LG HVAC Error Code 35

Error code 35 on an LG HVAC unit means the low pressure switch has opened because refrigerant pressure on the suction side of the system dropped below 14 PSI. The system shuts down the compressor automatically to prevent internal damage. This is a protective fault that requires diagnosis of the refrigerant circuit before normal operation can resume.

No. The system will not run the compressor while the fault is active, and you should not attempt to bypass or override the low pressure switch. Running a compressor with insufficient refrigerant pressure can cause overheating of compressor windings, oil starvation, and permanent compressor failure. Leave the system off until the underlying cause is diagnosed and corrected.

Resetting the unit by cycling power may temporarily clear the fault and allow the compressor to restart, but if the underlying low pressure condition still exists, the switch will open again and the error code will return quickly. A reset does not fix the cause of the low pressure. A proper diagnosis with refrigerant manifold gauges is necessary to resolve the fault permanently.

Some causes, like a dirty evaporator coil or blocked air filter, can be addressed without professional help. However, if the root cause is a refrigerant leak or a failed metering device, those repairs require EPA Section 608 certification to legally handle refrigerants and should be performed by a licensed HVAC technician. Attempting to add refrigerant without locating and repairing a leak is a temporary fix at best and illegal to vent refrigerant to the atmosphere.

Repair costs depend heavily on the root cause. A coil cleaning or filter replacement may cost between $75 and $200 in labor. If the system needs refrigerant and a leak repair, costs typically range from $200 to $800 or more depending on the refrigerant type, leak location, and labor involved. A failed TXV or low pressure switch replacement can add $150 to $400 in parts and labor. Always get a diagnosis before committing to repairs.