| 摘要 |
<p>PURPOSE:To keep a pressure in a tank at a value approximately near to an allowable pressure and to prevent the occurrence of deficiency in a pressure and deficiency in a flow rate at a hot water feed faucet by providing a control circuit to control a feed water control valve and a drain control valve by means of a signal from a pressure sensor for measuring the internal pressure of a tank. CONSTITUTION:A pressure in a tank 1 is detected by a pressure sensor 13, the detecting pressure is compared with a pressure set value by a control circuit 14, feedback control is made on the opening of a motor-operated feed water control valve 11, and a pressure in the tank 1 is kept at a specified value. When a pressure in a water feed source is rapidly increased and a pressure in the tank 1 is increased to a value higher than a set value resolution from the rapid decrease of a flow rate discharged through a hot water feed port 4, the control circuit 14 release a drain solenoid valve 12 to prevent the increase of a pressure in the tank 1. Even when a hot water feed faucet 15 is in a closed state and a pressure is increased through expansion of the volume of water during heating by a heater 6, the drain solenoid valve 12 is released to prevent the increase of a pressure. Further, since a difference in a pressure between an allowable pressure (a) of the tank 1 and a drain valve release set value (i) and a pressure set value (k) can be reduced and an effective pressure (m) during the feed of hot water is increased to a high value, deficiency in a pressure and deficiency in a flow rate at the hot water feed faucet 15 can be prevented from occurring.</p> |
