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237311

HF reactor module: Overtemperature heat sink

Siemens · FC1765DC Controller

What does 237311 mean?

This fault indicates that the heat sink temperature of the HF reactor module has exceeded the permissible limit, triggering an OFF2 reaction and stopping the drive. Causes include insufficient cooling (e.g., fan failure), module overload, or an ambient temperature that is too high, leading to a critical thermal condition. This fault requires immediate attention as sustained overtemperature can lead to irreversible damage to the reactor module and impact the drive's operational integrity and safety.

Common Causes

  • Cooling fan failure or reduced efficiency, leading to inadequate heat dissipation from the heat sink of the HF reactor module.
  • Blocked or fouled heat sink fins preventing effective heat transfer to the ambient air due to dust or foreign material buildup.
  • Insufficient thermal paste or improper mounting of power components to the heat sink, increasing thermal resistance.
  • Sustained operation of the reactor module above its nominal current (r0067), generating excessive heat beyond the heat sink's capacity.
  • Malfunctioning heat sink temperature sensor (e.g., NTC thermistor) or its connection (e.g., X11 terminal), providing false high readings.

Repair Steps & Checklist

Click steps to track your progress.

  1. 1

    Power down the module, visually inspect the cooling fan, and verify fan motor current draw (e.g., 0.1-0.5A) if accessible.

  2. 2

    Clean all heat sink fins thoroughly using compressed air and a non-conductive brush to remove dust and debris.

  3. 3

    Check the mounting bolts and thermal interface material (e.g., thermal paste) between the power semiconductors and the heat sink.

  4. 4

    Monitor the reactor's current (r0067) and compare it to the module's rated continuous current found on the nameplate.

  5. 5

    Measure the resistance of the heat sink temperature sensor at its terminals (e.g., X11) and verify against expected values for ambient temperature.

Browse all codes in this manual (28)
Verified technical data. Last updated: April 2026

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Source: Siemens FC1765DC Controller
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