Daikin mini split error code UF
Refrigerant piping and wiring mismatch (multi-split).
- TypeFault
- SystemOperation
- Can I fix it?Homeowner checks, then maybe a tech
What UF means on a Daikin
On a multi-split, an indoor unit's refrigerant lines are connected to one port and its wiring to another, so the outdoor unit cannot match them up.
On this platform, UF is a fault: something has failed or is disconnected and needs diagnosis.
Common causes
- Line set and cable for a zone landed on different ports at the outdoor unit.
- A service valve not opened on one port.
How to fix it yourself
Work through the checks below first; they resolve most cases. If they do not, the repair itself may need a technician.
- With power off, check that each zone's line set and cable go to the same lettered port.
- Open every service valve fully.
- Reset the system: switch the breaker (or the outdoor disconnect) off, wait a full five minutes so the boards fully discharge, then switch it back on and restart from the remote.
Switch off power at the breaker before opening either unit. Capacitors in the outdoor unit hold a charge for several minutes after power is cut.
When to call a technician
A technician can confirm which zone is crossed.
Which Daikin units show UF
This page applies to Daikin Aurora, 19 Series, Atmosphera, Emura, Quaternity and MXS multi-zone units. Daikin's own documentation lists UF as "Refrigerant piping and wiring mismatch (multi-split)", the same definition used across the Daikin it is built on. If your unit shows a code with a different shape (for example a four-character code, or a plain number), it is from a different table; use the lookup with your exact code.
Where Daikin shows this code
Most Daikin wall units do not show the code on the unit; the operation lamp blinks. To read the code, point the remote at the unit, hold CANCEL (or Timer Cancel) for about 5 seconds until 00 shows, then press CANCEL repeatedly. Each press shows a code; when the unit gives a long continuous beep instead of two short beeps, the code on the remote is the stored fault. Units with a wired controller show the code directly. A and C codes are indoor-unit faults, E, F, H, J, L and P codes are outdoor-unit faults and protections, and U codes are system-level problems such as communication, power supply and refrigerant shortage.
Other Daikin codes
Same part of the system as UF:
UF on other brands
The same characters do not always mean the same thing. Check the brand on your unit.
- Mitsubishi Electric UF Compressor over-current (locked compressor)
- Goodman UF Refrigerant piping and wiring mismatch (multi-split)
Questions people ask
Can I reset a Daikin UF code myself?
Yes. Turn the system off at the breaker for five minutes, then restart it. If UF comes back, the fault is real and needs the checks above.
Is it safe to keep running a Daikin showing UF?
The unit will usually refuse to run, or run with reduced output, until the fault is cleared. Repeated resets do not fix anything and can mask a problem that is getting worse.
Do I need a technician for Daikin UF?
Work through the checks below first; they resolve most cases. If they do not, the repair itself may need a technician. A technician can confirm which zone is crossed.
Sources
- Daikin residential (RA) service manuals (error code tables)
- Daikin operation manuals (remote controller self-diagnosis)
Updated September 2026. Codes and definitions vary by model year. If your manual disagrees with this page, your manual wins. Send a correction.