RETA Industrial Refrigeration Book 2 Exam
| Complete Questions and Correct Answers
| Graded A+ | Latest Version 2025 |
Verified Answers
In a double pumper drum system, what happens when the pumper drum is filled?
(pg. 6-21)
A) Liquid stops returning to the recirculator
B) Flow is stopped from the high-pressure receiver
C) The compressor shuts down
D) Flow from the recirculator stops ---------CORRECT ANSWER-----------------D) Flow
from the recirculator stops
What happens to flash gas in a pumped liquid overfeed system? (pg. 6-49)
A) It goes through the recirculator to the compressor
B) It goes directly to the evaporator
C) There is no flash gas in an overfeed system
D) It is used to power the pumper drum to circulate liquid Ammonia ---------
CORRECT ANSWER-----------------A) It goes through the recirculator to the
compressor
,Why does the liquid overfeed system require less evaporator surface than a DX
evaporator of the same capacity? (pg. 6-49)
A) Less refrigerant passes through the evaporator
B) The evaporator tubes are smaller
C) The evaporator tubes are larger
D) More of the evaporator surface is kept wet ---------CORRECT ANSWER-------------
----D) More of the evaporator surface is kept wet
What does a liquid overfeed system have that is not common to a DX system? (pg.
6-51)
A) Two-phase flow from the evaporator
B) An evaporator
C) A liquid solenoid valve
D) A receiver ---------CORRECT ANSWER-----------------A) Two-phase flow from the
evaporator
The pressure of the -20°F liquid supplied to the orifices of an evaporator's finned
tube circuits is roughly 16 PSIG. The pressure after the orifice is about 3.5 PSIG.
How much flash gas was formed by the pressure drop? (pg. 6-21)
A) The amount that would evaporate from 0°F to -20°F as the pressure drops on
the liquid passing through the orifice
B) Approximately 4% of each pound of liquid fed to the evaporator coils
C) No flash gas because there is no change in refrigerant temperature
D) More when the orifice diameter is increased ---------CORRECT ANSWER-----------
------C) No flash gas because there is no change in refrigerant temperature
,Given a system that is an Ammonia pumped liquid overfeed system where the
evaporators are bottom fed, operating at 20°F with hot as defrost entering the
evaporator at the top, where would you drain the oil that accumulates?
(pg. 6-48)
A) The recirculator
B) The oil separator
C) The suction line accumulator
D) The condenser outlet ---------CORRECT ANSWER-----------------A) The recirculator
Which of the following is not a problem associated with migrating oil in a system?
(pg. 6-48/49)
A) Inefficient operation of evaporators
B) Loss of lubrication in the compressor
C) Reduction of system capacity
D) Low condensing pressure ---------CORRECT ANSWER-----------------D) Low
condensing pressure
What precaution must be exercised in placing a check valve in any liquid line? (pg.
6-44)
A) The check valve should be at least one line size larger
B) The check valve must have a bypass line
C) Positive closing of the downstream line must be possible
, D) That no liquid refrigerant can be trapped ---------CORRECT ANSWER----------------
-D) That no liquid refrigerant can be trapped
What is NOT a requirement of a properly sized recirculator? (pg. 6-37)
A) It must be able to hold all surges from the evaporators
B) It must be able to hold all of the system's refrigerant
C) It must keep pump suction flooded
D) It must prevent liquid from passing through to the compressor ---------CORRECT
ANSWER-----------------B) It must be able to hold all of the system's refrigerant
Gravity flooded evaporators have greater heat transfer capability than dry
expansion evaporators of the same size and surface area because? (pg. 7-2)
A) They are completely filled with liquid
B) More of the heat transfer surface is wetted
C) Vapor is flowing at a higher velocity
D) There is more evaporator surface ---------CORRECT ANSWER-----------------B)
More of the heat transfer surface is wetted
The gravity flooded evaporator, in some applications, can have a higher
recirculation ratio than forced liquid overfeed systems because of? (pg. 7-4)
A) The accumulator
B) Pumped flow
C) No expansion valve
| Complete Questions and Correct Answers
| Graded A+ | Latest Version 2025 |
Verified Answers
In a double pumper drum system, what happens when the pumper drum is filled?
(pg. 6-21)
A) Liquid stops returning to the recirculator
B) Flow is stopped from the high-pressure receiver
C) The compressor shuts down
D) Flow from the recirculator stops ---------CORRECT ANSWER-----------------D) Flow
from the recirculator stops
What happens to flash gas in a pumped liquid overfeed system? (pg. 6-49)
A) It goes through the recirculator to the compressor
B) It goes directly to the evaporator
C) There is no flash gas in an overfeed system
D) It is used to power the pumper drum to circulate liquid Ammonia ---------
CORRECT ANSWER-----------------A) It goes through the recirculator to the
compressor
,Why does the liquid overfeed system require less evaporator surface than a DX
evaporator of the same capacity? (pg. 6-49)
A) Less refrigerant passes through the evaporator
B) The evaporator tubes are smaller
C) The evaporator tubes are larger
D) More of the evaporator surface is kept wet ---------CORRECT ANSWER-------------
----D) More of the evaporator surface is kept wet
What does a liquid overfeed system have that is not common to a DX system? (pg.
6-51)
A) Two-phase flow from the evaporator
B) An evaporator
C) A liquid solenoid valve
D) A receiver ---------CORRECT ANSWER-----------------A) Two-phase flow from the
evaporator
The pressure of the -20°F liquid supplied to the orifices of an evaporator's finned
tube circuits is roughly 16 PSIG. The pressure after the orifice is about 3.5 PSIG.
How much flash gas was formed by the pressure drop? (pg. 6-21)
A) The amount that would evaporate from 0°F to -20°F as the pressure drops on
the liquid passing through the orifice
B) Approximately 4% of each pound of liquid fed to the evaporator coils
C) No flash gas because there is no change in refrigerant temperature
D) More when the orifice diameter is increased ---------CORRECT ANSWER-----------
------C) No flash gas because there is no change in refrigerant temperature
,Given a system that is an Ammonia pumped liquid overfeed system where the
evaporators are bottom fed, operating at 20°F with hot as defrost entering the
evaporator at the top, where would you drain the oil that accumulates?
(pg. 6-48)
A) The recirculator
B) The oil separator
C) The suction line accumulator
D) The condenser outlet ---------CORRECT ANSWER-----------------A) The recirculator
Which of the following is not a problem associated with migrating oil in a system?
(pg. 6-48/49)
A) Inefficient operation of evaporators
B) Loss of lubrication in the compressor
C) Reduction of system capacity
D) Low condensing pressure ---------CORRECT ANSWER-----------------D) Low
condensing pressure
What precaution must be exercised in placing a check valve in any liquid line? (pg.
6-44)
A) The check valve should be at least one line size larger
B) The check valve must have a bypass line
C) Positive closing of the downstream line must be possible
, D) That no liquid refrigerant can be trapped ---------CORRECT ANSWER----------------
-D) That no liquid refrigerant can be trapped
What is NOT a requirement of a properly sized recirculator? (pg. 6-37)
A) It must be able to hold all surges from the evaporators
B) It must be able to hold all of the system's refrigerant
C) It must keep pump suction flooded
D) It must prevent liquid from passing through to the compressor ---------CORRECT
ANSWER-----------------B) It must be able to hold all of the system's refrigerant
Gravity flooded evaporators have greater heat transfer capability than dry
expansion evaporators of the same size and surface area because? (pg. 7-2)
A) They are completely filled with liquid
B) More of the heat transfer surface is wetted
C) Vapor is flowing at a higher velocity
D) There is more evaporator surface ---------CORRECT ANSWER-----------------B)
More of the heat transfer surface is wetted
The gravity flooded evaporator, in some applications, can have a higher
recirculation ratio than forced liquid overfeed systems because of? (pg. 7-4)
A) The accumulator
B) Pumped flow
C) No expansion valve
