The dynamic properties of district heating (DH) systems include water flow and heat propagation from production plants to consumers. The objective of this paper is to investigate the possibility of successful heat transition from DH plant "Vecmīlgrāvis" by decreasing of the supply temperature from the temperature graph 130-70 °C to the temperature graph 115-70 °C. The reliability and quality of the heat distribution to the customers must be kept unchanged. The flow ratio depends on the heat demand and the temperature of the hot water supply. With the goal of keeping the output temperature from DH plant as low as possible, it is necessery to determine the upper limit for the flow on the DH network, which depends on pipes, pumps etc. Operational data from the DH plant "Vecmīlgrāvis" were used to estimate theoretical calculations in this paper.