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4rth Year Diesel Apprentice Classes > Air Conditioning Fundamentals > Flashcards

Air Conditioning Fundamentals Flashcards

1
Q

Heat is:
a. energy
b. temperature
c. lack of cold
d. energy transfer

A

a. energy

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2
Q

Heat intensity is measured by:
a. BTU
b. specific heat.
c. temperature.
d. latent heat.

A

c. temperature

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3
Q

Heat energy moves from:
a. cold to hot substances.
b. hot to cold substances.
c. a liquid to a vapor.
d. a solid to a liquid.

A

b. hot to cold substances.

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4
Q

When a substance changes state from a liquid to a vapour:
a. heat is given off.
b. heat is aborbed.
c. temperature increases
d. latent heat is given off.

A

b. heat is absorbed.

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5
Q

R-134A refridgerant, when held at a gauge pressure of 1.9psi, turns into a vapour at a temperature of:
a. -30F
b. -10F
c. 30F
d. 70F

A

b. -10F

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6
Q

Calculate superheat for the following system and determine if the system is operating within the specified range and the required action.
Evaporator outlet temperature is 45F
Low pressure gauge reading is 26 psi

A

SH=Te-T1 Low side is 26 psi, convert 30F in table 1, evaporator is 45F, SH=45-30=15F

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7
Q

As the temperature of a confined refrigerant increases, so does its pressure.
True
False

A

True

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8
Q

Refrigerant oils, air conditioning hoses, air conditioning fittings and receiver/dryers/accumulators should be sealed when stored to:
a. prevent moisture from contaminating them.
b. exclude all possibility of dust and dirt entering them.
c. prevent air from contaminating them.
d. achieve all of the above.

A

d. all of the above.

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9
Q

The refrigerant enters the operating compressor as:
a. high pressure vapour
b. low pressure vapour
c. high pressure liquid
d. low pressure liquid

A

b. low pressure vapour

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10
Q

Refrigerant leaves the compressor as a:
a. low pressure vapour
b. low pressure liquid
c. high pressure liquid
d. high pressure vapour

A

c. high pressure liquid

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11
Q

If a cycling clutch air conditioning system that uses a thermal expansion valve has a sight glass installed, where would it be located?
a. Between the evaporator outlet and the compressor inlet.
b. Between the receiver/dryer outlet and the thermal expansion valve inlet.
c. Between the thermal expansion valve outlet and and the evaporator inlet.
d. Between the compressor discharge port and the condenser inlet.

A

b. Between the receiver/dryer outlet and the thermal expansion valve inlet.

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12
Q

The thermal expansion valve senses the refrigerant temperature at the:
a. evaporator outlet.
b. evaporator inlet.
c. condenser inlet.
d. condenser outlet.

A

a. evaporator outlet.

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13
Q

The basic function of an orifice tube, as installed in a cycling clutch orifice tube system, is to:
a. allow water to drain from the evaporator.
b. meter a continuous flow of refrigerant to the evaporator coil.
c. regulate air flow through the condenser
d. regulate air flow through the evaporator

A

b. meter a continuous flow of refrigerant to the evaporator coil.

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14
Q

Which of the following components is located on the high pressure side of an air conditioning system circuit?
a. evaporator
b. condenser
c. suction side of the compressor
d. accumulator on a cycling clutch orifice tube system.

A

b. condenser.

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15
Q

A pressure sensitive switch that controls the compressor clutch is used on some air conditioning systems that are equipped with:
a. a block type expansion valve.
b. an accumulator and an orifice tube.
c. a receiver/dryer and a thermal expansion valve.
d. none of the above.

A

b. an accumulator and an orifice tube.

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16
Q

Two styles of fittings used in air conditioning systems are _______ and ________.

A

flare and O-ring.

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17
Q

During the compression strokes the refrigerant _______ are forced out of the compressor through the one way ________ and a high pressure _________ hose to the condenser.

A

vapours, reed valves, discharge.

18
Q

During the downward stroke of the piston, the compressor pulls the refrigerant ________ from the evaporator, through the low pressure _________ hose, through the one way ________ and into the compressor’s cylinders.

A

vapours, suction, reed valves.

19
Q

The production of R-12 ceased in the mid 1990’s due to the concern for damage caused to the Earth’s protective ________ layer.

A

ozone

20
Q

The three methods by which heat energy moves are _______, ________, and _________.

A

conduction, convection, and radiation.

21
Q

The four events in an air conditioning system are:
a.
b.
c.
d.

A

a. expansion
b. evaporation
c. compression
d. condensation

22
Q

A lubricant that can be used to top up air conditioning system lubricant level is _________ lubricant.

A

polyol ester (POE)

23
Q

Subcooling is a term that is used in air conditioning systems when dealing with refrigerant _________.

A

liquids.

24
Q

Superheat is a term that is used in air conditioning systems when dealing with refrigerant __________.

A

vapours.

25
Q

The sight glass in the air conditioning system may include a __________ indicator.

A

moisture

26
Q

Air blower fans are used to push or pull air through the ________ of air conditioning condensers and evaporators.

A

fins

27
Q

Refrigerant hoses contain an _________ on the inside of the hose to prevent refrigerant leakage to the atmosphere.

A

inner-barrier layer.

28
Q

In ___________, the truck cab loses heat to the outside air.
a. hot climates
b. summer
c. winter
d. warm days

A

c. winter

29
Q

Heat quantity is measured by:
a. BTU
b. specific heat
c. temperature
d. latent heat.

A

BTU

30
Q

Latent heat refers to:
a. the heat energy that must be added to raise a liquid’s temperature 1 Degree F
b. lack of heat
c. the heat energy that must be added or removed to make a substance change state but not temperature.
d. the heat energy that must be added or removed to make a substance change temperature but not state.

A

c. the heat energy that must be added or removed to make a substance change state but not temperature.

31
Q

When a substance changes state from a vapour to a liquid.
a. heat is given off
b. heat is absorbed
c. temperature decreases
d. latent heat is required

A

a. heat is given off.

32
Q

In order to calculate superheat, which of the following is the correct formula?
a. SC=T1-T2
b. SC=Th-Tc
c. SH=T1-T2
d. SH=Te-T1

A

d. SH=Te-T1

33
Q

To store refrigerant as a liquid at room temperature, it must be:
a. kept under pressure
b. kept at a very low pressure
c. kept in a container with a sight glass
d. heated

A

a. kept under pressure

34
Q

Hydrocarbon refrigerants (HSs) such as propane and butane differ from other air conditioning refrigerants because:
a. they are expensive
b. they are flammable
c. they do not cool properly
d. they do not mix with refrigerant oils

A

b. they are flammable

35
Q

The function of the compressor is to:
a. circulate the refrigerant
b. cool the refrigerant
c. changes the state of the refrigerant.
d. both a and c are correct.

A

a. circulate the refrigerant

36
Q

The function of the condenser is to:
a. cool the incoming liquid refrigerant.
b. heat the incoming vapourized refrigerant.
c. cool the incoming vapourized refrigerant.
d. heat the incoming vapourized refrigerant.

A

c. cool the incoming vapourized refrigerant.

37
Q

The reciever dryer or accumulator removes the moisture from the refrigerant by:
a. heating the refrigerant.
b. using a desiccant material.
c. using a filter.
d. settling moisture out.

A

b. using a desiccant material.

38
Q

The thermal expansion valve controls the:
a. flow of refrigerant into the condenser.
b. condenser temperature
c. flow of refrigerant into the evaporator
d. flow of refrigerant by restricting the evaporator outlet.

A

c. flow of refrigerant into the evaporator.

39
Q

When the thermal expansion valve’s temperature sensing bulb senses a decrease in temperature, the thermal expansion valve orifice:
a. is not affected
b. moves to mid position.
c. increases the flow of refrigerant.
d. decreases the flow of refrigerant.

A

d. decreases the flow of refrigerant.

40
Q

The evaporator:
a. cools the refrigerant.
b. heats the refrigerant.
c. changes the refrigerant from vapour to liquid.
d. humidifies the cab air.

A

b. heats the refrigerant.

41
Q

Which of the following components is located on the low pressure side of an air conditioning system circuit.
a. evaporator.
b. condenser.
c. discharge side of the compressor.
d. reciever/dryer on a thermal expansion valve system.

A

a. evaporator.

4rth Year Diesel Apprentice Classes (26 decks)

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