Question 198Refrigeration & AC - Assistant Engineer
70% to passWhat is true concerning frost build-up on the evaporator coils of a multi-box direct expansion refrigeration system?
Athe frost can be removed by passing hot gas through the coils or energizing defrost heaters with the evaporator fan shut down
Bthe frost can be removed by passing hot gas through the coils or energizing defrost heaters with the evaporator fan still running
Cthe frost will increase the refrigeration effect
Dthe frost can be quickly removed by simply shutting down the compressor
AI Explanation
The correct answer is A. The frost build-up on the evaporator coils of a multi-box direct expansion refrigeration system can be removed by passing hot gas through the coils or energizing defrost heaters with the evaporator fan shut down. This is the standard method for defrosting the evaporator coils in such a system. Shutting down the compressor (option D) would not effectively remove the frost, and the frost build-up would actually decrease the refrigeration effect (option C is incorrect).
Related Questions
Q@q.QuestionNumber:Which of the installation steps listed is necessary for the proper operation of ... Q@q.QuestionNumber:Charging liquid HCFC-123 into a system under a deep vacuum could cause what to h... Q@q.QuestionNumber:If a refrigeration compressor had developed a slightly high suction pressure acc... Q@q.QuestionNumber:When the relief valve opens on a refrigeration compressor discharge line, it dis... Q@q.QuestionNumber:Capacity control of a centrifugal refrigeration compressor can be accomplished b...
Ready to test your knowledge?
Take a Refrigeration & AC - Assistant Engineer Practice ExamOfficial Resources
Want to practice with timed exams?
Download Coast Guard Exams for the full exam experience.
Get the App