FS-Elliott Centrifugal Compressor Fault Codes — Quick Reference
FS-Elliott centrifugal compressors use a dedicated controller (typically the OptiFlow or legacy panel) to monitor surge, bearing temperature, vibration, oil pressure, and process conditions. Unlike rotary screw compressors, centrifugals have unique aerodynamic alarms.
| Fault | Meaning | Quick Fix |
|---|---|---|
| Surge | Compressor operating in unstable region | Reduce discharge pressure or increase flow |
| High Bearing Temp | Bearing running hot | Check oil supply, cooler, and thrust load |
| High Vibration | Rotor or bearing issue | Stop unit, inspect for fouling or damage |
| Low Oil Pressure | Lube oil system fault | Check oil pump, filter, and level |
| High Discharge Temp | Air discharge temperature exceeded | Check intercooler and aftercooler |
| Motor Overload | Motor current too high | Check voltage, load, and inlet conditions |
| Inlet Filter DP High | Inlet filter restricted | Clean or replace inlet filter |
| High Oil Temp | Oil returning too hot | Check oil cooler and water supply |
Most Common Faults
Surge
Surge is the most dangerous condition for a centrifugal compressor. It occurs when flow drops below the minimum stable flow and the compressor loses aerodynamic stability, producing violent pressure reversals. Immediate corrective action: open the blow-off or recycle valve to increase flow. Investigate the root cause — a drop in demand, partial load operation, or discharge pressure too high.
High Vibration
Fouling on the impeller changes the mass balance and increases vibration. An offline water wash or mechanical cleaning may be needed. High vibration can also indicate bearing wear or a damaged impeller — require inspection before restart.
Low Oil Pressure
Centrifugal compressors rely on pressurized lube oil for bearings. Check the oil pressure transmitter, oil pump condition, and filter differential. Low oil pressure trips are non-negotiable — do not attempt to override and restart without identifying the cause.
Parts Often Needed
| Part | Notes |
|---|---|
| Inlet filter element | Amazon | High DP trips are common |
| Oil filter cartridge | Amazon | Replace at service interval |
| Bearing temperature sensors | Amazon | Common alarm source |
| Oil cooler cleaning | Amazon | Required if oil temps rise |
Jump to Fix
- Surge alarm → Open recycle/blow-off → Reduce discharge pressure → Check demand
- High vibration → Stop unit → Check impeller → Inspect bearings
- Low oil pressure → Check pump → Replace filter → Verify oil level
When to Call a Pro
Surge events that repeat, bearing temperature alarms, and vibration faults all require immediate engineering review. Centrifugal compressors run at very high speeds and damage propagates quickly.