Coast Guard Exams
Question 214Refrigeration/AC - Assistant Engineer70% to pass

A container unit's microprocessor-controlled temperature controller is set at -28.9°C, appropriate for a frozen cargo of ice cream. In this mode of operation, according to the illustrated temperature controller functional diagrams, what should be the operational status of the unit if the actual box temperature is -18.0°C? Illustration GS-RA-035

AI Explanation
The correct answer is D) cooling mode. When the actual box temperature of -18.0°C is higher than the set point temperature of -28.9°C, the temperature controller will activate the cooling mode to bring the temperature down to the desired level. This is the appropriate operational status for the container unit's microprocessor-controlled temperature controller in this scenario. The other options are incorrect because: A) heating mode would be used if the actual temperature was lower than the set point, B) modulating cooling mode is not applicable here, and C) air circulation mode does not directly affect the temperature regulation.