Power Engineering - 4B9 Practice
Exam Questions & Answers (Grade
A+)
Which of these statements about automatic expansion valves is
FALSE?
a. The automatic expansion valve maintains constant evaporator
pressure, while the compressor is operating, regardless of the
load.
b. The automatic expansion valve is usually used with multiple
cooling coils connected to the same compressor.
c. A spring exerting a downward force on the diaphragm tends to
open the automatic expansion valve.
d. When the compressor stops, the valve automatically closes. -
correct answer ✅b. The automatic expansion valve is usually used
with multiple cooling coils connected to the same compressor
Which of the following is an example of a loss of latent heat?
a. Steam condenses
b. Water evaporates
c. Ice melts
,Power Engineering - 4B9 Practice
Exam Questions & Answers (Grade
A+)
d. Refrigerant evaporates -
correct answer ✅a. Steam condenses
Which of the following statements about strainers is false?
a. Strainers prevent foreign particles from damaging compressor
valves.
b. Piping must be disconnected to clean the strainer.
c. Hermetic type compressors are equipped with a built-in suction
strainer.
d. Strainers typically consist of a fine mesh screen basket. -
correct answer ✅b. Piping must be disconnected to clean the
strainer.
The specific gravity of a brine sample provides an indication of the:
a. Acidity or alkalinity
b. Concentration of inhibitor
c. Concentration of ammonia
,Power Engineering - 4B9 Practice
Exam Questions & Answers (Grade
A+)
d. Freezing temperature -
correct answer ✅d. Freezing temperature
The major building occupancy classes include all of the following,
except:
a. Industrial
b. Commercial
c. Educational
d. Institutional -
correct answer ✅c. Educational
Elements of a safe operating procedure for draining oil from an
ammonia refrigeration system does not include:
a. The use of self-closing oil drain valves
b. The use of portable ammonia detectors
c. The use of proper PPE
, Power Engineering - 4B9 Practice
Exam Questions & Answers (Grade
A+)
d. The use of system pressure to facilitate the drain -
correct answer ✅d. The use of system pressure to facilitate the
drain
Refrigerant compressors:
a. Must have intercoolers
b. Could be the centrifugal type
c. Use automotive-style suction and discharge valves
d. Have more cooling fins than air compressors -
correct answer ✅b. Could be the centrifugal type
Which of these is not a requirement in a Class T machinery room?
a. Ventilation
b. Inward opening doors
c. Restricted access
d. Restrictions on open flames and hot surfaces -
correct answer ✅b. Inward opening doors
Exam Questions & Answers (Grade
A+)
Which of these statements about automatic expansion valves is
FALSE?
a. The automatic expansion valve maintains constant evaporator
pressure, while the compressor is operating, regardless of the
load.
b. The automatic expansion valve is usually used with multiple
cooling coils connected to the same compressor.
c. A spring exerting a downward force on the diaphragm tends to
open the automatic expansion valve.
d. When the compressor stops, the valve automatically closes. -
correct answer ✅b. The automatic expansion valve is usually used
with multiple cooling coils connected to the same compressor
Which of the following is an example of a loss of latent heat?
a. Steam condenses
b. Water evaporates
c. Ice melts
,Power Engineering - 4B9 Practice
Exam Questions & Answers (Grade
A+)
d. Refrigerant evaporates -
correct answer ✅a. Steam condenses
Which of the following statements about strainers is false?
a. Strainers prevent foreign particles from damaging compressor
valves.
b. Piping must be disconnected to clean the strainer.
c. Hermetic type compressors are equipped with a built-in suction
strainer.
d. Strainers typically consist of a fine mesh screen basket. -
correct answer ✅b. Piping must be disconnected to clean the
strainer.
The specific gravity of a brine sample provides an indication of the:
a. Acidity or alkalinity
b. Concentration of inhibitor
c. Concentration of ammonia
,Power Engineering - 4B9 Practice
Exam Questions & Answers (Grade
A+)
d. Freezing temperature -
correct answer ✅d. Freezing temperature
The major building occupancy classes include all of the following,
except:
a. Industrial
b. Commercial
c. Educational
d. Institutional -
correct answer ✅c. Educational
Elements of a safe operating procedure for draining oil from an
ammonia refrigeration system does not include:
a. The use of self-closing oil drain valves
b. The use of portable ammonia detectors
c. The use of proper PPE
, Power Engineering - 4B9 Practice
Exam Questions & Answers (Grade
A+)
d. The use of system pressure to facilitate the drain -
correct answer ✅d. The use of system pressure to facilitate the
drain
Refrigerant compressors:
a. Must have intercoolers
b. Could be the centrifugal type
c. Use automotive-style suction and discharge valves
d. Have more cooling fins than air compressors -
correct answer ✅b. Could be the centrifugal type
Which of these is not a requirement in a Class T machinery room?
a. Ventilation
b. Inward opening doors
c. Restricted access
d. Restrictions on open flames and hot surfaces -
correct answer ✅b. Inward opening doors
