LG Air Conditioner Error Code CH34

CH34 means the high pressure sensor has detected refrigerant pressure on the high side of the system that exceeds safe operating limits. The system shuts down automatically to protect the compressor from damage. Common triggers include blocked airflow, a closed service valve, or an overcharged refrigerant circuit. A technician should inspect the unit before restarting it.

No, you should not attempt to run the unit while the CH34 fault is active. Excessively high refrigerant pressure can damage the compressor, blow refrigerant circuit components, or create a safety hazard. The system is designed to shut down precisely to prevent these outcomes, so leave it off until the underlying cause is identified and corrected.

Resetting the unit may temporarily clear the CH34 code and allow the system to restart, but if the underlying cause of high pressure is not resolved, the fault will return quickly, often within the same operating cycle. A reset should only be performed after inspecting and correcting any airflow restrictions, valve positions, or other identifiable issues. Repeated resets without addressing the root cause can lead to compressor damage over time.

Some causes of CH34 can be addressed without professional help, such as cleaning a clogged air filter, removing debris from around the outdoor unit, or clearing blockages near the heat exchanger. However, checking refrigerant charge, testing the pressure sensor, or verifying service valve positions may require tools and knowledge that a certified HVAC technician should handle. Attempting to work on the refrigerant circuit without proper equipment and certification is not recommended.

Repair costs vary widely depending on the root cause. A simple cleaning of filters and coils may cost very little or nothing beyond a service call fee, which typically ranges from $75 to $150. If a fan motor needs replacement, expect parts and labor to range from $200 to $500. Refrigerant recovery and recharge services generally run between $150 and $400 depending on the refrigerant type and amount involved.