Daikin F6 Error Code: High pressure control in cooling
Updated October 2026 · Sourced from Daikin documentation
In cooling, the outdoor heat exchanger temperature exceeded the limit, so operation was halted or slowed. The manual lists an installation space that is not large enough, a dirty outdoor coil and a defective outdoor fan motor among the causes.
Is it safe to keep running? Check the steps below first. If it returns with clear airflow and a clean coil, a technician should check the outdoor fan and refrigerant circuit.
F6 at a glance
| Code / how it shows | Meaning | Applies to |
|---|---|---|
| F6 Shown on the remote controller (and as blinking lamps on the indoor unit) | High pressure control in cooling | Daikin FTXS-L / FDXS-L inverter pair ductless series (09 to 36 class, models FTXS09-36LVJU, FDXS09-12LVJU) |
Check this first
Only steps a homeowner can do safely. Do not open electrical panels or the burner area.
- Make sure nothing blocks airflow around the outdoor unit (plants, debris, covers).
- Switch off power and gently rinse dust or debris off the outside of the outdoor coil with a garden hose if it is dirty. Do not use a pressure washer.
- Switch the unit off at the breaker, wait a minute, then switch it back on and see whether the code returns.
🛑 Stop and call a licensed pro if
- If it returns with clear airflow and a clean coil, a technician should check the outdoor fan and refrigerant circuit.
- Any code pointing to refrigerant, the compressor, high pressure or the outdoor unit board. Refrigerant work legally needs a certified technician.
- Burning smell, sparks, or a breaker that trips again after a reset.
- Water leaking from the indoor unit that does not stop after the drain is clear.
Safe first steps for any Daikin code
- Write down the exact code and how it shows (remote display or number of lamp blinks). Similar codes mean different things on different series.
- Turn the system off at the remote, switch off the breaker or disconnect for the unit, wait a few minutes, then turn it back on.
- Clean or replace the indoor unit air filters, and make sure nothing blocks the indoor or outdoor unit.
- Check that the condensate drain line is not blocked or kinked where you can see it.
- Replace the remote controller batteries if the display is dim or the unit does not respond.
Source: Daikin Service Manual SiUS091133 - FTXS-L / FDXS-L Series, Troubleshooting p.123. Codes are series-specific, so your unit's own manual is the final word. Reviewed October 2026.
Shaun Cain · Certified HVAC & Refrigeration Technician · Ask an HVAC technician