A method for detecting stagnation and stagnation prevention in heat exchangers

摘要

The method for detecting and avoiding boiling and stagnation in the primary heat exchangers (2) in heating devices (1), in particular condensing boilers, detects the boiling previous Mikrosieden, wherein one or more the Mikrosieden characterizing process variables (21, 22, 31, 32, 33) is detected and compared with a threshold. When the threshold value is exceeded, an operating parameter is at least changed, which counteracts a boiling. When characterizing the process variables of the high-frequency component of the pressure (31, 32) to be heated heat transfer medium come, as measured by the heat exchanger (2) and / or system pressure (8), and / or the temporal decrease in the temperature increase of the heat transfer medium between input and output ( 22, 21) of the heat exchanger (2) in quasi-stationary operation in question. As a countermeasure, the burner (3) is switched off or the burner power can be reduced, the pump speed of the pump (4) can be increased or can be a bypass section (10) opened (9). When starting the burner may briefly increase the mass flow of heat transfer medium by increasing the pump speed of the pump (4).