Compressor Start and Rotation
LG CH26 Error Code
When an LG unit shows the LG CH26 error code, the outdoor inverter has tried to start the compressor but could not confirm that it is turning properly. It is one of the more serious LG codes, because the compressor is the heart of the system. This page explains what can cause it and how to respond without making things worse.
Understanding CH26
What Does the CH26 Code Mean on an LG?
Your LG outdoor unit contains an inverter compressor, a sealed pump that moves refrigerant around the system. Unlike older compressors, it has no separate start device. Instead, the inverter board starts it electronically by feeding carefully timed pulses to its motor windings and watching how the motor responds.
Most LG inverter compressors do not have a physical sensor that reports their position. The board works out where the rotor is by reading tiny electrical signals from the windings as the motor turns. If those signals never appear, or appear in a pattern that makes no sense, the board decides the compressor has not started. It stops trying and raises CH26.
LG describes CH26 as the inverter compressor having seized or not providing rotation. Another way to say it is a compressor start or rotor position detection failure. Either way, the result is the same. The compressor is not running, so the system cannot cool or heat.
CH26 does not always mean the compressor is ruined. The cause can lie with the drive board, the wiring, or the conditions the compressor is trying to start against. Proper testing is the only way to tell.
Parts Involved
Which Components Can Cause an LG CH26 Fault?
Several parts in the outdoor unit work together to start the compressor. A fault in any of them can produce CH26.
The Compressor Itself
Internal wear, a seized mechanism, or damaged windings can stop the compressor turning or make its signals unreadable.
The Inverter Drive
The power module and its control circuit generate the pulses that start the motor. A failed output means the compressor never receives a proper start signal.
Compressor Leads and Terminals
Three leads run from the board to the compressor terminals. A broken lead, a burnt terminal or a loose connector stops one phase reaching the motor.
System Pressures
If high and low pressures have not equalised, the compressor may struggle to start against the load. Overcharge or a blockage can also make starting harder.
What You Notice
What Are the Signs of CH26 Besides the Code?
The code itself appears on the indoor display as CH and 26, or as a blinking light pattern on models without a number screen. Ducted systems show it on the controller. Several other signs often come with it, and they are worth noting for the technician.
Outdoor Fan Runs, Compressor Does Not
You may hear the outdoor fan spin up but not the deeper hum of the compressor. After a short time, the fan stops and the code appears.
A Brief Hum or Click Then Silence
Some owners hear a short hum, buzz or knock from the outdoor unit as the board attempts a start, followed by nothing.
Repeated Start Attempts
Many LG units retry several times before locking out. You may hear the outdoor unit try, pause and try again before the code settles.
Air from the indoor unit will usually feel like room temperature, because the indoor fan keeps running while the compressor is idle.
Ranked Causes
Why Won’t My LG Compressor Start?
The causes of CH26 range from conditions that are easy to correct to serious internal failures. Here is the general order a technician considers them.
Lighter Causes
- A restart soon after a power cut, before pressures equalised
- Low supply voltage during a hot, high demand evening
- A loose compressor connector after transport or relocation
- A one off start failure that clears after a full reset
Heavier Causes
- A failed output on the inverter power module
- A burnt compressor terminal or damaged lead
- Refrigerant problems that leave the compressor starting against excessive load
- A seized compressor or failed motor windings
Systems that have sat unused for a long time deserve a special mention. Refrigerant oil can migrate and settle inside the compressor during long idle periods, particularly in cold weather. Some compressors struggle to start in that state. A technician will consider how long the unit had been off.
What You Can Do
What Are the Safe Owner Checks for CH26?
The outdoor board holds stored energy even after power is removed, and the compressor terminals carry high voltage. Your checks should be limited to switches and the surroundings of the unit.
- Record the code and any sounds you heard from the outdoor unit.
- Turn the system off at the remote and then at the circuit breaker.
- Leave it off for at least fifteen minutes. This gives system pressures time to balance and lets the board fully reset.
- Make sure the outdoor unit has space around it and the coil is not blocked by debris or stored items.
- Restore power and try one start in cooling mode, with a moderate set point.
- If CH26 returns, switch off at the breaker and leave it off.
Do not keep retrying throughout the day. Each failed start sends a burst of current through the compressor windings and power module, and repeated attempts can make a fixable fault worse.
Keep It Off
Is It Safe to Run My LG With CH26 Showing?
The system will not cool or heat while CH26 is active, so there is no comfort benefit in leaving it on. There is, however, a real risk in forcing restarts.
If the compressor is partly seized, repeated start attempts can overheat its windings. If the power module is weak, each attempt pushes it closer to complete failure. And if the fault is in the wiring, a burnt terminal can get worse with every surge.
One reset after a long wait is reasonable. Beyond that, leave the system off at the breaker and book a technician. A unit left switched off is not harmed by waiting a few days for a visit.
Technician Diagnosis
How Does a Technician Work Through LG CH26?
A careful CH26 diagnosis checks every part of the start chain before condemning the compressor. These are the typical steps.
Listen to a Start Attempt
The technician watches and listens as the unit tries to start, noting whether the compressor hums, knocks or stays silent.Measure Supply Voltage
Mains voltage is measured at the outdoor unit during the start attempt to confirm the supply holds up under load.Isolate and Discharge
Power is isolated and the board is allowed to discharge fully before any covers are removed.Inspect Leads and Terminals
The compressor terminal cover is removed and each lead checked for burning, looseness and correct connection.Test Compressor Windings
Resistance between each pair of terminals should be nearly equal, and there should be no path to earth. Uneven readings or earth leakage point to a compressor fault.Test the Drive Outputs
The power module outputs are checked for shorts or open circuits. Some technicians use a test load in place of the compressor to see whether the board produces a balanced output.Check Refrigerant Conditions
An ARCtick licensed technician may fit gauges to confirm pressures are balanced at rest and the system is not overcharged or blocked.
Open more detail
If the windings test well and the board output is balanced, but the compressor still will not turn, the cause is likely mechanical inside the compressor. Compressors are sealed units, so this generally means replacement. That is a substantial repair involving refrigerant recovery, brazing and evacuation, and it must be done by a licensed technician.
On older systems, the technician will talk you through the choice between replacing the compressor and replacing the system. Factors include the age of the unit, its refrigerant type and the condition of other parts. The decision is yours, made with clear information.
Climate and Power
Do Heat, Outages and Coastal Air Play a Part in CH26?
They can. Very hot days raise the pressure the compressor has to start against. If the unit has just stopped after a power blip and tries to restart immediately, the compressor may face a high pressure difference that it cannot overcome. LG builds in restart delays, but a quick power cycle by the owner can sometimes defeat them.
Voltage also drops on the hottest evenings, when everyone’s air conditioning runs at once. A compressor that starts easily on a mild morning may fail on a stinking hot afternoon if supply voltage sags and the load is high.
Salt air near the coast is a slower threat. It corrodes compressor terminals and board connections, raising resistance until one phase no longer delivers enough current. Storms can also damage drive circuits through surges. Units that sit idle over a cool season and then face a sudden heatwave in spring can be more prone to start problems on their first run.
Protecting the Compressor
How Can I Help Avoid CH26 in Future?
The compressor is the most expensive part of most systems. A few habits help it start smoothly for years.
Avoid Rapid Power Cycling
After switching off, wait several minutes before switching on again. This gives pressures time to equalise and reduces start stress.
Run It Occasionally
Running the system briefly every few weeks during the off season keeps oil moving and parts working freely.
Book Routine Servicing
A service includes a check of electrical connections, coil condition and operating behaviour, which can reveal start problems early.
Keeping the outdoor coil clean and the unit well ventilated lowers head pressure, which makes every start a little easier.
Common Questions
Is CH26 Always the End of the Compressor?
This is the question many owners ask first, and the honest answer is no. Many CH26 calls end with a much smaller repair. A loose or burnt terminal, a failed drive output, or a start attempted against unbalanced pressures can all produce the same code without any damage to the compressor itself.
That said, CH26 does have a higher chance of involving the compressor than most LG codes. The way to find out is testing, not guessing. A technician who replaces a compressor without checking the drive board and wiring first risks a repeat failure. A technician who replaces a board without checking the compressor windings risks the same.
The best thing you can do is protect the system while you wait. Leave it off, avoid repeated restarts, and pass on everything you noticed before the code appeared.
For Your Records
What Information Speeds Up a CH26 Repair?
Compressor faults can involve ordering parts, so good information at the booking stage can shorten the time your home goes without cooling or heating. These details are the most useful.
- The outdoor unit model number, from the rating label on its side or back panel.
- The approximate age of the system and whether it has been relocated or worked on.
- How long the system had been idle before the code appeared, if it was off for a season.
- A description of what the outdoor unit did, such as fan only, a hum, a knock or silence.
- Whether there was a storm, outage or heatwave around the time of the fault.
- Any earlier codes the unit has shown, even if they cleared.
A clear photo of the outdoor unit label and its surroundings, taken from a safe distance, is also helpful. It shows the technician what access is like and which model they are dealing with.
What if My LG Is Still Under Warranty?
Compressors often carry longer warranty cover than other parts. If your system is relatively new, check your warranty paperwork before arranging any repair. Some manufacturers require warranty work to be carried out through their own service network, and outside work could affect a claim.
If your system is outside warranty, or if you are unsure, we can still arrange a technician to diagnose the fault. Knowing the exact cause helps you decide on next steps, whether that is a repair, a warranty claim or planning for a replacement. Keep the purchase receipt and installation paperwork somewhere easy to find, since both are often requested when a claim is lodged.
Related Codes
Which LG Codes Are Closest to CH26?
These outdoor unit codes often share causes with CH26. Their pages explain how they differ.
LG CH21
A peak current trip in the inverter DC circuit.
LG CH41
The compressor discharge pipe sensor.
LG CH38
Low refrigerant protection, another outdoor protection code.
CH29, which relates to excessive inverter compressor current, is another close relative. Find all codes we cover on our LG error code hub or browse the error code library.
Getting a Technician Out
Where Can I Book a CH26 Compressor Diagnosis?
We arrange licensed technicians for LG compressor faults across Sydney, Melbourne, Brisbane, Perth and Adelaide. Pick your city below.
Perth
Hot, dry summers that load compressors heavily.
Adelaide
Intense heatwaves and high afternoon demand.
Sydney
Coastal air and summer storms.
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 for refrigerant work.
Questions
Frequently Asked Questions
How long should I wait before resetting after CH26?
Leave the unit off at the breaker for at least fifteen minutes. This lets pressures balance and the board reset fully before one more attempt.
Can low voltage cause CH26?
Yes. If supply voltage sags, especially on hot evenings, the inverter may not deliver enough to start the compressor. The technician measures voltage during a start.
My LG was off all winter and now shows CH26. Why?
Long idle periods can let oil settle in the compressor and connections oxidise. A technician can check whether it is a start condition or a component fault.
Is a compressor replacement a big job?
Yes. It involves refrigerant recovery, brazing, evacuation and recharging by a licensed technician. You will be given the options before any work starts.
Can I tap the outdoor unit to free the compressor?
No. Striking the unit can damage parts and is unsafe. Leave the system off and let a technician test it properly.
Does CH26 mean my LG has a refrigerant leak?
Not directly. CH26 is a start or rotation fault. A leak usually shows as CH38. The technician may still check pressures as part of the diagnosis.
Where can I learn more about other faults?
Try our troubleshooting guide, or read about air conditioning service Australia and how we book technicians.
Related Guides
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LG Compressor Not Starting?
Switch the system off and call us with your CH26 code. We will arrange a licensed technician to test the compressor, wiring and inverter before any parts are replaced.
Reviewed by AC repair and service specialist on 22 October 2026. How we write our articles