The invention provides a circulating
water heating system of a secondary pump, consisting of a heating medium water inlet
pipe, a heating medium water return
pipe, a
heat exchanger, a primary pump, a secondary pump, a bypass flow water mixer, a
temperature control valve, a control cabinet and a
tail-end heat user. The circulating
water heating system is characterized in that the heating medium water inlet
pipe is connected with a primary side inlet of the
heat exchanger through the
temperature control valve; the heating medium water return pipe is connected with the primary side outlet of the
heat exchanger; a
secondary side outlet of the heat exchanger is connected with a primary water inlet of the bypass flow water mixer through the primary
water supply pipe; the primary water outlet of the bypass flow mixer is connected with the primary pump through the primary water return pipe and than is butted with a
secondary side inlet of the heat exchanger. The invention adopts the primary pump constant flow and the secondary pump constant flow to operate so as to ensure that the
system can automatically adapt to the load change of the
tail-end heat user, controls the
water supply temperature of the primary
water supply pipe by matching
outdoor temperature variation, and has the characteristics of reasonable design, reliable operation, high efficiency, energy saving, capability of automatically adapting to the flow variation of the
secondary side tail-end heat user, and the like. The invention is particularly suitable for large and medium circulating
water heating systems.