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Daikin Air Conditioner A3 Error Code
Condensate water level too high. Here is what it means and how to clear it, easiest fix first.
The float switch in the indoor unit's drain pan has detected water that isn't draining away. A blocked drain line or one that runs uphill, a failed drain pump, or a faulty float switch are the usual causes.
Mainly seen on ducted, ceiling cassette and other units fitted with a drain pump and float switch. Daikin uses this code across its residential split, SkyAir and VRV ranges, but the exact meaning and causes can vary by series, model year and region, so confirm it in your unit's manual. How to read it: most Daikin ductless wall units only blink the operation lamp. On remotes such as the ARC433 series, press and hold the timer Cancel button for roughly 5 seconds until 00 blinks on the screen, then press Cancel again one step at a time; when the indoor unit answers with a long continuous beep, the code showing is the stored fault. SkyAir and VRV wireless remotes use a different sequence with the Inspection/Test, up/down and MODE buttons, and wired wall controllers usually show the code on their screen.
How to fix Daikin A3
Check the condensate drain line
With the breaker off, follow the drain hose from the indoor unit to where it ends outside or at a drain. Straighten any kinks, make sure the end isn't buried in soil, ice or a puddle, and clear dirt or algae from the open end. If the hose runs uphill anywhere, water can back up into the unit.
Clear the end of the drain line
Where the drain line ends outdoors, you can gently draw out a blockage with a wet/dry vacuum held over the open end for a minute or two. Don't push wire or rods up the line, which can damage it or the pan.
Reset the power at the breaker
Switch the system off with the remote, then turn off its circuit breaker in your home's main panel. Wait about 5 minutes, switch the breaker back on and restart the unit. Allow a few minutes for the drain pump to empty the pan after the restart.
When to call a technician
If the pan stays full or the code returns, the condensate pump or float switch may have failed, or the line may be blocked inside the wall. Call an HVAC technician, and switch the unit off if water is dripping from it.
Parts that commonly cause A3
- condensate pump
- float switch
- drain line
Order parts by your exact model number so they fit.
Other Daikin air conditioner codes
- U4Indoor and outdoor units can't communicate
- U0Low refrigerant or restricted refrigerant flow
- U2Power supply voltage problem
- UAIndoor and outdoor units don't match
- A1Indoor unit control board fault
- A5Freeze-up or overheat protection
- A6Indoor fan motor fault
- C4Indoor coil temperature sensor fault
- C9Indoor room air temperature sensor fault
- E1Outdoor unit control board fault
- E5Compressor overload or lock-up protection
- E6Compressor won't start
- E7Outdoor fan motor fault
- E8Compressor current too high
- F3Compressor discharge temperature too high
- F6High pressure in cooling mode
- H6Compressor position sensing error
- L4Inverter heat sink overheating
- L5Inverter output overcurrent
Frequently asked questions
What does A3 mean on a Daikin air conditioner?
The float switch in the indoor unit's drain pan has detected water that isn't draining away. A blocked drain line or one that runs uphill, a failed drain pump, or a faulty float switch are the usual causes.
Can I fix Daikin A3 myself?
Often. The first steps above are safe checks a homeowner can do. If they don't clear A3, the cause is likely a worn part that needs replacing.
What if A3 keeps coming back?
A code that returns after a reset and the checks above usually means a part is wearing out. Note when A3 appears (which cycle, how often) and have your model number ready; it helps a technician bring the right part on the first visit.
Last reviewed 2026-10-19. Codes and steps can vary by model; check your owner's manual.