What it means
Daikin's US service manual for wall units calls it high pressure control in cooling, and the code clears once the outdoor coil cools down. Daikin's global code list, which also covers its larger systems, words F6 as abnormal high pressure or refrigerant overcharged.
What to check, in order
- Clear around the outdoor unit
Move anything stacked against the outdoor unit and cut back plants so air can get in and out. Daikin's installation check asks whether obstacles block the airflow and whether the hot air blown out is being drawn straight back in.
- Look at the outdoor coil
If the fins on the outdoor unit look very dirty, Daikin's service checks say the coil should be cleaned. Leave that to an engineer.
- Restart with the remote
Daikin's troubleshooting page says to restart from the remote once nothing is blocking the unit.
When to call an engineer
If the area is clear, Daikin's service manual lists a dirty outdoor coil, a faulty outdoor fan motor, a faulty stop valve or expansion valve, a faulty outdoor coil thermistor and a faulty outdoor control board. If the unit is boxed in, Daikin's installation check says it may need moving or turning.
Quick answers
What does the Daikin F6 error code mean?
While cooling, the outdoor coil has got too hot, so the unit has slowed down or stopped to keep the pressure in check. The first cause Daikin lists is not enough space around the outdoor unit. Daikin's US service manual for wall units calls it high pressure control in cooling, and the code clears once the outdoor coil cools down. Daikin's global code list, which also covers its larger systems, words F6 as abnormal high pressure or refrigerant overcharged.
Can I fix Daikin F6 myself?
Easy (about 15 minutes). Start with: clear around the outdoor unit; look at the outdoor coil; restart with the remote. If the area is clear, Daikin's service manual lists a dirty outdoor coil, a faulty outdoor fan motor, a faulty stop valve or expansion valve, a faulty outdoor coil thermistor and a faulty outdoor control board. If the unit is boxed in, Daikin's installation check says it may need moving or turning.
Is Daikin F6 worth repairing?
Usually free. Often fixed by clearing space around the outdoor unit. If not, it needs an engineer.
Checked against
- Daikin Service Manual SiUS042113E, FTXM-V / RXM-V inverter pair wall mounted type (manualslib copy of the Daikin PDF)
- Daikin Service Manual SiUS04-924_A, RXS / FTXS H-series inverter pair wall mounted type (PDF)
- Daikin: Simple Self-Diagnosis by Malfunction Code, SM-TS3, list of error codes (PDF)
- Daikin Global: Troubleshooting, split and multi-split air conditioners
Last reviewed October 2026. Manufacturers update their pages, and your manual is the final word. Spotted a mistake? Email contact@appliance-error-codes.com.