Fujitsu Mini-Split TIMER lamp flashing: Timer or clock fault after power interruption
Updated October 2026 · Sourced from Fujitsu documentation
✅ Usually fine to keep running
After a power interruption the timer can be reset, so the TIMER lamp flashes. The manual says the timer setting needs to be set again.
Is it safe to keep running? Usually yes. No repair is needed. This is a timer fault from a power interruption, not a unit fault.
TIMER lamp flashing at a glance
| Code / how it shows | Meaning | Applies to |
|---|---|---|
| TIMER lamp flashing TIMER lamp on the indoor unit flashes | Timer or clock fault after power interruption | 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.
- Reset the clock and timer on the remote controller.
🛑 Stop and call a licensed pro if
- No repair is needed. This is a timer fault from a power interruption, not a unit fault.
- 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, Operating Tips (Auto Restart). 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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