Heating and hot water supply apparatus and control method thereof

A heating and hot water supply apparatus, comprising:

• a heating mechanism configured to heat a heating medium,
• a heating circulation path configured to circulate the heating medium heated by the heating mechanism with a heating terminal when a heating operation is performed,
• a hot water supply heat exchanger having a primary side path and a secondary side path for heat exchange between liquids,
• a bypass path branched from the heating circulation path and configured to join the heating circulation path again after causing the heating medium to flow through the primary side path of the hot water supply heat exchanger without passing through the heating terminal,
• a flow rate control mechanism configured to control a division ratio which is a ratio of a flow rate of the heating medium supplied to the bypass path to a total flow rate of the heating medium heated by the heating mechanism,
• a water inlet pipe connected to an input side of the secondary side path,
• a hot water outlet pipe connected to an output side of the secondary side path,
• an input unit configured to input a start reservation time of a hot water supply operation, and
• a control unit configured to control the flow rate control mechanism according to ON and OFF of the heating operation and the hot water supply operation,
• wherein the control unit controls the flow rate control mechanism to set the division ratio to a first value when only the heating operation is performed and to set the division ratio to a second value greater than the first value when a preheating start time set according to the start reservation time arrives during performance of only the heating operation, and
• the control unit also controls the flow rate control mechanism to set the division ratio to a third value greater than the second value during a simultaneous operation of the heating operation and the hot water supply operation and to set the division ratio to a fourth value greater than the third value when only the hot water supply operation is performed.