LG HVAC Error Code 33

Error code 33 on an LG HVAC system means the discharge pipe temperature on the single-speed compressor has reached or exceeded 105°C (220°F). This is a protective shutdown to prevent compressor damage. The most common cause is low refrigerant charge, though high-head pressure conditions from restricted airflow or a faulty thermistor can also trigger this fault.

No, you should not continue operating the system while this fault is active. Sustained high discharge temperatures can break down compressor lubricant, damage compressor valves, and lead to complete compressor failure. The system's protective shutdown is working as intended, and operating through it risks turning a refrigerant or sensor issue into a much more costly compressor replacement.

A reset may clear the fault code temporarily and allow the system to restart, but the error will return if the underlying problem is not corrected. If the discharge temperature exceeds 105°C again, the system will shut down again. Resetting without diagnosing and fixing the cause, whether low refrigerant, airflow restriction, or a faulty thermistor, only delays the repair and risks further damage to the compressor.

Some basic checks are within reach for a knowledgeable DIYer, such as inspecting the outdoor unit for blocked airflow, cleaning a dirty condenser coil, and confirming the condenser fan is running. However, checking refrigerant charge and testing the discharge thermistor with an ohmmeter require technical skill and, in the case of refrigerant handling, EPA certification. If the system is low on refrigerant, a licensed HVAC technician is needed to find the leak, repair it, and recharge the system properly.

Repair cost depends heavily on the root cause. A refrigerant leak repair and recharge can range from roughly $200 to $600 or more depending on leak location and refrigerant type. Replacing a discharge pipe thermistor is generally less expensive, typically in the $75 to $200 range including labor. Condenser coil cleaning is usually the least costly service. If the compressor has already sustained damage from prolonged overheating, costs rise significantly.