E4 04 (FJM Outdoor) — Outdoor unit overload (safety control)

What does E4 04 mean?

The FJM outdoor unit displays E4 04 when its safety control has detected an overload condition, leading to the compressor stopping to prevent damage. This suggests the unit is under too much strain.

• Incorrect pipe length (too long or too short)
• Refrigerant leakage or incorrect refrigerant charge
• Restricted airflow to the outdoor unit's coils

Click steps to track your progress.

1. 1

   Turn off the FJM outdoor unit at the main circuit breaker and wait 10-15 minutes to allow the system to reset.

2. 2

   Ensure the outdoor unit's coils are clean and there are no airflow obstructions.

3. 3

   Verify that all indoor unit air filters are clean and not restricting airflow.

4. 4

   Restore power and attempt to restart the system. If the issue persists, a qualified technician needs to check pipe lengths and refrigerant charge.