308A HVAC Ductwork Systems

Question 1

What is the primary function of a supply air duct in an HVAC system?

Accepted Answer

To deliver conditioned air from the air handling unit to occupied spaces

Answer

To remove stale air from occupied spaces

Answer

To drain condensation from cooling coils

Answer

To house electrical wiring for the system

Question 2

What is the difference between a return air duct and an exhaust air duct?

Accepted Answer

Return air recirculates air back to the AHU for reconditioning, while exhaust air is expelled outside the building

Answer

They are the same thing

Answer

Exhaust ducts are always larger

Answer

Return ducts are only used in summer

Question 3

What is the purpose of a 'plenum' in an HVAC duct system?

Accepted Answer

To serve as a large distribution or collection chamber that connects to multiple branch ducts

Answer

To filter the air

Answer

To heat the air

Answer

To measure airflow

Question 4

What is the standard gauge for residential HVAC ductwork made from galvanized steel?

Accepted Answer

26 to 28 gauge

Answer

16 gauge

Answer

12 gauge

Answer

30 gauge

Question 5

What is the purpose of turning vanes in a rectangular duct elbow?

Accepted Answer

To reduce turbulence and pressure loss by guiding airflow smoothly around the turn

Answer

To increase air velocity

Answer

To filter particles from the air

Answer

To support the weight of the duct

Question 6

What is 'static pressure' in an HVAC duct system?

Accepted Answer

The pressure exerted equally in all directions within the duct, representing stored energy that pushes air through the system

Answer

The weight of the ductwork

Answer

The noise level of the fan

Answer

The temperature of the air