How do you do avoid the bunt smell in your hair!!?

i flat iron my hair every other day which is when i wash my hair, but when i flat iron it my hair has this bunt smell!!! i use john frieda frizz ease heat defeat spray and the straight fixation, idk if its my flat iron? i just have one that i bought at walmart, it works very good, but im saving up to buy a chi..anyways how do i avoid this!!