Low Refrigerant Protection
LG CH38 Error Code
The LG CH38 error code tells you the system has detected that it is running low on refrigerant, often called gas, and has shut down to protect the compressor. Refrigerant does not get used up like fuel, so a low charge almost always means a leak or an installation problem. Here is what that means and what happens next.
The Meaning
What Does LG CH38 Mean in Simple Terms?
Refrigerant is the working fluid of your air conditioner. It circulates in a sealed loop of copper pipe between the indoor and outdoor units, picking up heat in one place and releasing it in another. The compressor pumps it around, and it relies on a correct amount of refrigerant to stay cool and lubricated.
LG units cannot see the refrigerant directly. Instead, the outdoor board watches temperatures at key points, such as the compressor discharge pipe and the coils, and compares them with what it expects at the current compressor speed. When the pattern matches a system that is short of refrigerant, the board stops the compressor and shows CH38.
LG’s own support material describes CH38 as the air conditioner being low on refrigerant. The board is effectively saying that it would be risky to keep pumping with too little gas in the loop.
The key point for owners is this. Refrigerant is not consumed. A healthy sealed system should hold its charge for its whole life. If the charge is low, it has escaped somewhere, or the system was never charged correctly to begin with.
Timing Matters
Does It Matter When CH38 First Appears?
Very much so. LG itself draws a distinction between CH38 appearing soon after installation and CH38 appearing during normal use. The likely causes, and who you should call, are different.
Soon After Installation or Relocation
The cause is often linked to the install itself. Flare joints may not be sealed properly, service valves may not be fully open, or the charge may not suit the pipe length. Contact your installer first, as this is part of their workmanship.
After Months or Years of Use
A system that cooled well for a long time and now shows CH38 has most likely developed a leak. Common spots include flare joints, the indoor coil, the outdoor coil and service valve cores.
There is also a third pattern. Some systems show CH38 only in very cold or very hot weather, at the edges of their operating range. In those cases, a marginal charge or a sensor reading can be involved. The technician will consider the conditions when the code appeared.
Seeing the Code
How Is CH38 Shown on LG Air Conditioners?
On LG splits with a numeric display, the code appears as CH and 38. Some models show only 38. Units with indicator lights only blink a two part pattern. Ducted and cassette systems show the code on the wired controller.
Before the code appears, many owners notice warning signs. Cooling becomes weaker over days or weeks. The unit runs for longer to reach the set temperature. In heating mode, the air may feel lukewarm. Some people spot frost or ice on the thinner copper pipe at the outdoor unit, or on the indoor coil behind the filters.
A hissing or bubbling sound near the pipes can point to an active leak, though many leaks are too small to hear. An oily stain on a pipe joint can also be a clue, because refrigerant carries a little compressor oil with it as it escapes.
Where Gas Escapes
What Causes an LG System to Lose Refrigerant?
Leaks can happen anywhere in the refrigerant loop. Some places are much more common than others, and the list below runs from the most frequent to the less common.
Common Leak Points
- Flare joints at the indoor and outdoor units that have loosened or cracked
- Service valve cores and caps at the outdoor unit
- Pipe sections rubbing against brackets, walls or roofing
- Joints disturbed during renovation, painting or roof work
Less Common Leak Points
- Pinhole corrosion in the indoor coil
- Corrosion in the outdoor coil from salt air
- Cracked brazed joints inside the outdoor unit from vibration
- Pipe damage from pests, sharp objects or garden tools
Not every CH38 is a leak. On rare occasions, a faulty temperature sensor or a blockage in the refrigerant circuit can produce readings that look like a low charge. That is one reason a proper diagnosis with gauges matters before refrigerant is added.
Owner Checks
What Can I Safely Check When CH38 Appears?
Refrigerant work is restricted by law in Australia. Only ARCtick licensed technicians may handle it. Your checks should rule out simple airflow problems that make the system work harder, and gather information for the technician.
- Photograph the code and note when it appeared, including whether the system was recently installed, moved or serviced.
- Turn the unit off at the remote, then switch it off at the breaker for five minutes. LG suggests this before calling for service.
- Clean the indoor filters, since blocked filters can cause coil icing that adds to the problem.
- Look at the outdoor unit from a safe distance for ice on the pipes, oily patches at joints, or damaged pipe insulation. Do not touch pipes or valves.
- Clear debris away from the outdoor coil.
- Restore power and test once. If CH38 returns, leave the system off.
Never try to tighten pipe nuts, remove valve caps or buy refrigerant to top up the system yourself. Doing so is unsafe, illegal for unlicensed people, and likely to make the leak worse.
Should It Run
Is It Safe to Keep Using My LG With CH38?
No. The protection exists for a good reason. Refrigerant carries heat away from the compressor and helps return oil to it. Running short of refrigerant makes the compressor overheat and can starve it of lubrication. Over time, that can lead to compressor failure, which is the most expensive repair on any system.
Running with a low charge also performs poorly. You pay for electricity while getting little cooling or heating. The indoor coil may ice up and then leak water as it melts.
There is an environmental side too. Refrigerants are greenhouse gases. Continuing to run a leaking system, or recharging it without fixing the leak, keeps releasing them into the atmosphere. Switch the unit off at the breaker and book a licensed technician.
How Does LG Detect a Low Charge Without a Gas Gauge?
LG systems infer the charge from how the refrigerant behaves. When there is too little refrigerant, the gas leaving the compressor runs hotter than normal, because there is less of it to carry heat away. At the same time, the coils do not show the temperature changes the board expects for the compressor speed it is running.
The board compares these readings over a period of running time rather than acting on a single moment. That is why CH38 often appears after the unit has been running for a while, not straight away. It also explains why accurate sensors matter. If a discharge or coil sensor is reading wrongly, the board can mistake a healthy system for a low one. A good technician therefore checks the sensors as well as the pressures before deciding on a repair.
What Should I Tell You When Booking?
Mention when the system was installed, whether it has been moved or regassed before, and whether you noticed weak cooling, ice or hissing. If someone has previously topped up the gas, say so. Repeat top ups are a strong sign of an unrepaired leak, and that history helps the technician focus the search.
The Proper Fix
How Does a Licensed Technician Repair LG CH38?
The right approach is to find and fix the leak first, then restore the correct charge. Simply topping up gas without repairing the leak treats the symptom, not the cause, and the code will return.
Confirm the Diagnosis
An ARCtick licensed technician connects gauges and reads pressures and temperatures to confirm the system really is low on charge, rather than suffering a sensor fault or blockage.Search for the Leak
They check common leak points first, using an electronic leak detector, bubble solution or both. Oil stains and frost patterns help narrow the search.Pressure Test if Needed
For hard to find leaks, the remaining refrigerant may be recovered and the system pressurised with dry nitrogen to locate the leak and confirm the repair holds.Repair the Leak
Repairs may involve remaking a flare joint, replacing a valve core, repairing a pipe section or, in some cases, replacing a coil.Evacuate the System
A vacuum pump removes air and moisture from the circuit. This step protects the compressor and the new refrigerant.Recharge by Weight
The correct refrigerant type is charged to the amount specified for your system and pipe length, then the system is run and checked.
Open more detail
LG residential systems sold in Australia use different refrigerants depending on age and model. Newer systems commonly use R32, while older systems often use R410A. The technician confirms the type from the rating label and never mixes refrigerants. Each type needs the right gauges and recovery equipment.
If the leak is in a coil, the technician will discuss whether replacing the coil makes sense for the age of the system. Coil leaks from corrosion can recur elsewhere in the same coil, so the overall condition of the unit is part of that conversation.
A Common Myth
Why Isn’t a Regas Alone Enough for CH38?
Many people believe air conditioners need regular regassing, a bit like topping up the oil in a car. That is not how a sealed system works. If refrigerant has gone, it has leaked out, and it will keep leaking until the leak is repaired.
A regas without leak repair can make the system run for a few weeks or months. Then the charge falls again and CH38 returns. Over time, you pay for refrigerant several times over, and the compressor keeps cycling through stressful low charge periods.
A proper leak repair costs more on the day than a simple top up. It usually works out better value over the life of the system, and it is the responsible choice for the environment. You can read more on our split system regas pages for each city.
Australian Conditions
How Do Local Conditions Contribute to Refrigerant Leaks?
Several features of Australian life put refrigerant pipework under extra strain. Coastal salt air is one of the biggest. It slowly corrodes the aluminium fins and copper tubes in outdoor coils, and eventually pinholes form. Homes within a short distance of the beach often see this sooner than inland homes.
Temperature extremes also matter. Pipework on a north or west facing wall can bake in summer sun and cool sharply at night. That daily expansion and contraction works at flare joints over the years. In hot, dry regions, pipe insulation can break down in the sun, exposing pipes to further stress.
Storms and high winds can shift outdoor units or damage exposed pipes. Renovations, roof replacements and painting are also common triggers, because pipes get bumped or bent while work goes on around them. If CH38 appears soon after building work, mention it to the technician.
Prevention
How Can I Reduce the Chance of CH38?
Leaks cannot always be prevented, but you can lower the risk and catch problems early.
Protect Pipework
Keep exposed pipe covers and insulation in good repair. Ask tradespeople working near the system to take care around the pipes and outdoor unit.
Rinse Coastal Units Gently
In salty areas, a gentle rinse of the outdoor coil with a garden hose on low pressure can reduce salt buildup. Switch off at the isolator first and never use a pressure washer.
Act on Early Warning Signs
If cooling fades or you see ice on the pipes, book a check before CH38 appears. Early repair often means a smaller leak to find and less stress on the compressor.
Related Codes
Which LG Codes Are Linked With CH38?
A low charge affects temperatures throughout the system, so other codes sometimes appear before or alongside CH38.
LG CH41
The discharge pipe sensor, which plays a key role in detecting low charge.
LG CH61
Outdoor coil high temperature, which a low charge can contribute to.
LG CH02
The indoor coil sensor, sometimes confused with low charge.
CH32, which relates to high discharge temperature, is another code that can accompany a low charge. See all codes on our LG error code hub or browse the error code library.
Getting a Technician Out
Where Can I Book LG Leak Detection and Repair?
We arrange ARCtick licensed technicians for LG refrigerant faults in Sydney, Melbourne, Brisbane, Perth and Adelaide. Choose your city for local repair and regas information.
Sydney
Leak repairs for coastal and inland homes alike.
Melbourne
Diagnosis for systems used hard in both seasons.
Brisbane
Support for systems facing long humid summers.
Perth
Help for pipework baked by strong sun.
Adelaide
Repairs for units facing extreme summer heat.
Rapid Air Cooling is a booking service and is not affiliated with LG. The technicians we send hold the licences their work requires, including ARCtick licensing.
Questions
Frequently Asked Questions
Does CH38 always mean a gas leak?
Usually, but not always. A new system may have an installation fault, and occasionally a sensor or blockage mimics low charge. Gauges and leak testing confirm the cause.
Can I just get my LG regassed?
A regas without fixing the leak only buys time. The charge will drop again and CH38 will return. A licensed technician should find and repair the leak first.
CH38 appeared a week after installation. Who do I call?
Contact your installer first. Early CH38 often points to flare joints, valves or charge, which fall under the installer’s workmanship.
Is a refrigerant leak dangerous to my family?
Small leaks in a ventilated home are not usually a direct health risk, but refrigerant should not be released. Switch the system off and arrange a licensed repair.
Why is there ice on the outdoor pipe?
Ice on the thinner pipe often goes with a low charge, because pressure drops and the pipe gets colder. It can also come from airflow problems. Leave the unit off and book a check.
Which refrigerant does my LG use?
It depends on the model and age. The type is printed on the rating label of the outdoor unit. The technician will confirm it before any work.
Where can I find more help?
Our troubleshooting guide covers other symptoms, and our page on air conditioning service Australia explains how we arrange technicians.
LG Showing CH38?
Switch the system off and call us with the code. We will arrange an ARCtick licensed technician to find the leak, repair it and restore the correct charge.
Reviewed by AC repair and service specialist on 22 October 2026. How we write our articles