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Error code · Room Air Conditioner

LG Air Conditioner Codes CH66, CH90 to CH93: Installation and Test Run

These codes appear on LG air conditioners that show CH codes, mostly split systems after a new installation or relocation. They point to an installation or test-run problem: wrong wiring, a test run that was not…

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Code
CH66, CH90, CH91, CH92, CH93
Appliance
Room Air Conditioner
Brand
LG
Warranty
30-day workmanship

What CH66, CH90, CH91, CH92, CH93 means

These codes appear on LG air conditioners that show CH codes, mostly split systems after a new installation or relocation. They point to an installation or test-run problem: wrong wiring, a test run that was not finished, or restricted refrigerant flow. CH66 is a communication line or piping connection problem, CH90 and CH91 appear during a test run and may show as F4, and CH93 is a communication problem that on post-2021 models can mean the outdoor unit gets no power.

Common causes of CH66, CH90, CH91, CH92, CH93

  • Communication wiring connected wrongly during installation
  • Test run not completed
  • Piping connection restricting refrigerant flow
  • Outdoor unit without power on a post-2021 model
✓ One safe check you can try

1. If the code appeared after installation or relocation, contact the installer. 2. Otherwise, switch the unit off and reset power for five minutes. 3. For CH93, check that the power cords and cable connections are seated. 4. Restart and see whether the code returns.

! Why to stop there
  • The group covers several conditions, so we confirm the wiring and piping connections first.
  • We read the unit through a test run to see where it stops.
  • We tell you the finding and quote in writing before any repair.
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 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 FLLG Air Conditioner Code FL: Condensate Tank Full HiLG Air Conditioner Message Hi: High Room Temperature
CH66, CH90, CH91, CH92, CH93CH66, CH90, CH91, CH92, CH93 questions
Why do these codes appear after a move?

A relocation disturbs wiring and piping connections. If one is wrong or a test run was skipped, the unit reports one of these codes until it is corrected.

What does CH93 mean on a newer unit?

On models made after 2021, CH93 can mean the outdoor unit is not getting power. Check the cord and cable connections, as we do when we arrive.

Is the installer responsible for these codes?

If the code shows soon after an installation, the installer is the first call. If it appears later or the installer is gone, we test the system and tell you what we find.

Book a visit

Still seeing CH66, CH90, CH91, CH92, CH93?

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

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