Question 151Refrigeration & AC - 1st Asst/Chief

The correct answer is D) a liquid line restriction. Frosting or sweating of a liquid line is usually indicative of a restriction in the liquid line, which causes the refrigerant to undergo a pressure drop. This pressure drop results in the refrigerant cooling below the dew point, causing condensation or frosting on the liquid line. The other answer choices are incorrect because: A) Proper cooling would not cause frosting or sweating on the liquid line. B) High relative humidity would not directly cause a liquid line restriction. C) Refrigerant contamination with moisture would not necessarily cause a liquid line restriction.