What causes Siemens SINUMERIK alarm 120022?

Normal control operation generated this status message. User action or program command triggered this notification. System configuration or commissioning activity produced this message. Machine data or parameter change created this notification.

How do I fix Siemens SINUMERIK alarm 120022?

1. Read the complete message text on the SINUMERIK screen — note any parameter values shown. 2. If action is required, follow the instructions in the message. 3. Acknowledge the message on the operator panel to continue operation. 4. Consult the Siemens SINUMERIK alarm documentation for message 120022 if clarification is needed. 5. If this message appears unexpectedly, review recent parameter or configuration changes.

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Siemens SINUMERIK Controller

Program/G-code · Intermediate · 30-120 minutes

Alarm 120022

Siemens 840D 120022 - PCU fan monitoring housing fan 2

This alarm indicates a failure or malfunction of housing fan 2 in the PCU (Power Control Unit). The fan monitoring system has detected that the fan is not operating properly, which can lead to overheating and system damage.

Siemens SINUMERIKProgram/G-codeIntermediate30-120 minutes

120022

Siemens 840D 120022 - PCU fan monitoring housing fan 2

PCU fan monitoring housing fan 2

Root Cause Summary

This alarm indicates a failure or malfunction of housing fan 2 in the PCU (Power Control Unit). The fan monitoring system has detected that the fan is not operating properly, which can lead to overheating and system damage.

Safety

Refer to Siemens documentation
Ensure qualified technician performs repairs

Causes and Fixes

1
Power down safely
Turn off the machine and disconnect power following lockout/tagout procedures.
2
Inspect fan
Visually inspect housing fan 2 for damage, obstruction, or debris buildup.
3
Clean or replace
Clean debris if present, or replace fan if damaged. Ensure proper electrical connections.
4
Test operation
Power up system and verify fan operation and alarm clearance.

Service Recommendedmedium confidence

Call a technician if:

·Always - electrical work on PCU requires qualified personnel
·If fan replacement is needed
·If wiring repairs are required
·If alarm persists after basic cleaning

Prevention

Regular cleaning of fan filters and housing
Periodic inspection of fan operation during maintenance
Keep PCU area free of debris and obstructions
Monitor ambient temperature in electrical cabinet

Common Mistakes

Ignoring the alarm and continuing operation
Attempting electrical repairs without proper qualifications
Not following lockout/tagout procedures

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Seeing another alarm with this one? Enter the code.

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Always verify with your machine manual or a certified technician before performing service procedures.