Daikin mini split error code A3
Drain water level abnormal (float switch).
- TypeFault
- SystemCondensate drain
- Can I fix it?Usually a homeowner fix
What A3 means on a Daikin
The condensate level in the indoor unit rose high enough to trip the float switch. The unit stops cooling so it does not overflow.
On this platform, A3 is a fault: something has failed or is disconnected and needs diagnosis.
Common causes
- A blocked or kinked condensate drain.
- A drain line without continuous fall.
- A failed condensate pump (if fitted).
- A stuck float switch.
How to fix it yourself
You can almost always clear this yourself with the steps below.
- Find the drain outlet outside and confirm water flows while cooling.
- Clear the drain with a wet/dry vacuum at the outlet or flush it.
- Make sure the drain line falls continuously with no traps or dips.
- If a pump is fitted, check it runs and the float moves freely.
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 replace a failed pump or float switch.
Which Daikin units show A3
This page applies to Daikin Aurora, 19 Series, Atmosphera, Emura, Quaternity and MXS multi-zone units. Daikin's own documentation lists A3 as "Drain water level abnormal (float switch)", 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
A3 on other brands
The same characters do not always mean the same thing. Check the brand on your unit.
- Goodman A3 Drain water level abnormal (float switch)
Questions people ask
Can I reset a Daikin A3 code myself?
Yes. Turn the system off at the breaker for five minutes, then restart it. If A3 comes back, the fault is real and needs the checks above.
Is it safe to keep running a Daikin showing A3?
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 A3?
You can almost always clear this yourself with the steps below. A technician can replace a failed pump or float switch.
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.