The L3 error code in air conditioners typically indicates issues related to the outdoor unit fan. This error is commonly found in brands such as Electrolux, Bluestar, Gree, Trane, Sharp, and Mundoclima.
Why Does This Error Appear?
In many systems, the indoor fan may operate normally, but the L3 error appears because the outdoor unit is completely inactive. Neither the fan nor the compressor runs, although the PCB (Printed Circuit Board) is operational, and the diode blinks continuously.
For most units displaying the L3 error, the outdoor unit fan uses a BLDC motor (Brushless Direct Current Motor). This motor is powered by three wires supplying energy to three coils, controlled by an IPM (Intelligent Power Module).
The IPM manages the voltage outputs through integrated transistors.
Steps to Diagnose and Solve the L3 Error
1. Disconnect the Power Supply:
Turn off the equipment and disconnect it from the electricity. Check if the error persists.
2. Inspect the Fan Movement:
Ensure that the outdoor unit fan and blades move properly.
- If the fan moves correctly, issues related to blockage or motor shaft bearings can be ruled out.
3. Check the Connector Connections:
Inspect the fan connector for loose connections.
- A loose contact point can trigger the error. Disconnect, adjust, and reconnect to ensure proper contact.
4. Measure the Fan Resistance:
Disconnect the fan from the external electronic board.
- Use a multimeter on the resistance scale to measure the resistance between the fan wires. The values should be nearly identical.
- If the resistance values differ, replace the fan.
5. Verify the IPM Screws:
Ensure the screws securing the IPM and the heat sink are properly installed.
- A poorly installed heat sink can cause overheating and IPM failures.
6. Inspect the Capacitors:
Visually examine the electrolytic capacitors.
- Keep in mind that capacitors may hold a charge even when the board is disconnected. Discharge capacitors using a resistor by bridging their pins.
- Measure each capacitor’s capacitance with a capacitance meter, ensuring it matches the indicated values.
7. Test IPM Continuity:
Ensure the IPM output pins have continuity with the connector that powers the outdoor unit fan.
Additional Considerations for Other Manufacturers
- Carrier: The L3 error code detects an overcurrent in one motor phase.
- AUX: The L3 error relates to compressor protection.
- Daikin: The L3 error indicates an increase in temperature within the electrical panel.
