| 摘要 |
PURPOSE: To accurately calculate the residual water amount of a bathtub by correcting the residual water amount in response to a using gas type when the residual water amount at that time is calculated according to the heat generation rate per unit time of a burner, the burning time of the burner, the thermal efficiency and the hot water temperature change amount before and after reheating of bathtub water. CONSTITUTION: The atmospheric temperature is detected by an F point thermistor 25, and when it is lower, the thermal efficiency is lowered, while when it is higher, the efficiency is raised. On the other hand, by considering that the longer the length of a reheating circuit 2 of bathtub water, i.e., a bath return tube 16 or a bath forward tube 17 is, the more the radiating amount from the tube becomes and hence the thermal efficiency is lowered, thermal efficiency regulating means which can regulate the thermal efficiency in response to the length of the tube is provided in a controller 24 of a remote controller. Thus, the using gas type is discriminated, and the optimum thermal efficiency is set to perform the calculation of the residual water amount in the bathtub, and hence accurate hot water filling can be achieved. |
