Hot water supply apparatus

A hot water supply apparatus including:

• a heating section configured to heat water;
• and a tank configured to store the water heated by the heating section, the hot water supply apparatus being configured to form a low-temperature layer (L), a medium-temperature layer (M), and a high-temperature layer (H) from a lower end to an upper end of the tank, the hot water supply apparatus comprising:
• a first channel configured to send water in the medium-temperature layer (M) to the heating section;
• and
• a second channel configured to return the water heated by the heating section to the medium-temperature layer (M) of the tank,
• the second channel having an outflow port at a lower position than an inflow port of the first channel,
• the hot water supply apparatus further comprising a control unit configured to execute:
• a preparation operation of controlling the hot water supply apparatus so as to create a first hot water storage state in which the low-temperature layer (L), the medium-temperature layer (M), and the high-temperature layer (H) are formed in the tank;
• and
• a first operation of causing the water in the medium-temperature layer (M) in the tank in the first hot water storage state to flow through the first channel and causing all the water having flowed from the medium-temperature layer (M) into the first channel to flow through the heating section and the second channel sequentially, after the preparation operation,
• wherein, in the first operation, the heating section heats water flowing through the first channel,
• the hot water supply apparatus further comprises:
• a third channel configured to return the water heated by the heating section to the high-temperature layer (H) of the tank;
• a fourth channel configured to send water in the low-temperature layer (L) or water from a water source to the heating section;
• and
• a plurality of sensors configured to sense the temperatures of the low-temperature layer (L), the medium-temperature layer (M), and the high-temperature layer (H) and the temperature of water exiting from the heating section, and
• the preparation operation includes:
• a first preparation step, in response to a sensed temperature of water at the medium-temperature layer (M) being below a first set temperature, the controller is configured to cause water from the low-temperature layer (L) of the tank to flow to the heating section via the fourth channel and return via the third channel until the sensed temperature of water at the medium-temperature layer (M) is the first set temperature;
• and
• a second preparation step where, in response to a sensed temperature of water at the high-temperature layer (H) being below a second set temperature and a temperature of the water at the medium-temperature layer being at or above the first set temperature, the controller is configured to cause water from the medium-temperature layer (M) of the tank to flow to the heating section via the first channel and return via the third channel until the sensed temperature of the water at the high-temperature layer (H) is the second set temperature, the heating section heating the water from the medium-temperature layer (M) to a second temperature in the second preparation step, the second temperature being higher than the first temperature.