Samsung Air Conditioner Error Code E172

E172 indicates that during the system's piping check sequence, the evaporator inlet temperature of an indoor unit that was not being actively tested changed unexpectedly. This suggests refrigerant is flowing into the wrong circuit, which typically points to incorrect piping connections, mismatched indoor unit address settings, or an EEV that is not controlling refrigerant flow correctly. The error is most common during initial installation or after system modifications.

E172 occurs during the piping check commissioning phase and indicates a refrigerant circuit issue that has not been resolved during setup. Running the system in this state risks improper cooling performance and potential refrigerant circuit stress. It is best to avoid operating the system until the piping configuration and addressing have been verified and corrected by a qualified technician.

Repair costs depend on what is causing the error. If the fix involves only reprogramming indoor unit addresses or reseating an EEV connector, labor costs might range from $75 to $200. If piping must be rerouted or an EEV needs replacement, costs can range from $200 to $600 or more depending on system complexity, refrigerant handling requirements, and local labor rates. Getting a diagnostic visit from a certified HVAC technician is the best way to get an accurate estimate.

Resolving E172 generally requires someone with HVAC technical knowledge and access to the system's wiring diagrams and configuration settings. Checking indoor unit address settings is something an informed installer can do, but tracing refrigerant piping, inspecting EEV wiring, and running a piping check sequence safely requires proper tools and training. Homeowners should contact a certified HVAC technician to diagnose and correct this error.

A simple reset will not permanently clear E172 because the error is tied to the results of the piping check sequence, not a temporary communication glitch. The system will repeat the piping check upon restart and will generate the error again if the underlying issue, such as incorrect piping or address settings, has not been corrected. The root cause must be resolved before the piping check can complete successfully and the error will clear.