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Hissing or clicking sound

Hissing or clicking sound from unit

MHI · Air Conditioning

What does Hissing or clicking sound mean?

You hear a hissing or clicking sound from the unit. This sound is caused by the normal operation of the refrigerant control valves or other electric components within the air conditioner.

Common Causes

  • Operation of refrigerant control valves (normal)
  • Operation of electric components (normal)

Repair Steps & Checklist

Click steps to track your progress.

  1. 1

    This is a normal operational sound and does not indicate a fault.

  2. 2

    No action is typically required for this sound.

  3. 3

    Ensure all covers on the indoor and outdoor units are properly closed and secured.

  4. 4

    If the sound is accompanied by a loss of performance, contact your dealer.

  5. 5

    Do not attempt to open the unit to investigate these sounds.

Browse all codes in this manual (124)
Verified technical data. Last updated: April 2026

Related Faults

00Outdoor Board LED only green lights up after startup - No outdoor unit of address 0 / Remote controller transmission wire open1OPERATION INDICATOR lamp blinks 1 time (Pattern A) - Indoor/outdoor unit communication error (Transmitting error - Outdoor unit)14OPERATION INDICATOR lamp blinks 14 times (Pattern A) - Other errors
Source: MHI Air Conditioning
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