Unit 37 Exam Air Distribution & Balance Questions With All
Correct Answers
One reason for using a reducing plenum
system is to keep ____. correct answer -a. the velocity of the air constant
b. the noise level low
c. the duct pressures constant
d. both a and c
Answer : D
By design, which of the following air ducts will
allow 250 cfm to flow with a velocity of 500 ft/min? correct answer -a. 9" ´ 8"
b. 16" ´ 9"
c. 10" ´ 9"
d. none of the above
Answer : A
Technician "A" says that if the air filter on an
air-conditioning system is totally blocked with dirt, the amperage draw of the
evaporator fan motor will go down. Technician "B" says that if you close down
one supply register on a duct system, the volume of air feeding the other
locations will increase slightly. Which of the following statements is correct?
correct answer -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
Answer : A
If the equivalent length of a transition piece of
ductwork is 10 feet and the main duct in series with it is 20 feet, what is the
length used to estimate the total frictional loss? correct answer -a. 10 feet
b. 30 feet
c. 60 feet
d. 20 feet
Answer : B
, The pressure in a duct system is measured in: correct answer -a. psig
b. psia
c. " Hg
d. " WC
Answer : D
Measuring velocity pressure in a duct
indicates the ____. correct answer -a. volume of air through a duct
b. speed at which the air is moving
c. pressure against the sides of the duct
d. weight of the air moving through the duct
Answer : B
If the resistance against a centrifugal blower
is doubled, the cfm output decreases, and the
amperage draw of the motor ____. correct answer -a. decreases slightly
b. increases slightly
c. stays the same
d. overheats the motor
Answer : A
If the resistance against a propeller fan is
doubled, the cfm output decreases, but the amperage draw of the motor ____.
correct answer -a. decreases
b. increases
c. stays the same
d. overheats the motor
Answer : B
Which of the following is typically measured
with an inclined water manometer? correct answer -a. static pressure in a
duct system
b. pressure in a refrigeration system
c. manifold pressure in a gas fired furnace
d. nozzle pressure of an oil burner
Answer : A
Correct Answers
One reason for using a reducing plenum
system is to keep ____. correct answer -a. the velocity of the air constant
b. the noise level low
c. the duct pressures constant
d. both a and c
Answer : D
By design, which of the following air ducts will
allow 250 cfm to flow with a velocity of 500 ft/min? correct answer -a. 9" ´ 8"
b. 16" ´ 9"
c. 10" ´ 9"
d. none of the above
Answer : A
Technician "A" says that if the air filter on an
air-conditioning system is totally blocked with dirt, the amperage draw of the
evaporator fan motor will go down. Technician "B" says that if you close down
one supply register on a duct system, the volume of air feeding the other
locations will increase slightly. Which of the following statements is correct?
correct answer -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
Answer : A
If the equivalent length of a transition piece of
ductwork is 10 feet and the main duct in series with it is 20 feet, what is the
length used to estimate the total frictional loss? correct answer -a. 10 feet
b. 30 feet
c. 60 feet
d. 20 feet
Answer : B
, The pressure in a duct system is measured in: correct answer -a. psig
b. psia
c. " Hg
d. " WC
Answer : D
Measuring velocity pressure in a duct
indicates the ____. correct answer -a. volume of air through a duct
b. speed at which the air is moving
c. pressure against the sides of the duct
d. weight of the air moving through the duct
Answer : B
If the resistance against a centrifugal blower
is doubled, the cfm output decreases, and the
amperage draw of the motor ____. correct answer -a. decreases slightly
b. increases slightly
c. stays the same
d. overheats the motor
Answer : A
If the resistance against a propeller fan is
doubled, the cfm output decreases, but the amperage draw of the motor ____.
correct answer -a. decreases
b. increases
c. stays the same
d. overheats the motor
Answer : B
Which of the following is typically measured
with an inclined water manometer? correct answer -a. static pressure in a
duct system
b. pressure in a refrigeration system
c. manifold pressure in a gas fired furnace
d. nozzle pressure of an oil burner
Answer : A
