237311

HF reactor module: Overtemperature heat sink

Siemens · DAsl Diagnostics and Alarms

What does 237311 mean?

The heat sink temperature of the HF reactor module has surpassed its maximum permissible limit. This condition is often due to insufficient cooling (e.g., fan malfunction), an overloaded system causing the module to generate excess heat, or an ambient temperature that is too high for safe operation. Persistent high temperatures can lead to damage and failure of the reactor module.

Common Causes

  • Malfunction or blockage of the cooling fan specifically designed for the reactor module's heat sink.
  • Accumulation of dust and debris on the heat sink fins, reducing its heat dissipation efficiency.
  • Operating the system with sustained high output current (r0067) which exceeds the reactor's thermal design limits.
  • High ambient temperature within the electrical cabinet, hindering effective cooling of the heat sink.
  • Faulty thermistor or temperature sensor embedded in the heat sink, reporting an erroneous high temperature.

Repair Steps & Checklist

Click steps to track your progress.

  1. 1

    Power down and visually inspect the heat sink and fan of the HF reactor module for obstructions or fan motor failure.

  2. 2

    Use compressed air or a brush to thoroughly clean any dust or foreign material from the heat sink fins.

  3. 3

    Monitor the system's output current (r0067) and reduce the load if it consistently operates near or above the reactor's rated current.

  4. 4

    Measure the internal cabinet temperature with a thermometer and compare it against the module's specified maximum operating temperature.

  5. 5

    If possible, verify the heat sink temperature sensor's resistance values against manufacturer specifications, or compare with an external IR thermometer.

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Verified technical data. Last updated: March 2026

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Source: Siemens DAsl Diagnostics and Alarms