A simple continuity test to determine the health of the Flow meter isolation barriers.
Checking for pulses on the safe side of the barriers
Remove the two wires from the safe side of the barriers as shown in the diagram below. You must now connect your multi meter across the terminals where the wires were removed and check once more for continuity whilst the paddle wheel is rotated.
If no pulses are present whilst the rotor is being turned, the isolation barriers will need replacing.
If pulses are present here yet you have no flow present at the flow meter totaliser and the wiring is double checked correct, the totaliser will need investigation.