AIRC 1020 Unit 25 Quiz

A suction line accumulator is used to ensure that liquid refrigerant enters the compressor. True False

False

Helical oil separators are about 58% efficient in separating oil. True False

False

Oil separators work on the principle of low refrigerant and oil velocity. True False

True

The crankcase pressure regulator (CPR) puts a limit on the pressure that can return to the compressor. True False

True

Two-temperature operation is desirable when more than one evaporator is used with one compressor. True False

True

How does the receiver ensure that only 100% liquid refrigerant enters the liquid line? a. By means of a dip tube b. It only allows refrigerant to enter the liquid line when it is filled with liquid. c. The spring loaded relief valve opens. d. None of the above are correct.

a. By means of a dip tube

Which of the following is another type of low ambient temperature head pressure control? a. air volume control using shutters and fan cycling b. programmed defrost timer c. timer and liquid line solenoid for automatic pump down d. compressor internal heat

a. air volume control using shutters and fan cycling

Frequently on smaller condensing units, one fan will run continuously and the other fan will be cycled on and off with a(n) ____. a. ambient temperature controller b. ambient pressure valve c. thermal expansion valve d. thermal control valve

a. ambient temperature controller

The normal position for a suction service valve during normal operation is ____. a. back seated b. front seated c. cracked off the back d. mid-seated

a. back seated

The refrigeration compressor motor can be operated at about ____% over its rated capacity without harm during this pulldown. a. 5 b. 10 c. 15 d. 20

b. 10

Refrigeration systems are designed to operate year round. For this reason they are equipped with ____. a. relief valves b. a low ambient control c. oversized evaporator coils d. EEPR valves

b. a low ambient control

Two-temperature operation of a refrigeration system is necessary when ____. a. the compressor must be protected from overloading b. more than one evaporator is used with one compressor c. the coil in the evaporator is excessively long d. a multiple-circuit distributor is used

b. more than one evaporator is used with one compressor

To protect the compressor during periods of hot pull down, a(n) ____ valve is used. a. TXV (thermostatic expansion valve) b. EPR (evaporator pressure regulator) c. CPR (crankcase pressure regulator) d. LAC (low ambient control)

c. CPR (crankcase pressure regulator)

Technician "A" says that a multi-evaporator system equipped with three evaporators (one high temperature, one medium temperature, and one low temperature) will use one evaporator pressure regulator and two flow check valves. Technician "B" says that the crankcase pressure regulator is used to keep the low-temperature compressor from overloading on a hot pulldown. Which of the following statements is correct? a. Technician "A" is correct. Technician "B" is correct. b. Technician "A" is correct. Technician "B" is incorrect. c. Technician "A" is incorrect. Technician "B" is correct. d. Technician "A" is incorrect. Technician "B" is incorrect.

c. Technician "A" is incorrect. Technician "B" is correct.

Which of the following is a type of low ambient temperature head pressure control? a. CPR b. EPR c. fan cycling d. off-cycle defrost

c. fan cycling

Defrost using internal heat is accomplished using ____. a. a sail switch b. electric heating elements c. hot gas from the compressor d. mullion heaters

c. hot gas from the compressor

EPR valves are also referred to as ____ valves a. DRP b. ORC c. ORN d. ORI

d. ORI

____ are snap-acting valves that open and close very fast with the electrical energy to the coil. a. Contactors b. Condensers c. Relays d. Solenoid valves

d. Solenoid valves

The EPR valve is installed in the suction line at the evaporator outlet and it ____. a. modulates the refrigerant vapor to the compressor b. prevents the boiling point in the evaporator from dropping below a pre-set point c. when used with a TX valve the system has the characteristics of maintaining a constant superheat and keeping the pressure from going too low d. all of the above

d. all of the above

When a system pumps down, where is the refrigerant stored? a. receiver b. evaporator c. condenser d. both a and c

d. both a and c

Random defrost is accomplished ____. a. with a timer b. using a high pressure control c. using a low pressure control d. when the refrigeration system has enough reserve capacity to cool more than the load requirement

d. when the refrigeration system has enough reserve capacity to cool more than the load requirement