The most important factor of increasing power efficiency of heat supply of buildings is the quality of work of hydrotransport complexes. It is followed by different transition processes characterized by considerable changes of pressure, expense, hy-draulic power, liquid movement speed, etc., de-pending on the consumption of water volume at the pressure difference of 105 PA. The change of coef-ficient of waste valve conducts to change of such parameters, as pressure difference and the ex-pense of the heat carrier via the valve. All this sig-nificantly reduces the stability of temperature condi-tion of hydrotransport system. One of the ways of decreasing dynamic processes is the stabilization of temperature conditions of pipeline system of heat supply reducing the differences of pressure and temperature of the heat carrier. Mathematical mod-eling of dynamic modes of heat conductor of the system of heat supply is given in the study. The modeling is executed on the basis of the structure of transcendental transfer functions analysis. The flowchart of heat conductor is developed in Matlab-Simulink. The developed mathematical model of heat conductor is used for the processes of model-ing the system of heat supply performance in the conditions of transition processes and allows re-ceiving quantitative characteristics of the parame-ters influencing hydraulic stability regarding the in-fluence of the speed of the stream on the tempera-ture condition of the system of buildings heat sup-ply. Underheating of the heat carrier at the expense of increase in the speed of the stream is compen-sated by the increase in heat transfer coefficient.