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Even if a flow meter has excellent performance, it is only natural for it to develop faults during use. Today, we have summarized three common causes of flowmeter failures for everyone. I. Scaling on the inner wall of the pipeline The media measured by flow meters are often those containing suspended particles or are quite dirty; as a result, the likelihood of the formation of an adhering layer on the inner wall is much higher. If the conductivity of the coating layer is similar to that of the liquid, the instrument can still output a signal properly. However, in the cases of a coating layer with high conductivity or an insulating coating layer, the electromotive force between the electrodes will be short-circuited, and the insulation around the electrodes will break the measurement circuit. II. Lightning strikes Lightning is an inevitable natural force for flow meters; when lightning strikes a circuit, it causes instantaneous high voltages and surge currents, which can damage the meter if they reach it. There are 3 pathways through which lightning can damage instruments: the power supply cable, the flow signal line between the sensors and converters, and the excitation cable. However, from the analysis of component damage caused by lightning interference, it can be seen that the high voltages and surge currents that cause this interference mostly originate from the power supply lines in the control room, with the other two pathways being less common. III. Changes in on-site conditions This reason is mainly due to the presence of interference sources during the actual use of the flow meter. For example, during the calibration phase, there are no such interference sources and the instrument operates normally; however, during operation new interference sources emerge, such as pipe welding near or at a distance from the measurement point, which disrupt the normal operation of the instrument and cause significant fluctuations in the output signal.