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? GS-RA-035

Illustration GS-RA-035: the U.S. Coast Guard has not released this illustration.

Question

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? GS-RA-035

Illustration GS-RA-035: the U.S. Coast Guard has not released this illustration.

Accepted Answer

Option D: cooling mode. When actual box temperature (-18.0 ° C) remains significantly warmer than the extreme setpoint (-28.9 ° C) required for ice cream cargo, the microprocessor demands maximum heat extraction, locking the control system into full cooling mode to lower compartment temperature.