LG Heat Pump Error Code P512

P512 means the compressor has been shut down by the low pressure sensor protection control, specifically protection sequence 3. The system detected that refrigerant suction pressure dropped below a safe threshold and locked out the compressor to prevent damage. This fault indicates a persistent or escalating low-pressure condition rather than a simple one-time dip. A technician should inspect refrigerant charge, airflow, the expansion device, and the low pressure sensor itself.

No, you should not continue operating the unit while P512 is active. The system has already shut down the compressor as a protective measure. Forcing the unit to run under low-pressure conditions can cause severe compressor damage, including loss of lubrication and internal mechanical failure. Leave the unit off until the root cause has been diagnosed and corrected.

Repair costs vary depending on the cause. A refrigerant recharge following a leak repair can range from $200 to $600 or more depending on refrigerant type and the extent of the leak. Replacing a low pressure sensor typically costs between $100 and $250 including labor. A failed expansion valve replacement can range from $250 to $500 or higher. Diagnostic service calls generally run $75 to $150 before any parts or repairs.

Some causes, such as a dirty air filter or blocked airflow, can be corrected without professional help. However, if the issue involves refrigerant levels, a refrigerant leak, a faulty expansion valve, or a failed pressure sensor, a licensed HVAC technician is required. Refrigerant handling legally requires EPA 608 certification. Attempting refrigerant work without proper credentials and equipment is both illegal and unsafe.

A power reset may temporarily clear the fault and allow the system to restart, but the code is likely to return if the underlying problem has not been fixed. Because P512 is classified as protection control sequence 3, the system has already cycled through earlier protective attempts, making a simple reset unlikely to provide a lasting solution. Address the root cause before relying on a reset.