Samsung Air Conditioner Error Code P508

Error code P508 on a Samsung air conditioner indicates that the compressor has been shut down due to high pressure sensor protection control 2. This is a refrigerant-side safety event where the system detects that the high-side refrigerant pressure has exceeded safe operating thresholds. The high pressure sensor monitors discharge pressure from the compressor continuously, and when a secondary threshold is reached (designated as protection control 2, which typically represents a more severe or persistent overpressure condition than a first-stage trigger), the control board commands the compressor to stop to prevent mechanical damage.

High pressure faults of this nature point to conditions that prevent normal heat rejection on the condenser side. The most common culprits include restricted airflow across the outdoor condenser coil, a failed or underperforming condenser fan motor, a refrigerant overcharge, or a blocked or contaminated coil. In some cases, a faulty high pressure sensor itself can generate a false reading, causing the unit to shut down even when actual system pressures are within range.

Because this is a protection-level shutdown rather than a simple fault reset, the underlying cause must be identified and corrected before the system will return to normal operation. Simply resetting the unit without addressing the root cause will typically result in the error recurring. A technician should connect manifold gauges to verify actual system pressures and compare them against the unit's rated operating range before proceeding with further diagnosis.