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ErrorLib — Industrial Fault Code Library

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E31

Unit Address Duplication / Outdoor Unit Address Error

Mitsubishi Electric · R410A Systems

What does E31 mean?

An indoor unit has a duplicated address number (within the range U00-U47), or there is an incorrect address setting for the outdoor unit. This leads to communication conflicts and prevents proper system control.

Common Causes

  • Duplicate unit addresses detected on the control network.
  • Outdoor unit's address setting is incorrect or duplicated.
  • Conflict with a newly added unit's address.
  • Re-addressing process failed to resolve conflicts.

Repair Steps & Checklist

Click steps to track your progress.

  1. 1

    Review and verify the DIP switch or parameter settings for the address of each indoor unit, ensuring all are unique within the U00-U47 range.

  2. 2

    Check the outdoor unit's address settings to ensure it is configured correctly and not conflicting with indoor unit addresses.

Browse all codes in this manual (60)
Verified technical data. Last updated: April 2026

Related Faults

E0Transmitting/Receiving Signal ErrorE112Auto Addressing Conflict / Factory Address Setting ErrorE14Master/Slave System Configuration Error
Source: Mitsubishi Electric R410A Systems
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