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Common issues

• Piston stage valve wear or leakage causing loss of final-stage pressure or capacity
• Intercooler/aftercooler fouling reducing cooling efficiency and raising discharge temperature
• Moisture or condensate carryover into the high-pressure stage if separators are not drained
• Rotary screw stage bearing or rotor wear reducing volumetric efficiency
• Seal and packing wear on the piston stages allowing oil carryover into the compressed air
• High-pressure safety/relief valve fouling or sticking

Inspection checklist

• Check discharge pressure and temperature at each stage against baseline readings
• Inspect and test high-pressure relief valves for correct set pressure
• Check condensate drains/separators at each stage for correct operation
• Inspect piston rings, valves and packing at scheduled overhaul
• Check intercooler/aftercooler for fouling and leakage
• Monitor vibration and bearing temperature on the rotary screw stage
• Check compressed air quality (oil carryover, moisture), particularly where used for seismic source guns
• Verify safety interlocks and pressure switches trip at the correct settings

Service intervals

Typical wear limits

Ranges are typical for this design class. Always confirm against the manufacturer documentation for your serial number.

Critical spares

• Piston stage valve plates/reeds
• Piston ring and packing set
• Intercooler/aftercooler element
• Relief/safety valve (per stage)
• Condensate separator/drain trap

Safety

• High-pressure air storage in the 138-207 bar range - isolate and vent before opening any stage or fitting
• Compressed-air adiabatic heating risk - never lubricate high-pressure air systems with unapproved oils (fire/explosion risk)
• Noise exposure from compressor operation - hearing protection required in the compressor space
• Stored energy in receivers - lock out and tag out before maintenance

Class survey

High-pressure air receivers and downstream piping fall under pressure vessel/piping survey requirements; safety and relief valves require periodic testing and certification, and the compressor's safety interlocks (high temperature, low oil pressure) are typically function-tested at survey.

Estimated lifetime: Major components (piston stage, screw rotors) are typically rebuilt on a running-hours basis rather than run to a single lifetime figure; near-continuous running in seismic survey duty will shorten overhaul intervals compared with intermittent marine service - confirm with the maker's duty-specific guidance.