The simulation of network temperatures in the Network Temperatures dialog applies to a stagnant network.
The assumption is that the water in all pipes, even in circulating pipes, is stagnant. After assigning insulation material and ambient temperatures, the program can determine either for individual section parts or for the entire network, which temperatures will occur after which time. The temperature in a pipe is always determined depending on the there assigned ambient temperature. This enables easy detection of problem zones like pipes without insulation.