LG Aircon CH35 Error Code
LG CH35 is a low-pressure protection warning. The key question is why pressure dropped: leak, restriction, undercharge, or sensing fault.
LG CH35: What It Means
LG CH35 means the low-pressure side has dropped below the safe range. The system is warning that refrigerant flow is not enough for normal cooling and compressor protection.
Active refrigerant leak at flare joints, outdoor coil, indoor coil, or pipework.
System undercharged after a previous top-up, incomplete repair, or installation issue.
Restriction, expansion-valve issue, pressure sensor fault, or compressor protection after pressure readings are checked.
What To Do Now
Use these steps before another reset, gas work, pressure check, or parts quote.
Stop using the unit if CH35 returns
Also stop if cooling is weak or the outdoor unit trips again after restart.
Do not rely on reset
A reset may clear CH35 briefly, but it will not fix low refrigerant pressure or a leak.
Send these to us
CH35 display, cooling-loss timeline, affected rooms, last gas top-up date, and outdoor unit photos
What To Check Before Repair
Use this split before approving another gas top-up or low-pressure repair quote.
| You Can Check | Technician Should Confirm |
|---|---|
| Stop using the unit if cooling is weak or CH35 returns after reset. | Pressure-test and leak-check before recommending another gas top-up. |
| Note when cooling first became weak and when the last gas top-up was done. | Inspect flare joints, indoor coil, outdoor coil, and accessible pipe routes. |
| Send outdoor unit photos and tell us how many rooms are affected. | Confirm charge, restriction signs, pressure-sensor readings, compressor operation, and protection history. |
What Changes The Next Step
These clues separate an active leak from undercharge, restriction, pressure-sensor, or compressor protection issues.
| What You See | What It Points To |
|---|---|
| Cooling faded again after a recent gas top-up. | An active leak is more likely than normal gas loss, so leak testing should come before topping up again. |
| Several rooms on the same condenser are weak. | The shared refrigerant circuit or outdoor unit needs priority checking. |
| CH35 appears under load or after the system runs for a while. | The system may be operating near the low-pressure threshold; leak, restriction, and compressor checks matter before more gas is added. |
Low Pressure Repair Or Replacement Decision
CH35 should not be treated as a simple gas top-up decision. Find the pressure drop first. Replacement only becomes serious when the leak is in an uneconomical coil, the compressor is stressed, or the system is near end of life.
A gas top-up alone is poor value if the leak source is not found.
Accessible flare, service-valve, or pipe-joint leaks are usually repair-first decisions.
Indoor coil, outdoor coil, or compressor-related findings can become a repair-versus-replace discussion on older systems.
Read Next
Use these if the quote mentions gas top-up, leak repair, pressure testing, expansion valve, outdoor coil, or compressor risk.
Real Diagnostic Cases
How we approached similar faults on actual jobs.
Need A Clear Next Step?
Send the CH35 display, cooling-loss timeline, last gas top-up, and affected rooms. We can help separate leak repair from blind top-up.