Appliance Code Check

LG · Ductless air conditioner

CH90

Safe checks availableService if the code returns

error code

LG CH90 is a test-run protection display associated with installation piping checks.

Display form
CH90
Lookup normalization
CH90
Alternate forms
None retained in the official record

Check the display exactly as shown. The decoder ignores case and spaces, but it never substitutes O/0, I/1, or S/5.

Official meaning, scoped to this source

LG CH90 is a test-run protection display associated with installation piping checks.

Manufacturer
LG
Document
[LG Air Conditioner] Guide to Error Codes · Official error-code index
Product family
split-system air conditioners
Market and locale
US · en-US

This is an official-source interpretation for the stated scope, not a confirmed diagnosis. Meaning can change across brands, models, product families, and markets.

Market, product family, and model applicability

US · en-US · LG split-system air conditioners covered by the cited US guide

Exact model applicability has not been verified.

This release retains family or source-index scope only. Do not infer that an arbitrary model uses this code; confirm it in the exact manufacturer manual.

Open the official model/manual lookup (opens in a new tab)

Safe external checks

Use the documented five-minute power reset and request service if the display persists or returns.

  1. Disconnect power for five minutes, restore power, and observe whether the display returns.

Safe checks and when to request service

Request LG service if the display persists or returns after the supported reset.

  • Consult the installation technician if CH90 followed installation or relocation.
  • Request LG service if the display persists or returns after the supported reset.

Separate hazard signs such as smoke, flooding, sparks, or a burning smell require the manufacturer's safety instructions.

Do not do

Do not open electrical panels, access wiring, handle refrigerant, alter piping, or work on internal fans or compressors.

Use only exterior observations and the documented power reset; leave internal electrical, fan, piping, and refrigerant work to qualified professionals.

Check warranty before authorizing service

Warranty coverage depends on the country, model, purchase date, and manufacturer terms. Have the model and serial number available, open the manufacturer's official support or warranty page, and ask whether the service route is authorized before paying for work.

This public record does not make a coverage determination. Use the official model lookup and warranty information linked below.

Open official model lookup (opens in a new tab)↗View source and warranty links

If the message returns

If the display persists or returns after the reset, request LG service.

Source and scope

Official source verified at release
Market and locale
US · en-US
Product family
split-system air conditioners
Content and safety verified on
July 26, 2026
Source updated by manufacturer
Not supplied in the official record

LG

[LG Air Conditioner] Guide to Error Codes · Official error-code index

Open official source (opens in a new tab)

Verification and review status

  • Content meaning and safety verifiedJuly 26, 2026
  • Source reachability statusOfficial source verified at release
  • Automated evidence review completedPassed · July 26, 2026
  • Automated safety rules checkPassed for this published safety boundary
  • Human technical reviewPending — no human completion is claimed
  • Publication gateAutomated publication checks passed · July 26, 2026
  • Official-source conflictNo unresolved conflict admitted to this public release

Automated checks and release approval are not a substitute for a qualified service professional or the exact manufacturer manual.

Evidence used for this guidance

  • CH90 / CH91 section

    Source-backed summary

    CH90 and CH91 appear during test run to protect the appliance; consult the installer after installation, otherwise power cycle and request service if persistent.

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Send a privacy-minimal correction signal. It cannot change public content automatically.

Report a model or source mismatch

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