First, power off the system and check wiring connections for loose or damaged cables. Inspect the indoor unit’s PCB and sensors for faults or corrosion. Reset the controller by turning off power for 5 minutes, then restart.

The U1 error on a Daikin AC typically indicates a communication error between the indoor unit and controller. Check wiring connections for loose or damaged cables. Inspect the indoor unit’s PCB and sensors for faults.

U1 · Reverse phase, open phase · Power supply reverse phase · T phase open phase · Defective outdoor unit PCB (A1P) k k k k k k k · U2 · Malfunction of power supply or · instantaneous power failure · Abnormal power supply voltage · Instantaneous power failure · Defective main circuit wiring · k k k k · k k · U3 · Check operation not executed or · transmission error ·

By checking the error code, you are able to identify the status and the issue of the air conditioner/air conditioning system.

April 2, 2026 - U1 – Reverse phase – The three phase power supply has been reversed. U2 – Open phase or power voltage imbalance – There may be an open phase or a voltage imbalance in the power supply.

November 6, 2024 - Given that a faulty outdoor unit circuit board is a severe issue, it's best to contact the Daikin service center or a professional air conditioning technician for assistance. During the process of troubleshooting and fixing the U1 error code on Daikin air conditioners, pay attention to the following issues to ensure safety:

Capacity setting error · Incorrect capacity setting · • · • · Trouble Shooting · www.climatecenter.co.uk · Daikin Trouble Shooting Guide · Past & Current Models · Daikin Fault Codes · System Fault Codes · Fault Code · Definition · Supposed Causes · Split · Skyair · VRV · Package · HRV · U0 · Shortage of refrigerant · Undercharged, EEV fault, faulty sensor · • · • · • · • · U1 ...

After a power outage, check wiring connections for looseness or damage. Reset the system by turning off power for 5 minutes, then restart. Inspect the PCB boards for faults or corrosion.

U1 − 01 Reverse phase/open phase for power supply (Master) U1 − 04 Reverse phase for power supply [with power supply turned ON] (Master) U1 − 05 Reverse phase/open phase for power supply (Slave 1) Refer to the “U1” flow chart of each manual and make a diagnosis of the relevant unit based on the Error code shown to U1 − 06 Reverse phase for power supply [with the left.

Daikin systems are designed to be flexible, reliable, efficient, and effective — that’s why so many professionals select and recommend the comfort and peace of mind that Daikin offers.

December 22, 2022 - The U4-01 error on Daikin units typically indicates a temperature sensor or communication fault. First, power off the unit and check sensor wiring connections for looseness or damage. Clean the air filters and ensure no obstructions block airflow.

UNIT NO. 1 · 3. Press MODE · selector button · 4. Change the · upper digit · 1. Press · INSPECTION/TEST · button · 6. Change the

July 20, 2025 - Easily identify Daikin HVAC system faults with this complete list for simple self-diagnosis & troubleshooting. Includes VRV, SkyAir, HRV systems, and more.

November 10, 2025 - Master Daikin troubleshooting with our updated 2024 guide. Reset your air conditioner and solve common issues easily.

December 22, 2022 - U0 System Shortage of refrigerant or EEV failure U1 System Negative phase, Open phase U2 System Power supply insufficient U3 System Wiring check operation not executed U3 System Mismatch of indoor and outdoor units – Split only U4 System Transmission between indoor units U5 System Transmission to remote controller U6 System Malfunction transmission outdoor to BP unit U7 System Transmission between outdoor units U8 System Transmission between master and slave RC U9 System Transmission error between indoor to outdoor UA System Excessive number of fancoils UC System Address duplication of central controllers UE System Transmission error between indoor and central UF System Refrigeration system not set wiring – piping UF System Terminals 1 and 3 crossed (Split Skyair) UH System System error Refrigeration system set up

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We lost power in our house (street? it's been pretty windy) earlier this morning and our Daikin aircon/heating system didn't like it. When we try to turn on the

Complete Daikin error code list for mini-splits, VRV systems, and air conditioners. Find meanings, causes, and troubleshooting solutions for all Daikin fault codes.