What is “phantom flow” and how can it be eliminated?

“Phantom flow” refers to a situation where flow shows up on the electronics display even when there is no flow going through the line. This sometimes occurs with electromagnetic flow meters when there is electrical noise interference coming from another device. This issue can usually be resolved with grounding modifications.

How can I determine whether it is the sensor or the controller that is not working properly?

For mechanical meters, a voltmeter can typically be used to check for pulse output. See this video for how this should be done. For the insertion magmeter, the pulse output is too fast to be seen with a voltmeter, this is why there is an LED indicator light which indicates whether the meter is sensing …