Johnson Controls York Stack Fan Operating Manual page 13

Piezometer Ring Data (Continued)
Calculation when using the Piezo Ring
For standard air (ρ = 0.075 lb/ft3):
(CFM) = K Factor * √(delta pressure)
• K Factor = value from chart
• Delta Pressure (ΔP) = The differential in static pressure
from the piezometer ring and the front pressure tap
(inches w.g.)
To Piezo Ring
To Front Panel
YORK ® STACK FAN
P
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