PURPOSE: To protect a back-flow prevention device from tap water supply pressure by closing a water solenoid valve when the open state of an opening/closing valve is detected or after the opening/closing valve is opened.
CONSTITUTION: A hot water output pipe 13 is branched into two pipes, one getting a connection pipe 18 to a bath circulation circuit 30, on which pipe 18 a hot water supply solenoid valve (water solenoid valve) 19 opened and closed in response to an instruction of hot water supply is provided, and further downstream thereof a back-flow prevention device 20 is provided. Downstream the back-flow prevention device 20 there are disposed a hot water supply opening/closing valve for performing the opening/ closing operation associated with the opening/closing operation of the hot water supply valve 19 and an opening/closing valve 28, and downstream of the opening/closing valve 28 the connection pipe 18 is connected with the bath circulation circuit 30. Upon the hot water supply, the opening/closing valve 28 is opened prior to the hot water supply valve 19, and the hot water supply valve 19 is opened in the state where a flow rate is limited by a hot water amount servo 16. Hereby, in a hot water supply circuit 10 water supply from a water supply pipe 11 passes through a main heat exchanger 12 and is heated, and hot water passes through the hot water supply valve 19, back-flow prevention device 20, and opening/closing valve 28 and flows into the bath circulation circuit 30.
KUMAZAWA HIROAKI
OKADA SADAO
KURIKI KEIICHI
| JPH01131950U | 1989-09-07 | |||
| JPH01178547U | 1989-12-21 |