| 摘要 |
PURPOSE:To excellently maintain the hot water feed characteristic without frequently starting and stopping a heating unit and to increase the available hot water storage amount by operating the heating unit when a hot water storage tank thermostat emits an ON signal, and stopping the operation thereof when a logical product of the OFF signal from the hot water storage tank thermostat and the OFF signal from an outlet side thermostat is obtained. CONSTITUTION:When the detected temperature of a sensor 19 becomes less than the set temperature of a temperature setter 20 by 90 deg.C or more, a temperature control circuit 27 emits an ON signal 'H', and a temperature control circuit 30 and a delay off timer device 32 emit 'H' outputs. Hence, a transistor 41 is turned ON, and a pump control circuit 43 starts the operation of a circulation pump 7. When a flow switch 9 detects flowing water and is turned ON, power is supplied to a burner control circuit 44 to operate an exhaust fan 14 and open a fuel valve 13, thus causing a burner 11 to conduct the combustion. When the heating is completed and both temperature control circuits 27 and 30 emit OFF signals 'L', outputs from an OR circuit 36 and an AND circuit 38 become 'L', and hence the transistor 41 is turned off to cut off the power supply to the burner control circuit 44, thus stopping the operations of circulation pump 7 and the heating unit 10. |
