What should be done last if a bubbler tube flow meter does not read properly?

In the context of troubleshooting a bubbler tube flow meter, blowing the transmission line out with high-pressure air is a logical final step after other checks have been performed. This method is intended to clear any potential blockages or debris that could interfere with the proper function of the meter. If the device is not reading correctly, it is essential first to ensure that the power supply is adequate, and the sensor alignment is correct, as these are foundational checks that might resolve the issue quickly.

Additionally, calibration is necessary to ensure that the readings are accurate based on the specific setup and conditions of the operation. However, if all preliminary checks—power supply, alignment, and calibration—have been done and the device still does not function properly, clearing out the transmission line becomes a practical measure to ensure that flow readings are not being affected by restrictions in the line. This reinforces that ensuring clear pathways for airflow or liquid flow is crucial for accurate measurement, making it a sensible last step in troubleshooting.