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Interprovincial Review Questions > Heating, Ventilation, and Air Conditioning > Flashcards

Heating, Ventilation, and Air Conditioning Flashcards

0
Q

Low evaporator pressure increases the possibility of compressor damage.

a. True
b. False

A

a. True

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1
Q

Some compressor control circuits have several switches wired in series.

a. True
b. False

A

a. True

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2
Q

Refrigerants exposed to open flame or combustion create a toxic gas.

a. True
b. False

A

a. True

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3
Q

Flooding the evaporator can damage the compressor.

a. True
b. False

A

a. True

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4
Q

The fixed-orifice tube is located in the evaporator outlet line.

a. True
b. False

A

b. False

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5
Q

A desiccant is used in both the accumulator and the receiver-drier.

a. True
b. False

A

a. True

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6
Q

An absolute pressure gauge will read 14.7 psi when not connected to a system.

a. True
b. False

A

a. True

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7
Q

Alternative refrigerants cannot be mixed.

a. True
b. False

A

a. True

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8
Q

Heat cannot be destroyed, but it can be transferred.

a. True
b. False

A

a. True

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9
Q

Today’s air-conditioning systems are more efficient than operating the car with the windows open.

a. True
b. False

A

a. True

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10
Q

The percentage of water vapour in the air compared to the capacity of the air at that temperature is its relative humidity.

a. True
b. False

A

a. True

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11
Q

Excessive refrigerant is stored in the accumulator or the receiver-drier.

a. True
b. False

A

a. True

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12
Q

The blend door controls coolant flow to regulate air temperature.

a. True
b. False

A

b. False

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13
Q

Refrigerant boils in the condenser.

a. True
b. False

A

b. False

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14
Q

Refrigerant boiling removes heat from the passenger compartment.

a. True
b. False

A

a. True

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15
Q

A swashplate changes rotary action to reciprocating action.

a. True
b. False

A

a. True

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16
Q

In a thermostatic-cycling system, the compressor cycle is controlled by the temperature of the evaporator.

a. True
b. False

A

a. True

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17
Q

When servicing an air-conditioning system, always wear safety glasses.

a. True
b. False

A

a. True

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18
Q

Water dripping on the passenger floor may be caused by a plugged evaporator drain hose.

a. True
b. False

A

a. True

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19
Q

Oily residue on hose connections is an indication of leaks.

a. True
b. False

A

a. True

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20
Q

The air conditioning system controls humidity by:

a. Drying the air
b. Warming the air
c. Pressurizing the air
d. Melting frost

A

a. Drying the air

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21
Q

What is “ambient temperature”?

a. Refrigerant temperature
b. Desired passenger compartment temperature
c. Passenger compartment temperature with system off
d. Air temperature outside the vehicle

A

d. Air temperature outside the vehicle

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22
Q

Solar radiation is trapped in vehicles that have a lot of [blank]

a. Vinyl
b. Roof area
c. Glass
d. Humidity

A

c. Glass

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23
Q

Tech A says passengers are a significant source of passenger compartment heat.
Tech B says passengers are a significant source of passenger compartment humidity.
Who is correct?
a. A only
b. B only
c. Both A and B
d. Neither A nor B

A

c. Both A and B

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24
Q

Tech A says HVAC systems raise or lower passenger compartment temperature to maintain passenger comfort and safety.
Tech B says HVAC systems raise and lower humidity to maintain comfort and safety.
Who is correct?
a. A only
b. B only
c. Both A and B
d. Neither A nor B

A

a. A only?

25
Q

To what percentage of its capacity can a refrigerant container be filled?

a. 100
b. 90
c. 60
d. It depends on the refrigerant type

26
Q

Heat that is added to a substance which does not result in a temperature change is:

a. Wasted
b. Sensible
c. Specific
d. Latent

27
Q

Tech A says the compressor separates the high and low sides in an air-conditioning system.
Tech B says the expansion device separates the high and low sides. Who is correct?
a. A only
b. B only
c. Both A and B
d. Neither A nor B

A

c. Both A and B

28
Q

High-pressure refrigerant is cooled below its boiling point in the:

a. Evaporator
b. Compressor
c. Condenser
d. Accumulator

A

c. Condenser

29
Q

Tech A says any pressure less than normal atmospheric pressure is a vacuum.
Tech B says atmospheric pressure changes with altitude.
Who is correct?
a. A only
b. B only
c. Both A and B
d. Neither A nor B

A

c. Both A and B

30
Q

You are monitoring a compressor clutch coil circuit with a voltmeter and notice a large voltage spike in the control wire every time the coil is de-energized. What should you test next?

a. Nothing, this is normal
b. Compressor diode
c. Compressor coil
d. Compressor switch

A

b. Compressor diode

31
Q

Tech A says with vacuum motors, the vacuum pulls against spring tension. Tech B says diesel engines do not produce useable vacuum. Who is correct?

a. A only
b. B only
c. Both A and B
d. Neither A nor B

A

c. Both A and B

32
Q

Temperature control is achieved in some systems by moving the:

a. Mode door
b. Recirculation door
c. Bi-level door
d. Blend door

A

d. Blend door

33
Q

Which of the following is a part of the low side of the air-conditioning system?

a. Receiver-drier
b. Condenser
c. Evaporator
d. Compressor outlet

A

c. Evaporator

34
Q

Pressure on the refrigerant is reduced at the:

a. Expansion valve
b. Accumulator
c. Reed valve
d. Receiver-drier

A

a. Expansion valve

35
Q

Pistons in the axial-type compressor are driven by:

a. A driveshaft
b. A crankshaft
c. Elliptical lobes
d. A swashplate

A

d. A swashplate

36
Q

Tech A says when a compressor clutch cycles off, the pulley continues to freewheel.
Tech B says when a compressor clutch cycles off the refrigerant flow stops.
Who is correct?
a. A only
b. B only
c. Both A and B
d. Neither A nor B

A

c. Both A and B

37
Q

Tech A says the compressor may be deactivated during some engine load conditions.
Tech B says the compressor may be deactivated during engine idle. Who is correct?
a. A only
b. B only
c. Both A and B
d. Neither A nor B

A

c. Both A and B

38
Q

Tech A says cycling the compressor clutch controls low-side pressure.
Tech B says cycling the compressor clutch controls low-side temperature. Who is correct?
a. A only
b. B only
c. Both A and B
d. Neither A nor B

A

b. Both A and B

39
Q

The purpose of the compressor clutch diode is to:

a. Turn the clutch on and off
b. Suppress voltage spikes
c. Prevent overheating of the compressor
d. Provide high voltage for activation

A

b. Suppress voltage spikes

40
Q

The size of the expansion valve orifice is controlled by:

a. Evaporator temperature
b. Condenser pressure
c. Compressor outlet pressure
d. Refrigerant flow through the accumulator

A

a. Evaporator temperature?

41
Q

In a fixed-orifice tube system, refrigerant flow is controlled by:

a. Cycling the compressor clutch
b. Adjusting the pintle valve
c. Throttling the suction line
d. Regulating the accumulator bypass

A

a. Cycling the compressor clutch

42
Q

Tech A says the condenser adds heat to the refrigerant from the outside air.
Tech B says the evaporator cools the refrigerant using passenger compartment air.
Who is correct?
a. A only
b. B only
c. Both A and B
d. Neither A nor B

A

d. Neither A nor B

43
Q

Tech A says the desiccant helps remove humidity from the passenger compartment air.
Tech B says the evaporator helps remove humidity from the passenger compartment air.
Who is correct?
a. A only
b. B only
c. Both A and B
d. Neither A nor B

44
Q

The high-pressure relief valve typically opens at:

a. 150 to 200 psi
b. 250 to 300 psi
c. 350 to 400 psi
d. 450 to 550 psi

A

d. 450 to 550 psi?

45
Q

Tech A says high coolant temperature may prevent operation of the compressor.
Tech B says high coolant temperature may prevent operation of the condenser fan.
Who is correct?
a. A only
b. B only
c. Both A and B
d. Neither A nor B

46
Q

Tech A says pressure-cycling switches are commonly used on fixed-orifice tube systems.
Tech B says pressure-cycling switches are designed to be open at pressures below 20 psi.
Who is correct?
a. A only
b. B only
c. Both A and B
d. Neither A nor B

A

c. Both A and B

47
Q

The power-steering pressure switch turns the air-conditioning compressor off:

a. When the power-steering belt breaks
b. During high speed maneuvering
c. In stop-and-go traffic
d. During parking maneuvers

A

d. During parking maneuvers

48
Q

Tech A says thermostatic expansion valve systems use a temperature sensor at the evaporator outlet.
Tech B says fixed-orifice tube systems use a temperature sensor mounted between the evaporator and the accumulator.
Who is correct?
a. A only
b. B only
c. Both A and B
d. Neither A nor B

49
Q

Tech A says a successful troubleshooting strategy begins with the identification and verification of the complaint.
Tech B says a successful troubleshooting strategy ends with making the repairs.
Who is correct?
a. A only
b. B only
c. Both A and B
d. Neither A nor B

50
Q

If a blower does not operate at any speed, first check the:

a. Resistor
b. Relay
c. Switch
d. Fuse

51
Q

Evacuating removes water from the air-conditioning system by:

a. Boiling it
b. Condensing it
c. Mixing it with the oil
d. Pulling it into the desiccant

A

a. Boiling it

52
Q

Which of the following is NOT a recommended method of determining correct refrigerant charge?

a. Refrigerant weight
b. Sight-glass appearance
c. Refrigerant volume
d. System pressures

A

c. Refrigerant volume

53
Q

A refrigerant container has been found to have a pressure above the maximum for its temperature. What should you do?

a. Vent air from the container into the atmosphere.
b. Store the container in a cooler place.
c. Recycle the refrigerant in the container.
d. Use a vacuum pump to correct the container pressure.

A

a. Vent air from the container into the atmosphere?

54
Q

Tech A says a scan tool can be used on some systems to retrieve codes.
Tech B says a scan tool can be used on some systems to perform system operations.
Who is correct?
a. A only
b. B only
c. Both A and B
d. Neither A nor B

A

c. Both A and B

55
Q

Frost on high-side refrigeration fittings may indicate:

a. Too much lubrication oil in the system
b. Restriction in the system
c. Compressor failure
d. Low refrigerant level

A

b. Restriction in the system

56
Q

The outlet line from the evaporator should be:

a. Hot
b. Warm
c. Cool
d. Frost-covered

A

c. Cool…

57
Q

An air-conditioning performance check requires:

a. A thermometer and a hydrometer
b. A thermometer and a vacuum pump
c. A thermometer and a manifold gauge set
d. A manifold gauge set and a volt-ohmmeter

A

c. A thermometer and a manifold gauge set

58
Q

If both the low side and the high side show low readings, what might be the problem?

a. Low refrigerant charge or leaks
b. Condenser malfunction
c. Cooling fan malfunction
d. TXV stuck open

A

a. Low refrigerant charge or leaks

59
Q

The most common cause of compressor failure is:

a. Belt failure
b. Contaminated refrigerant
c. Insufficient lubrication
d. Clutch failure

A

c. Insufficient lubrication

Interprovincial Review Questions (21 decks)

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