I didn't put KitKat back on my S5. I rooted it while on KitKat and have left it there. Unfortunately there is no way to return to 4.4 without bricking your device. You may find instructions online, but I can't comfortably point you to one because more people have bricked their device than have had success. Especially if you're on a Verizon S5 with anything over 5.0.
Sorry! [emoji31]
S5 tap'n
Sorry! [emoji31]
S5 tap'n