Air Conditioning Repair Certification (ETI) Practice Exam

A refrigerant overcharge in a capillary tube air conditioning system can lead to high suction pressures due to an excess of refrigerant in the evaporator coil. When too much refrigerant is present, it may not completely evaporate and can end up in the suction line, causing elevated suction pressure readings.

Additionally, with the discharge pressures, the presence of excessive refrigerant could lead to the compressor working harder than normal, resulting in higher discharge pressures as well. However, the specific combination selected indicates a scenario where the evacuation of the refrigerant is inefficient, causing a low discharge pressure—a symptom of structural inefficiency.

Therefore, in this context, high suction and low discharge pressures reflect a malfunction caused by overcharging, as the capillary tube restricts refrigerant flow. Normal operating pressures would not indicate an overcharge, as they would suggest a balanced and appropriate refrigerant level.