RACT Unit 25 Review Questions

Question 1

Which of the following is not a major component of the compression refrigeration cycle?

a) evaporator
b) compressor
c) condenser
d) suction line drier

Answer 1

d) suction line drier

Question 2

To throttle or regulate the flow of fluid as opposed to just starting and stopping it is called _______

a) modulating
b) mixing
c) rationing
d) pulsing

Answer 2

a) modulating

Question 3

The purpose of the crankcase pressure-regulating valve is to

a) prevent a compressor overload condition
b) maintain constant pressure in the evaporator
c) maintain constant pressure in the crankcase
d) prevent a compressor from going into vacuum

Answer 3

a) prevent a compressor overload condition

Question 4

The ___________ valve can move in very small increments or steps to either open or close the suction line in response to the discharge air temperature of a refrigerated case

a) electronic evaporator pressure-regulating
b) thermostatic expansion
c) crankcase pressure-regulating
d) electronic expansion

Answer 4

a) electronic evaporator pressure-regulating

Question 5

An automatic pumpdown system may be used to:

a) prevent surges of liquid refrigerant from entering the compressor (slugging) during start up
b) prevent liquid refrigerant from being trapped in the receiver
c) maintain a constant evaporator pressure during low-load conditions

Answer 5

a) prevent surges of liquid refrigerant from entering the compressor (slugging) during start up

Question 6

On a “one-time” or non-short-cycling pumpdown system

a) a leaking solenoid valve or compressor discharge valve will cause the system to turn back on
b) once the system has been pumped down, it will lockout , requiring service
c) only the thermostat calling again for cooling will take the refrigeration system out of pump down
d) the refrigerant is stored in a liquid receiver and must be manually released back into the system

Answer 6

c) only the thermostat calling again for cooling will take the refrigeration system out of pump down

Question 7

The two types of relief valves are

a) spring loaded and one time
b) one time and multi use
c) manual and ball
d) check and spring loaded

Answer 7

d) check and spring loaded

Question 8

To prevent the head pressure from dropping to the point that the expansion valve will not feed correctly

a) a high pressure control is used
b) an evaporator pressure regulator is used
c) low-ambient controls are used

Answer 8

c) low ambient controls are used

Question 9

Which of the following is not a method of low-ambient control on air-cooled equipment?

a) fan-cycling controls
b) modulating TXV
c) fan speed control
d) condenser flooding

Answer 9

b) modulating TXV

Question 10

Which of the following is used as protection against operation with a low charge or as a temperature control for some refrigerant evaporators

a) oil safety switch
b) thermostat
c) high-pressure switch
d) low-pressure switch

Answer 10

d) low pressure switch

Question 11

Which of the following is used to protect the compressor and high-side of the system components from operating with excessive pressure?

a) low-ambient controls
b) oil-safety switch
c) high-pressure switch
d) low-pressure switch

Answer 11

c) high-pressure switch

Question 12

Which of the following is a pressure differential control which protects the compressor from operating without sufficient lubrication?

a) compressor thermistor
b) oil safety switch
c) low-pressure switch
d) high-pressure switch

Answer 12

b) oil safety switch

Question 13

A ________ allows the compressor to cycle on internal overload without affecting the operation of the oil safety control

a) low-pressure switch
b) lockout relay
c) current sensing relay
d) oil pressure transducer

Answer 13

c) current sensing relay

Question 14

A type of defrost used by medium-temperature systems that uses the evaporator fans to circulate air in cooler over the coil when the compressor is de-energized is called

a) radiant defrost
b) off cycle defrost
c) hot gas defrost
d) electric heat defrost

Answer 14

b) off-cycle defrost

Question 15

Two methods for accomplishing defrost on low temp refrigeration systems are

a) hot gas and electric defrost
b) hot gas and off cycle defrost
c) planned and random defrost
d) radiant and electric defrost

Answer 15

a) hot gas and electric defrost

Question 16

Two types of off-cycle defrost used on medium temperature refrigeration systems are

a) planned and random defrost
b) hot gas and off cycle
c) hot gas and electric defrost

Answer 16

a) planned and random defrost

Question 17

A component used to remove moisture and foreign matter from refrigerant is a

a) sight glass
b) filter drier
c) accumulator

Answer 17

b) filter drier

Question 18

The component, located on the suction line, that is used to prevent liquid refrigeration from entering the compressor is called a

a) refrigerant distributor
b) accumulator
c) filter drier
d) receiver

Answer 18

b) accumulator

Question 19

The component, located on the liquid line, that is used to store liquid refrigerant as it leaves the condenser is called a

a) filter drier
b) refrigerant distributor
c) receiver

Answer 19

c) receiver

Question 20

The function of the evaporator pressure regulator is to maintain a

a) minimum pressure in the evaporator
b) maximum pressure in the evaporator
c) constant evaporator temperature
d) constant evaporator pressure

Answer 20

a) minimum pressure in the evaporator

Question 21

The component used to prevent compressor oil from having to circulate through the entire system before returning to the compressor crankcase is called a

a) accumulator
b) oil separator
c) crankcase pressure regulator
d) oil safety control

Answer 21

b) oil separator

Question 22

A __________ is often placed in or on the suction line leaving the evaporator and improves the evaporator capacity by increasing the liquid sub cooling

a) refrigerant distributor
b) heat exchanger
c) evaporator pressure regulator
d) oil separator

Answer 22

b) heat exchanger

Question 23

The component located on the outlet of the receiver that can be used to trap the refrigerant into the receiver in order to perform system service is called a

a) refrigerant distributor
b) electronic evaporator pressure regulator
c) schrader valve
d) king valve

Answer 23

d) king valve

Question 24

Condenser flooding maintains head pressure by

a) filling the receiver with liquid refrigerant, raising head pressure
b) storing liquid refrigerant in the evaporator during the off-cycle
c) backing up liquid refrigerant into the condenser, acting like an overcharge
d) splitting the condenser into two equally sized condensers, referred to as summer and summer/winter

Answer 24

c) backing up liquid refrigerant into the condenser, acting like an overcharge

Question 25

A component that has a magnetic coil, can be normally open or normally closed, and is used to control fluid flow is a

a) solenoid valve
b) lockout relay
c) current sensing relay
d) refrigerant check valve

Answer 25

a) solenoid valve