Samsung Air Conditioner Error Code E427

E427 indicates that the outdoor ambient temperature has dropped below -5 degrees Celsius, causing the unit to automatically block cooling mode operation. This is a built-in protective restriction, not a product fault. The system is designed to prevent compressor and refrigerant circuit damage that can occur when cooling is run in very cold outdoor conditions. No repair is required under normal circumstances.

E427 is not a safety hazard. It is a protective feature that prevents the unit from operating in conditions outside its designed cooling temperature range. The restriction protects the compressor and refrigerant system from damage. The unit remains safe, and heating or fan modes may still be available depending on your model.

If E427 is caused by genuine cold weather conditions, there is no repair cost involved. If a faulty outdoor temperature sensor is responsible, sensor replacement typically costs in the range of $75 to $200 depending on labor rates and parts pricing in your area. Control board replacement, if needed, generally runs higher, often in the range of $200 to $600 including labor.

If outdoor temperatures are genuinely below -5 degrees Celsius, there is nothing to fix. The restriction will lift automatically once temperatures rise above that threshold. If the code appears when it is warmer than -5 degrees Celsius outside, the outdoor temperature sensor or its wiring should be inspected for a fault that may be causing an inaccurate reading.

A reset will not permanently clear E427 if outdoor temperatures remain below -5 degrees Celsius, because the control system will re-evaluate the outdoor temperature and re-apply the restriction. The code will only clear and stay cleared once ambient outdoor temperatures rise above the -5 degree Celsius threshold. If temperatures are above this threshold and the code persists after a reset, a faulty outdoor temperature sensor should be investigated.