Question 155Refrigeration & AC - 1st Asst/Chief

The correct answer is A) frosting at the evaporator inlet. An obstructed expansion valve can cause incomplete cooling of the evaporator, leading to frosting at the evaporator inlet. This is because the restricted expansion valve reduces the flow of refrigerant into the evaporator, resulting in an uneven temperature distribution across the evaporator coil. The other options are incorrect because: B) Frosting at the suction side of the compressor is more indicative of a problem with the compressor or low refrigerant charge. C) A higher than normal discharge pressure is more likely caused by a problem with the condenser or excessive refrigerant charge. D) A decrease in the amount of frosting across the drier is not a symptom of an obstructed expansion valve, as the drier is located upstream of the expansion valve.