Air Conditioning Repair Certification (ETI) 2025 – 400 Free Practice Questions to Pass the Exam

The operating superheat in an R410A system is indicated by the suction line temperature at the condensing unit. Superheat is defined as the difference between the actual temperature of the refrigerant vapor as it leaves the evaporator and its saturation temperature at the same pressure.

In a refrigerant system, the suction line carries the refrigerant vapor back to the compressor from the evaporator. By measuring the temperature of the suction line, technicians can determine how much heat has been added to the refrigerant after it has evaporated in the evaporator coil. This is crucial for ensuring that the refrigerant is fully vaporized before it reaches the compressor, helping to prevent potential damage and ensuring efficient operation.

Other options, while relevant to the system's operation, do not provide the specific indication of operating superheat. For instance, discharge line temperature refers to the temperature of refrigerant leaving the compressor, which is not related to the superheat. Temperature at the evaporator measures the refrigerant before it is superheated, and pressure readings from the compound gauge can provide useful information but do not indicate superheat directly without the corresponding temperature data.