CASCADE SYSTEM AND CONTROL METHOD OF THE CASCADE SYSTEM AND A HEATING BOILER COMPRISING THE CASCADE SYSTEM

摘要

PURPOSE: A cascade system, a method for controlling the same, and a heating boiler are provided to simplify the whole system because a hydro separator and etc. for solving the lack of hot water are not necessary. CONSTITUTION: A cascade system comprises a boiler-side pump and a heating load-side pump. A three way valve and a controller are formed in a plurality of boilers. The three way valve selectively switches a path for hot water circulating along hot water return pipe toward a hot water supply pipe connected to the inlet or outlet of a heat exchanger. The controller controls the direction of the three way valve according to heating loads.