Samsung Air Conditioner Error Code 18

Error code 18 on a Samsung air conditioner indicates a BLDC compressor starting or rotation error. This means the system's inverter control board attempted to start the compressor but did not receive confirmation that the compressor rotor was spinning correctly. The cause can range from a loose wiring connection or closed service valve to a failed compressor that must be replaced.

No. When error code 18 is active, the system shuts down operation to protect the compressor and inverter board from damage caused by repeated failed start attempts. Attempting to bypass or ignore the fault and force the unit to run could cause additional damage to the inverter components or burn out the compressor windings entirely. Leave the unit off until the fault has been diagnosed and resolved.

Repair costs vary widely depending on the cause. If the fix is a reconnected wire or opened service valve, the cost is primarily the technician's diagnostic labor, typically in the range of $75 to $150. If the EEV needs replacement, parts and labor can range from $150 to $400. A compressor replacement is the most expensive outcome, often ranging from $600 to $1,500 or more depending on the model and whether refrigerant recovery and recharge are required.

Some causes of error code 18 can be addressed without specialized tools, such as verifying that service valves are fully open or reseating a disconnected EEV connector. However, testing compressor winding resistance, diagnosing inverter board output, and replacing a locked compressor all require electrical knowledge and proper equipment. Refrigerant-related work also requires EPA certification in the United States, so a licensed HVAC technician should handle the repair if the issue goes beyond basic connection checks.

A power reset may temporarily clear the displayed error and allow the unit to attempt a restart, but if the underlying cause such as a locked compressor, closed valve, or wiring fault has not been corrected, the error will return as soon as the system tries to start again. Repeated failed start attempts can worsen damage to the compressor or inverter board, so resetting without diagnosing the root cause is not recommended.