EL
ErrorLib
Brands
||
  1. Home
  2. Lenze
  3. 9300 Series
  4. OH
About·Privacy·Terms

ErrorLib — Industrial Fault Code Library

Disclaimer: ErrorLib is an independent technical reference tool. While we aim for accuracy, always verify with the manufacturer’s official service manuals before performing maintenance on industrial equipment. ErrorLib is not affiliated with the brands listed.

OH

Heatsink Overtemperature Warning

Lenze · 9300 Series

What does OH mean?

The drive has detected a heatsink overtemperature condition. This is a warning that indicates the heatsink temperature has exceeded its normal operating range, but the drive continues to operate in a controlled manner.

Common Causes

  • Blocked cooling fins on the heatsink due to dust, dirt, or debris accumulation, restricting airflow.
  • Failure of the cooling fan(s) on the drive, or reduced fan speed due to bearing wear or power supply issues.
  • Ambient temperature in the control cabinet exceeding the drive's specified maximum operating temperature (e.g., 40°C or 50°C).
  • Insufficient clearance around the drive for proper airflow or inadequate cabinet ventilation causing heat buildup.
  • Continuous operation at high load current (P0-04) close to or exceeding the drive's rated output.

Repair Steps & Checklist

Click steps to track your progress.

  1. 1

    1. Power down the drive, use compressed air to thoroughly clean dust and debris from the heatsink fins and cooling fan inlets/outlets.

  2. 2

    2. Verify the cooling fan operation by observing its rotation during startup and checking for unusual noises or vibrations.

  3. 3

    3. Measure the ambient temperature inside the control cabinet using a thermometer and compare it to the drive's specified maximum.

  4. 4

    4. Check for proper cabinet ventilation (e.g., verify air filters are clean, fans are operating, and exhaust vents are clear).

  5. 5

    5. Monitor the drive's output current (P0-04) and heatsink temperature (P0-02) during operation to identify peak loads and corresponding temperature rises.

Browse all codes in this manual (145)
Verified technical data. Last updated: April 2026

Related Faults

0011OC1 Overcurrent in motor cable0012OC2 Motor cable earth fault0013OC3 Overload during acceleration
Source: Lenze 9300 Series
Open Manual (Page 449)Search more codes in this manual