[D2L] Final Exam

Question 1

What is happing in an evaporator?

1) the coil is releasing heat
2) the coil is absorbing heat
3) the coil is releasing cold
4) the coil is absorbing cold

Answer 1

the coil is absorbing heat

Question 2

What colour is r22?

Answer 2

Green

Question 3

When charging air conditioning systems with R-410A, the refrigerant must be added as a vapour?

T or F

Answer 3

False

Question 4

Where do we find the slinger blade?

Answer 4

Window Shaker

Question 5

Specific Gravity =

Answer 5

A ratio of a substances density divided by water density at 4C

Question 6

convert 53kpag to kpaa

Answer 6

154.3 kpaa

Question 7

convert 7psia to “hg

Answer 7

15.7

Question 8

Convert 126C to rankine

Answer 8

718 R

Question 9

Convert 0F to C

Answer 9

-18C

Question 10

A compressed gas cylinder of 10cu/ft is filled to 36psig. Trent dropped the bottle from the building and dented it, reducing the volume to 4cu/ft. as the ambient temperature has remained constant, what is the new pressure in the bottle?

Answer 10

112 psig

Question 11

A balloon has a predictable expansion rate affected at 100psig. if the balloon is moved from an ambient area of 55F to an ambient area at 105F, and it started at 5cuft, what should the current volume of the balloon be?

Answer 11

5.49 cuft

Question 12

A 7cu/ft cylinder of gas in a 58F room has a reading of 56psig. if the cylinder were to be heated to 186F, what would you expect the gauge to read?

Answer 12

73 psig

Question 13

In a 65F room sits a bottle labelled r404a, on it a digital gauge that reads 135.5psig what is in the bottle.

Answer 13

saturated refrigerant

Question 14

In a 65F room sits a bottle labelled r134a, you hook up a gauge that reads 110psi what would you assume is in the bottle?

Answer 14

unknown

Question 15

What refrigerant code is ammonia?

Answer 15

R-717

Question 16

If you are going to remove or attach gauges to a system, the service valve should be in which position first?

Answer 16

Backseated

Question 17

The unit for specific heat is Btu/lb/farenheit degree

T or F

Answer 17

True

Question 18

Specific heat is the amount of heat required to change one pound of substance by one Fahrenheit degree.

Answer 18

True

Question 19

As water is heated the molecules move faster

Answer 19

True

Question 20

Which method of heat transfer uses liquids and gases and involves fast vibrating molecules take up more space than slower vibrating molecules?

Answer 20

Convection

Question 21

What kind of mechanical energy do we use to transfer from a low zone to a high zone?

1) Pumps
2) Compressors
3) Fans
4) All of the above

Answer 21

All of the above

Question 22

When looking at a thermostat we are reading Latent heat

T or F

Answer 22

False

Question 23

What is the state change called when a substance changes from a liquid to a vapour?

Answer 23

Evaporating

Question 24

Positive displacement compressors (Reciprocating) have cylinders and pistons

T or F

Answer 24

True

Question 25

Potential energy is energy based on position T or F

Answer 25

True

Question 26

How does a centrifugal compressor increase refrigerant pressure?

Answer 26

Forces the acceleration of refrigerant

Question 27

Absolute zero is when molecular motion stops. T or F

Answer 27

True

Question 28

Which law is the sum of each individual gas equals the total pressure?

Answer 28

Daltons law

Question 29

Lower CoP (Coefficient of Performance) values result in an effective performance T or F

Answer 29

False, higher CoP is considered effective

Question 30

Lower CR (Compression Ratio) values result in a greater system performance T or F

Answer 30

True

Question 31

What are the units for enthalpy?

Answer 31

btu/lb

Question 32

If the dry bulb temperature is equal to the wet bulb temperature, the water vapour will begin to condense. T or F

Answer 32

True

Question 33

How many grains of moisture are in one pound of water?

Answer 33

7000 grains

Question 34

What does VOC stand for?

Answer 34

Volatile Organic Compounds

Question 35

Oxygen makes up the majority of our air.

Answer 35

False

Question 36

Which anemometer uses a propeller to detect airflow?

Answer 36

rotating vane type

Question 37

Where are the Terminal units often located when a hydronic system is used?

Answer 37

In the duct work above the zone it's used in

Question 38

What is not recommended regarding belts? 1) check belt tension every 6 months 2) If you change 1 belt on a sheave you change all of them 3) replacement of a 4L belt is ok with an A or AX belt 4) use belt dressing or lubrication on the belt to reduce slippage

Answer 38

use belt dressing or lubrication on the belt to reduce slippage

Question 39

What is the airflow direction of an axial fan?

Answer 39

Parallel to the shaft

Question 40

What is the minimum fresh air that must enter a building?

Answer 40

10-20%

Question 41

What is the purpose of a Make up air unit?

Answer 41

to replace exhausted air

Question 42

Why do you not oil sleeve bearings?

Answer 42

the sleeve bearing loses its lubricating lead

Question 43

The filter test which is a timed test and uses white paper downstream of a filter, which dust then lands on and light is shone through the paper is which type of test?

Answer 43

Atmospheric dust spot test

Question 44

What is velocity pressure?

Answer 44

A force applied by a fluid's motion in one direction

Question 45

What are the three main types of filters?

Answer 45

dry, wet, electric

Question 46

What is a by-product of an electronic air cleaner?

Answer 46

Polluting version of ozone gas

Question 47

What is the range of MERV rating for a good residential air filter?

Answer 47

5 to 9

Question 48

In Alberta, which organization administers the B52-05 Mechanical Refrigeration Code?

Answer 48

Alberta Boilers Safety Association = ABSA

Question 49

The scope of the B52-05 Mechanical Refrigeration Code provides for the minimum requirements of design, construction, installation and maintenance.

Answer 49

True

Question 50

The B52 code applies to private residences. T or F

Answer 50

False

Question 51

What is the main purpose of the Code of Practice?

Answer 51

to protect the Earth's ozone layer

Question 52

Which organization is responsible for administering the Code of Practice and refrigerant release in Alberta?

Answer 52

Alberta Environment

Question 53

What is the safety rating of most refrigerants in our industry?

Answer 53

A1

Question 54

Which of the following chemicals is not covered under the Code of Practice? 1) chlorofluorocarbons 2) chlorines 3) hydrofluorocarbons 4) refrigerants used in automobiles

Answer 54

chlorines

Question 55

How is a ball valve used?

Answer 55

as a movable hole or as a plug

Question 56

What is a valve's operator?

Answer 56

any device used to move a control valve's stem and disk

Question 57

Which valve has the greatest pressure drop?

Answer 57

Globe Valve

Question 58

Which valve is for Water ONLY?

Answer 58

Gate Valve

Question 59

What is the flow pattern for a diverting valve?

Answer 59

One inlet pipe, and two separate outlet pipes

Question 60

Where is an evaporator pressure regulator located on a dual temp system?

Answer 60

Downstream of the Coolers evaporator

Question 61

What is the refrigerant group for R-12?

Answer 61

Methane

Question 62

Who is responsible for the phase-out schedules for ozone depleting substances?

Answer 62

The Montreal Protocol est. 1987

Question 63

What is a negative quality for synthetic oils?

Answer 63

highly hygroscopic

Question 64

What position should refrigerant cylinders be transported?

Answer 64

upright and secured

Question 65

HEPA filters are 99.7% eff (0.3 microns) and ULPA filters are 99.9% (0.1 microns)

Answer 65

True

Question 66

In a draw through fan, the blade should be how far into the shroud

Answer 66

2/3

Question 67

What is the volume flow rate of air moving at a velocity of 400fpm in a 10" round duct

Answer 67

218 CFM

Question 68

How much heat is removed from air crossing a cooling coil if the air volume flow rate is 210 cfm and the amount of heat removed is 10btu for every cubic ft of air

Answer 68

9450 btu/min

Question 69

A cooling coil with a 600CFM blower drops the temperature from 85F to 55F. How much sensible heat has been removed?

Answer 69

19440 BTUH

Question 70

How much heat would be required to turn 226 lbs of 85F water into 263F steam?

Answer 70

253224

Question 71

pitot tube position A, B, C, D Pv in. wc 0.025, 0.030, 0.040, 0.035 Pv mm wc 1.016, 1.270, 1.397, 1.524 What is the average velocity?

Answer 71

722 FPM

Question 72

What is the definition of pressure?

Answer 72

Force applied over an Area

Question 73

Keeping temperature constant. The air will have a higher Enthalpy at a lower Relative Humidity than at a Higher Relative humidity.

Answer 73

False

Question 74

a 5 ton AC unit is equal to how many BTU/min?

Answer 74

1000

Question 75

Second law of thermodynamics

Answer 75

Energy moves from an area of high heat to an area of low heat

Question 76

Which fan is not good at creating pressure

Answer 76

Axial

Question 77

Lowest efficient centrifugal fan type is

Answer 77

Forward curve

Question 78

What is the formula BTUH = 1.08 x CFM x ΔT?

Answer 78

Sensible Heat Transfer

Question 79

Which property does not get plotted on a Psychrometric chart?

Answer 79

Entropy

Question 80

Fluid Pressure based on the height of a column of liquid is

Answer 80

Head/Static pressure

Question 81

You should take your Duct traverse readings how far away from an elbow or tee?

Answer 81

6-10 duct diameters

Question 82

A receiver can hold a max of

Answer 82

90% at 90F

Question 83

How long do we keep records of anything refrigerant related?

Answer 83

5 years

Question 84

Maximum Refrigerant Recovery weight is

Answer 84

80% at 70F

Question 85

What is Bernoulli's Theorem or Law?

Answer 85

An increase in velocity pressure results in a decrease in static pressure.

Question 86

Refrigerant R-410A, Head pressure of 388psi What is the saturated discharge temp?

Answer 86

115F

Question 87

Which of the following is a chlorofluorocarbon?

Answer 87

R-12.

Question 88

What is the approximate pressure reading at the top of a 50ft condo, when the pressure on the main floor is 30 psig?

Answer 88

5 psig.

Question 89

The most common place refrigerant 717 is used is in a rack system T or F

Answer 89

False

Question 90

The superheat added to the refrigerant vapour in an evaporator is 10C degrees. What is it in Fahrenheit?

Answer 90

18F

Question 91

What is the tonnage capacity of a refrigeration system that must remove the following heat load in one day?Product load ................................................ 160,998 BTU/Day Wall load ........................................................ 15,620 BTU/Day People load .................................................... 18,514 BTU/Day Lights, Fans etc. Load ..................................... 12,238 BTU/Day

Answer 91

0.72 Tons

Question 92

What is the velocity of the refrigerant flowing through the refrigeration system?

Answer 92

Mass flow rate

Question 93

The Line of constant Entropy on a PE chart is

Answer 93

From the inlet of the compressor to the outlet of the compressor

Question 94

On a pressure enthalpy chart, where do you find the Heat of rejection(HoR)?

Answer 94

across the entire length of the top