MAN Energy Solutions Compressor Fault Codes — Quick Reference
MAN Energy Solutions large reciprocating and centrifugal compressors are used in refineries, chemical plants, and gas processing. Their control systems (PLC-based, often Siemens or ABB) generate alarms and shutdown signals tied to process, mechanical, and safety conditions.
| Fault Category | Typical Alarm | Quick Fix |
|---|---|---|
| High Discharge Temp | Discharge gas temperature high | Check cooling water flow and coolers |
| Low Lube Oil Pressure | Oil system fault | Check oil pump, filter, and level |
| High Vibration | Mechanical issue detected | Stop and inspect bearings, couplings |
| High Differential Pressure | Valve or piston ring issue (recip) | Inspect suction/discharge valves |
| Rod Drop | Piston rod wear detected | Measure rod drop, replace packing |
| High Coolant Temp | Cooling water outlet too hot | Check cooling water flow and fouling |
| High Gas Temp (inter-stage) | Intercooler performance low | Clean intercooler |
| ESD Activated | Emergency shutdown | Investigate shutdown cause before restart |
Most Common Faults
High Discharge Temperature
In large recips, high discharge temp usually signals a valve problem — worn or broken suction or discharge valves reduce volumetric efficiency and raise discharge temperature. Also check cooling water flow rate and temperature to the aftercooler.
High Vibration
MAN compressors use vibration probes on crossheads and bearings. A vibration trip requires immediate shutdown. Root causes include loose connections, worn bearings, piston ring failure, or liquid carry-over into the cylinder. Never run through a vibration alarm on a large recip.
Rod Drop / Rider Ring Wear
Rider rings support the piston and rod in horizontal cylinder compressors. As they wear, the piston drops and the rod drop sensor triggers. Schedule a planned shutdown to replace rider rings before they allow metal-to-metal contact.
Parts Often Needed
| Part | Notes |
|---|---|
| Suction/discharge valve assemblies | Most common recip wear item |
| Rider rings and piston rings | Replace on rod drop alarm |
| Packing rings | Inspect when discharge temp is high |
| Lube oil filter elements | Replace at interval |
Need Replacement Parts?
Finding the right replacement parts for your equipment is critical to getting it running again. Check current prices on Amazon — prices and availability change frequently.
Jump to Fix
- High discharge temp → Check cooling water → Inspect valves → Check intercooler
- High vibration → Stop immediately → Inspect bearings and crosshead → Check for liquid
- Rod drop → Measure and record → Schedule rider ring replacement
When to Call a Pro
MAN Energy compressors require factory-trained personnel for valve replacement, piston ring service, and alignment. Contact MAN Energy Solutions service for major overhauls.