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Error code reference

Samsung Air Conditioner Error Code RED_FLICKER_GRN_ON

DC-link overvoltage error

Samsung codesSamsung air conditioner codes

DC-link overvoltage error

First step from the service manual

Check outdoor control board

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

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What RED_FLICKER_GRN_ON means on a Samsung air conditioner

The RED_FLICKER_GRN_ON error code on Samsung air conditioners indicates a DC-link overvoltage fault within the inverter drive circuit of the outdoor unit. The DC-link is the intermediate high-voltage DC bus that sits between the AC rectifier stage and the inverter's IGBT output stage. When the voltage on this bus rises above the acceptable operating threshold, the control board's protection logic shuts down the inverter to prevent damage to the power semiconductors, capacitors, and other sensitive components in the drive circuit.

Overvoltage conditions on the DC-link can originate from several sources. Regenerative voltage spikes can occur when the compressor motor decelerates rapidly and feeds energy back into the DC bus. Incoming AC supply voltage that is abnormally high will also elevate the rectified DC-link voltage proportionally. Degraded or failing DC-link filter capacitors lose their ability to absorb voltage transients, allowing momentary spikes to exceed the protection threshold. A defective outdoor control board that misreads or fails to properly regulate the bus voltage can also trigger this fault incorrectly.

Diagnosis begins with the outdoor control board, which contains the rectifier, DC-link capacitors, and the inverter module. The board should be inspected for signs of physical damage such as burned components, bulging capacitors, or discolored PCB areas. Supply voltage at the outdoor unit should be measured and confirmed to be within the unit's rated input range. If the supply voltage and wiring check out, the capacitors and inverter module become the next focus of investigation.

Source: manufacturer service documentation.

Common causes of RED_FLICKER_GRN_ON

  1. 01

    Faulty outdoor control board

    Part replacement

    The outdoor control board houses the rectifier and voltage regulation circuitry. A board failure can cause incorrect voltage regulation on the DC-link bus or false overvoltage readings, and is the first component to inspect.

  2. 02

    High or unstable supply voltage

    Wiring / connection

    If the incoming AC line voltage is elevated above the unit's rated input range, the rectified DC-link voltage rises proportionally and can trip the overvoltage fault. Measure supply voltage at the outdoor unit disconnect under load to confirm.

  3. 03

    Degraded DC-link capacitors

    Part replacement

    The electrolytic filter capacitors on the DC bus suppress voltage transients. Capacitors that have lost capacitance due to age or heat stress allow voltage spikes to exceed the protection threshold. Visually inspect for bulging tops or electrolyte leakage.

  4. 04

    Regenerative voltage spike from compressor deceleration

    Wiring / connection

    During rapid compressor slowdown, the motor can act as a generator and push voltage back onto the DC-link bus. This is more common when the inverter drive settings are mismatched or the compressor load changes abruptly.

  5. 05

    Faulty inverter module (IPM or IGBT)

    Part replacement

    A partially failed intelligent power module can create abnormal voltage conditions on the DC bus during switching. This typically appears alongside other symptoms such as unusual compressor noise or repeated fault cycling.

See the test procedure for each cause

Frequently asked questions about RED_FLICKER_GRN_ON

What does RED_FLICKER_GRN_ON mean on a Samsung air conditioner?
This error code indicates a DC-link overvoltage fault detected in the inverter circuit of the outdoor unit. The system measured a voltage level on the internal DC bus that exceeded the safe operating limit and shut down to protect the power electronics. The outdoor control board is the starting point for diagnosis. A qualified technician should inspect the board, supply voltage, and DC-link capacitors to identify the root cause.
Can I fix the RED_FLICKER_GRN_ON error myself?
This fault involves high-voltage DC circuits inside the outdoor unit that retain dangerous charge even after power is disconnected. DIY repair is not recommended unless you have training in inverter drive servicing and appropriate safety equipment. A homeowner can safely check that the outdoor unit's power supply voltage is within normal range at the breaker, but internal component testing and replacement should be handled by a licensed technician.
Is it safe to keep running my Samsung AC with this error active?
No. The system has already shut itself down as a protective measure, so continued operation is not possible until the fault is cleared. Attempting to force the unit to run while an overvoltage condition exists could permanently damage the inverter module, compressor, or control board. The unit should remain off until a technician has diagnosed and corrected the underlying cause.
Will resetting the unit clear the RED_FLICKER_GRN_ON error?
A power reset may temporarily clear the fault code and allow the unit to restart, but if the underlying cause is still present the error will return, often quickly. Resetting without diagnosis does not fix the root problem. If the fault reappears after a reset, the DC-link voltage condition is persistent and requires component-level inspection of the outdoor control board, supply voltage, and capacitors.
How much does it cost to repair a Samsung AC with a DC-link overvoltage error?
Repair costs vary depending on what component has failed. A service call and diagnostic fee typically runs between $75 and $150. If only the supply voltage needs correction, additional parts costs may be minimal. Replacing the outdoor control board generally adds $200 to $600 in parts depending on the model, while an inverter module replacement can add $150 to $500 or more. Total repair costs including labor commonly fall in the range of $300 to $900 for component failures.

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