Heating and hot water supplying device

A heating and hot water supplying device comprising:

• a combustion means;
• a heat exchanger;
• a circulation passage which connects the heat exchanger with an external heating terminal;
• a circulation pump which is provided in the circulation passage;
• a bypass passage which branches from the circulation passage and bypasses the heating terminal;
• a heat exchanger for hot water supply which is provided in the bypass passage;
• a water supply passage which supplies tap water to the heat exchanger for hot water supply;
• a hot water supply passage which supplies hot water heated by the heat exchanger for hot water supply at a preset hot water supply temperature;
• a control unit which controls operations comprising a heating operation and a hot water supplying operation;
• an operation terminal which is connected with the control unit to be able to communicate with the control unit and performs various operations;
• and
• an external air temperature sensor which detects an external air temperature,
• wherein a distribution valve is provided in a branching portion of the bypass passage, the distribution valve is able to adjust a distribution ratio so that each of the heating operation, the hot water supplying operation, and a simultaneous heating and hot water supplying operation is possible, and a prohibit switch which prohibits the simultaneous heating and hot water supplying operation is provided at the operation terminal, and
• wherein when the external air temperature detected by the external air temperature sensor is equal to or higher than a predetermined reference temperature, an operation of the prohibit switch is invalidated.