KraussMaffei MC100: Hydraulic System Pressure Failure — Emergency Diagnostics
Published: 2026-05-27
KraussMaffei MC100 indicates that the main hydraulic system pressure has fallen below the minimum setpoint required for safe machine operation. This is a machine-wide stop alarm — all hydraulic axes (clamp, injection, ejector, core pulls) are...
KraussMaffei MC100 indicates that the main hydraulic system pressure has fallen below the minimum setpoint required for safe machine operation. This is a machine-wide stop alarm — all hydraulic axes (clamp, injection, ejector, core pulls) are disabled until pressure is restored.
Systematic Troubleshooting
Step 1 — Check Hydraulic Oil Level: Low oil level is the single most common cause. Check the sight glass with all cylinders retracted. Top up with the specified hydraulic oil grade (typically HLP 46 or as specified in the machine manual). Step 2 — Inspect for External Leaks: Under machine guarding, check all hydraulic hoses, fittings, and cylinder seals for active leaks. A pinhole leak in a high-pressure line can drain the system in seconds. Step 3 — Test Pressure Relief Valve: A relief valve stuck partially open will bleed pressure back to the tank. Listen for continuous flow noise at the tank return line when the pump is running but no axes are moving. Step 4 — Check Accumulator Pre-Charge: On KM machines with bladder accumulators, the nitrogen pre-charge pressure should be checked with a nitrogen gas charging kit. A ruptured bladder results in zero accumulator function, causing pressure spikes and drops. Step 5 — Pump Diagnosis: If the pump motor runs but pressure does not build, the pump itself may have internal damage (broken vanes in a vane pump, or worn pistons in an axial piston pump). Measure case drain flow — excessive case drain indicates internal pump leakage.
Alarm Details
| Alarm Code | MC100 |
|---|---|
| Brand / Machine | KraussMaffei |
| Severity | Critical (Machine Stop — Hydraulic Failure) |
| Component | Hydraulic Pump / Pressure Relief Valve / Accumulator |
| Affected Systems | Main Hydraulic Circuit — All Axes |
Troubleshooting Protocol
Identify which zone/component triggered the alarm. Record the error code, timestamp, and any measured deviation values shown on the diagnostic screen.
Power down the machine and follow Lock-Out Tag-Out procedures. Visually inspect the affected component for physical damage, loose connections, polymer leakage, or carbonized material.
Using a multimeter, check resistance/continuity on the affected circuit. Verify SSR functionality and fuse integrity. Compare readings to OEM specifications.
Replace the failed component with an OEM-approved part. Do not substitute with generic equivalents unless validated for the specific machine model and operating conditions.
Restart the machine, verify the alarm is cleared, run a test cycle, and document the root cause, repair performed, and parts replaced in the machine maintenance log.
Equivalents & Cross-References
| Equivalent / Alternate | Action |
|---|---|
| engel-alarm-510 | |
| netstal-alarm-301 |
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References & Industry Standards
- ASTM International. Standard Specifications for Engineering Plastics & Thermoplastics. astm.org
- UL Prospector. Plastics & Elastomers Material Database. ulprospector.com
- MatWeb. Material Property Data for Engineering Thermoplastics. matweb.com
- ISO 1043. Plastics — Symbols and Abbreviated Terms. iso.org