LG Heat Pump Error Code P715

P715 indicates that the outdoor unit has activated its SUMP DOWN 3 protection control, which is a safety shutdown designed to protect the compressor from operating with compromised lubrication. This typically occurs when refrigerant migrates into the compressor sump and dilutes the oil, or when oil levels drop too low. The system halts compressor operation to prevent internal mechanical damage. A certified HVAC technician is needed to diagnose the root cause.

No, you should not attempt to force the unit to continue operating while the P715 fault is active. The protection control exists specifically to prevent compressor damage from running under inadequate lubrication conditions. Bypassing or repeatedly resetting this fault without resolving the underlying cause can result in compressor failure, which is one of the most expensive repairs on a heat pump system.

Repair costs depend heavily on the root cause. Replacing a crankcase heater is a relatively straightforward repair and typically falls in the range of $150 to $400 including labor. If the issue involves refrigerant recharge or leak repair, costs generally range from $200 to $600 or more depending on the refrigerant type and leak location. Compressor replacement, if damage has already occurred, can cost $1,000 to $2,500 or higher depending on the unit size and model.

Most causes of the P715 fault require professional tools and certifications to address properly. Checking refrigerant charge, replacing a crankcase heater, or diagnosing a faulty control board all involve working with refrigerants or high-voltage components. Homeowners should not attempt these repairs without proper training and equipment. Contact a licensed HVAC technician to safely diagnose and resolve the fault.

A power reset may temporarily clear the P715 code, but if the underlying condition causing the sump protection to activate has not been corrected, the fault will return, often quickly. Because P715 is a stage 3 protection event, it suggests the fault has occurred persistently. Clearing the code without addressing the root cause risks compressor damage over time.