Theory

Question 1

What angle must you have when drilling stainless?

Answer 1

135 degrees

Question 2

How is spring back compensated when bending stainless?

Answer 2

Over bending

Question 3

What method of power braking should be used with stainless?

Answer 3

Air bending

Question 4

From where are Alberta outdoor design temperatures taken?

Answer 4

The Alberta building code January 2.5%

Question 5

What is design temperature difference ?

Answer 5

The difference from indoor design temperatures to outdoor design temperatures

Question 6

Which way does heat travel?

Answer 6

Hot to cold

Question 7

Define effective temperature.

Answer 7

Effective temperature could be defined as how a person feels at a set temperature

Question 8

What 4 factors affect building temperature?

Answer 8

• building envelope
• mechanical systems
• occupants
• appliances

Question 9

What fibre has the greatest r value ?

Answer 9

Glass fibre

Question 10

True or false. Above and below grade have the same r value.

Answer 10

True

Question 11

What 3 factors are used to find the correct infiltration factor?

Answer 11

• site exposure
• penetrations
• air tightness

Question 12

Duct passing through an unconditioned space must be ______.

Answer 12

Insulated

Question 13

Define Ventilation ( fresh air ) loss

Answer 13

Ventilation losses are direct loss to the appliance and need to be added to the total conductive heat loss to ensure the correct appliances are selected.

Question 14

Where is the summer design temp found?

Answer 14

July chart. Temp is factored off of 75 degree indoor temp

Question 15

Does radiant head add a load to the building ?

Answer 15

Yes

Question 16

When must a solar adjustment be made ?

Answer 16

When the summer mean temp is greater than 8 degrees Celsius

Question 17

What is the solar adjustment for fully shaded walls and doors?

Answer 17

-11*F

Question 18

What is the default when calculating heat gains and losses ?

Answer 18

No shades and drapes are used

Question 19

What must be done if the direction of the house is unknown?

Answer 19

The wall with the most windows shall be calculated as if it were facing east or west

Question 20

1 ton of cooling = _____btuh

Answer 20

12 000

Question 21

What are cooling units sized in relation too?

Answer 21

The heat gain calculation

Question 22

A properly sized cooling unit will be within ____ %to ____ % of the buildings total heat gain calculation.

Answer 22

80% - 125%

Question 23

How far are supply air outlets from the wall?

Answer 23

8”

Question 24

How many supply airs must be in a unfinished basement for every 430ft squared?

Answer 24

1

Question 25

How many return air inlets should be on each floor ?

Answer 25

1

Question 26

Where should return air inlets never be installed ?

Answer 26

Kitchens, bathrooms, laundry rooms, utility rooms and crawl spaces

Question 27

What are 2 things to consider when ventilation air is introduced to residential HVAC system ?

Answer 27

- fresh air inlet size | - mixed air temperature

Question 28

What are 2 things to consider when it comes to ventilation air inlet sizing ?

Answer 28

The connection shall be between the nearest return air branch and the blower. The connection shall be at least 10’ from the blower or connected using an acceptable mixing device

Question 29

What temperature should the mixed air ( return air ) be ?

Answer 29

No lower then 60*F or 16*c

Question 30

What 4 factors must you consider when designing an HVAC system?

Answer 30

- proper duct size - ducts running through unconditioned spaces - zoning for houses with special heating and cooling needs - combustion and dilution air

Question 31

What must happen to duct that passes through an unconditioned space ?

Answer 31

-sealed air right. Must be insulated. Vapour barrier on warm side of insulation. If supply more then 50ft long increase size by 10% airflow

Question 32

How much air should be collected from the basement ?

Answer 32

50% of the supply airflow to the basement

Question 33

What is the heating airflow proportioning factor ?

Answer 33

A portion of the cfm required to deliver 1 btuh of heat at the heating flow rate

Question 34

Where is the room heating load taken from ?

Answer 34

Heat loss / gain calculation sheets

Question 35

True or false. It is good trade practice to have more than 1 return air per floor.

Answer 35

True

Question 36

What is acceptable air velocity for the main supply ?

Answer 36

700-900 fpm

Question 37

To determine inlet and supply openings

Answer 37

2x4 walls Number of openings= floor return air cfm / 120 2x6 walls you divide by 180

Question 38

What are 3 advantages of continuous blower operation?

Answer 38

- improved air filtration - increased building comfort - reducing cold areas in the building

Question 39

True or false duct systems will be different sized for heating than for cooling.

Answer 39

True

Question 40

Why is it important to balance a residential HVAC system?

Answer 40

If a system is not balanced there will be cold areas in the building

Question 41

What do Dwyer meters measure ?

Answer 41

They measure pressure in water columns not CFM

Question 42

What do manometers measure ?

Answer 42

They are for low pressure. Inclined manometers are more accurate than u tube manometers

Question 43

What are the 2 basic types of anemometers ?

Answer 43

Thermal and rotating valve

Question 44

What is atmospheric pressure at sea level?

Answer 44

14.7 “ w.c.

Question 45

What is static pressure ?

Answer 45

Air will exert pressure on the walls of the vessel in which it is confined

Question 46

What causes dynamic pressure losses ?

Answer 46

Dynamic pressure losses are the result of changes in the direction and velocity of air flow. They occur when an airstream makes turn or has changes.

Question 47

What is the aspect ratio ?

Answer 47

4:1

Question 48

What is equivalent length ?

Answer 48

The comparison of the calculated pressure drop through a fitting to the pressure drop through a straight length of duct the same size

Question 49

How is the radius ratio of an elbow calculated?

Answer 49

By using the centre line radius ( one half the width of an elbow + the throat radius) of the elbow dividing it by the width of the elbow

Question 50

Why are splitters installed in elbows?

Answer 50

To reduce the dynamic pressure losses

Question 51

What is the maximum angle of an eccentric diverging fitting ?

Answer 51

30*

Question 52

What is the maximum angle of a concentric diverging fitting ?

Answer 52

60*

Question 53

Where are two piece streamliners used ?

Answer 53

In areas where the ductwork cannot be made to offset around an obstruction and that would exceed 20% of the cross sectional area of the duct.

Question 54

How do you calculate air velocity ?

Answer 54

V= 4005 square root PV

Question 55

What two requirements does the Alberta Building code state about fuel fired appliances installed on the roof of the building or any location outside the building ?

Answer 55

1.2m from property line, measured horizontally 3m from an adjacent wall same building.

Question 56

What is sensible cooling load?

Answer 56

Refers to the dry bulb temperature of the building and the latent cooling load refers to the wet bulb temperature of the building.

Question 57

Which location is duct velocity taken ?

Answer 57

The trunk air velocity is recorded at a location closest to the equipment

Question 58

What is outlet throw ?

Answer 58

Usually displayed in feet . Is the distance the air travels from the centre of the diffuser outward to a point where the air velocity drops to 50 fpm

Question 59

What 2 factors are plotted onto a ductulator or friction table when finding the diameter of a supply air branch duct ?

Answer 59

Adjusted duct pressure and outlet flow rate

Question 60

What are the 2 classes of fans ?

Answer 60

- axial ( propeller) | - centrifugal ( radial)

Question 61

Define axial fans.

Answer 61

Air enters and leaves the impeller in a direction parallel to the fan axis. All of the static pressure comes from the change in velocity as the air passes through the impeller. More suited for low volumes and pressures.

Question 62

The wheels of axial fans

Answer 62

K wheel- blades can’t be adjusted A wheel- blades can be adjusted only when fan is on C wheel - blades can be adjusted when fan running

Question 63

What are the 3 types of axial fans ?

Answer 63

- propeller - tube axial - vane axial

Question 64

What are the most commonly used fans ?

Answer 64

Propeller fans

Question 65

What are the 4 types of fan blades ?

Answer 65

- forward curved blades - backward inclined blades - airfoil blades - radial blades

Question 66

The backward inclined airfoil fan is a refinement of the flat bladed backward inclined centrifugal fan in what respect ?

Answer 66

It has better static efficiency and it is quieter

Question 67

What type of fan blade arrangement is usually used in air pollution control applications with high particulate loadings?

Answer 67

Radial blades

Question 68

Which fan should never be used in a ductless system?

Answer 68

Forward curved blade centrifugal fan

Question 69

What is the best fan to use on a blowpipe system in a sawmill?

Answer 69

Radial blades centrifugal fan

Question 70

The most accurate volume control of air is obtained by using what type of damper?

Answer 70

Opposed blade damper

Question 71

What is an accepted method of determining the length of a splitter damper ?

Answer 71

1 1/2 times the width of the small duct

Question 72

Which damper is generally used in locations where it is either fully opened or fully closed?

Answer 72

Parallel blade damper

Question 73

Which fans provide right angle airflow in a rectangular shape and are useful in applications such as air curtains over doorways?

Answer 73

Cross flow fans

Question 74

What dampers are the best for modulating air flow ?

Answer 74

Parallel blade dampers

Question 75

One foot of water equals ____ PSI

Answer 75

0.433 PSI