LG Air Conditioner Error Code 173

Error code 173 on an LG air conditioner indicates a failure of the main constant speed compressor to operate. The code points to one of three conditions: the compressor is mechanically locked and cannot turn, the check valve is leaking or installed incorrectly, or the compressor motor windings have suffered dielectric breakdown. A technician should test the compressor electrically and mechanically to determine which fault is present.

No, you should not continue operating the unit while error 173 is active. A locked or electrically compromised compressor can draw excessive current, overheat, and cause further damage to the system or create an electrical hazard. Turn the unit off and have it inspected before attempting to restart it.

Repair costs depend heavily on which fault is present. Replacing a check valve or repairing electrical connections typically costs in the range of $150 to $400 including labor. Compressor replacement is significantly more expensive, generally ranging from $800 to $2,000 or more depending on the unit size, parts availability, and labor rates in your area. A technician should diagnose the specific cause before you commit to a repair.

Basic checks like inspecting wiring connections and confirming the magnetic switch contactor is functioning can be done by a knowledgeable DIYer. However, measuring insulation resistance with a megohmmeter, inspecting the refrigerant-side check valve, and replacing a compressor all require professional tools, refrigerant handling certification, and experience. Most repairs related to this code are best left to a licensed HVAC technician.

Resetting the unit may temporarily clear the code, but it will return if the underlying compressor fault has not been repaired. If the compressor is mechanically locked or has dielectric breakdown, no amount of resetting will resolve the problem. Clearing the code without fixing the cause can lead to additional component damage.