313D Air Distribution and Ducting 2

Question 1

What is the purpose of a static pressure tap in a duct system?

Accepted Answer

To measure the pressure of air against the duct wall

Answer

To measure air velocity directly

Answer

To balance airflow between supply and return

Answer

To detect refrigerant leaks in the air handler

Question 2

Which duct shape provides the most efficient airflow per unit of material used?

Accepted Answer

Round

Answer

Square

Answer

Rectangular with 2:1 aspect ratio

Answer

Oval

Question 3

A residential duct system has excessive external static pressure. What is the most likely result?

Accepted Answer

Reduced airflow and potential equipment damage

Answer

Increased airflow and better comfort

Answer

Higher humidity levels in the supply air

Answer

Faster refrigerant cycle times

Question 4

When installing flexible duct, what maximum sag per foot of run is generally acceptable?

Accepted Answer

1/2 inch per foot

Answer

1 inch per foot

Answer

2 inches per foot

Answer

No sag is acceptable

Question 5

What term describes the pressure loss caused by air changing direction in a duct fitting?

Accepted Answer

Dynamic pressure loss

Answer

Velocity pressure drop

Answer

Static regain

Answer

Equivalent length loss

Question 6

A supply register is delivering noticeably warm air on one side and cool air on the other side. What is the most likely cause?

Accepted Answer

Poor air mixing due to stratification upstream

Answer

Undersized return duct

Answer

Refrigerant overcharge

Answer

Incorrect thermostat setpoint

Question 7

What is the recommended maximum length for a flexible duct run without a support hanger?

Accepted Answer

4 feet

Answer

2 feet

Answer

6 feet

Answer

8 feet