| 摘要 |
PURPOSE:To perform an accurate sensing of a water level in a bath tub and complete a hot water feeding within a short period of time by a method wherein a returning side of an additional boiling circulation pipe passage is provided with an opening or closing valve, branched to a first returning branch pipe and a second branch pipe, the first return branch pipe is communicated and connected with a bottom part of the bath tub, the second returning branch pipe is connected to s wall surface in the bath tub and a pressure sensor for use in sensing a water level is connected to the first returning branch pipe. CONSTITUTION:A circulation port of a returning pipe 5 in an additional, boiling circulating pipe passage 3 is provided with opening or closing valves 20a and 20b of a returning pipe, branched into a first returning branch pipe 21 and a second returning branch pipe 22. A returning circulation port in the first returning branch pipe 21 is connected to a water drain pipe 17 at the bottom part of the bath tub 1 and a return circulation port in the second return branch pipe 22 is communicated and connected to a side wall of the bath tub 1. A pressure sensor 8 for use in sensing a water level in the bath tub 1 is communicated with and connected to the first return branch pipe 21. A burner combustion of a heat exchanger 12 is started, hot water got from a water supplying pipe 13 through a hot water feeding opening or closing valve 15 is dropped into the bath tub 1 through the going-pipe 6 and the second return branch pipe 22 and then the hot water feeding is completed within a short period of time. Since the opening or closing valve 20a in the return pipe is closed during the additional boiling operation, the pressure sensor 8 does not accept any dynamic pressure of the circulating hot water and then the water level in the bath tub 1 can be accurately detected. |
