Daikin Mini Split Error Code UA: How to Fix It
Medium 30-60 minutes Medium Severity
Verified June 2026
- Error Code
- UA
- Brand
- Daikin
- Product Type
- mini_split
- Severity
- Medium
- DIY Difficulty
- Medium
- Estimated Fix Time
- 30-60 minutes
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Tools You'll Need
- Screwdriver set
- Multimeter
- Installation manual for your specific Daikin model
How to Fix Error Code UA
-
Turn Off Power to Both Units
Always disconnect power before working on HVAC equipment to avoid electric shock. -
Check Dip Switch Settings on Outdoor Unit
-
Verify Indoor Unit Dip Switch Settings
-
Inspect Wiring Between Units
Double-check polarity if required by your system (e.g., S1, S2, S3). -
Reset and Test
-
Perform a Field Setting Reset
Performing a reset will clear all custom settings; you may need to reconfigure them.
Parts You May Need
Communication cable
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Communication cable
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Communication cable
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Communication cable
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When to Call a Professional
If error UA persists after checking all dip switches and wiring, or if you're uncomfortable working with electrical components, contact a certified HVAC technician. Professional diagnosis may involve checking the main PCB for faults.Frequently Asked Questions
What does error code UA mean on a Daikin mini split?
UA stands for field setting abnormal. It means the indoor and outdoor units have incompatible settings or wiring, often due to incorrect dip switch positions or communication issues.
Can I fix error code UA myself?
Yes, in many cases you can fix it by checking dip switches and wiring between units. If you are handy with tools and have the manual, follow the steps above. If not, call a professional.
How do I reset Daikin error code UA?
First correct any setting or wiring issues. Then turn off power, wait, and restore power. Some outdoor PCBs have a reset button (e.g., SW4) to clear field settings.
Does error code UA require a new PCB?
Not usually. UA is typically caused by configuration errors, not hardware failure. Only after verifying all settings and wiring should you suspect a faulty PCB, which would need professional replacement.
Why does error UA appear after installation?
It commonly occurs when dip switches on the indoor or outdoor unit are not set according to the installation manual, or when communication wires are incorrectly connected.