Samsung Air Conditioner Error Code E477

E477 is a liquid compressor protection code that activates when the system detects liquid refrigerant entering the digital compressor. Because liquid cannot be compressed, this condition can cause severe internal compressor damage. Samsung's control system triggers E477 to halt or restrict operation until the problem is resolved. A technician should inspect the sump and discharge sensors first, then evaluate the refrigerant charge and expansion components.

No, you should not continue operating the unit when E477 is active. The protection mode exists specifically to prevent liquid refrigerant from damaging the compressor internals. Running the system through or past this error risks permanent compressor failure, which is a significantly more expensive repair than addressing the underlying cause early.

Repair costs vary widely depending on the cause. If the fix is simply reseating a loose sensor, labor costs may be minimal, typically in the range of $75 to $150 for a service call. If the expansion valve needs replacement, costs can rise to $200 to $500 or more depending on parts and labor rates. Compressor replacement, if damage has already occurred, can range from $800 to $2,000 or higher depending on the unit size and model.

The first step, checking that the sump sensor and discharge sensor are correctly connected, is something a technically inclined homeowner can perform safely with the unit powered off. However, diagnosing refrigerant overcharge, flood-back conditions, or a faulty expansion valve requires specialized tools and EPA certification to handle refrigerants. Most repairs beyond sensor inspection should be handled by a qualified HVAC technician.

A reset may temporarily clear the code and allow the unit to restart, but if the root cause has not been corrected, E477 will return. Repeated triggering of the protection routine without fixing the underlying issue can still result in compressor wear over time. A reset is only appropriate as a temporary step while arranging for a proper diagnostic inspection.