Daikin Heat Pump Error Code F6

F6 indicates a high pressure control fault in cooling mode triggered when the outdoor heat exchanger thermistor reads above 57.5 to 61 degrees Celsius. The system detects that the outdoor coil is overheating, which signals that refrigerant pressure on the high side has risen to a potentially damaging level. The unit shuts down automatically to protect the compressor and refrigerant circuit.

No. The F6 error triggers an automatic shutdown precisely to prevent serious damage to the compressor and other high-pressure components. Repeatedly resetting and running the unit without resolving the root cause can lead to compressor failure, which is a costly repair. Leave the unit off until the underlying issue is identified and corrected.

Resetting the unit will clear the active fault and allow the system to restart, but the error will return if the underlying cause has not been fixed. A reset is useful for confirming whether the fault was a one-time event caused by a temporary condition such as an unusually hot day combined with reduced airflow, but it is not a repair. If F6 returns after a reset, further diagnosis is needed.

Some causes of F6 are DIY-friendly, such as cleaning the outdoor coil, removing debris or vegetation blocking the unit, and ensuring there is adequate clearance around the outdoor cabinet. However, if the fault persists after addressing airflow issues, the problem may involve the fan motor, refrigerant charge, or thermistor, which require a qualified HVAC technician to diagnose and repair safely.

Repair costs vary widely depending on the cause. A professional coil cleaning service typically runs in the range of $75 to $200. An outdoor fan motor replacement can cost between $250 and $600 including labor. Refrigerant adjustment or a thermistor replacement will generally fall somewhere in that same range, though costs depend on your location and the specific unit model.