F5
Hitachi High Pressure Protection / Condenser Overload

Unit stops with F5, often during cooling in very hot weather

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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

Severely blocked outdoor coil, Outdoor fan not running or slow, Overcharged refrigerant, Non‑condensable gas in system, Faulty high‑pressure switch or sensor

How to Fix / Troubleshooting

Safety first: High refrigerant pressure is dangerous. Do not tamper with service valves or refrigerant lines.

User‑level steps:

  • Clean outdoor coil: Turn OFF power. Clean the coil fins thoroughly with a soft brush and low‑pressure water. Ensure full airflow through the coil.
  • Check outdoor fan: Confirm the fan starts and runs at full speed when the unit is cooling. Remove any obstructions.
  • Clear surroundings: Ensure at least the manufacturer‑recommended clearance around the outdoor unit (typically 30–50 cm sides, 1 m front).

If F5 recurs: A technician must check system pressures, refrigerant charge, and high‑pressure protection devices.

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Repair Difficulty

Professional Required 5/5

Required Part

Outdoor Condenser Coil and High‑Pressure Switch/Sensor
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