- HVAC
- Air conditioner
CH38
LG CH38 on an air conditioner: low refrigerant protection
Risk level
High
Professional inspection is recommended.
Urgency
Medium
Quick answer
On LG air conditioners, CH38 (F4 on some models) appears when the refrigerant level is low and the unit protects itself. If it was just installed, call the installer; otherwise cut power for 5 minutes and, if it returns, call a technician.
Safety first
Stop and check this first
- LG warns not to disassemble the air conditioner or replace internal parts yourself: it may cause fire, electric shock, serious injury or death. Boards, wiring and refrigerant are service technician work.
Safe checks you can perform
- When the code appeared
- Five-minute reset
- Charge and leak check
Leave these tasks to a qualified professional
- Do not attempt this professional task: Find the leak before recharging
- Do not attempt this professional task: Test after charging
What a technician must be able to justify
Technician visit
These are the steps they must carry out and show you. Tick them as they work: if steps are skipped, do not accept a part swap.
These are not instructions for opening or handling the equipment yourself. They are the checks that should support a technical conclusion.
Find the leak before recharging
What they doThe technician locates and repairs the loss before adding refrigerant.
They must show youwhere the leak was.
In writingthe repair, amount and type of refrigerant charged and the certificate number.
Test after charging
What they doAfter the repair the technician runs the unit and checks that CH38 does not return.
They must show youthe unit running with no code.
In writingdate and result.
Before accepting a part or repair
Nothing has been shown yet. Do not accept a part swap based on the code alone.
Follow these steps
Note: Follow the documented order. An error code identifies the affected system, but it does not prove by itself which part has failed.
When the code appeared
- Who:
- you.
- How:
- note whether CH38 appeared soon after installation or after a period of normal use.
- Result that matters:
- LG treats each case differently.
- If after installation:
- call the installer to check the refrigerant charge.
- If after a period of use:
- do the 5 minute reset.
- Evidence to keep:
- the installation date and the date of the code.
Evidence: LG Air Conditioner - Inspection code: CH38
Five-minute reset
- Who:
- you.
- How:
- unplug the unit or switch off its breaker and restore power after 5 minutes.
- Result that matters:
- whether CH38 reappears.
- If it does not return:
- note the date and watch for repeats.
- If it returns:
- LG asks for an inspection by a qualified technician.
- Evidence to keep:
- a note of each occurrence.
Evidence: LG Air Conditioner - Guide to Error Codes · LG Air Conditioner - Inspection code: CH38
Charge and leak check
- Who:
- an F-gas certified technician.
- How:
- checks whether the refrigerant amount is sufficient and searches for the leak before recharging.
- Result that matters:
- whether refrigerant is missing and where it is lost.
- If it is low and the leak is found:
- the cause is confirmed; repair before charging.
- If the charge is correct:
- a leak is ruled out and the reason for the protection is checked.
- Evidence to keep:
- a job sheet with the measured charge and the leak point.
Refrigerant work: only an F-gas certified technician.
Evidence: LG Air Conditioner - Inspection code: CH38
Still not solved
If the error persists, stop here. See what the technician must do and show you.
Where this code applies
A code is meaningful only inside the right product and version context.
Primary scope
- System
- HVAC
- Brand
- LG
- Product type
- Air conditioner
Known code variants
- CH 38
- F4
- LG CH38
What it means
LG says CH38 appears when the refrigerant level of the appliance is low, to protect it. If it happens right after installation, LG asks the technician to check there is enough refrigerant; if it happens after a period of use, it asks for a 5 minute power reset and, if the code stays, a technical inspection. The code is a control protection: on its own it does not prove a leak or show where it is. Measuring the charge and finding the leak is work for an F-gas certified technician.
Warnings and stop conditions
- Highsource verified
LG warns not to disassemble the air conditioner or replace internal parts yourself: it may cause fire, electric shock, serious injury or death. Boards, wiring and refrigerant are service technician work.
Evidence: LG Air Conditioner - Inspection code: CH38 · How to Troubleshoot Error Codes CH01, CH02, CH06 on Your LG Air Conditioner
Symptoms and causes
Probable causes · in order
- Insufficient charge since installationPossible
If CH38 appears from the first days, LG points to checking the amount of refrigerant the installer left.
Evidence: LG Air Conditioner - Guide to Error Codes · LG Air Conditioner - Inspection code: CH38
- Refrigerant loss over timePossible
If the unit ran well for a while, a loss of charge is the most direct explanation; a leak search confirms it.
Evidence: LG Air Conditioner - Guide to Error Codes · LG Air Conditioner - Inspection code: CH38
- Protection tripped without a real lossPossible
If the code does not return after the 5 minute reset, the protection may have tripped once; the technician rules it out by measuring.
Evidence: LG Air Conditioner - Guide to Error Codes · LG Air Conditioner - Inspection code: CH38
Virtual technician
Does CH38 still appear after these checks?
Answer a few questions to narrow down the likely cause and the safest next action. Guidance only - it never replaces a professional.
Sources and technical references
- 1
LG Air Conditioner - Guide to Error Codes
LG Electronics · 2026 · official_doc
- 2
LG Air Conditioner - Inspection code: CH38
LG Electronics · 2024 · official_doc
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