high. Accordingly, since no voltage is applied to the valve 3, the burner 2 is not burned, a third display lamp 20 continuously lights, and a bath furnace cannot be used. |
