LG Air Conditioner Error Code CH37

CH37 indicates that the compressor compression ratio has exceeded its allowable limit. The ratio of discharge pressure to suction pressure rose too high, triggering a protective shutdown to prevent compressor damage. This condition can result from blocked airflow, refrigerant leakage, a closed service valve, a fan problem, or a faulty pressure sensor.

No. The unit shuts down when CH37 is triggered specifically to protect the compressor from damage caused by excessive pressure ratio. Attempting to bypass or repeatedly reset the fault without resolving the underlying cause risks a compressor failure, which is the most expensive component in the system to replace.

Repair cost depends entirely on the cause. Clearing airflow blockages or opening a service valve may cost nothing beyond a service call fee, typically in the range of $75 to $150. Refrigerant leak detection and recharge can run $200 to $600 or more depending on the refrigerant type and leak severity. Pressure sensor replacement is generally $100 to $300 in parts and labor, while a compressor replacement can reach $1,000 to $2,500 or higher for larger systems.

Some causes of CH37 are owner-serviceable. Cleaning or replacing clogged filters, clearing debris from around the outdoor unit and heat exchanger coils, and confirming service valves are fully open can all be done without special tools. However, diagnosing refrigerant leaks, recharging refrigerant, and testing pressure sensor resistance require EPA certification and professional equipment, so those steps should be handled by a licensed technician.

A power reset may temporarily clear the fault, but CH37 will return if the underlying condition is not corrected. If the compression ratio exceeds the limit again at startup or during operation, the control board will trigger the fault code again. A reset is only appropriate after the root cause, such as a blockage, valve position, or refrigerant issue, has been identified and corrected.