Troubleshooting error code 25 on an LG air conditioner

Is your LG air conditioner displaying error code 25? Don’t worry, this is a problem that you can fix yourself without the need for a costly service call, and we’re here to help!

If you find out that you need any replacement parts for your appliance while you’re troubleshooting, you can enter your model number at AppliancePartsPros.com to order them. Most orders arrive in just two business days, and we have thousands of free guides to show you how to install your new parts.

The troubleshooting information provided in this article may not apply to your specific appliance model. While we strive to offer helpful advice for DIY appliance repairs, variations in models and configurations can lead to differences in troubleshooting steps, error codes and part replacements. For the most accurate guidance, we strongly recommend consulting the technical sheet for your specific appliance model.

What the error code means

Error code 25 on an LG multi split air conditioner indicates a problem with the incoming power supply to the system.

This fault code is triggered when the voltage of the incoming power supply is outside the acceptable range between 140V AC and 300V AC.

This error code is a safety measure to protect the internal components of the air conditioner from potential damage due to over-voltage or under-voltage conditions. Operating the system with an improper power supply can lead to various issues, such as reduced performance, component failure, or even safety hazards.

Safety precautions

When working on any appliance, remember to keep safety first. Here are some tips to keep in mind: 

• Always power off and unplug your appliance or switch off the circuit breaker before attempting any maintenance or replacement work. This keeps you safe by preventing any risk of injury from electric shock.
• Wear insulated work gloves to protect your hands from sharp metal parts, pinching hazards and debris.
• Take your time and don’t rush while working to prevent accidents and personal injuries.
• Work in a well-lit area so you can clearly see and access the interior parts.
• Clear your workspace of clutter and other obstacles. Keep children and pets away from the work area.
• Never work on internal parts with bare wet hands. Make sure the work area is completely dry.
• Check your user manual to see if there are specific installation or safety instructions for your part or appliance. 
• Be gentle when handling or removing parts. Excessive force might damage the appliance or cause injury.
• Wear safety glasses when working with chemicals, dust or cleaning large debris to prevent injury. 
• If the appliance has recently been used, give it plenty of time for any heating parts to cool down before working on it. 
• Take pictures or make a note of wiring terminals or other connections before disconnecting to prevent any problems with reassembly.
• When working with wires, avoid touching any exposed wires or terminals. If you need to touch a wire, use a non-conductive tool or wear insulating gloves to prevent electrical shock.

Tools and materials needed

• Multimeter
• Screwdrivers

Important: The specific tools required may vary depending on the model of your appliance and the type of fasteners used on it. Always consult the user manual or refer to any specific instructions provided by the manufacturer for the recommended tools for your appliance model.

Troubleshooting steps

LIVE VOLTAGE WARNING: For this test, the appliance needs to be plugged in and powered on. Please be very careful to protect yourself from electric shock, which has the potential to cause serious injuries. Don’t ever test live voltage if you’re uncomfortable using a multimeter.

1. Use a digital multimeter to measure the voltage of the incoming power supply to the outdoor unit of the LG multi split air conditioner.
2. Locate the electrical panel or disconnect switch that supplies power to the outdoor unit.
3. Set the multimeter to the AC voltage setting and place the probes on the live and neutral terminals of the power supply.
4. Observe the voltage reading on the multimeter. The voltage should be between 140V AC and 300V AC for the system to operate correctly.
5. If the voltage is outside this range, an electrician will need to check the connection from the electrical outlet. 
6. If the incoming power supply voltage is within the correct range of 140V AC to 300V AC, then the issue is likely with the outdoor unit PCB.
7. Visually inspect the PCB for any obvious signs of damage, such as scorch marks, bulging capacitors, or loose connections.
8. Replace the PCB if there is any damage or the voltage is normal to the board. 
9. After replacing the outdoor unit PCB, restore power to the system and turn on the air conditioner.
10. Monitor the operation of the system and observe the control panel or indoor unit display for any error codes or abnormal behavior.

Additional information

Thank you for reading! We hope this guide helped you get your LG multi split air conditioner working again.

If you have any other appliance repair needs or projects, don’t hesitate to explore our other troubleshooting guides and videos. 

If you need replacement parts or some extra help with ordering them, grab your model number and head over to AppliancePartsPros.com, where you can chat with a pro, read our DIY blog and more.

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