I am working with ONICON ft-3000 electromagnetic flow meters. The flow meters are positioned on drain lines which drain or "blowdown" water from water return lines. When the control valve on this drain line begins from closed, the flow meter reads very stable flow until the valve is opened greater than 40%. After 40%, the flow becomes very erratic, with spikes as much as +/- 25%. If the valve is above 40% and thus reading erratically, it must be closed to 30% before it begins reading stable flow again. The flow coming out of the pipe into the drain appears to be very stable as well, even with the valve open 100%.
There are two identical (or at least nearly identical) lines that have identical behavior. The thinking is that since we are able to get very stable readings from both lines, there is not an issue with grounding or any type of electromagnetic interference. There is a number of bends in this drain line, but the mechanical team seems confident this won't cause irregular flow. I'm not mechanically savvy, but I am not sure if they are correct.
There are two identical (or at least nearly identical) lines that have identical behavior. The thinking is that since we are able to get very stable readings from both lines, there is not an issue with grounding or any type of electromagnetic interference. There is a number of bends in this drain line, but the mechanical team seems confident this won't cause irregular flow. I'm not mechanically savvy, but I am not sure if they are correct.