Question 174Refrigeration & AC - 1st Asst/Chief

The correct answer is A) lack of refrigerant. When a refrigeration unit is low on refrigerant, it will tend to short-cycle, meaning it will turn on and off more frequently than normal. This is because the lack of refrigerant reduces the system's ability to absorb heat, causing the compressor to cycle on and off more often to maintain the desired temperature. The other answer choices are incorrect because they do not directly lead to short-cycling. Starting conditions (B) and heavy loads (C) may affect the system's performance, but do not necessarily cause short-cycling. Hot gas defrost (D) is a specific defrosting method and does not directly relate to short-cycling.