Fujitsu Mini-Split OPERATION 5 flashes, TIMER 8 flashes, ECONOMY flashing: Intake grille not closed
Updated October 2026 · Sourced from Fujitsu documentation
🧭 Check a few things first
If the intake grille is not completely closed, the air conditioner will not operate and the lamps flash in this pattern.
Is it safe to keep running? Check the steps below first. If the pattern continues with the grille closed, call authorized service personnel.
OPERATION 5 flashes, TIMER 8 flashes, ECONOMY flashing at a glance
| Code / how it shows | Meaning | Applies to |
|---|---|---|
| OPERATION 5 flashes, TIMER 8 flashes, ECONOMY flashing OPERATION lamp flashes 5 times, then TIMER lamp 8 times, repeating, while ECONOMY keeps flashing | Intake grille not closed | AOU9-12-15RLS2 / ASU RLS2 wall-mounted series |
Check this first
Only steps a homeowner can do safely. Do not open electrical panels or the burner area.
- Turn the unit off and close the intake grille fully, with the grille tabs seated and the grille stay in place.
- Make sure the air filters are fitted properly behind the grille.
- Restart the unit.
🛑 Stop and call a licensed pro if
- If the pattern continues with the grille closed, call authorized service personnel.
- Any code pointing to refrigerant, the compressor, high pressure or the outdoor unit board. Refrigerant work legally needs a certified technician.
- Burning smell, sparks, or a breaker that trips again after a reset.
- Water leaking from the indoor unit that does not stop after the drain is clear.
Safe first steps for any Fujitsu code
- Write down the exact code and how it shows (remote display or number of lamp blinks). Similar codes mean different things on different series.
- Turn the system off at the remote, switch off the breaker or disconnect for the unit, wait a few minutes, then turn it back on.
- Clean or replace the indoor unit air filters, and make sure nothing blocks the indoor or outdoor unit.
- Check that the condensate drain line is not blocked or kinked where you can see it.
- Replace the remote controller batteries if the display is dim or the unit does not respond.
Source: Fujitsu General Operating Manual (OM) AOU9-12-15RLS2, Cleaning the Air Filters section, p.20. Codes are series-specific, so your unit's own manual is the final word. Reviewed October 2026.
Shaun Cain · Certified HVAC & Refrigeration Technician · Ask an HVAC technician
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