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WorksheetsHAC-101 Final Exam
Total questions: 110
Worksheet time: 55mins
The Clean Air Act (CAA)___________.
Mandates that each shop maintain a current government-issued license.
Outlines the specific refrigerants that can be safely used for each application.
Sets the standard for shops that do air-conditioning work.
All of the above.
The 609 license never expires.
True
False
The 609 License ensures that the technician knows how to repair the automotive air-conditioning systems.
True
False
Section 609 of_____ the federal law regulates air emissions from stationary and mobile sources contains all of the motor vehicle air-conditioning (MVAC) requirements and laws.
The OSHA code and compliance guidelines
The Clean Air Act (CAA)
The Department of Transportation (DOT)
None of the above
The_____ of the refrigerant system system is designed to allow easy transformation of the refrigerant from a liquid to a gas.
High Side
Low Side
Medium Side
None of the above
The amount of heat required to raise the temperature of 1 pound of water at 32*F (0*C) and at atmospheric pressure by 1*F would be:_____
1 Kelvin
1 BTU
1 Joule
1 Rankine
When the pressure of a gas is raised, it's temperature:
goes down
remains unchanged
goes up
becomes unstable
Radiation describes the amount of heat it takes to move temperature up or down in degrees.
True
False
The A/C compressor clutch is engaged and is disengaged by using:_____
Hydraulic pressure
Vacuum
Compressed air
Electromagnetism
The air-conditioning hose connections are secure to the hose using special unions known as _____ that must be carefully assembled to avoid leaks.
Wobbles
Billets
Crimps
Baffles
The A/C Condenser is normally positioned:
in front of the radiator
behind the radiator
in the cabin air box
on the firewall
_____, a member of the CFC family of gases, was the first common refrigerant to be used in a automotive air-conditioner.
HFO-1234yf
Tetrafluoroethan (r134A)
Dichlorodifluoromethane (R-12)
Pentafluoroethane (R-410a)
Fixed orifice tube automotive air-conditioning systems use a(n) _____ to ensure that a pure gas is delivered to the compressor.
Thermal expansion valve
Evaporator
Condenser
Accumulator
The_____ is installed on the low-pressure refrigerant line or the accumulator to turn the air-conditioning clutch on and off at certain pressures.
Pressure cycling switch
Fixed orifice tube
Accumulator
Variable-pressure cycling switch
When the compressor switches on, the suction from the compressor removes refrigerant vapor from the evaporator and _____ it's pressure.
Lowers
Raises
Varies
None of the answers listed.
The fixed orifice tube in an A/C system is a metering device that forces a high-pressure:
gas into a low-pressure gas
gas into a low-pressure liquid
liquid into a low-pressure liquid
liquid into a low-pressure gas
The resistor pack or resistor block uses resistors in _____ to regulate the speed of the blower motor fan.
Parallel
Series
Modified parallel
All of the answers listed
When the pressure on hot coolant (above 212 degrees F) is lowers. it:
Leaks out
Boils instantly
Forms a gel-like substance
None of the answers listed
Servos are devices designed to:
do work
cool
heat
charge A/C systems
A vehicles heating and ventilation blend doors can be operated___________.
Mechanically
By vacuum
By electric motors
All of the above
Air conditioning systems absorb heat from a cab interior through a(n)
Condenser
Evaporator
Compressor
Blower
How do the late-model vehicles help maintain a cleaner and dust-free cab interior?
Equipped with an air ventilator located at the cab air inlet
Equipped with an air filter located at the cab air inlet
Equipped with an air compressor located at the cab air inlet
Equipped with an air filter located at the cab air outlet
Moisture condensed on a cold_____ helps remove dirt and other air particulates
Condenser
Evaporator
Compressor
Ventilator
Which measurement of heat best describes the quantity of heat required to produce a change of state from a solid to a liquid or a liquid to a gas?
Latent heat
Radiant heat
Specific heat
Sensible heat
Heating is regulated by circulating engine coolant through an in-cab heat exchanger called a _____
Radiator core
Heat core
Condenser
Pressure control switch
Technician A says removing heat from an object or substance is simple, because cold always moves toward a warmer object. Technician B says all that is necessary for cooling is to provide an even warmer substance for cold to flow into. Who is correct?
Technician A
Technician B
Both Technician A and Technician B
Neither Technician A nor Technician B
Which of the following holds true for refrigeration systems?
They add moisture to the air passing through the evaporator.
The compressor is an engine-driven pump that decreases refrigerant pressure.
Air conditioning and refrigeration systems transfer heat from the cab and passenger compartment to the air stream outside the vehicle.
The refrigeration system operates in an open loop.
The thermal expansion valve device lowers the pressure of the warm, high-pressure liquid refrigerant entering the ______
Evaporator
Condenser
Compressor
Orifice
Which of these holds true for H-Valve thermal expansion valve (TXV) operation?
TVX meters the refrigerant into the evaporator at a variable rate.
It maintains the evaporator at low temperature and pressure.
Spring tension acting on the orifice ball regulates the quality of refrigerant flow.
Inlet temperature also can change the position of the linkage.
The coldest air temperature from the evaporator is when the blower is operated at its _______
Molecular
Slowest
Fastest
Road
An important component in the cooling action of the evaporator is the
Blower fan
Receiver drier
Condenser fan
Driver evaporator module
Technician A says accumulators often incorporate an important diagnostic aid-the refrigerant sight glass. Technician B says accumulators collect liquid refrigerant leaving the evaporator and separate vapor from liquid before the refrigerant enters the compressor. Who is correct?
Technician A
Technician B
Both Technician A and Technician B
Neither Technician A nor Technician B
The_______ is located in the low-pressure side of the system.
Dryer
Accumulator
Compressor
Condenser
What is the viscosity of the oil used in reciprocating piston compressors?
10-30w
15-40w
85-100w
90-120w
When released into the atmosphere, HFO-1234yf decomposes, giving it a lifetime of _______
11 years
11 days
200 days
2500 years
The air conditioning controls are necessary to _______
Adjust operator comfort levels in the cab of the vehicle
Expose major components to damage
Improve freezing inefficiency of the system
Operate an evaporator by switching it on and off
What switch has three sets of internal contacts?
Trinary
Thermostatic
Pressure-cycling
Ambient temperature
Which of the following best explains APADS?
The unit receives input from two trinary switches and a thermostat.
Operates both air conditioning controls and analog controls
Extends the lifespan of the air conditioning system on medium- and heavy-duty trucks
The output signals are interpreted by control logic.
Whenever a system fault is detected, the _______
Air conditioning protection and diagnostic system (APADS) receives inputs from the vehicle data link
Compressor is not allowed to run
Air conditioning system is turned off
APADS broadcasts diagnostic information over the data bus
When discussing the function of the air distribution system, Technician A says actuators for the cab air door controls are operated by brush-type stepper motors providing low power consumption. Technician B says a Hall-effect sensor is built into many motors to provide position feedback to the microcontroller to verify the actuators are correctly positioning. Who is correct?
Technician A
Technician B
Both Technician A and Technician B
Neither Technician A nor Technician B
The first step in the diagnostic process of the HVAC system is _______
Diagnosing any faults that are causing the system to operate incorrectly
Evacuating the air-conditioning system
Reclaiming the air-conditioning system before any repair or nitrogen testing is required
Carrying out a performance test of the air-conditioning system
Tech A states that the HVAC system is an easy system with a single principle involved in making the unit function properly. Tech B states that successful diagnosis and repair of the HVAC system requires a general step-by-step, strategy-based diagnosis process. Who is correct?
Tech A
Tech B
Both A and B
Neither A nor B
The best way to make sure the air-conditioning system is properly charged is to _________
Top off the refrigerant with clean fluid
Remove all refrigerant from the system and reinstall the proper amount of refrigerant
Remove all refrigerant from the system and let it sit for 12 hours
Perform an acid test on the HVAC system.
If an air-conditioning system cannot be discharged for any reason and the state of charge needs to be determined, then you need to start your diagnosis by performance testing the air-conditioning system on the vehicle.
True
False
If the gauges of an air-conditioning system read low pressure on the high side, high pressure on the low side, or about equal pressures, it usually means that:
the system may be low on refrigerant.
the compressor is not working.
there is a blockage in the low side of the system.
there is a blockage on the high side.
If the low side of an air-conditioning system reads as a vacuum:
the compressor is not working.
the system may be low on refrigerant.
there is a blockage on the high side or an airflow restriction across the condenser.
there is a blockage in the low side of the system that is not allowing refrigerant to pass.
Because warm, moist air is passed through the cold evaporator, most of the moisture condenses on the surface of the evaporator and drips to the bottom of the air box.
True
False
If the HVAC evaporator housing drain tube becomes clogged with leaves or debris over time, the water will not be able to drain; it will stagnate and begin growing bacteria, creating an unpleasant odor.
True
False
The most accurate way to test the velocity of the air that is moving through the A/C system is with a(n):
flow gauge.
anemometer.
micron gauge.
manifold pressure gauge set.
Allowing sealant to be drawn into a(n) ______ can ruin it.
Refrigerant identifier
Air-conditioning machine
Both A and B
Neither A nor B
In testing, R-134a passing by the diode is broken down, thereby creating an electrical current charge; the internal mechanics of the diode use this charge to determine how much refrigerant has passed.
Manual sniffer
Nitrogen
Ultraviolet leak dye
Electronic sniffer
Types of electronic sniffers include all of the following EXCEPT:
ultrasonic.
heated diode.
pre-amplifier.
corona suppression.
Tech A states that when the air-conditioning machine displays an alert that it needs service, the local service department for the machine should be contacted. Tech B states that this alert is merely a precaution, and can be overlooked. Who is correct?
Tech A
Tech B
Both A and B
Neither A nor B
Changing the vacuum pump oil regularly will extend the life of the vacuum pump and make it reach maximum vacuum quicker.
True
False
Tech A states that when evacuating an air-conditioning system, the vacuum should be maintained for approximately 10 minutes after the system reaches the boiling point pressure of water. Tech B states that the primary purpose of evacuating an air-conditioning system is to remove any moisture from the system. Who is correct?
Tech A
Tech B
Both A and B
Neither A nor B
Technician A says that you should evacuate the system for no longer than 10 minutes. Technician B says that you should evacuate the A/C system for a minimum of 5 minutes. Who is correct?
Technician A
Technician B
Both Technician A and Technician B
Neither Technician A nor Technician B
The typical electrical resistance for an automotive A/C compressor's electrical portion of the A/C clutch should be:
3 - 5 ohms.
1 - 2 ohms.
8 - 12 ohms.
15 - 20 ohms.
An air-conditioning compressor ______ may need service when noise is detected from the bearing as the engine is running.
Pulley
Bearing
Both A and B
Neither A nor B
may need service when noise is detected from the bearing as the engine is running. The process for removing the air-conditioning condenser varies by
Vehicle type
Make
Model
All of the above
Technician A says that when replacing A/C lines, the O-rings must always be replaced. Technician B says that if A/C lines use a spring lock, the spring lock must be replaced with a new one every time it is opened. Who is correct?
Electronic leak detectors for R-1234yf should meet:
J2297.
J2298.
J2913.
J1628.
Technicians servicing an MVAC system should do any of these EXCEPT:
store refrigerant in a disposable container.
avoid direct contact with the refrigerant.
wear safety goggles.
work in a well-ventilated area.
Requirements for recovery/recycling/recharging equipment for R-1234yf refrigerant are set by SAE standard:
J1990.
J2788.
J2843.
J2209.
R-1234yf refrigerant has a global warming potential (GWP) of:
1.
4.
124.
1430.
R-1234yf is a preferred refrigerant over R-134a because:
R-1234yf is highly flammable.
R-1234yf has a high GWP.
R-1234yf depletes the ozone layer.
R-1234yf has a low GWP.
Technician A says that SAE standard J639 spells out details for system design, implementation, and service. Technician B says that SAE standard J639 specifies refrigerant fitting types and sizes for each refrigerant. Who is right?
A only
B only
Both A and B
Neither A nor B
Servicing MVAC systems on hybrid and electric vehicles requires:
an electronic leak detector dedicated to hybrid and electric vehicle MVAC systems.
following J1989 for refrigerant recovery.
service fittings specially designed for hybrid and electric vehicle MVAC systems.
special service procedures to disable the high-voltage system prior to service.
Technician A says that anyone servicing MVAC systems for hire must be trained and certified. Technician B says that each piece of refrigerant handling equipment that is used to service motor vehicle air conditioners must be approved and certified. Who is right?
A only
B only
Both A and B
Neither A nor B
Which of these is a flammable refrigerant, unacceptable under SNAP as a substitute for CFC-12?
HC-12a
R406A
R-176
GHG-X4
Empty disposable R-134a refrigerant containers should be:
disposed of according to J2196.
evacuated into a recovery/recycling machine.
flushed with R-152a refrigerant.
flushed with R-134a refrigerant.
_____ the refrigerant before any repair or nitrogen testing is required by the Environmental Protection Agency (EPA), Section 609 of the Clean Air Act.
Leak testing
Dye testing
Topping up
Reclaiming
The process done for a typical vehicle brought in for an air-conditioning repair contains all of the following steps EXCEPT:
Performance testing
Leak testing
Discharging
Reclaiming
The under hood A/C sticker should detail:
A/C system oil capacity
A/C system charge amount
type of refrigerant to use
All answers listed
In a typical orifice tube systems, which of the following indicates an undercharge of refrigerant?
Both the low and the high side gauges are running higher than normal.
The air-conditioning compressor clutch runs for a long time before it shuts off.
The air in the ducts feels cold
The air-conditioning clutch has a rapid cycle time
If the low side of an air conditioning system reads as a vacuum:
the compressor is not working
the system may be low on refrigerant
there is a blockage on the high side or an airflow restriction across the condenser
there is a blockage in the low side of the system that is not allowing refrigerant to pass
The air-conditioning box has a _____ that allows removal of water collected from the moist air as it condenses on the cold evaporator and drips into the box.
collection grid
drain tube
window vent
level sensor
The cabin air filter should be inspected during every service and replaced according to the manufacturers specified interval, typically every _____
6,000 to 10,000 miles
3,000 to 5,000 miles
20,000 to 30,000 miles
12,000 to 15,000 miles
Tech A states that an air-conditioning performance test usually requires that an auxiliary condenser fan be used during the test. Tech B states that a performance test will show if the air-conditioning system is contaminated with sealer. Who is correct?
Tech A
Tech B
Both A and B
Neither A nor B
The low-pressure gauge is unique in that it displays both pressure and:
weight of the refrigerant
amount of vacuum
results of the A/C performance test
None of the answers listed
_____ measure the velocity of the air in the FPM.
PT charts
Vacuum gauges
Micron gauges
Anemometers
Leak testing can be done by any of the following methods EXCEPT:
sniffer testing
dye testing
pressure testing
nitrogen testing
Which of the following types of testing requires an empty air-conditioning system?
Corona suppression
Heated diode testing
Dye testing
Nitrogen testing
When servicing the vacuum pump, you will need a drain pan for the old oil and new vacuum pump oil for the vacuum pump
True
False
Tech A states that when the air-conditioning machine displays an alert that it needs service, the local service department for the machine should be contacted. Tech B states that this alert is merely a precaution, and can be overlooked. Who is correct?
Tech A
Tech B
Both A and B
Neither A nor B
When using a micron gauge, if the pressure gauge falls from 1,300 to 1,000 instantly, the vehicle needs to:
be moved to a warmer environment
be started up and accelerated to 1500 RPMs
be left alone with the vacuum pump
None of the answers listed
The micron gauge should reach the boiling point of pressure within _____ minutes of turning on the vacuum pump
5
10
15
20
The typical electrical resistance for an automotive A/C compressor's electrical portion of the A/C clutch should be:
3 - 5 ohms
1 - 2 ohms
8 - 12 ohms
15 - 20 ohms
The air-conditioning system requires that the compression move the refrigerant at the correct velocity for the cooling of the passenger compartment to be at its peak efficiency
True
False
If an air-conditioning systems hoses are bolted together, _____ should be used to remove them
O-ring tools
Spring lock release tools
Serpentine belt tools
Line wrenches
Anytime air-conditioning lines are loosened. The O-rings in the fittings must be reseated or there will be potential for leaks
True
False
The first step in the diagnostic process of the HVAC system is _____.
Diagnosing any faults that are causing the system to operate incorrectly
Evacuating the air-conditioning system
Reclaiming the air-conditioning system before any repair or nitrogen testing is required
Carrying out a performance test of the air-conditioning system.
Tech A states that the HVAC system is an easy system with a single principle involved in making the unit function properly. Tech B states that successful diagnosis and repair of the HVAC system requires a general step by step, strategy-based diagnosis process. Who is correct?
Tech A
Tech B
Both A and B
Neither A nor B
The best way to make sure the air-conditioning system is properly charged is to _____.
Top off the refrigerant with clean fluid
Remove all refrigerant from the system and reinstall the proper amount of refrigerant
Remove all refrigerant from the system and let it sit for 12 hours
Perform an acid test on the HVAC system
If an air conditioning system system cannot be discharged for any reason and the state of charge needs to be determined, then you need to start you diagnosis by performance testing the air conditioning system on the vehicle
True
False
If the gauges of an air conditioning system read low pressure on the high side, high pressure on the low side, or about equal pressures, it usually means that:
The system may be low on refrigerant
The compressor is not working
there is a blockage in the low side of the system
there is a blockage on the high side
If the low side of an air conditioning system reads as a vacuum:
The compressor is not working
The system may be low on refrigerant
there is a blockage on the high side or an airflow restriction across the condenser
there is a blockage in the low side of the system that is not allowing the refrigerant to pass
Because warm, moist air is passed through the cold evaporator, most of the moisture condenses on the surface of the evaporator and drips to the bottom of the air box
True
False
If the HVAC evaporator housing drain tube becomes clogged with leaves and debris over time, the water will not be able to drain; it will stagnate and begin growing bacteria, creating an unpleasant odor
True
False
The most accurate way to test the velocity of the air that is moving through the A/C system is with a(n):
Flow gauge
anemometer
micron gauge
manifold pressure gauge set
Allowing sealant to be drawn into a(n) _____ can ruin it
Refrigerant identifier
Air-conditioning machine
Both A and B
Neither A nor B
In _____ testing, R-134a passing by the diode is broken down, thereby creating an electrical current charge; the internal mechanics of the diode use this charge to determine how much refrigerant has passed.
Manual sniffer
Nitrogen
Ultraviolet leak dye
Electronic sniffer
Types of electronic sniffers include all of the following EXCEPT:
ultrasonic
heated diode
pre-amplifier
corona suppression
Tech A states that when the sir conditioning machine displays an alert that it needs service, the local service department for the machine should be contacted. Tech B stated that this alert is merely a precaution, and can be overlooked. Who is correct?
Tech A
Tech B
Both A and B
Neither A nor B
Changing the vacuum pump oil regularly will extend the life of the vacuum pump and make it reach maximum vacuum quicker
True
False
Tech A states that when evacuating an air conditioning system, the vacuum should be maintained for approximately 10 minutes after the system reaches the boiling point pressure of water. Tech B states that the primary purpose of evacuating an air conditioning system is to remove any moisture from the system. Who is correct?
Tech A
Tech B
Both A and B
Neither A nor B
Tech A says that you should evacuate the system for no longer than 10 minutes. Tech B says that you should evacuate the A/C system for a minimum of 5 minutes. Who is correct?
Tech A
Tech B
Both A and B
Neither A nor B
The typical electrical resistance for an automotive A/C compressor's electrical portion of the A/C clutch should be:
3-5 ohms
1-2 ohms
8-12 ohms
15-20 ohms
An air conditioning compressor _____ may need service when noise is detected from the bearing as the engine is running
Pulley
Bearing
Both A and B
Neither A nor B
The process for removing the air conditioning condenser varies by _____.
Vehicle type
Make
Model
All of the above
Tech A says that when replacing A/C lines, the O-rings must always be replaced. Tech B says that if A/C lines use a spring lock, the spring lock must be replaced with a new one every time it is opened. Who is correct?
Tech A
Tech B
Both A and B
Neither A nor B
