Error code · Room Air Conditioner

LG Air Conditioner Codes CH21, CH23, CH26, CH29, E9: Compressor Circuit

High · stop use, call now

Code: CH21, CH23, CH26, CH29, E9
Appliance: Room Air Conditioner
Brand: LG
Warranty: 30-day workmanship

What CH21, CH23, CH26, CH29, E9 means

This group covers LG air conditioners that show CH codes, including wall-mounted split inverter and ceiling-mounted systems with an outdoor unit. The codes point to the outdoor unit compressor or the circuits that drive and protect it, which can include a temporary power issue, the compressor itself, the drive or protection circuit, or an electrical part in that path. One shared explanation covers all five. The owner sees the code, and the room stops cooling because the outdoor unit has shut down to protect itself.

Common causes of CH21, CH23, CH26, CH29, E9

Brief power disturbance that trips the protection circuit
Compressor drive or protection circuit on the outdoor control
Compressor winding or start-up behavior
Electrical part in the compressor supply path

✓ One safe check you can try

1. Switch the unit off and turn its breaker off. 2. Wait five minutes, then restore power. 3. Start cooling and listen for the outdoor unit to start. 4. If the code returns, leave the unit off rather than restarting it again and again.

! Why to stop there

The shared explanation does not say which of the five paths is involved, so we test the supply and the drive output separately.
Repeated restarts can stress the compressor, so we measure before cycling it more.
You get the finding and a written price before any repair begins.

Opening a panel yourself does not automatically cancel a manufacturer warranty, but it can cause accidental damage, and some manufacturers set their own service conditions. Check your warranty terms, or ask us, before deciding.

→Same appliance

Other Room Air Conditioner codes

LED Too BrightLG Air Conditioner LED Too Bright: Remote Brightness Control LoLG Air Conditioner Message Lo: Low Room Temperature "Outdoor Unit" MessageLG Air Conditioner "Outdoor Unit" Message: Status Display SP, CP, POLG Air Conditioner Codes SP, CP, PO: Power Cooling Mode HiLG Air Conditioner Message Hi: High Room Temperature Lamp Does Not LightLG Air Conditioner Lamp Off After Shutdown: Filter Alarm Timing LED Blinking After Power OffLG Air Conditioner LED Blinking After Power Off: Auto Drying F1, F2, F3LG Air Conditioner Codes F1, F2, F3: Fan Speed Readout

CH21, CH23, CH26, CH29, E9CH21, CH23, CH26, CH29, E9 questions

Why shouldn't I keep restarting the unit?

Each restart asks the compressor to start against pressure and load. If the code keeps returning, repeated attempts can add wear, so after one reset it is better to leave it off until it is tested.

Are all five codes the same repair?

They share one explanation about the compressor and its control circuits, but the cause behind each can differ. We measure the supply, the drive, and the compressor to see which applies.

Can a power dip trigger these codes?

Yes. A temporary power issue is one of the named causes, so a reset may clear a single event. A code that comes back points to the circuit or the compressor itself.

Book a visit

Still seeing CH21, CH23, CH26, CH29, E9?

A technician diagnoses it on site and gives you the price in writing before any work starts.

(713) 597-5662