Daikin aircon UA error code
Use this Daikin UA error code guide to confirm the source table meaning, capture the reporting equipment and model, and match the service manual before diagnosis. Match the model first; same-looking codes can point to different rows.
What does Daikin UA mean?
Daikin UA is listed as defect of indoor/outdoor power supply, improper combination of indoor and outdoor units, and indoor-outdoor unit combination fault in mixed model-family source rows, including VRV X RXQ-A(N)R cooling only, VRV IV+ REYQ / REMQ heat recovery, VRV 5-S RXYSA R32, and VRV 5 Heat Recovery REMA / REYA R32. The loaded row is source-backed by official diagnostic material. Do not collapse this code across model families; use the model, series, or system type to choose the right row. Confirm the exact model, series, or signal row before accepting a parts quote.
Choose the matching source row
The same visible code has more than one source-backed meaning. Match the model family, system type, or reporting unit before approving parts.
| Code | What it means | What to check first |
|---|---|---|
| General RA self-diagnosis guide | Defect of indoor/outdoor power supply | Match this row to the installed model or reporting unit, then use the source-specific checks below. |
| Fan Coil | Improper combination of indoor and outdoor units | Match this row to the installed model or reporting unit, then use the source-specific checks below. |
| EZi | Indoor-outdoor unit combination fault | Match this row to the installed model or reporting unit, then use the source-specific checks below. |
| VRV X RXQ-A(N)R cooling only | Improper indoor-unit, outdoor-unit, or remote-controller combination | Match this row to the installed model or reporting unit, then use the source-specific checks below. |
| UA-03 - system | Indoor-unit connection malfunction or refrigerant-type mismatch | Check other indoor-unit faults and confirm that the indoor-unit mix is allowed. Match the alternating UA-03 display to the system source row. |
| UA-31 - system | Wrong unit combination in a multi system | Check whether the unit types are compatible. Match the alternating UA-31 display to the system source row. |
| UA-20 - system | Wrong outdoor unit connected | Disconnect the incorrect outdoor unit. Match the alternating UA-20 display to the system source row. |
| UA-27 - system | No branch-selector unit connected | Connect the required branch-selector unit. Match the alternating UA-27 display to the system source row. |
| UA-28 - system | Old branch-selector unit connected | Disconnect the incompatible branch-selector unit. Match the alternating UA-28 display to the system source row. |
| UA-53 - system | Branch-selector unit DIP-switch abnormality | Check the branch-selector unit DIP switches. Match the alternating UA-53 display to the system source row. |
| VRV 5-S R32 - UA / VRV 5 Heat Recovery R32 - UA | Connected indoor-unit type or combination mismatch | Confirm that every connected indoor-unit type is permitted for the system. |
What to do now
Use these steps to record evidence and match the installed model to its service manual before diagnosis or a repair quote.
Record UA and match the service manual
Record UA and stop there; the source table gives no customer reset procedure. Arrange diagnosis with the matching service manual.
No manufacturer reset steps listed for UA
Capture the complete UA error code and model stickers first. The source table lists the meaning but no customer reset procedure; do not treat a generic power-cycle as manufacturer guidance.
Send these to us
UA error code, a clear display photo, Daikin indoor and outdoor model stickers, the controller, gateway, or unit that reported the code, operating mode and affected area, and any power or setting changes made after the code appeared
Source-specific guidance
These diagnostic-reference notes help match the code to the exact model. Electrical, refrigerant, wiring, resistance, and component checks are technician work, not DIY steps.
| Source detail | What it says |
|---|---|
| Singapore / model note | Official Daikin SM-TS3 row; this is separate from UA combination faults in model-family manuals. |
| Singapore / model note | Official Daikin SM-TS3 self-diagnosis row. Manual causes: Excess connected indoor units; Defective outdoor unit PCB; Indoor and outdoor refrigerant type mismatch. |
| Singapore / model note | This row is taken from the selected Daikin operation manual's remote-controller fault diagnosis table. |
What to check before repair
The source table establishes the code meaning, not a repair procedure. Capture evidence first; model-specific tests belong to the matching service manual.
| You can check | Technician should confirm |
|---|---|
| Photograph the complete UA error code before taking any action. | Confirm UA exactly and record which controller, gateway, or unit reported it. |
| Capture the Daikin indoor and outdoor model stickers and identify which controller or unit reported it. | Match the indoor and outdoor model stickers, installed family, and reporting equipment to the source scope. |
| The source table provides no customer reset procedure. Preserve the evidence and use the matching service manual for any system action. | Follow the matching service-manual procedure and keep measured test evidence before naming a failed part. |
Source-bounded repair decision
Daikin UA confirms the source-table fault label, not a failed part or repair procedure. Match the installed model to its service manual and require measured diagnostic evidence before approving parts, settings, or refrigerant work.
Whether the reporting controller or unit and exact installed model are confirmed.
What the matching service-manual procedure and measured tests show.
Whether the proposed repair names the evidence for the failed part or condition.
Daikin UA questions
What does the Daikin UA error mean?
Can I fix a Daikin UA error myself?
Is it safe to keep running the aircon with a UA error?
What causes a Daikin UA error?
Will a Daikin UA error need a repair or a full replacement?
What should I send a technician about a Daikin UA error?
Confirm the fault
Share the error code, model number and symptoms so we can assess the likely cause.
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Use this quote-check guide only after the matching service manual identifies the diagnostic path.