LG Heat Pump Error Code P515

P515 indicates that the outdoor unit has activated its SUMP DOWN 3 protection control, which is a compressor protection function. This code triggers when the system detects conditions that suggest liquid refrigerant is present in the compressor sump area, which can dilute lubricating oil and cause serious mechanical damage. The unit shuts down or restricts operation to prevent compressor failure until the underlying issue is resolved.

No, you should not continue operating the heat pump while P515 is active. The code indicates a protection shutdown designed to prevent compressor damage from liquid refrigerant in the sump. Running the system through this condition risks destroying the compressor, which is the most expensive component in the unit. Leave the system off until a technician can diagnose and correct the cause.

Repair costs depend heavily on the root cause. If the issue is simply a refrigerant adjustment or expansion valve replacement, costs typically range from around 150 to 500 dollars. If the compressor has already sustained damage from liquid slugging, replacement costs can range from 1,000 to 2,500 dollars or more depending on the unit size and labor rates in your area. Early diagnosis prevents the most expensive outcomes.

Most of the root causes behind P515 require licensed HVAC technician work, including measuring refrigerant charge, checking subcooling and superheat, and inspecting or replacing expansion valves. Homeowners can check for basic issues like dirty air filters or blocked airflow on the indoor unit, but refrigerant-related diagnostics and repairs must be handled by a certified professional.

A power reset may temporarily clear the P515 code and allow the unit to restart, but if the underlying condition causing refrigerant floodback or sump accumulation is not corrected, the code will return. In some cases the protection will escalate, making the situation worse. A reset without proper diagnosis is not a solution and risks compressor damage.