The paper describes the methods of analytical calculation and modeling of hydraulic modes of thermal networks. These methods can be used to calculate water, ventilation, gas and other hydraulic networks. The book is intended for engineering and technical workers involved in the design, operation and adjustment of hydraulic networks, as well as for students of higher educational institutions . The main elements of the heating systems and their hydraulic characteristics. Closed systems with constant water consumption of subscribers. Closed systems with constant resistances of heating subscribers. Open Systems . Hydraulic modeling of thermal networks. Electrical modeling of thermal networks. Calculation of networks on the digital electronic computer "Ural" .