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Error code reference

LG Hvac Error Code 62

Inverter ODU PCB heat sink temperature 85°C/185°F or higher.

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Inverter ODU PCB heat sink temperature 85°C/185°F or higher.

First step from the service manual

Verify air flow across heat sink, verify PCB tight to heat sink, use thermal paste. Thermistor = 10,000Ω at 25°C/77°F & 20,700Ω at 10°C/50°F. With perfect thermistor & plug connection, change PCB.

The complete diagnostic procedure includes additional test steps, resistance specifications, wiring diagram references, and component test points.

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  • Step-by-step tests with expected resistance, voltage, and continuity values
  • Wiring diagram references and connector pinouts from the OEM service manual
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What 62 means on a LG hvac

Error code 62 on an LG inverter outdoor unit (ODU) indicates that the heat sink temperature on the inverter PCB has reached or exceeded 85°C (185°F). The inverter PCB drives the compressor motor by converting incoming AC power to variable-frequency DC, and this process generates substantial heat. That heat must be transferred efficiently through direct contact between the PCB and the heat sink, then dissipated into the surrounding air. When the system detects this over-temperature condition via a dedicated thermistor, it shuts down operation to prevent permanent damage to the inverter components.

The thermistor responsible for monitoring heat sink temperature has known reference values: 10,000 ohms at 25°C (77°F) and 20,700 ohms at 10°C (50°F). If resistance readings deviate significantly from these values, or if the connector to the thermistor shows corrosion or a loose fit, the thermistor circuit itself may be misreporting temperature. Confirming accurate thermistor readings is a critical early diagnostic step before condemning the board.

Beyond thermistor accuracy, restricted airflow across the heat sink is the most common physical cause of genuine overheating. Blocked fins, a failed condenser fan motor, or debris accumulation can all prevent adequate heat dissipation. Additionally, poor thermal contact between the PCB and heat sink, due to missing or degraded thermal paste or loose mounting hardware, dramatically reduces heat transfer efficiency. If airflow is confirmed adequate, thermistor values are within spec, and all connections are secure, the inverter PCB itself is the likely failed component.

Source: manufacturer service documentation.

Common causes of 62

  1. 01

    Restricted airflow across heat sink

    Wiring / connection

    Blocked condenser fins, debris accumulation, or a failed outdoor fan motor can prevent the heat sink from shedding heat properly. Inspect the fan operation and clean the area around the outdoor unit thoroughly.

  2. 02

    Poor thermal contact between PCB and heat sink

    Wiring / connection

    If the inverter PCB is not mounted tightly against the heat sink, or if the thermal paste has dried out or was never applied, heat transfer is severely reduced. Remove the PCB, clean both surfaces, apply fresh thermal paste, and reinstall securely.

  3. 03

    Faulty heat sink thermistor

    Part replacement

    The thermistor should read approximately 10,000 ohms at 25°C and 20,700 ohms at 10°C. Readings outside these values, or a loose or corroded connector, can cause a false over-temperature fault even when the board is not actually overheating.

  4. 04

    Failed inverter PCB

    Part replacement

    If airflow is unobstructed, thermal paste is properly applied, the PCB is mounted firmly, and the thermistor reads correctly with a solid plug connection, the inverter PCB itself has likely failed internally and requires replacement.

See the test procedure for each cause

Frequently asked questions about 62

What does 62 mean on a LG hvac?
Error code 62 means the inverter PCB heat sink on the outdoor unit has reached or exceeded 85°C (185°F). The system monitors this temperature with a dedicated thermistor and shuts down to prevent component damage when this threshold is hit. The cause can be restricted airflow, poor board-to-heat-sink contact, a faulty thermistor, or a failed PCB.
Can I fix error code 62 myself on my LG outdoor unit?
Some causes are accessible to a knowledgeable DIYer. Clearing debris from the outdoor unit, confirming the condenser fan is spinning, and checking thermistor resistance with a multimeter are reasonable starting points. However, reseating or replacing the inverter PCB and working near high-voltage inverter components should be handled by a qualified HVAC technician.
Is it safe to keep running my LG unit when error code 62 appears?
No. The unit shuts itself down when error 62 is triggered specifically to protect the inverter components from heat-related damage. Attempting to repeatedly reset and restart the unit without resolving the underlying cause can lead to permanent failure of the inverter PCB or compressor drive circuitry.
Will resetting the unit clear error code 62 on a LG hvac?
A power reset may temporarily clear the fault and allow the unit to restart, but the error will return if the root cause is not corrected. If airflow is restricted or the PCB is not making proper contact with the heat sink, the temperature will climb again quickly and the fault will reappear. The underlying issue must be diagnosed and repaired for a lasting fix.
How much does it cost to repair a LG hvac showing error code 62?
Repair costs vary depending on the cause. Cleaning the outdoor unit or applying fresh thermal paste are low-cost services, typically in the range of $75 to $200 for a technician visit. If the thermistor requires replacement the cost is moderate. Replacing the inverter PCB is the most expensive scenario, with parts and labor often ranging from $400 to $900 or more depending on the model.

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