HVAC Code Lookup

Fujitsu Mini-Split Code 15

WarningShown as: OPERATION lamp blinks 1 time, TIMER lamp blinks 5 times, ECONOMY lamp blinking continuously

On multi-zone (RLF/RLF1) systems: check-run unfinished. The installer's commissioning 'check run' was never completed, so the system refuses a run command from the remote. On RGLX ducted/cassette models the same pattern means automatic air flow adjustment error (the indoor fan could not complete its airflow learning routine).

Manual wording: “Check-Run Unfinished - When the operation command is inputted by the remote controller without check operation completion.”

Documented for: Multi-zone: ASU7/9/12RLF1, ASU18RLF, ASU15RLS, ASU15RLS2, ASU15RLF1, ASU24RLF, ARU/AUU/AGU RLF series, AOU48RLXFZ (E156). RGLX: AUU/ARU 12-48RGLX

Likely causes, most common first

  1. Multi-zone: the check-run commissioning procedure was not completed after installation
  2. Multi-zone: wrong indoor unit count connected, or an indoor unit was powered on part way through check run
  3. RGLX: indoor fan caught, obstructed, or the motor is locked
  4. RGLX: excessive ambient temperature around the indoor fan motor

What you can safely check yourself

  • Make sure the return air filter is clean and the supply and return grilles are open and unobstructed
  • Turn all indoor units off with their remotes, shut off the breaker/disconnect for 5 minutes, then restore power

When to call a technician

The check-run procedure has to be re-initialized by the installer at the outdoor unit and branch boxes. If this is a new install, call the installing contractor back - the system was never commissioned.

A Fujitsu mini-split throwing this code repeatedly has a reason — clearing the code without fixing the cause just hides it.

Sources

Other Fujitsu codes