Question 111Refrigeration & AC - 1st Asst/Chief

You are correct that the answer is A) cooling mode. The microprocessor-controlled temperature controller is set at -28.9°C, which is the appropriate setting for frozen cargo like ice cream. However, the actual box temperature is -18.0°C, which is warmer than the set point. In this case, the temperature controller should be in cooling mode to bring the box temperature down to the desired -28.9°C. The other options are incorrect because: B) modulating cooling mode is not necessary since the temperature is not already at the set point, C) air circulation mode would not actively cool the box, and D) heating mode would be the opposite of what is needed to cool a frozen cargo.