EN

Severity: Moderate

LG AC / Heat Pump Error CH10 – Indoor Fan Motor Locked (BLDC Fan)

CH10: the indoor unit's fan motor isn't turning or isn't reporting its speed, so the unit shuts down.

At a glance

Severity: 3/5 – Moderate3/5

Severity: Moderate

Meaning
Indoor Fan Motor Locked (BLDC Fan)
Typical repair cost
$0–$650
DIY difficulty
Moderate

LG's error tables describe CH10 as an indoor fan lock – a fan motor operation failure. The indoor unit uses a brushless DC motor that reports its speed back to the control board through a feedback signal. When the board commands the fan to run but gets no speed pulses back for a set time, it assumes the fan is jammed and stops the whole system so the coil doesn't freeze or overheat without airflow. The fan wheel may truly be stuck – a foreign object, a failed motor bearing – or the motor may spin but its internal electronics no longer send the signal. A loose motor plug or a damaged drive circuit on the indoor board completes the picture.

How it looks on the display

LG Air Conditioner / Heat Pump display showing error CH10

Model families & display variants

Model familyShowsNote
Wall units with 2-digit display (Art Cool, Mega, Standard)CH ↔ 10The display alternates between CH and the number.
Models without a numeric displayLED blinksThe heating and cooling LEDs blink out the digits; LG's code chart for the model gives the pattern.
Ducted and cassette units with wired controllerCH10Shown on the wired controller; on multi-zone systems only the affected head stops.

Safety first · Consult a professional

Switch the breaker off before reaching near the fan wheel; the indoor board feeds the fan motor with around 310 V DC. Only look through the air outlet with a flashlight – don't remove the casing or unplug anything yourself.

  • Unplug the appliance or switch off the breaker before opening any panel. Mains voltage can kill.

Symptoms

  • CH and 10 alternating on the indoor unit display
  • No air coming out, although the louvers open
  • Grinding, scraping or rattling noise just before the unit stopped
  • Fan tries to start, twitches and stops again
  • On models without a code display, the indoor LEDs blink a matching pattern

Possible causes

Ranked by how often each cause is behind this code (editorial estimate).

  1. Indoor BLDC fan motor failed – bearings seized or internal electronics dead 40%
  2. Fan wheel blocked by a foreign object or loose part 20%
  3. Motor connector loose or corroded at the indoor board 15%
  4. Fan drive circuit on the indoor control board damaged 15%
  5. Crossflow fan wheel cracked or rubbing on the housing 10%

Fix it step by step

Diagnostic flow: CH101Power off and look inside the outlet2Check that the wheel turns freely3Clear light obstructions only4Restart and listen5Technician motor test

  1. Power off and look inside the outlet

    Switch off the breaker, open the louvers by hand and shine a flashlight onto the long barrel-shaped fan behind them. Look for paper, a toy, a broken louver clip or anything wedged between the blades.

    Tools: Flashlight

  2. Check that the wheel turns freely

    With power still off, gently push one blade with a plastic chopstick or wooden spoon handle. It should spin easily and coast. If it doesn't move, feels gritty or wobbles on its shaft, the motor or fan wheel is the problem.

    Tools: Flashlight

  3. Clear light obstructions only

    Remove an object only if you can reach it through the outlet without tools. Anything stuck deeper, or a fan that has come loose on its shaft, needs a technician to take the unit apart.

    Tools: Gloves

  4. Restart and listen

    Turn the power back on and start fan-only mode on high. A healthy fan ramps up quietly within a few seconds. If CH10 comes back straight away while the wheel turns freely by hand, the motor electronics or the board are at fault.

  5. Technician motor test

    The technician checks the supply voltages at the motor plug (high DC bus and the low control voltage), the speed command and the feedback pulses while the board tries to start the fan. No feedback with good supply means a new motor; no supply means a new board.

    Tools: Multimeter

How to reset CH10

  1. Turn the unit off with the remote
  2. Switch off the breaker for 3–5 minutes
  3. Restore power and start in fan mode first to confirm the fan runs

Where the parts are

Split AC / heat pump: indoor and outdoor unit – CH10123456
Split AC / heat pump: indoor and outdoor unit
  1. 1Fan
  2. 2Temperature sensor
  3. 3CAN bus
  4. 4Outdoor unit
  5. 5Compressor
  6. 6Engine computer (ECM)

Repair options & costs

RepairDIY?Estimated cost
Remove object from fan (no tools needed) Yes $0
Technician diagnosis No $100–$200
Indoor fan motor replacement No $300–$600
Crossflow fan wheel replacement No $200–$450
Indoor control board replacement No $300–$650

Rough US estimates; technician call-out fees vary by region. Not a quote.

When to call a technician

Call an HVAC technician if the fan won't turn by hand, if CH10 returns after clearing an obstruction, or if you heard grinding before the stop. Replacing the motor means removing the front casing, drain pan and often the coil fasteners on a wall unit – a job with refrigerant lines and live wiring close by.

Frequently asked questions

Can I run the unit in cooling without the indoor fan?

No, and the board won't let you. Without airflow the indoor coil would ice up in cooling or overheat in heating, which is exactly what CH10 prevents.

Is CH10 the outdoor fan?

No. CH10 is the indoor fan. The outdoor fan has its own code on LG systems, so a silent outdoor fan points elsewhere.

The fan spins freely by hand – why the error?

The motor's built-in electronics or the board's drive circuit can fail without any mechanical binding. The board then sees no speed signal and reports a lock even though nothing is stuck.

Sources