Line CC Air Measurement Quiz: Exam 2 Flashcards
What pressure units are used for measuring duct pressure?
inches water column
What two pressures are created by air moving through a duct system?
static pressure, velocity pressure
What instrument is used for measuring duct pressure?
manometer + pitot tube
Explain how to take static pressure reading on a duct system?
use pitot tube and hookup static pressure port to oil side of manometer
Explain how to take velocity pressure reading on a duct system?
use manometer
What units are used to measure air velocity?
FPM
What tools are used to measure velocity?
manometer, pitot tube, hoses
What units are used to measure air volume?
cubic feet per minute (CFM)
How does a flow hood measure airflow?
measures VP and does CFM calculation based on area of flow hood
What is the typical airflow required per ton of residential air-conditioning equipment?
400CFM/Ton
If the resistance against a backward curved centrifugal blower is doubled, the cfm output decreases, and the amperage draw of the motor
a) decreases slightly
b) increases slightly
c) stays the same
d) overheats the motor
a) decreases slightly
If the resistance against a propeller fan is doubled, the cfm output decreases, but the amperage draw of the motor
a) decreases
b) increases
c) stays the same
d) overheats the motor
b) increases
