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Non-Operating Unit Warm/Water Sound

Non-operating indoor unit feels warm with water flow sound - Refrigerant flow

Mitsubishi Electric · MSZ-AP Air Conditioners

What does Non-Operating Unit Warm/Water Sound mean?

In a multi-system setup, an indoor unit that is not currently operating may feel slightly warm, and you might hear a sound similar to water flowing from it.

Common Causes

  • A small amount of refrigerant continues to flow through the indoor unit even when it is not actively operating, especially in multi-system configurations.

Repair Steps & Checklist

Click steps to track your progress.

  1. 1

    This is a normal phenomenon in multi-system installations and does not indicate a malfunction; no action is required.

  2. 2

    The slight warmth and sound are a natural result of the shared refrigerant lines.

  3. 3

    Continue using the operating units as normal without concern for the non-operating unit.

Browse all codes in this manual (87)
Verified technical data. Last updated: April 2026

Related Faults

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Source: Mitsubishi Electric MSZ-AP Air Conditioners
Open Manual (Page 17)Search more codes in this manual