mypros+
Error code reference

LG Hvac Error Code 26

Inverter compressor seized, not rotating or not proving rotation.

LG codesLG hvac codes

Inverter compressor seized, not rotating or not proving rotation.

First step from the service manual

Verify 3 compressor windings all equal at 0.5-4Ω, verify ∞Ω to ground, verify equal voltage on compressor 3-phase legs. Verify no flow restrictions (cool mode will pump down system, heat mode will dead-head compressor).

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

MyPros+ Max

Get the full diagnostic procedure for 26.

  • Step-by-step tests with expected resistance, voltage, and continuity values
  • Wiring diagram references and connector pinouts from the OEM service manual
  • Verified part numbers when replacement is required
Get the full procedure

$29/month · Cancel anytime · Or $9.95 3-day pass

What 26 means on a LG hvac

Error code 26 on an LG inverter-driven HVAC system indicates that the inverter compressor has seized or is failing to rotate, and the inverter board cannot confirm rotation feedback. The inverter drive monitors current draw and rotation confirmation signals from the compressor. When the compressor motor windings fail to produce the expected back-EMF pattern, or when mechanical seizure prevents the rotor from turning despite applied voltage, the system triggers this fault and shuts down to prevent further damage to the inverter board and compressor assembly.

The root cause is typically either an electrically faulted compressor or a mechanically seized one, though refrigerant system restrictions can also produce this code. In cooling mode, a flow restriction causes the system to pump down excessively. In heating mode, a blockage such as a failed reversing valve or clogged strainer can dead-head the compressor, creating excessive discharge pressure that prevents rotation. Electrical diagnosis begins with measuring all three compressor winding resistances, which should read equally in the 0.5 to 4 ohm range, and verifying infinite resistance between each winding terminal and the compressor shell ground. Balanced three-phase output voltage from the inverter board to the compressor terminals must also be confirmed before condemning the compressor itself.

Source: manufacturer service documentation.

Common causes of 26

  1. 01

    Mechanically seized compressor

    Part replacement

    Internal bearing failure or loss of lubrication causes the compressor rotor to lock up. Winding resistance will check within spec but the compressor will not spin under load.

  2. 02

    Open or shorted compressor winding

    Part replacement

    One or more of the three motor windings has failed open or shorted, showing resistance outside the 0.5 to 4 ohm range or showing continuity to ground. The inverter cannot establish rotation with an unbalanced or faulted winding set.

  3. 03

    Refrigerant flow restriction

    Wiring / connection

    A blocked strainer, failed expansion device, or stuck reversing valve creates a pressure condition that prevents compressor rotation. In heating mode this dead-heads the compressor; in cooling mode it causes excessive pump-down. Check system pressures and valve operation before replacing the compressor.

  4. 04

    Inverter board output failure

    Part replacement

    If the inverter board is not producing balanced three-phase voltage across all three compressor legs, the compressor cannot start. Measure voltage at the compressor terminals during a start attempt to rule out a board-side fault.

  5. 05

    Poor wiring connection at compressor terminals

    Wiring / connection

    Loose, corroded, or heat-damaged terminals on the compressor connector can cause high resistance on one or more phases, preventing proper rotation. Inspect and clean all three compressor terminal connections.

See the test procedure for each cause

Frequently asked questions about 26

What does 26 mean on a LG hvac?
Error code 26 on an LG HVAC system means the inverter compressor is seized or is not rotating. The inverter board, which controls compressor speed, has detected that the compressor motor is not spinning or cannot confirm that rotation is occurring. The system shuts down automatically to prevent damage to the compressor and inverter components.
Can I fix error code 26 on my LG HVAC myself?
Some causes of error code 26, such as loose wiring connections at the compressor terminals, can be inspected by a knowledgeable DIYer. However, diagnosing this code properly requires measuring three-phase winding resistance, testing inverter board output voltage, and evaluating refrigerant system pressures, all of which require specialized tools and, in the case of refrigerant work, EPA certification. Compressor replacement is a refrigerant-system repair that must be performed by a licensed technician.
Is it safe to keep running my LG HVAC when error code 26 appears?
No. Error code 26 indicates the compressor is not rotating, and the system should already be in a protective shutdown state. Attempting to force the system to run with a seized or faulted compressor risks damaging the inverter board, burning compressor windings, and causing refrigerant system pressure faults. Leave the system off and contact a qualified technician.
Will resetting my LG HVAC clear error code 26?
A power reset may temporarily clear the fault and allow a restart attempt, but if the underlying cause is a seized compressor, a faulted winding, or a refrigerant restriction, the code will return quickly, often within the first few seconds of the next start attempt. Resetting without diagnosing the root cause does not fix the problem and can cause additional damage.
How much does it cost to repair error code 26 on an LG HVAC?
Repair costs vary significantly depending on the cause. If the fix is a wiring connection or a refrigerant restriction such as a clogged strainer, costs may range from a few hundred dollars for labor and parts. If the inverter board has failed, board replacement typically runs in the several-hundred-dollar range. A seized or electrically faulted compressor is the most expensive outcome, with compressor replacement on an inverter system commonly ranging from one thousand to several thousand dollars depending on system size, refrigerant type, and labor rates in your area.

Related LG hvac codes

All LG hvac codes
View all 75 LG hvac codes

78,000+ service manuals · 160,000+ error codes · 55+ brands

Get Started

$29/month · Cancel anytime · Or $9.95 3-day pass