Daikin Air Conditioner Error U1
⚡ Quick Answer: The U1 error code on Daikin air conditioners indicates a communication failure between the indoor and outdoor units due to a power supply issue, speci... ✅ DIY Fixable
What Does Error U1 Mean?
The U1 error code on Daikin air conditioners indicates a communication failure between the indoor and outdoor units due to a power supply issue, specifically a three-phase abnormality such as phase reversal or phase loss. This error can prevent the unit from starting and may lead to a lack of cooling or heating. If the error persists after basic troubleshooting, it is crucial to address the electrical supply and phase verification to restore normal operation.
Common Symptoms:
- Unit fails to start or stops running when U1 is displayed
- Possible lack of cooling/heating operation
- Error persists even after basic power cycling
Possible Causes
- Three‑phase power supply abnormality (reverse phase or missing phase) (high)
- Power supply voltage imbalance or instability (medium)
- Breaker or power wiring issue (medium)
How to Fix Error U1
DIY Fix Check Power Supply and Breakers
- Ensure the unit’s main breaker is ON and has not tripped
- Confirm three‑phase power supply wiring matches the unit’s required phase sequence
- Check for obvious loose connections or burnt wiring at the breaker panel
Technician Only Electric Power and Phase Verification
- Use a multimeter to measure three‑phase voltages at the unit’s power terminals
- Verify correct phase rotation and absence of missing phase
- Inspect and tighten electrical connections, terminal blocks, and breakers
- Replace defective breakers, fuses, or wiring as needed
Parts needed: multimeter, breaker panel components (breakers, fuses), power wiring, connectors
- If you cannot identify a safe power supply issue
- If phase rotation/ imbalance is present but unresolved
- If the error recurs after power and wiring verification
Next step
Choose the next step for U1
Confirm the diagnosis before ordering. An error code can identify the system involved, but it does not prove that a specific part has failed.
Browse by model — no specific failed part is claimed
Model-compatible Air Conditioner parts
Enter the complete model number to browse compatible replacement parts. This is a model-based parts search, not a diagnosis that a specific component failed.
Where can I find the model number?
Check the rating label around the door, lid, frame, rear panel, or inside the appliance cabinet. Use the complete model number, including suffixes.
Search results are not a diagnosis. Verify both the complete appliance model and the retailer's fit information before ordering.
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Optional routine care
Maintenance supplies
These products support cleaning or routine upkeep. They are separate from the possible repair components above and are not claimed to fix this error code or symptom.
Air Conditioner Fin Cleaner
For routine cleaning of accessible coil fins when permitted by the manufacturer. Disconnect power and follow product and appliance instructions.
Model-Compatible Washable AC Filter
A reusable filter option only where the appliance supports one. Match the full model, dimensions, and filter specification.
Compatibility check required: use the complete appliance model and compare the existing filter, bag, or specification before ordering.
Affiliate disclosure: As an Amazon Associate I earn from qualifying purchases. Recommendations are based on routine-care relevance, not commission rate.
Technical Specifications
| note | The previous model-independent part specification was removed. Verify the full model number and diagnosis in the manufacturer's official parts catalog before ordering. |
|---|---|
| part_number | None |
Common Questions
What does U1 error mean on daikin air conditioner?
The U1 error indicates a communication failure due to a power supply issue, preventing the unit from starting.
Can I fix daikin air conditioner U1 error myself?
Yes, check the power supply and breakers, ensuring the main breaker is ON and the phase sequence is correct.
How much does it cost to fix U1 error?
Repair costs typically range from ¥10,000 to ¥50,000+, depending on parts and labor.
When should I call a technician for U1?
Call a technician if you can't identify a power supply issue or if the error persists after checking wiring.
Sources & References
- Daikin Proshop — U1 Error Explanation (official)
- Daikin U1 Error — HVAC QuickAir Explanation (community)
Data last verified: 2026-07-31
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