HEAT-EXCHANGER FOR HOT WATER SUPPLYING APPARATUS

摘要

PROBLEM TO BE SOLVED: To provide a heat-exchanger for hot water supplying apparatus, which can prevent the reduction of a temperature right after the resumption of a hot water supplying after the usage of the hot water supplying is shut off, from generating. SOLUTION: A heat absorbing pipe of a heat-exchanger consists of a plurality of paths 12-22 being connected by fins 15, and combining pipes 24-32 which connect between respective paths. To the fourth combining pipe 30, a by-pass pipe 17 which is branched from a water supplying pipe is joined. The heat absorbing quantity for the upstream side part from the fourth combining pipe 30 of the heat absorbing pipe, is selected from a range from 30% to 65% of the heat absorbing quantity of the overall heat absorbing pipe. The ratio of the flow rate of the by-pass pipe 17 to the total flow rate is set at 0.50. The internal diameters of the first path 12-the fourth path 18 are set smaller than the internal diameters of the fifth path 20 and the sixth path 22.