In brief
Fault code LC on Gree sapphire service manual 18mbh and 24mbh models a means: Fault code LC indicates a start failure of the AC (inverter) compressor. This fault manifests as a compressor lock in cooling or dry mode, or a complete unit shutdown in heating mode. Most common cause: The main causes are poor contact of the compressor UVW cables, a faulty compressor itself, or a malfunction of the compressor drive board. First action: Verify that the U, V, and W phases of the compressor cables are correctly connected.. Call a registered engineer if the fault returns after basic checks or involves refrigerant work (F-Gas registered engineer required).
According to the Gree service manual, the LC fault code indicates a start failure of the AC inverter compressor, with diagnosis performed on the ODU main board display.
LC • Gree • sapphire service manual 18mbh and 24mbh models a
Gree Fault Code LC: Causes, Diagnosis and Solution
Fault code LC indicates a start failure of the AC (inverter) compressor. This fault manifests as a compressor lock in cooling or dry mode, or a complete unit shutdown in heating mode.
Source: Gree documentation (service manual – according to product reference)
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What does fault code LC on Gree mean?
Fault code LC indicates a start failure of the AC (inverter) compressor. This fault manifests as a compressor lock in cooling or dry mode, or a complete unit shutdown in heating mode.
The main causes are poor contact of the compressor UVW cables, a faulty compressor itself, or a malfunction of the compressor drive board.
Symptômes
- The compressor stops while the indoor fan continues to run (cooling/dry mode).
- The entire unit stops in heating mode.
- The compressor remains locked in the start-up phase without transitioning to operation.
- Display of 'LC' code on the LED screen of the outdoor unit main board.
- Compressor synchronisation or start failure.
Diagnostic
1. Check Connections and Phases
- Verify that the U, V, and W phases of the compressor cables are correctly connected.
- Measure the resistance between the windings of each compressor phase (typically less than 2 ohms and equal between them).
2. Check Insulation and Associated Faults
- Check the insulation to earth of the compressor phase windings (typically greater than 2 megohms).
- Check if other faults have occurred simultaneously (e.g., compressor asynchrony H7, phase current overcurrent P5, or module current protection H5).
How to reset fault code LC on Gree?
If the connections are correct and the resistance and insulation are normal, but other faults such as asynchrony or overcurrent are present, the compressor is damaged and must be replaced. If no other anomalies are detected, replace the compressor drive board.
When should you call an F-Gas engineer?
This code occurs when the compressor remains locked in start-up mode without transitioning to operating mode. The specific behaviour depends on the mode: in cooling or dry mode, the compressor stops while the indoor fan continues to run; in heating mode, the entire unit stops.
Affected models
- Sapphire Service Manual 18MBH and 24MBH
- Flexx Eco Service Manual A
- Flexx Service Manual AC BH
- Flexx Ultra R32 Service Manual A
- X-Pac R32 Service Manual A
- High Static Slim Duct Service Manual B
Field context
This code occurs when the compressor remains locked in start-up mode without transitioning to operating mode. The specific behaviour depends on the mode: in cooling or dry mode, the compressor stops while the indoor fan continues to run; in heating mode, the entire unit stops.
Technical source data
The LC fault code indicates a start failure of the AC (inverter) compressor. Diagnosis is performed on the ODU main board display (neon tube or LED); note that some extracts mention a 'PJ' display condition for this fault (Extract 1, 3). The identified causes are: poor contact of the compressor UVW cables, a faulty compressor itself, or a malfunction of the drive board. The troubleshooting procedure requires first checking the resistance between windings (typically < 2 ohms) and insulation to earth (> 2 MΩ). If these values are normal but faults such as asynchrony (H7), overcurrent (P5), or module current protection (H5) coexist, the compressor is damaged and must be replaced. Otherwise, if the UVW connections are correct, the drive board must be replaced.
Sources: flexx eco service manual a — flexx-eco-service-manual-a.pdf (p. 50) · flexx service manual ac bh — flexx-service-manual-ac-bh.pdf (p. 42) · flexx ultra r32 service manual a — flexx-ultra-r32-service-manual-a.pdf (p. 50)
Questions fréquentes
What is the specific behaviour of the unit when the LC code appears?
When the LC code appears, the behaviour varies depending on the operating mode. In cooling or dry mode, the compressor stops while the indoor fan continues to run. In heating mode, the entire unit stops. This symptom indicates the compressor's inability to start and switch to stable operating mode.
What is the first diagnostic step for the LC code?
The first step is to check the UVW cable connections of the compressor to ensure they are properly connected. Next, measure the resistance between the windings of each phase (which should typically be less than 2 ohms and equal between them) as well as the insulation to earth (typically greater than 2 megohms). If these measurements are normal, proceed to check for other faults.
How do you distinguish a compressor fault from a drive board problem?
If the UVW connections are correct and the resistance and insulation are normal, check for other simultaneous faults such as asynchrony (H7), overcurrent (P5), or module current protection (H5). If these faults are present, the compressor is damaged and must be replaced. If no other anomalies are detected, the cause is a malfunction of the drive board.
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