How House Works

Daikin F3: high discharge pipe temperature

By How House Works EditorialBased on Daikin manualsChecked against sources Updated

Daikin remote controller display

F3

“HIGH TEMPERATURE DISCHARGE PIPE CONTROL”

FTXM-WVJU9, FTXQ-ASBU9, FTX/FTXN-NMVJU, FTXS30/36 · FTXM-WVJU9 Operation Manual, p. 50; FTXQ-ASBU9 Operation Manual, p. 28; FTX/FTXN-NMVJU Operation Manual, p. 30; FTXS30/36 Operation Manual, p. 36
Technician

The FTXM-WVJU9 and FTXQ-ASBU9 manuals put F3 in one box with U0, which leads to “Turn off the circuit breaker and call your dealer.” (FTXM-WVJU9 Operation Manual, pp. 49–50; FTXQ-ASBU9 Operation Manual, pp. 27–28). The FTXM-W/V service manual calls F3 “Discharge pipe temperature control” (FTXM-W/V Service Manual SiUS042113EA, p. 96).

What it means

A thermistor on the discharge pipe reads its temperature. When the reading rises above a set limit, the compressor stops; the error clears when the temperature falls below a lower limit. If F3 repeats, the system shuts down, and it resets after about 60 minutes of continuous running without any other error FTXM-W/V Service Manual SiUS042113EA, p. 122.

The FTXS-L service manual prints its limits. On the 15/18 class the compressor stops above 230°F (110°C) and the error clears below 203°F (95°C); on the 24/30/36 class the figures are 248°F (120°C) and 224.6°F (107°C); on the 09/12 class the stop limit depends on compressor frequency, from 210.2°F (99°C) to 230°F (110°C) FTXS-L Service Manual SiUS091133, p. 121. Those numbers are for FTXS-L units only.

A faulty discharge pipe temperature sensor has its own code in the owner’s tables, J3 FTXM-WVJU9 Operation Manual, p. 50. The service manual still lists a defective discharge pipe thermistor among the causes of F3 FTXM-W/V Service Manual SiUS042113EA, p. 122.

Check these first

The owner’s manuals give no owner check for F3:

  1. Check that the OPERATION lamp blinks at about 0.5-second intervals and read the code, as described in the Daikin code guide FTXM-WVJU9 Operation Manual, p. 49; FTXQ-ASBU9 Operation Manual, p. 27.
  2. On FTXM-WVJU9 and FTXQ-ASBU9 units, F3 is in the same box as U0, and the box leads to “Turn off the circuit breaker and call your dealer.” FTXM-WVJU9 Operation Manual, pp. 49–50; FTXQ-ASBU9 Operation Manual, pp. 27–28.
  3. On FTX/FTXN-NMVJU and FTXS30/36 units the manuals have only the general rule for a blinking lamp: restart with the circuit breaker, and if the lamp still blinks, check the code and call your dealer or the service shop FTX/FTXN-NMVJU Operation Manual, p. 27; FTXS30/36 Operation Manual, p. 34.
  4. On FTX/FTK-BXVJU units the poster says to switch off the power when you notice a malfunction and to call your local dealer or serviceman if the fault persists FTX/FTK-BXVJU Operation Manual, p. 1, section 10.

When to call a licensed technician

The FTXM-W/V service manual lists these causes for F3 FTXM-W/V Service Manual SiUS042113EA, p. 122:

  • a defective discharge pipe thermistor, or a defective outdoor heat exchanger thermistor or outdoor temperature thermistor;
  • a defective electronic expansion valve or its coil, or a defective four way valve;
  • refrigerant shortage or water mixed in the refrigerant;
  • a defective stop valve or a defective outdoor unit PCB.

The AXVJU manual’s list is close and names water mixed in the local piping AXVJU Service Manual SM-5WM-Y-NA-B1, p. 46. Several of these causes are in the refrigerant circuit, and refrigerant work is for a technician certified under EPA Section 608. Daikin’s service manual says: “Servicing shall be performed only as recommended by the manufacturer and licensed or certified in their jurisdiction.” FTXM-W/V Service Manual SiUS042113EA, p. 2.

Notes for different models

  • FTX/FTK-BXVJU, the remote manuals and the AXVJU service manual call F3 “Discharge pipe overheat” FTX/FTK-BXVJU Operation Manual, p. 1, section 9; BRC52B Remote Controller Manual, p. 1-3; BRC51D61 Wired Remote Controller Manual, p. 11; AXVJU Service Manual SM-5WM-Y-NA-B1, p. 34. The FTX-W and FTXS-L service tables call it “Discharge pipe temperature control” FTX-W Service Manual SiUS042228E, p. 68; FTXS-L Service Manual SiUS091133, p. 94.
  • F8, on FTXM-WVJU9, FTXQ-ASBU9 and FTX30/36WVJU9 units, is a separate code for compressor internal temperature. The FTXM-W/V manual stops operation when the discharge pipe thermistor reads above 261.5°F (127.5°C) during forced cooling operation and lists air intrusion among the causes FTXM-W/V Service Manual SiUS042113EA, p. 126. On FTXM-WVJU9 units F8 shares the U0 and F3 box FTXM-WVJU9 Operation Manual, p. 49.

Related Daikin codes

  • U0 “REFRIGERANT SHORTAGE”
  • J3 “FAULTY DISCHARGE PIPE TEMPERATURE SENSOR”
  • F8 “OPERATION HALT DUE TO COMPRESSOR INTERNAL TEMPERATURE”

See also

Other ductless mini-splits: Fujitsu, Mitsubishi Electric, MrCool

All Daikin codes

Daikin is a trademark of its owner. How House Works is not affiliated with or endorsed by Daikin.

Sources

  1. Daikin Comfort Technologies North America (document library). FTXM-WVJU9 Operation Manual. 3P686871-1A, page stamp 2022/05/30; covers FTXM09/12/18/24WVJU9. Listed under ATMOSPHERA in Daikin's document library.. Accessed Oct 13, 2026.
  2. Daikin Comfort Technologies North America (document library). FTXQ-ASBU9 Operation Manual. 3P741457-13J, English; page stamp 2024/11/19; covers FTXQ09ASBU9 and FTXQ12ASBU9. Listed under OTERRA 115V. The library list shows only the French and Spanish files of this manual; the English file is served at this address.. Accessed Oct 13, 2026.
  3. Daikin Comfort Technologies North America (document library). FTX/FTXN-NMVJU Operation Manual. 3P379751-4C, page stamp 11/6/2015; covers FTX09/12/15/18/24NMVJU and FTXN09/12/18/24NMVJU. Not in Daikin's current library list; the file is still served from daikincomfort.com.. Accessed Oct 13, 2026.
  4. Daikin Comfort Technologies North America (document library). FTXS30/36 Operation Manual. 3P228444-4K, page stamp 3/28/2013; covers FTXS30HVJU, FTXS36HVJU, FTXS30LVJU and FTXS36LVJU. Not in Daikin's current library list; the file is still served from daikincomfort.com.. Accessed Oct 13, 2026.
  5. Daikin Comfort Technologies North America (document library). FTX/FTK-BXVJU Operation Manual. 3P601789-2 E (cover label); no printed date; covers FTX, FTXB and FTK09/12/18/24BXVJU; R410A. A poster with one page per language (English, Spanish, French) and no page numbers: citations give PDF page 1 and the poster section. The same file is also listed under ENTRA.. Accessed Oct 13, 2026.
  6. Daikin Comfort Technologies North America (document library). BRC52B Remote Controller Manual. OM-BRC52B-0617(2)-DAIKIN USA, Part No. R08019046595B; print stamp 10/30/2017; covers remote controllers BRC52B61/62/63/64/65. Does not name the indoor units. The library lists it under ENTRA.. Accessed Oct 13, 2026.
  7. Daikin Comfort Technologies North America (document library). BRC51D61 Wired Remote Controller Manual. R08019049297B; print stamp 7/12/2022. Does not name the indoor units. The library lists it under OTERRA (cooling only) and ENTRA.. Accessed Oct 13, 2026.
  8. Daikin Comfort Technologies North America (document library). FTXM-W/V Service Manual SiUS042113EA. SiUS042113EA, revision of 01/2023; covers FTXM09/12/18/24WVJU9 and FTXM-VVJU with RXM outdoor units. Accessed Oct 13, 2026.
  9. Daikin Comfort Technologies North America (document library). AXVJU Service Manual SM-5WM-Y-NA-B1. SM-5WM-Y-NA-B1; no printed date (PDF created 2021-09-29); covers FTKB/FTKN/FTXB/FTXN09/12/18/24AXVJU. Listed under ENTRA.. Accessed Oct 13, 2026.
  10. Daikin Comfort Technologies North America (document library). FTX-W Service Manual SiUS042228E. SiUS042228E, first edition 10/2022; covers FTX30/36WVJU9 with RK30/36WMVJU9 or RX30/36WMVJU9. Listed under POLARA.. Accessed Oct 13, 2026.
  11. Daikin Comfort Technologies North America (document library). FTXS-L Service Manual SiUS091133. SiUS091133; no printed date (PDF created 2013-01-11); covers FTXS09–36LVJU and FDXS09/12LVJU. Not in Daikin's current library list; the file is still served from daikincomfort.com.. Accessed Oct 13, 2026.