| 摘要 |
<p>A through flow water heater has an inlet (12) and an outlet (13) and electrical heating means (17-21) controlled by control means (30). An inlet water temperature sensor (36) and an inlet flow rate sensor (31) provide inputs to the control (31) in order to maintain the temperature of the outflowing water constant. An outlet temperature sensor (40) provides a further input to the control means at least during the period immediately after the heater is switched on, so allowing for calibration of the heater, and after the outlet water temperature reaches a steady state, plays no further part in the control. Water temperature or flow rate may be varied through a control panel (48, Fig. 2) which provides further inputs to the control (31). <IMAGE></p> |
