UA

Compressor Overcurrent (Terminal Relay Operation)

Mitsubishi Electric · R410A Systems

What does UA mean?

The compressor has experienced an overcurrent condition, specifically detected via the terminal relay. This indicates an electrical overload or fault related to the compressor's power circuit or the relay itself.

Common Causes

  • Compressor overcurrent detected.
  • Operation of the terminal relay due to current.
  • Excessive current draw from the compressor motor.

Repair Steps & Checklist

Click steps to track your progress.

  1. 1

    Measure compressor running current on all three phases using a clamp meter — compare to nameplate FLA.

  2. 2

    Inspect the compressor terminal relay for signs of damage, overheating, or pitting on its contacts.

  3. 3

    Check for loose connections at the compressor terminals and at the terminal relay itself.

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Verified technical data. Last updated: March 2026

Related Faults

Source: Mitsubishi Electric R410A Systems