Does CH10 always mean the fan motor has failed?

No. CH10 indicates the motor could not rotate, but the cause can be mechanical — a cracked blower wheel, debris caught in the fan housing, or a seized bearing. The motor itself may be perfectly fine.

How can I tell if the blower wheel is cracked?

A cracked blower wheel often produces a clicking or scraping noise before the unit shuts down. If you open the front panel and manually rotate the fan barrel, you may feel resistance or hear contact at a specific point in the rotation.

Why did the previous contractor diagnose a PCB fault?

The PCB controls the motor and reports the error, so it is sometimes assumed to be the source. However, in this case the PCB was correctly detecting a motor lock condition caused by a mechanical obstruction. The board was working as intended.

LG CH10 Fan Motor Lock From Cracked Blower Wheel

Aircon case in Woodlands, Singapore: airflow traced to cracked blower wheel catching on fan housing triggering motor lock protection after targeted diagnosis checks.

Case Details

Reported: The aircon makes a clicking sound and then stops. It shows an error code after that. My previous contractor said the main board is faulty and needs replacing. I wanted a second opinion before spending on a new board.
Unit: LG · Wall-mounted · 3–7 years
Location: HDB · Woodlands, Singapore

What We Checked

CH10 error was present — the unit attempted to start, clicked, then shut down.
The fan motor received power normally and attempted to spin.
Manual rotation of the blower wheel revealed resistance at one specific point in the rotation.
Closer inspection showed a crack in the blower wheel — the cracked section was flexing outward and catching on the fan housing.
The fan motor spun freely once the blower wheel was removed, confirming the motor itself was undamaged.

The Diagnosis

The blower wheel had developed a crack, likely from material fatigue over several years of continuous use. During rotation, the cracked section flexed outward just enough to make contact with the inner wall of the fan housing. This contact caused the motor to stall, triggering the CH10 motor lock protection. The clicking noise was the cracked section striking the housing on each attempted rotation.

What Fixed It

We recommended replacing the blower wheel only. The fan motor tested fine once the obstruction was removed, and the PCB was functioning correctly — it was doing exactly what it should by shutting down the motor when it detected a lock condition. Replacing the PCB would not have resolved the issue. We sourced a replacement blower wheel compatible with the unit model.

The new blower wheel was installed and the unit started normally. CH10 cleared and airflow returned to full strength. No clicking noise, no further motor lock events.

Why This Happens

Why motor lock errors are often mechanical, not electrical.

A motor lock error means the motor was unable to rotate — but the cause is often physical obstruction, not motor or PCB failure.
Blower wheels can develop hairline cracks over time, especially in humid environments. The crack allows a section to flex outward and catch on the housing during rotation.
Manually spinning the blower wheel with the unit powered off is a simple diagnostic step that can reveal physical contact points before any electrical testing.

Same situation with your aircon?

Describe what’s happening. We’ll work out the likely cause and tell you the right next step.

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