HVAC Code Lookup

Daikin Mini-Split Code F6

Warning

On pair systems, high pressure control in cooling - the outdoor coil sensor went above about 140-149F so the unit cut back or halted. On RMXS multi-split systems F6 instead means the system is overcharged with refrigerant.

Manual wording: “F6 High pressure control in cooling”

Documented for: FTXS-L, H-Series, FTXM-W/V pair systems; RMXS multi-split (refrigerant overcharged)

Likely causes, most common first

  1. The installation space is not large enough
  2. Dirty outdoor heat exchanger
  3. Defective outdoor fan motor
  4. Defective stop valve
  5. Defective electronic expansion valve or coil
  6. Defective outdoor heat exchanger thermistor
  7. Defective outdoor unit PCB
  8. Refrigerant overcharge (multi-split)

What you can safely check yourself

  • Check the outdoor coil is not blocked with dirt, cottonwood, leaves or grass clippings
  • Clear shrubs, fencing or stored items crowding the outdoor unit
  • Check the outdoor fan is running and not obstructed
  • Turn the system off at the breaker or disconnect switch and back on once

When to call a technician

If the outdoor unit has clear airflow and a clean coil and F6 persists, a technician needs to check charge, the fan motor and the outdoor coil sensor.

A Daikin mini-split throwing this code repeatedly has a reason — clearing the code without fixing the cause just hides it.

Sources

Other Daikin codes