Unexpected leakage can come from incomplete travel, debris, a damaged seat, incorrect direction or conditions beyond the selected configuration. Investigate systematically instead of increasing actuator force without a defined limit.
Confirm what is leaking
Distinguish internal leakage through the closed seat from external leakage at the shaft, body or flange. Establish the actual pressure, temperature and flow direction. A field observation should be compared with the agreed test basis; not every audible downstream flow proves a seat has failed.
Check movement and setup safely
Use the site’s isolation procedure before mechanical inspection. Confirm that the actuator reaches the actual closed position and that the indication is correct. A mis-set stop or slipping coupling can leave a sound seat partly open. Review changes made during maintenance or positioner calibration.
Examine the process and trim
Debris, abrasive damage, corrosion or incompatible seat materials may prevent sealing. Repeatedly forcing the valve shut can worsen damage or overload the shaft. Follow the specific disassembly and repair instructions, identify replacement parts by the exact series and retest according to the approved acceptance requirements.
Practical checklist
- Internal versus external leakage identified.
- Actual service compared with the selected limits.
- Closed position and coupling checked.
- Repair and retest documented for the exact assembly.
Discuss your application
Send the process conditions and required valve function for a configuration review. Request a technical quotation ↗