The bypass factor (B.P.F.) in case of sensible heating of air is (Where td<sub>1</sub> = Dry bulb temperature of air entering the heating coil, td<sub>2</sub> = Dry bulb temperature of air leaving the heating coil and td<sub>3</sub> = Dry bulb temperature of heating coil)

Correct Answer: $$\frac{{{\text{t}}{{\text{d}}_3} - {\text{t}}{{\text{d}}_2}}}{{{\text{t}}{{\text{d}}_3} - {\text{t}}{{\text{d}}_1}}}$$
The bypass factor (B.P.F.) in case of sensible heating of air is $$\frac{{{\text{t}}{{\text{d}}_3} - {\text{t}}{{\text{d}}_2}}}{{{\text{t}}{{\text{d}}_3} - {\text{t}}{{\text{d}}_1}}}$$
Where,
td1 = Dry bulb temperature of air entering the heating coil,
td2 = Dry bulb temperature of air leaving the heating coil and
td3 = Dry bulb temperature of heating coil