H4
Airwell System Lockout / Multiple Protection Triggered

Indoor unit shows H4; unit may not start or may shut down quickly; often indicates a protection lockout.

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Safety Warning

This repair may involve working with high voltage components or water connections. Always unplug the appliance before removing any panels.

If you are not confident in your ability to perform this repair safely, we strongly recommend contacting a professional technician.

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Possible Causes

Repeated overcurrent or overheat events, Multiple sensor faults, PCB internal protection, Incorrect wiring or power supply

How to Fix / Troubleshooting

Safety: Turn off power at the breaker before any inspection.

Steps:

  • 1. Note history: If H4 appears after other error codes (H3, F4, etc.), address those root causes first.
  • 2. Power reset: Turn off power for 30 minutes to clear lockout. Restore power and observe operation.
  • 3. Check for obvious faults: Inspect indoor and outdoor units for burnt smells, unusual noises, or visible damage.
  • 4. Professional diagnosis: H4 usually indicates serious or repeated faults. A technician should perform a full diagnostic, including electrical and refrigerant checks.
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Repair Difficulty

Professional Required 5/5
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