Air Flow Flashcards
How can you attain indoor quality
To have a furnace with adequate volume of air but also have continuous operation
Continuous fan will reduce what
Hot and cold blast what is known as stratification Layering
Properly designer HVAC system will have what
A good balance between supply duct and return duct
When designing an HVAC system which has cooling design to
We only designed to heating system
A typical air conditioner moves how many CFM per ton of cooling across the coil
400 cfm per ton
A lower CFM per ton of cooling will do what the air
The temperature will not lower but remove humidity called Latent heat removal
When selecting a furnace it shouldn’t be less than what? The heat loss calculations should be no more then? I was he lost
100 percent
40 percent
When the furnace is probably design what’s the approximate run time per hour
35-40 min per hour
The centre of “t” off of a main shaft pilot tube is used to measure
Static pressure
One psi will support a water colume of how high 
2.31 ft
27.72 “
What does a magnehelic gauge measure
It is used pressure differential 0”to2” wc
Atmospheric pressure at sea level is how much
14.7 psig
A barometer will 14.7 psig as a pressure gauge on a boiler will read what
0 psig
What is velocity pressure
It’s a pressure that cannot be measured it’s found by subtracting static pressure with a monomitre
What is dynamic pressure loss
Are loses in velocity or changes in directions of air (grills and dampers )
What is the max ratio of duct construction
1:4.
24x6
What is the best ratio of duct construction
1:1
12x12
Equivalent length of a 90 elbow is what
1:5 full throat
When are splitters used on a elbow
They are used to improve the ratio on 90 elbow
A dwyer air meter can measure cfm directly
False
A velometer cannot be use to measure static pressures over
10@ wc
What is the max angle of a eccentric diverting fitting
30 percent
What’s the max angle of a concentric diverging fitting
60 percent
