Air Flow Flashcards

1
Q

How can you attain indoor quality

A

To have a furnace with adequate volume of air but also have continuous operation

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2
Q

Continuous fan will reduce what

A

Hot and cold blast what is known as stratification Layering

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3
Q

Properly designer HVAC system will have what

A

A good balance between supply duct and return duct

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4
Q

When designing an HVAC system which has cooling design to

A

We only designed to heating system

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5
Q

A typical air conditioner moves how many CFM per ton of cooling across the coil

A

400 cfm per ton

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6
Q

A lower CFM per ton of cooling will do what the air

A

The temperature will not lower but remove humidity called Latent heat removal

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7
Q

When selecting a furnace it shouldn’t be less than what? The heat loss calculations should be no more then? I was he lost

A

100 percent
40 percent

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8
Q

When the furnace is probably design what’s the approximate run time per hour

A

35-40 min per hour

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9
Q

The centre of “t” off of a main shaft pilot tube is used to measure

A

Static pressure

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10
Q

One psi will support a water colume of how high 

A

2.31 ft
27.72 “

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11
Q

What does a magnehelic gauge measure

A

It is used pressure differential 0”to2” wc

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12
Q

Atmospheric pressure at sea level is how much

A

14.7 psig

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13
Q

A barometer will 14.7 psig as a pressure gauge on a boiler will read what

A

0 psig

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14
Q

What is velocity pressure

A

It’s a pressure that cannot be measured it’s found by subtracting static pressure with a monomitre

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15
Q

What is dynamic pressure loss

A

Are loses in velocity or changes in directions of air (grills and dampers )

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16
Q

What is the max ratio of duct construction

A

1:4.
24x6

17
Q

What is the best ratio of duct construction

A

1:1
12x12

18
Q

Equivalent length of a 90 elbow is what

A

1:5 full throat

19
Q

When are splitters used on a elbow

A

They are used to improve the ratio on 90 elbow

20
Q

A dwyer air meter can measure cfm directly

A

False

21
Q

A velometer cannot be use to measure static pressures over

A

10@ wc

22
Q

What is the max angle of a eccentric diverting fitting

A

30 percent

23
Q

What’s the max angle of a concentric diverging fitting

A

60 percent