Question 1

Which of the following accurately describes the function of the fusible plug used in an A/C system?

Accepted Answer

A)  provides a measure of fire safety in the event of an underhood fire 
B)  melts and releases engine coolant if temperature exceeds 245 degrees Fahrenheit 
C)  melts and releases refrigerant if temperature exceeds 230 degrees Fahrenheit 
D)  provides a measure of explosion protection when ambient temperatures climb to 115° F 
A)  provides a measure of fire safety in the event of an underhood fire 
B)  melts and releases engine coolant if temperature exceeds 245 degrees Fahrenheit 
C)  melts and releases refrigerant if temperature exceeds 230 degrees Fahrenheit 
D)  provides a measure of explosion protection when ambient temperatures climb to 115° F C

Question 2

Which of the following best describes the branch of physics known as thermodynamics?

Accepted Answer

A)  behavior of cold 
B)  behavior of heat 
C)  study of air-conditioning systems 
D)  study of heat exchangers 
A)  behavior of cold 
B)  behavior of heat 
C)  study of air-conditioning systems 
D)  study of heat exchangers B

Question 3

Technician A says that when a mineral oil installed into a R-134a system it will not dissolve into the refrigerant and can clog up circulation.Technician B says that all R-12 systems use mineral oils.Who is correct?

Accepted Answer

A)  Technician A only 
B)  Technician B only 
C)  Both A and B 
D)  Neither A nor B 
A)  Technician A only 
B)  Technician B only 
C)  Both A and B 
D)  Neither A nor B C

Question 4

If the low-side pressure is too high and the high-side pressure is too low,what is the most likely cause?

Accepted Answer

A)  damaged compressor 
B)  moisture in the system 
C)  blend-air door stuck 
D)  80/20 door stuck 
A)  damaged compressor 
B)  moisture in the system 
C)  blend-air door stuck 
D)  80/20 door stuck

Question 5

In which stage of a typical refrigeration cycle does high-pressure gas change state to become a high-pressure liquid?

Accepted Answer

A)  compression stage 
B)  condensation stage 
C)  expansion stage 
D)  evaporation stage 
A)  compression stage 
B)  condensation stage 
C)  expansion stage 
D)  evaporation stage

Question 6

What must be done with an A/C system before replacing any system component?

Accepted Answer

A)  vent the refrigerant to atmosphere 
B)  recover all refrigerant to an A/C station 
C)  equalize low side and high side pressures 
D)  ensure there is sufficient refrigerant to recharge the system 
A)  vent the refrigerant to atmosphere 
B)  recover all refrigerant to an A/C station 
C)  equalize low side and high side pressures 
D)  ensure there is sufficient refrigerant to recharge the system

Question 7

What federal legislation controls mobile refrigerant standards,usage,and disposal?

Accepted Answer

A)  Clean Air Act 
B)  National Highway Traffic Safety Administration 
C)  Federal Motor Vehicle Safety Standards 
D)  Highway Traffic Act 
A)  Clean Air Act 
B)  National Highway Traffic Safety Administration 
C)  Federal Motor Vehicle Safety Standards 
D)  Highway Traffic Act

Question 8

An ideal refrigerant should be:

Accepted Answer

A)  non-combustible 
B)  non-toxic 
C)  have convenient freeze/ boil temperatures 
D)  all of the above 
A)  non-combustible 
B)  non-toxic 
C)  have convenient freeze/ boil temperatures 
D)  all of the above

Question 9

When a current truck uses an electronically controlled A/C system,which of the following is usually true?

Accepted Answer

A)  networked to J1939 data bus 
B)  controller is SA 25/MID 190 
C)  A/C compressor clutch is an ECU output 
D)  all of the above 
A)  networked to J1939 data bus 
B)  controller is SA 25/MID 190 
C)  A/C compressor clutch is an ECU output 
D)  all of the above

Question 10

Technician A says that all matter on earth contains some heat energy.Technician B says that a substance with no heat energy would have a temperature of minus 459 Fahrenheit or absolute zero.Who is correct?

Accepted Answer

A)  Technician A only 
B)  Technician B only 
C)  Both A and B 
D)  Neither A nor B 
A)  Technician A only 
B)  Technician B only 
C)  Both A and B 
D)  Neither A nor B

Question 11

Which of the following air conditioning components is located in the truck cab?

Accepted Answer

A)  compressor 
B)  condenser 
C)  evaporator 
D)  all of the above 
A)  compressor 
B)  condenser 
C)  evaporator 
D)  all of the above

Question 12

At which stage in a typical refrigeration cycle does low-pressure liquid become a low-pressure gas?

Accepted Answer

A)  compression stage 
B)  condensation stage 
C)  expansion stage 
D)  evaporation stage 
A)  compression stage 
B)  condensation stage 
C)  expansion stage 
D)  evaporation stage

Question 13

When the blend air door on a truck A/C system is allowing both air conditioned and heated air to mix,how is the system being operated?

Accepted Answer

A)  defrost mode 
B)  default mode 
C)  maximum cooling 
D)  maximum heating 
A)  defrost mode 
B)  default mode 
C)  maximum cooling 
D)  maximum heating

Question 14

Which of the following components is a heat exchanger?

Accepted Answer

A)  compressor 
B)  receiver/dryer 
C)  condenser 
D)  thermostat 
A)  compressor 
B)  receiver/dryer 
C)  condenser 
D)  thermostat

Question 15

Technician A says that bubbles can be seen through the sight glass on an R-134a system even when it is operating normally.Technician B says that many R-134a truck A/C systems are no longer fitted with sight glasses.Who is correct?

Accepted Answer

A)  Technician A only 
B)  Technician B only 
C)  Both A and B 
D)  Neither A nor B 
A)  Technician A only 
B)  Technician B only 
C)  Both A and B 
D)  Neither A nor B

Question 16

What color is an R-12 refrigerant container?

Accepted Answer

A)  white 
B)  light blue 
C)  cream 
D)  light pink 
A)  white 
B)  light blue 
C)  cream 
D)  light pink

Question 17

How is the A/C compressor effective cycle managed in truck air conditioning systems?

Accepted Answer

A)  electronically 
B)  thermostat 
C)  centrifugal clutch 
D)  all of the above 
A)  electronically 
B)  thermostat 
C)  centrifugal clutch 
D)  all of the above

Question 18

Which of the following failures would NOT result in both the high- and low-side pressures to read too high?

Accepted Answer

A)  damaged compressor 
B)  system overcharged 
C)  large amount of air in the system 
D)  overcharge of oil 
A)  damaged compressor 
B)  system overcharged 
C)  large amount of air in the system 
D)  overcharge of oil

Question 19

Which of the following terms is used as a metric measurement of heat energy?

Accepted Answer

A)  BTUs 
B)  joules 
C)  watts 
D)  farads 
A)  BTUs 
B)  joules 
C)  watts 
D)  farads

Question 20

Which refrigerant is most commonly used in current reefer trailers?

Accepted Answer

A)  R-12 
B)  R-22 
C)  R-134a 
D)  propane 
A)  R-12 
B)  R-22 
C)  R-134a 
D)  propane

Exam 35: Heavy-Duty Heating, ventilation, and Air Conditioning Systems

Which of the following accurately describes the function of the fusible plug used in an A/C system?

Which of the following best describes the branch of physics known as thermodynamics?

Technician A says that when a mineral oil installed into a R-134a system it will not dissolve into the refrigerant and can clog up circulation.Technician B says that all R-12 systems use mineral oils.Who is correct?

If the low-side pressure is too high and the high-side pressure is too low,what is the most likely cause?

In which stage of a typical refrigeration cycle does high-pressure gas change state to become a high-pressure liquid?

What must be done with an A/C system before replacing any system component?

What federal legislation controls mobile refrigerant standards,usage,and disposal?

An ideal refrigerant should be:

When a current truck uses an electronically controlled A/C system,which of the following is usually true?

Technician A says that all matter on earth contains some heat energy.Technician B says that a substance with no heat energy would have a temperature of minus 459 Fahrenheit or absolute zero.Who is correct?

Which of the following air conditioning components is located in the truck cab?

At which stage in a typical refrigeration cycle does low-pressure liquid become a low-pressure gas?

When the blend air door on a truck A/C system is allowing both air conditioned and heated air to mix,how is the system being operated?

Which of the following components is a heat exchanger?

Technician A says that bubbles can be seen through the sight glass on an R-134a system even when it is operating normally.Technician B says that many R-134a truck A/C systems are no longer fitted with sight glasses.Who is correct?

What color is an R-12 refrigerant container?

How is the A/C compressor effective cycle managed in truck air conditioning systems?

Which of the following failures would NOT result in both the high- and low-side pressures to read too high?

Which of the following terms is used as a metric measurement of heat energy?

Which refrigerant is most commonly used in current reefer trailers?

Introduction to Servicing Heavy-Duty Trucks

Shop Safety and Operations

Tools and Fasteners

Preventive Maintenance Program

Fundamentals of Electricity

Fundamentals of Electronics and Computers

Batteries

Charging Systems

Cranking Systems

Chassis Electrical Circuits

Diagnosis and Repair of Electronic Circuits

Multiplexing

Hydraulics

Clutches

Standard Transmissions

Standard Transmission Servicing

Torque Converters

Automatic Transmissions

Automatic Transmission Maintenance

Electronically Automated Standard Transmissions

Electronically Controlled Automatic Transmissions Ecats

Driveshaft Assemblies

Heavy-Duty Truck Axles

Heavy-Duty Truck Axle Service and Repair

Steering and Alignment

Suspension Systems

Wheels and Tires

Truck Brake Systems

Hydraulic Brakes and Air-Over-Hydraulic Brake Systems

Abs and Ebs

Air Brake Servicing

Vehicle Chassis Frame

Heavy-Duty Truck Trailers

Fifth Wheels and Coupling Systems

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