How to Troubleshoot LG Mini Split: A Comprehensive DIY Guide

As a DIY user with advanced hands-on skills and technical knowledge, troubleshooting an LG mini split can be a complex yet rewarding task. This comprehensive guide will provide you with the critical details and advanced troubleshooting techniques to identify and resolve issues with your LG mini split system.

Check for Error Codes

The first step in troubleshooting an LG mini split is to check for error codes on the indoor unit or remote control. However, if the error code is not displayed, it is recommended to inspect the outdoor unit’s LED for error codes. This can provide valuable information about the specific issue affecting your system.

To check for error codes:

Locate the indoor unit or remote control and look for any error codes displayed.
If no error code is visible, proceed to the outdoor unit and inspect the LED lights for any error codes.
Refer to the LG mini split error code guide to identify the specific issue and the appropriate troubleshooting steps.
If the error code is not listed or you are unsure of the meaning, it is recommended to consult the LG technical support or a qualified HVAC technician for further assistance.

Power Supply Checks

Image source: LG Ac By Dinkun Chen

Ensuring the proper power supply is crucial for the smooth operation of your LG mini split. Start by checking the circuit breaker, power line, and power supply to ensure they are functioning correctly.

Verify that the circuit breaker is not tripped and is in the “on” position.
Check the power line for any visible damage or loose connections.
Measure the voltage of the power supply to ensure it is within the recommended range:
Single-phase: 220 volts ± 10%
Three-phase: 380 volts ± 10%
If the power supply is not within the recommended range, identify and address the underlying issue, such as a faulty circuit breaker or power line.

Installation Space

The installation space of the outdoor unit is crucial for the proper air circulation and efficient operation of the LG mini split. Ensure that the outdoor unit’s installation space fits the standard condition.

Measure the clearance around the outdoor unit to ensure it meets the manufacturer’s recommended specifications.
Check for any obstructions or obstacles that may be impeding the air current around the outdoor unit.
Ensure that the outdoor unit is installed on a level surface and is not tilted or uneven.
If the installation space is not within the recommended parameters, consider relocating the outdoor unit or removing any obstructions to improve air circulation.

High-Low Pressure Service Valve

The high-low pressure service valve of the outdoor unit plays a critical role in the refrigerant system. Verify that this valve is opening and closing correctly.

Locate the high-low pressure service valve on the outdoor unit.
Observe the valve to ensure it is opening and closing as expected during the unit’s operation.
If the valve is not opening or closing properly, it may indicate a problem with the refrigerant system or the valve itself.
In such cases, it is recommended to consult a qualified HVAC technician for further diagnosis and repair.

EEV Harness Terminal

The Electronic Expansion Valve (EEV) harness terminal must be properly connected to the outdoor unit’s main PCB. Ensure that the connection is secure and free from any issues.

Locate the EEV harness terminal on the outdoor unit’s main PCB.
Visually inspect the terminal for any signs of damage, corrosion, or loose connections.
Firmly reconnect the EEV harness terminal to the main PCB, ensuring a secure and proper connection.
If the connection appears to be damaged or the issue persists, it may indicate a problem with the EEV or the main PCB, and further investigation by a qualified technician is recommended.

Compressor Connection Harness

Check the compressor connection harness for any signs of carbonization or damage. Additionally, measure the phase-to-phase resistance and insulation resistance to ensure they are within the recommended range.

Locate the compressor connection harness on the outdoor unit.
Visually inspect the harness for any signs of carbonization or physical damage.
Measure the phase-to-phase resistance and insulation resistance of the compressor using a multimeter.
Compare the measured values to the manufacturer’s recommended specifications.
If the resistance values are not within the recommended range or if there are signs of carbonization, it may indicate a problem with the compressor or the connection harness, and replacement may be necessary.

Inverter PCBA

The Inverter Printed Circuit Board Assembly (PCBA) is a critical component in the LG mini split system. Measure the voltage at the terminal and the P and N of the inverter PCBA DC link to ensure they are within the recommended range. Additionally, check for any carbonization traces in the IPM and screw and connector joint parts of the inverter PCBA.

Locate the inverter PCBA in the outdoor unit.
Measure the voltage at the terminal and the P and N of the inverter PCBA DC link using a multimeter.
Compare the measured values to the manufacturer’s recommended specifications.
Visually inspect the inverter PCBA for any signs of carbonization, especially in the IPM (Insulated Gate Bipolar Transistor) and the screw and connector joint parts.
If the voltage measurements are not within the recommended range or if there are signs of carbonization, it may indicate a problem with the inverter PCBA, and replacement or repair by a qualified technician may be necessary.

Temperature Sensor

The temperature sensor plays a crucial role in the proper operation of the LG mini split. Ensure that the sensor is accurately reading the room temperature.

Locate the temperature sensor, which is typically located on the indoor unit.
Compare the temperature reading on the indoor unit or remote control to an independent, calibrated thermometer.
If the temperature sensor is not reading the appropriate room temperature, it may cause the unit to malfunction.
In such cases, the temperature sensor may need to be recalibrated or replaced by a qualified technician.

Fan Motor Harnesses

Check the fan motor harnesses for any issues, such as loose connections or signs of carbonization. Separate the PCB and inspect the rear side for any carbonization.

Locate the fan motor harnesses on the indoor and outdoor units.
Visually inspect the harnesses for any signs of damage, loose connections, or carbonization.
Separate the PCB and inspect the rear side for any carbonization or other issues.
If you find any issues with the fan motor harnesses, it may indicate a problem with the fan motor or the associated electrical components, and replacement or repair by a qualified technician may be necessary.

Power Issues

Finally, check for any power issues that may be affecting the operation of your LG mini split, such as a tripped circuit breaker or a blown fuse.

Verify that the circuit breaker is not tripped and is in the “on” position.
Check for any blown fuses in the electrical panel or the outdoor unit.
If the unit is not powering on, it may be due to a power outage in the home or a defective component in the unit.
If the power issue persists, it is recommended to consult a qualified HVAC technician for further diagnosis and repair.

By following these advanced troubleshooting techniques, you can identify and resolve a wide range of issues with your LG mini split. Remember, if you are unable to resolve the issue or feel uncomfortable performing any of the steps, it is always best to seek the assistance of a qualified HVAC technician.