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Daikin Air Conditioner UA Error Code

Indoor and outdoor units don't match. What it means, which models show it, and how to clear it, easiest fix first.

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UA
May need a pro

Most often this means the outdoor unit doesn't accept the connected indoor unit as a valid partner, for example the wrong model, too many indoor units, or a replacement circuit board that hasn't been set up. It usually shows up right after installation or a board replacement.

Compatible models

Daikin doesn't publish a model list for this code; it appears on Daikin air conditioners with a digital display. Check your owner's manual.

Also shown as

Daikin's service list gives UA more than one meaning depending on the system: a mismatched indoor/outdoor combination (including the wrong refrigerant type or too many indoor units), a power supply fault, or a disconnected wire on a remote temperature-setting accessory. 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.

Difficulty

Try the basic checks, but the usual fix is a technician's job.

Safety first: unplug the air conditioner (or switch off its breaker) before touching filters, hoses or panels. If you smell burning or gas, or see water near the outlet, stop and call a professional.

How to fix Daikin UA

  1. 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. If UA appears on a system that has run normally for years, the power reset is worth one try before calling for service.

  2. Record the details for the technician

    Write down the exact code, the model numbers from the labels on the indoor and outdoor units, and what the system was doing when the code appeared. Leave the unit switched off if the code keeps returning, so a fault doesn't cause further damage.

When to call a technician

UA is usually an installation or setup issue. Contact the installer, who needs to confirm the model pairing, wiring and board settings.

Parts linked to UA

These are the parts most often behind this code. Tap one to see what it does and the signs it is failing.

Order parts by your full model number so they fit.

Frequently asked questions

What does UA mean on a Daikin air conditioner?

Most often this means the outdoor unit doesn't accept the connected indoor unit as a valid partner, for example the wrong model, too many indoor units, or a replacement circuit board that hasn't been set up. It usually shows up right after installation or a board replacement.

Which Daikin models show the UA code?

Daikin doesn't publish a model list for this code; it appears on Daikin air conditioners with a digital display. Check your owner's manual.

Can I fix Daikin UA myself?

Only the basic checks. You can safely try the steps above, but UA usually points to a part or fault that needs a technician.

What if UA keeps coming back?

A code that returns after a reset and the checks above usually means a part is wearing out. Note when UA appears (which cycle, how often) and have your model number ready; it helps a technician bring the right part on the first visit.

Other Daikin air conditioner codes

Last reviewed 2026-10-19. Codes and steps can vary by model; check your owner's manual.

Sources we checked