LG CH 90 error code

What it means

CH 90 is typically shown during the test-run phase to protect the appliance. LG says installation or relocation cases need piping-connection inspection; during normal use, the same display may be temporary but should not be ignored if it returns.

Urgency

Likely causes

1. Test-run phase protection
2. Piping connections needing inspection after installation or relocation
3. Refrigerant flow problem during test run
4. Temporary fault from unstable power or other electrical factors during normal use

Homeowner fix

If CH 90 appears on a new or relocated system, contact the installer. During normal use, power cycle once if safe; if it returns, leave the system off.

When to call a pro

Call a licensed HVAC technician if CH 90 returns or appeared during commissioning. Tell them LG identifies CH 90 as test-run protection with piping/refrigerant-flow checks.

Repair vs replace

A setup or piping correction may be repairable. If diagnosis points to leak, coil, line-set, or compressor work on older equipment, compare repair with replacement.

• LG Mega R-32 9,000 BTU (115V)

  Mega R-32

• LG Mega R-32 9,000 BTU (230V)

  Mega R-32

• LG Mega R-32 12,000 BTU (115V)

  Mega R-32

• LG Mega R-32 12,000 BTU (230V)

  Mega R-32

For your technician

Technician note: inspect installation piping connections, refrigerant flow, test-run status, and model-specific F4/CH 90 protection path. Page context: LG maps this display to the Mega R-32 line; source: LG official support pages: [LG Air Conditioner] Guide to Error Codes; [LG Air Conditioner] How to Check Air Conditioner Error Codes; LG status-display help articles; LG Korea [LG Air Conditioner] Air conditioner error inquiry cross-check; display convention: match the letter C, letter H, and ninety marker exactly before comparing neighboring codes.

Which systems show it

Mega R-32

Related troubleshooting

Use the symptom guide alongside the exact display code if the unit is flashing, cycling, or showing comfort symptoms.

Related codes

Source

Next step