LG Heat Pump Error Code P773

P773 is an outdoor unit compression rate 3 error on LG heat pumps. It means the control board has detected that the compressor's pressure ratio, the relationship between its high-side discharge pressure and low-side suction pressure, is outside the acceptable operating range. The system shuts down to prevent damage to the compressor. A qualified technician should diagnose the refrigerant circuit, pressure sensors, and compressor condition to resolve this fault.

No, it is not safe to continue running the unit while P773 is active. The system has detected an abnormal compressor operating condition, and continuing to operate it could cause further internal damage to the compressor or other refrigerant circuit components. Leave the unit off until a technician can assess the fault and complete the necessary repairs.

Repair costs vary widely depending on the root cause. Replacing a faulty pressure sensor typically runs in the range of $150 to $400 including labor. Refrigerant leak repairs and recharging can range from $300 to $800 or more depending on the extent of the leak. Compressor replacement is the most expensive scenario, often ranging from $1,200 to $2,500 or higher depending on the unit size and labor rates in your area. A proper diagnosis is essential before estimating costs.

Most of the root causes behind P773 require specialized equipment and EPA certification to address, particularly anything involving refrigerant handling. A homeowner can check that the outdoor unit is not obstructed and that air can flow freely through the coil, but diagnosing compressor performance, pressure sensor readings, and refrigerant charge levels requires professional tools and training. Attempting to bypass this fault without proper diagnosis risks permanent compressor damage.

A power reset may temporarily clear the error display, but the code will return if the underlying problem has not been corrected. If the compression ratio remains outside acceptable limits once the system restarts, the control board will detect the fault again and re-enter the error state. A reset is not a fix and should only be used as part of a structured diagnostic process, not as a substitute for proper repair.