To prevent the danger possessed by a conventional pressure sensor and to precisely read the deformation quantity of an elastically deformable pressure receiving body so that the internal pressure of a liquid vessel can be more precisely detected.
This structure comprises a hot water storage vessel 4, a connecting pipe 12 connected to the vessel 4, and a pressure sensor 9 connected to the connecting pipe 12 to detect the internal pressure of the vessel 4. The pressure sensor 9 comprises a chamber 9c facing the atmospheric pressure on the side opposite to the vessel 4. The deformation quantity of the elastically deformable pressure receiving body 9a arranged within the pressure sensor 9 is read to detect the pressure. The top end of a pipe 10 connected to the chamber 9c facing the atmosphere is set so as to be a rated quantity height of the vessel 4 or more.
HOSHIKA KUNIHIRO
WAKAFUJI SHIYUUJI
