Samsung Air Conditioner Error Code 477

Error code 477 on a Samsung air conditioner indicates that the liquid compressor protection control has activated due to refrigerant liquid entering the digital compressor. Compressors are designed to compress only refrigerant vapor, and liquid inflow can cause severe internal damage through a condition called liquid slugging. The system intervenes automatically to protect the compressor from mechanical failure.

No, you should not continue operating the unit while error code 477 is active. The protective control is designed to prevent compressor damage from liquid slugging, and bypassing or ignoring it risks destroying the compressor entirely. Continued operation could also create unsafe refrigerant pressure conditions within the system.

Repair costs vary widely depending on the root cause identified during diagnosis. Sensor replacements or connection repairs are typically the least expensive, often in the range of $100 to $300 including labor. EEV replacements or discharge check valve repairs can range from $200 to $600 or more. If the compressor has already sustained liquid slugging damage and requires replacement, costs can reach $800 to $2,000 or higher depending on the unit.

Some portions of the diagnosis, such as checking sensor connections and verifying sensor positioning on the compressor body, can be performed by a knowledgeable DIYer. However, inspecting and testing the EEV valves, checking the discharge check valve for leakage, and verifying refrigerant charge require specialized tools and refrigerant handling certification. It is strongly recommended to have a certified HVAC technician handle the full repair.

A simple power reset may temporarily clear the fault and allow the unit to restart, but if the underlying cause such as a faulty EEV, sensor issue, or leaking check valve is not corrected, the error will return. In many cases, liquid slugging damage accumulates over multiple events, so resolving the root cause before restarting is critical to protecting the compressor long-term.