Daikin Mini-Split Code F3
Soft lockout
Discharge pipe temperature control. The compressor discharge line got too hot (about 221 to 248F depending on model and speed) so the compressor stopped. It clears once the pipe cools back down.
Manual wording: “F3 Discharge pipe temperature control”
Documented for: FTXS-L, H-Series, FTXM-W/V, RMXS outdoor units
Likely causes, most common first
- Refrigerant shortage
- Defective discharge pipe thermistor (or outdoor heat exchanger / outdoor temperature thermistor)
- Defective electronic expansion valve or coil
- Defective four way valve
- Water mixed in refrigerant
- Defective stop valve
- Defective outdoor unit PCB
What you can safely check yourself
- Check the outdoor unit is clear of leaves, snow and debris and has clearance around it
- Check and replace the indoor unit air filters
- Turn the system off at the breaker or disconnect switch and back on once
When to call a technician
F3 is nearly always low refrigerant charge or a restriction. A technician has to check charge and the expansion valve - do not just keep resetting it.
A Daikin mini-split throwing this code repeatedly has a reason — clearing the code without fixing the cause just hides it.
Sources
- Service Manual - Inverter Pair FTXS-L Series / FDXS-L Series (SiUS091133) (Daikin, FTXS09/12/15/18/24/30/36LVJU wall mount, FDXS09/12LVJU ducted, RKS/RXS09-36LVJU outdoor) · checked 2026-08-25
- Service Manual - Inverter Pair Wall Mounted Type H-Series (SiUS04-924_A) (Daikin, FTXS30/36HVJU indoor, RKS30/36HVJU and RXS30/36HVJU outdoor) · checked 2026-08-25
- Service Manual - Inverter Pair Wall Mounted Type FTXM-W/V Series (SiUS042113EA) (Daikin, FTXM-W / FTXM-V (Daikin Atmosphera) wall-mount heat pump) · checked 2026-08-25
- Service Manual - Multi-Split Type Air Conditioners RMXS-L Series (SiUS181631EA) (Daikin, RMXS48LVJU outdoor, BPMKS048A2U/049A3U branch provider, CTXG/CTXS/FTXS/CDXS/FDXS/FVXS/FFQ indoor units) · checked 2026-08-25