Dual pipe heat exchanger of instantaneous boiler for house heating and hot water and boiler

An instantaneous boiler for supplying heating water and hot water, the boiler comprising:

• a heat exchanger including an outer pipe used for a hot water pathway, to which combustion heat is directly transferred from a burner in a combustion chamber, and an inner pipe used for a heating water pathway, which extends through the outer pipe;
• a heating water supply pipe connected to the inner pipe of the heat changer;
• a heating water line connected to the heating water supply pipe;
• and
• a heating water returning pipe connected to the inner pipe,
• wherein the inner pipe of the heat exchanger, the heating water supply pipe, the heating water line, and the heating water returning pipe are connected to one another in series, and
• a circulation pump that is coupled to the inner pipe and is configured to operate when only heating water is supplied and is configured to operate if a quantity of heat to be required in the hot water is less than a maximum quantity of heat that can be supplied during use of the hot water, when both hot water and heating water are supplied.

A controlling method of an instantaneous boiler for supplying heating water and hot water, the boiler comprising

• a heat exchanger including an outer pipe used for a hot water pathway, to which combustion heat is directly transferred from a burner in a combustion chamber, and an inner pipe used for a heating water pathway, which extends through the outer pipe,
• a heating water supply pipe connected to the inner pipe of the heat exchanger,
• a heating water line connected to the heating water supply pipe,
• a heating water returning pipe connected to the inner pipe, wherein the inner pipe of the heat exchanger, the heating water supply pipe, the heating water line, and the heating water returning pipe are connected to one another in series, and
• a circulation pump that is connected to the inner pipe,
• the method comprising
• operating the circulation pump when only heating water is supplied and when both hot water and heating water are supplied, a quantity of heat to be required in the hot water is less than a maximum quantity of heat that can be supplied during use of the hot water.