Samsung Heat Pump Error Code E123

E123 means the heat pump has shut down its compressor due to low pressure protection. The system detected suction-side refrigerant pressure below 2.6 kg/cm2G during cooling or below 1.4 kg/cm2G during heating. This is a protective shutdown designed to prevent compressor damage from operating under insufficient refrigerant pressure. Common causes include a closed service valve, a refrigerant leak, or a faulty low pressure sensor.

No, you should not attempt to bypass or ignore E123. The compressor has shut down specifically to protect itself from damage caused by low refrigerant pressure. Continuing to run the system without resolving the underlying cause could result in compressor failure, which is a significantly more expensive repair than addressing the original pressure issue.

Repair costs vary widely depending on the cause. If the issue is simply a closed service valve, a diagnostic service call fee may be the only cost, typically in the range of $75 to $150. If the system needs refrigerant due to a leak, expect costs between $200 and $600 or more depending on the refrigerant type, leak location, and labor. A low pressure sensor replacement generally falls in the $150 to $350 range including parts and labor, while expansion valve or filter drier replacement can range from $300 to $700 or higher.

Some causes are easy to check yourself, such as confirming the service valves on the refrigerant lines are fully open. However, diagnosing the actual refrigerant pressure requires a manifold gauge set and S-net diagnostic tool, and any work involving refrigerant handling, leak repair, or sensor replacement requires a certified HVAC technician. Attempting refrigerant work without proper certification is illegal in most jurisdictions and can be dangerous.

A reset may temporarily clear the error and allow the unit to restart, but E123 will return quickly if the underlying pressure problem has not been resolved. The low pressure sensor continuously monitors refrigerant pressure during operation, and the compressor will shut down again as soon as pressure drops below the protective threshold. A reset is not a fix and should only be used after the root cause has been diagnosed and corrected.