Fujitsu Mini-Split Code 23
Hard lockoutShown as: OPERATION lamp blinks 2 times, TIMER lamp blinks 3 times, ECONOMY lamp blinking continuously
Combination error. The outdoor unit has detected that the indoor unit connected to it is not a matching model - for example a multi-zone indoor head wired to a single-zone condenser, or an unsupported condenser on a multi-zone system.
Manual wording: “Combination Error - The outdoor unit received a signal that the applied indoor unit is that of a multi type.”
Documented for: RGLX, RL2/RLS3/RLB/RLXB wall mounted, RLF/RLF1 multi-zone
Likely causes, most common first
- Mismatched indoor and outdoor unit models
- Incorrect wiring between the indoor and outdoor units
- An unsupported multi-zone condenser installed for the indoor units fitted
- Failed outdoor main PCB (after the model match is confirmed correct)
When to call a technician
This means the equipment pairing or wiring is wrong. Only the installing contractor can verify model matching and correct the connection.
A Fujitsu mini-split throwing this code repeatedly has a reason — clearing the code without fixing the cause just hides it.
Source
- 410A Mini-Split Troubleshooting Guide (Part # 6-26-FG2020 Rev. 5/2019) (Fujitsu General America, Inc., All R410A Halcyon mini-splits: RGLX, RL2/RLS3/RLS3H/RLS3Y/RLB/RLXB/RLXEH wall mounted, RLF/RLF1 multi-zone indoor units, RLXFZ multi-zone outdoor units, RML/RMLQ, RULX/RSLX universal-mount, RCLX cassettes) · checked 2026-08-25