Pressure Safety & Relief Valve Maintenance

1. Inspect outside and clean body , bonnet, inlet and outlet nozzle by instrument air.
2. Record Tag NO, Mfr,  data in check sheet.
3. Remove spindle nut.
4. Marking adjust bolt lock nut ,bonnet , valve body and record in check sheet.
5. Remove the adjusting bolt lock nut.
6. 6.Remove stud bolt between bonnet and valve body.
7. Disassembly bonnet and valve body.
8. Marking guide ring and nozzle ring.
9. Cleaned spindle spring washer , nozzle , disc ,disc holder insert and guide.
10. After cleaning and component , then inspect nozzle and disc. If damage they were need to
11. repair or lapping.
12. Assembly all parts and accessory.
13. Test popping , setting and leak test.

Lift up safety valve vertical on the test bench.

1. Applied air pressure, Nitrogen or water ( hydro test high pressure ) in to test system.
2. Increase pressure until setting pressure or safety valve popping if setting pressure correct specification do not adjust bolt spring, but the setting pressure not correct their need to adjust bolt spring until setting pressure correctly specification.
3. After popping test finish do to tightening adjusting bolt lock nut.
4. Seat leak test or seat tightness test at 90% of set pressure conform API 527 standard as
   following attachment sheet.
5. Record data and wire seal

1. After inspect nozzle and disc then it was found  scratch point should be lapping .
2. If disc and nozzle have more damage , it needs to re-machine.
3. If disc and nozzle can not lapping or re-machine it need to change with spare part.
4. After lapping finish should be clean with water , Acetone , cleaning Thinner and drying by
5. Instrument air.
6. Assembly all parts.
7. Test popping and leak test as follow up to procedure.