Component
Pressure-actuated valves that open to vent overpressure, protecting vessels and systems from rupture.
Operating principle
A spring-loaded valve opens when system pressure overcomes the spring setpoint, venting excess pressure until pressure drops below the reset point. Required on every pressure vessel and compressor discharge.
Components
- Valve body
- Spring & poppet/disc
- Adjustment cap (sealed)
- Discharge outlet
- Test lever (some)
Common issues
- Weeping/leaking → scale, debris on seat, weakened spring
- Won't pop at set pressure → wrong setpoint, tampering
- Chattering → undersized, excessive backpressure
- Corrosion → never opens
Maintenance
- Test (lift) annually per jurisdiction
- Never adjust a sealed setpoint without OEM/jurisdiction
- Replace, don't repair, corroded valves
- Keep discharge unobstructed and piped to a safe area
Field tips
- Setpoint must be ≤ vessel MAWP; never above
- Tampering with the sealed cap is illegal in most jurisdictions
- Test levers verify movement, not setpoint
- Every stage/vessel needs its own relief device