| 摘要 |
PURPOSE:To prevent the temperature of supplied hot water from over-shooting and hunting even when the amount of water changes in a state where the target temperature does not change, and to secure a high response to the supply hot water temperature thereby to save energy by providing gain changeover means for increasing or decreasing a gain of proportional integration-differentiation (PID) means in accordance with the increase or decrease of the deviation. CONSTITUTION:Even in a state where the target temperature is not changed, when the amount of water is changed, it results in producing a deviation between a target temperature signal and a detected temperature signal. When the amount of water has increased, the detected temperature decreases and the deviation increases. Accordingly, the gain changeover means 27 increases the gain of the PID control means 25. The PID output having the gain thus increased evades the ovrshooting and hunting of the supply hot water temperature and further imparts a high response to the supply hot water temperature. Further, when the amount of water has decreased, the deviation also decreases. Accordingly, the gain changeover means 27 decreases the PID control means 25. In any case, since the response to the supply hot-water temperature is high, energy is saved.
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