Question: how to calculate cfh gas?
Answer: CFH = < (1600) X (150 - 50) > ÷ 800.
CFM = (FACE AREA) X (VELOCITY)
CFH =< (GPM WATER) X (°F OUT - °F IN) X 1.1 > ÷ 2.
CFH =< (10) X (120) X 1.1 >÷ 2.
CFH = 660.