and Answers
Which of the following components is unique to reefer refrigeration operation? - Answer-
Three-way valve
Which of the following is correct concerning the defrost cycle? - Answer-All of the
choices are correct.
Which of the following are sources of heat that enter the refrigerated area of the trailer?
- Answer-All of the choices are correct.
Technician A says that controlling the direction of refrigerant flow essentially determines
whether the reefer is in cooling or heating mode. Technician B says that the three-way
valve directs hot refrigerant gas to either the evaporator (when in cool mode) or directly
to the condenser (when in the heat or defrost mode). Who is correct? - Answer-
Technician A
Refrigeration is a process of transferring heat away from a product storage container to
achieve a temperature of: - Answer-65°F (18°C).
Technician A says that the cooling or heating capacity is measured in Btu per hour.
Technician B says that Btu per minute is the amount of heat required to change the
temperature of one pound of water one degree Fahrenheit. Who is correct? - Answer-
Technician A
What type of refrigerant is used in modern truck-trailer refrigeration units? - Answer-
R404a
Technician A says that refrigeration compressors are much like engines, with moving
parts that require constant lubrication. Technician B says that without oil, a compressor
quickly overheats and destroys itself. Who is correct? - Answer-Both Technician A and
Technician B
Technician A says that most units will not enter the defrost mode unless the evaporator
coil temperature is below approximately 45°F (7.2°C). Technician B says that timed
defrosts can be scheduled to defrost the evaporator automatically every 1, 3, or 5 hours
of operation. Who is correct? - Answer-Technician A
Technician A says that most engines require oil and filter changes at 1,500 hours, or
about once every three to six months. Technician B says that the use of synthetic oil
lengthens the interval between oil drains to between 2,000 and 2,500 hours. Who is
correct? - Answer-Technician A