How to check why fill-no-bottle function fails on filler?

To check why the fill-no-bottle function fails, first determine if the issue affects all filling heads simultaneously or just a single valve position. For a single-valve failure, inspect the local photoelectric sensor for water splashes or mineral buildup, verify the pneumatic actuator response, and ensure the bottle guides are correctly aligned for your specific container size (e.g., 300–1,500mL PET or 18.9L barrels). If the issue is system-wide, check the main compressed air supply, central PLC communication, and primary sensor power. Always test the pneumatic relay manually before replacing parts. Note that while cleaning and mechanical adjustments are standard, modifying PLC logic to bypass alarms crosses the boundary of safe maintenance and requires manufacturer support.