How to Reset Daikin Aircon Green Light Flashing: Expert Technical Walkthrough

When the green light on your Daikin indoor fan coil unit begins to flash continuously, it is more than just a minor aesthetic distraction. In Daikin engineering, a blinking LED is a proactive diagnostic signal. It indicates that the system's electronic brain, the printed circuit board, has detected an operating anomaly and has temporarily shut down to protect expensive components like the compressor. By learning how to pull the exact malfunction code and perform a systematic reset, you can determine if a simple restart will resolve the glitch or if you require an expert technician. This guide walks you through the step-by-step diagnostic process. --- ## 1. How to Extract the Daikin Error Code (Step-by-Step) Before resetting the power, you should always extract the precise error code stored in your system's memory. Resetting the unit first will wipe this log, making it more difficult for a professional technician to perform an accurate diagnostic check later. Here is how you can use your standard Daikin wireless remote controller to retrieve the code: 1. **Find the Cancel Button:** Locate the small button labeled "Cancel" near the bottom of your remote control. 2. **Press and Hold:** Point the remote at the flashing indoor unit and hold down the "Cancel" button for 5 seconds. 3. **Wait for Double Zero:** The temperature display on the remote screen will disappear, replaced by a blinking "00" (double zero) with a short beep sound. 4. **Scroll Through Codes:** Press the "Cancel" button repeatedly to scroll through the alphabetic and numeric error codes. 5. **Listen for the Long Beep:** As you pass most codes, the indoor unit will make a quick single beep. When you land on the actual active malfunction code, the unit will sound a continuous, long beep for several seconds. 6. **Note the Code:** Read the code on the remote screen (for example, U4, A6, or E7) and write it down. --- ## 2. Deciphering Common Daikin Malfunction Codes Daikin multi-split inverter systems utilize precise codes to isolate faults. Below is a detailed breakdown of the most common codes you might encounter: | Error Code | Core Meaning | Physical Condition and Mechanical Impact | | :--- | :--- | :--- | | **00** | Normal State | System is operating optimally or error log has been cleared. | | **A5** | Freeze-up Protection / High-Pressure Control | Low indoor fan speed or severely dirty filters are restricting airflow over cold coils. | | **A6** | Fan Motor Malfunction | The indoor fan motor speed is abnormal, or the blower wheel is mechanically locked. | | **E7** | Outdoor Fan Motor Fault | The outdoor condenser fan is blocked, or its electrical connector is loose. | | **F3** | Discharge Pipe Temp Control | The compressor discharge pipe is overheating, often due to insufficient refrigerant charge. | | **H9** | Outdoor Thermistor Abnormality | The ambient temperature sensor on the condenser has failed or drifted out of normal resistance ranges. | | **U4** | Indoor/Outdoor Link Transmission Error | A critical signal breakdown between the indoor board and the outdoor controller board. | | **UA** | System Configuration Mismatch | The outdoor unit is not paired with compatible indoor models, or a setting was modified incorrectly. | --- ## 3. How to Perform a Safe System Hard Reset If the error code points to a simple transient glitch (such as a temporary electrical fluctuation), performing a systematic hard reset can restore normal operation. Follow these guidelines: ### Step 1: Remote Control Power Off Press the Power button on your remote control to turn the system off completely. Do not attempt to reset power while the compressor is actively trying to start. ### Step 2: Switch off the Main Aircon Isolator Locate your double-pole aircon isolator switch (typically located near your outdoor condenser unit or in your kitchen/utility yard, labeled "Aircon") or your main electrical DB board circuit breaker. Switch it to the "OFF" position. ### Step 3: Wait Exactly 3 to 5 Minutes This delay is crucial. It allows all electrical residual energy inside the PCB capacitors to completely discharge, resetting the electronic memory register to its starting condition. ### Step 4: Switch the Power Back On Flick the isolator switch or circuit breaker back to the "ON" position. ### Step 5: Start the Aircon via Remote Point the remote at the indoor unit and switch it on. Allow the system up to 5 minutes to run its internal sensor self-checks. If the green light stays solid, the temporary glitch has been resolved! --- ## 4. When a System Reset Will Not Work While a power reset is an excellent initial step, it is important to understand that resetting will not repair physical mechanical damage or hardware failures. If the green light resume flashing immediately after a power cycle, or if the system shuts down after a few minutes of operation, the error represents a real, non-transient mechanical or electrical fault. Attempting to repeatedly bypass these warnings by forcing hard resets can put immense stress on your compressor and other sensitive electronics, leading to much larger repair costs later. Working with a registered, professional HVAC company protects your investment and ensures your safety. --- ## Professional Diagnostics and Care in Singapore At Sky Blue Aircon, our licensed engineering experts diagnose and resolve complex Daikin faults every day. Whether your unit requires a thorough fan motor replacement, thermistor calibration, or an electronic circuit board repair, we ensure your split systems are serviced to the highest engineering standards. **Is your Daikin green light flashing, or did your remote reveal an error code? Schedule a professional, comprehensive diagnostic inspection with our certified technicians today. Reach out on WhatsApp at [+65 9248 7291](https://wa.me/6592487291) or contact our hotlines at 6556 4042 to schedule your service!**