Question 90Refrigeration/AC - QMED70% 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 A) cooling mode.
The key is that the actual box temperature of -18.0°C is higher than the microprocessor-controlled temperature setting of -28.9°C. This indicates that the cooling mode should be active in order to lower the box temperature down to the desired -28.9°C setting. The cooling mode will engage the refrigeration system to actively remove heat from the container and maintain the frozen cargo temperature.
The other options are incorrect because: B) heating mode would be used to increase the temperature, which is not needed in this case; C) modulating cooling mode would be used to maintain a narrower temperature range, not the current wide gap; and D) air circulation mode alone would not actively cool the container to the set temperature.
Related Questions
#88 In a refrigeration system featuring low-side pump down prior to the automatic shutdown of the compressor, the temperature of the refrigerated space is controlled by the action of a thermostat wired to what device? #89 How does a refrigeration solenoid valve differ from a modulating valve? #91 The sensing line for the low-pressure cutout switch for a refrigeration system is typically connected at what location? #92 In a multi-evaporator refrigeration system, a solenoid valve is installed in the liquid line prior to what device? #93 Which of the following electrically operated refrigeration system valves would be most appropriate for use as a 2 position diverting hot gas bypass solenoid valve? Illustration GS-RA-19