When designing steam-generating devices, it is necessary to consider the issue of determining the limits of their stable operation. Such stable operation limits can be determined by testing a model that reflects the main design features of a full-scale steam generator. For this purpose, JSC OKBM Afrikantov has developed and tested a steam generator model. The results obtained in the tests for determining the limits of hydrodynamic stability can be used to determine the permitted range of operating loads for steam generators.