For Agilent HPLC pump pressure instability, you can try the following troubleshooting steps:

1. Check liquid flow: Open the purge valve, set the flow rate to 1-2ml/min, start the pump, observe if there is stable flow (no backflow; use a graduated cylinder to verify flow accuracy).
2. Inspect for leaks: Check pipelines connected after the pump for leaks, as leaks often cause unstable pressure.
3. Maintain the purge valve: If the pressure exceeds 10bar when purging with pure water at 5mL/min, replace the PTFE filter inside the purge valve.
4. Perform regular pump maintenance: Replace pump heads as needed; for systems with plunger rod cleaning function, enable and use it daily.
5. Balance the chromatographic system properly using appropriate methods.

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