Question 1

What is the minimum size of vacuum pump required to evacuate a bus air conditioning system?

Accepted Answer

A)  2 CFM 
B)  3 CFM 
C)  4 CFM 
D)  5 CFM 
A)  2 CFM 
B)  3 CFM 
C)  4 CFM 
D)  5 CFM B

Question 2

Whenever the main liquid line solenoid is energized which evaporator will be operating at all times?

Accepted Answer

A)  The drivers evaporator 
B)  The main evaporator 
C)  The left parcel rack evaporator 
D)  The right parcel rack evaporator 
A)  The drivers evaporator 
B)  The main evaporator 
C)  The left parcel rack evaporator 
D)  The right parcel rack evaporator B

Question 3

What component is designed to create less flash gas to increase refrigeration efficiency and performance?

Accepted Answer

A)  The condenser 
B)  The evaporator 
C)  The thermostatic expansion valve 
D)  The subcooler 
A)  The condenser 
B)  The evaporator 
C)  The thermostatic expansion valve 
D)  The subcooler D

Question 4

What is the source of heat that causes the refrigerant to boil in the evaporator?

Accepted Answer

A)  The ambient air 
B)  The heat of compression 
C)  The heat from the interior of the bus 
D)  The heat from the bus engine 
A)  The ambient air 
B)  The heat of compression 
C)  The heat from the interior of the bus 
D)  The heat from the bus engine

Question 5

The thermostatic expansion valve controls the flow of refrigerant into the evaporator based upon:

Accepted Answer

A)  Evaporator inlet temperature only 
B)  Evaporator outlet temperature and pressure 
C)  Evaporator outlet pressure only 
D)  Evaporator inlet temperature and pressure 
A)  Evaporator inlet temperature only 
B)  Evaporator outlet temperature and pressure 
C)  Evaporator outlet pressure only 
D)  Evaporator inlet temperature and pressure

Question 6

What state is the refrigerant in when it exits the condenser on its way to the receiver tank?

Accepted Answer

A)  Superheated vapor 
B)  Subcooled liquid 
C)  Supercooled liquid 
D)  Subcooled vapor 
A)  Superheated vapor 
B)  Subcooled liquid 
C)  Supercooled liquid 
D)  Subcooled vapor

Question 7

What can result if moisture is allowed to enter into the air conditioning system?

Accepted Answer

A)  Moisture can freeze in the system causing a blockage. 
B)  Refrigerant oil can for sludge the can cause blockages. 
C)  Acid can form causing copper plating of the bearing surfaces and eventual compressor failure. 
D)  of the above can result from too much moisture entering the system. 
A)  Moisture can freeze in the system causing a blockage. 
B)  Refrigerant oil can for sludge the can cause blockages. 
C)  Acid can form causing copper plating of the bearing surfaces and eventual compressor failure. 
D)  of the above can result from too much moisture entering the system.

Question 8

What component does not store refrigerant during a low side pump down?

Accepted Answer

A)  The main evaporator 
B)  The subcooler 
C)  The condenser 
D)  The receiver tank 
A)  The main evaporator 
B)  The subcooler 
C)  The condenser 
D)  The receiver tank

Question 9

What procedure would you use if you wanted to repair the main liquid line solenoid valve and replace the filter drier without removing the entire refrigerant charge?

Accepted Answer

A)  Compressor pump down 
B)  Discharge valve pump down 
C)  Low side pump down 
D)  A parcel rack pump down 
A)  Compressor pump down 
B)  Discharge valve pump down 
C)  Low side pump down 
D)  A parcel rack pump down

Question 10

What is the purpose of the discharge line check valve?

Accepted Answer

A)  To restrict the flow of refrigerant in the discharge line. 
B)  To prevent the migration of liquid refrigerant back into the compressor in the heat mode. 
C)  To prevent the migration of liquid refrigerant back into the compressor in the cool mode. 
D)  To prevent the migration of liquid refrigerant back into the compressor in the off mode. 
A)  To restrict the flow of refrigerant in the discharge line. 
B)  To prevent the migration of liquid refrigerant back into the compressor in the heat mode. 
C)  To prevent the migration of liquid refrigerant back into the compressor in the cool mode. 
D)  To prevent the migration of liquid refrigerant back into the compressor in the off mode.

Question 11

Which of the following could cause high compressor discharge pressure?

Accepted Answer

A)  Refrigerant overcharged 
B)  Dirty condenser coil 
C)  Incorrect fan rotation 
D)  Any of the above could cause the high compressor discharge pressure. 
A)  Refrigerant overcharged 
B)  Dirty condenser coil 
C)  Incorrect fan rotation 
D)  Any of the above could cause the high compressor discharge pressure.

Question 12

What is requires in order to calculate the superheat setting of a bus air conditioning system?

Accepted Answer

A)  Evaporator outlet temperature and evaporator inlet temperature pressure and a refrigerant pressure temperature chart. 
B)  Evaporator outlet temperature, evaporator inlet pressure and a refrigerant pressure temperature chart. 
C)  Condenser inlet temperature, evaporator inlet pressure and a refrigerant pressure temperature chart. 
D)  Evaporator outlet temperature, suction pressure and a refrigerant pressure temperature chart. 
A)  Evaporator outlet temperature and evaporator inlet temperature pressure and a refrigerant pressure temperature chart. 
B)  Evaporator outlet temperature, evaporator inlet pressure and a refrigerant pressure temperature chart. 
C)  Condenser inlet temperature, evaporator inlet pressure and a refrigerant pressure temperature chart. 
D)  Evaporator outlet temperature, suction pressure and a refrigerant pressure temperature chart.

Question 13

Which of the following will not cause a bus compressor to have lower than normal suction pressure?

Accepted Answer

A)  TXV superheat setting is to low 
B)  Broken TXV or capillary tube broken 
C)  Refrigerant overcharged 
D)  Plugged filter drier 
A)  TXV superheat setting is to low 
B)  Broken TXV or capillary tube broken 
C)  Refrigerant overcharged 
D)  Plugged filter drier

Question 14

What valve must be front seated while the air conditioning is running in order to perform a low side pump down?

Accepted Answer

A)  Discharge check valve 
B)  Suction service valve 
C)  The discharge check valve 
D)  The receiver outlet valve 
A)  Discharge check valve 
B)  Suction service valve 
C)  The discharge check valve 
D)  The receiver outlet valve

Question 15

What component is used to turn a bus compressor on or off?

Accepted Answer

A)  The drive pulley 
B)  The electromagnetic clutch 
C)  A centrifugal clutch 
D)  An over-running clutch 
A)  The drive pulley 
B)  The electromagnetic clutch 
C)  A centrifugal clutch 
D)  An over-running clutch

What is the minimum size of vacuum pump required to evacuate a bus air conditioning system?

Whenever the main liquid line solenoid is energized which evaporator will be operating at all times?

What component is designed to create less flash gas to increase refrigeration efficiency and performance?

What is the source of heat that causes the refrigerant to boil in the evaporator?

The thermostatic expansion valve controls the flow of refrigerant into the evaporator based upon:

What state is the refrigerant in when it exits the condenser on its way to the receiver tank?

What can result if moisture is allowed to enter into the air conditioning system?

What component does not store refrigerant during a low side pump down?

What procedure would you use if you wanted to repair the main liquid line solenoid valve and replace the filter drier without removing the entire refrigerant charge?

What is the purpose of the discharge line check valve?

Which of the following could cause high compressor discharge pressure?

What is requires in order to calculate the superheat setting of a bus air conditioning system?

Which of the following will not cause a bus compressor to have lower than normal suction pressure?

What valve must be front seated while the air conditioning is running in order to perform a low side pump down?

What component is used to turn a bus compressor on or off?

History of Hvac

Environmental and Safety Practices

Thermodynamics

Air Conditioning Components: Compressor, Condenser, and Receiver-Drier

Air-Conditioning Components: Metering Devices, Evaporator, Accumulator

Air Conditioning Systems

Service Procedures

Truck Engine Cooling Systems

Climate Controlsupplemental Truck Heatingcooling

Trouble Shooting

Apadsacpu Air Conditioning Control Systems Air Conditioning Protection Unit

Truck Trailer Refrigeration Equipment

Truck Trailer Refrigeration Components

Truck Trailer Refrigerant Flow Control

Truck Trailer Refrigeration Electrical Components

Truck Trailer Refrigeration Maintenance Procedures

Filters

Exam 12: Coach Air Conditioning

What is the minimum size of vacuum pump required to evacuate a bus air conditioning system?

Whenever the main liquid line solenoid is energized which evaporator will be operating at all times?

What component is designed to create less flash gas to increase refrigeration efficiency and performance?

What is the source of heat that causes the refrigerant to boil in the evaporator?

The thermostatic expansion valve controls the flow of refrigerant into the evaporator based upon:

What state is the refrigerant in when it exits the condenser on its way to the receiver tank?

What can result if moisture is allowed to enter into the air conditioning system?

What component does not store refrigerant during a low side pump down?

What procedure would you use if you wanted to repair the main liquid line solenoid valve and replace the filter drier without removing the entire refrigerant charge?

What is the purpose of the discharge line check valve?

Which of the following could cause high compressor discharge pressure?

What is requires in order to calculate the superheat setting of a bus air conditioning system?

Which of the following will not cause a bus compressor to have lower than normal suction pressure?

What valve must be front seated while the air conditioning is running in order to perform a low side pump down?

What component is used to turn a bus compressor on or off?

History of Hvac

Environmental and Safety Practices

Thermodynamics

Air Conditioning Components: Compressor, Condenser, and Receiver-Drier

Air-Conditioning Components: Metering Devices, Evaporator, Accumulator

Air Conditioning Systems

Service Procedures

Truck Engine Cooling Systems

Climate Controlsupplemental Truck Heatingcooling

Trouble Shooting

Apadsacpu Air Conditioning Control Systems Air Conditioning Protection Unit

Truck Trailer Refrigeration Equipment

Truck Trailer Refrigeration Components

Truck Trailer Refrigerant Flow Control

Truck Trailer Refrigeration Electrical Components

Truck Trailer Refrigeration Maintenance Procedures

Filters