Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

Test > HVAC > Flashcards

HVAC Flashcards

Study For First Test

1
Q

What is the second law of thermodynamics according to Randy?

A

Heat flows from hot to cold.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What does BTU mean?

A

British Thermal Unit

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What are the two ways to cool a structure

A

Sensible Heat and Latent Heat

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Does Latent Mean Hidden in Latin?

A

Yes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What does it mean when we speak of Latent?

A

That we are going to remove water or moisture from the air

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What are the forms of water?

A

Solid, Water and Gas

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

There exist to types of latent heat of fusion for water which are they?

A

Latent Heat of Freezing and Latent Heat of Melting

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

400 Series Refrigerants like 410A or 407 are what type of refrigerants

A

Zeotropes meaning a combination of two substances

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

How do we charge refrigerants according to Randy?

A

As a liquid not a gas

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What is Super Heat?

A

The temperature ABOVE saturation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What is Super Cool?

A

The temperature BELOW saturation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

The Greater The Temperature The Greater the?

A

Heat flow

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What does hermetic mean?

A

All inclusive or enclosed

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

How does a compressor cool itself down?

A

Cool Suction Line Vapors

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

How many BTUs does it take to place 1 pound of water into the air?

A

970 BTUs

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What is Dew Point?

A

This is when the air cannot hold any more moisture

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Gases occupy?

A

All Space They Are in

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What is the Latent Heat of Ice?

A

144 BTUs

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Who does more work sensible heat or latent heat?

A

Latent Heat

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

PSI means pounds per square inch. What does PSIG mean?

A

The G stands for gauge. This means the PSI inside the system the gauges are measuring

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What are the two ways a compressor can fail?

A

Mechanically or Electrical

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

How do you measure super heat?

A

On the low side of the system you convert the pressure to temperature then subtract that from the actual temperature in the suction line and you have the super heat

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

The actual second law of thermodynamics is

A

energy cannot be created nor destroyed

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

What does Delta T (ΔT) mean?

A

Change in temperature. Delta or the triangle symbol means change in HVAC Delta T means the change between ONE substance.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

TD (TΔ) Means?

A

This is the change between TWO substances

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

Which do we want to measure in air conditioning Delta T (ΔT) or T Delta (TΔ)

A

Delta T (ΔT)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

1 Pound of Water in the AIR equals?

A

1 Pint of Actual Water

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

How many cubic feet per minute (CFM) are in one ton?

A

400 CFM

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

1 Watt Generates how many BTUs an hour?

A

3.414 BTUs

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

What does charging a system mean?

A

It means either adding or removing refrigerant

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

What do you calibrate your gauges too?

A

0 or 14.7 atmospheric pressure

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

400 Series refrigerants are charged how?

A

As liquid because they are zoetrope

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

What type of heat does not create a change in temperature?

A

Latent Heat

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

Is Nitrogen a Non-Condensable gas?

A

Yes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

Is Moisture a Non-Condensable Gas?

36
Q

When do you mix refrigerants?

A

Never under NO exception do you mix them

37
Q

When do you purge your manifolds?

A

Always Before and After Using them

38
Q

What volt ranges will you experience?

A

208v, 460v, 1v, 25v and 24v

39
Q

In a thermostat what does the R wire mean?

40
Q

In a thermostat what does the G wire mean?

41
Q

In a thermostat what does the W wire mean?

42
Q

In a thermostat what does the Y wire mean?

43
Q

In a thermostat what does the C wire mean?

44
Q

What tool is used to measure Voltage?

45
Q

What tool is used to measure Amps?

46
Q

What tool is used to measure OMHs?

47
Q

What does induced mean?

A

Magnetic Field

48
Q

Amps are measured how with a amp meter?

A

In Series?

49
Q

How do you test OHMs?

A

You first need to turn off the power

50
Q

What does OL mean in a meter?

51
Q

NO and NC mean what?

A

Normally Open & Normally Closed

52
Q

What is a motor?

A

Electrical energy turned into mechanical motion

53
Q

What does RLA on a compressor mean?

A

Rated Loaded Amps

54
Q

What 3 pins do one phase motors have?

A

Run, Start, Common

55
Q

How many winding’s do 3 phase motors have?

56
Q

What is the resistance between all 3 windings in 3 phase motors?

A

It is all the same resistance or OHMs

57
Q

PSC Motors means?

A

Permanent Split Capacitor motor

58
Q

What are the 3 ways heat can be transfered?

A

Radiation, Conduction and Convection

59
Q

12,000 BTU equals how much

60
Q

How do we measure a vacuum?

A

Inches of mercury

61
Q

What is voltage or EMF?

A

The flow of electrons caused by a potential difference in atomic charge

62
Q

What is resistance? or OMH

A

How resistant a material is to the flow of electrons on its surface.

63
Q

What is an electrical circuit?

A

A COMPLETE path for electrons to flow

64
Q

What is a LOAD?

A

Any device that consumes electricity to perform work

65
Q

What is induced magnetism?

A

When any material being capable of being magnetized becomes a magnet and is placed inside a magnetic field.

66
Q

What happens when you move a conductor across a magnetic field?

A

If a conductor is moved across a magnetic field an electromotive force EMF will be generated that induces current in the conductor

67
Q

What is a relay?

A

a relay is an electrical switching device that turns lets power flow or stops the flow of power

68
Q

What is a Solenoid?

A

is an electromagnetic device that has a plunger that is pulled down when current flows and when current stops it pulls the plunger back

69
Q

What are the two main parts of a motor?

A

A Stator and Rotor

70
Q

What happens to a motor when it is placed under a heavy load? or work?

A

It increases its consumption of electricity increases greatly

71
Q

How does a motor start?

A

Through phase splitting between the Run and Start windings

72
Q

You can add WHAT and HOW to a motor run and start windings?

A

A capacitor in series to the START winding

73
Q

What two types of capacitors are used in a motor?

A

Run and Start Capacitors

74
Q

Can you place a capacitor in the motors stator windings?

75
Q

What is a CSIR motor?

A

A single phased motor with a start capacitor wired IN SERIES with the motor

76
Q

What is a Hermetic Compressor Motor?

A

is a motor enclosed inside with the compressor

77
Q

VOLTMETERS are used to measure what?

78
Q

How are VOLTMETERS connected when testing a circuit?

A

In Parallel

79
Q

How are OHM meters connected when testing a circuit?

80
Q

What do clamp ampmeters do?

A

Measure the alternating current flowing through the conductor

81
Q

What is a metering orifice

A

A fixed orifice (hole) used as a metering device for refrigerant before it enters the evaporator

82
Q

What happens when you increase super heat too much?

A

This starves the evaporator by only allowing an amount of liquid refrigerant into the evaporator

83
Q

What does CS mean in CSIR and CSCR

A

Capacitor Start

84
Q

How are capacitors wired in a CSCR Motor

A

The start and run capacitor are wired in SERIES with the START winding BUT the run capacitor and start capacitor are wired in parallel

85
Q

How do CSCR Motors work?

A

Current runs through both run and start windings creating phase splitting which produces high torque but the start capacitor drops out after the motor has reached its desired levels

86
Q

How does a PSC Motor (permanent split capacitor) work?

A

Current flows through the run,start and the capacitor during the motors whole operation

Test (1 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions