Very good your help, Zab!
You're a master in C.
Would be very difficult for me to find the reason of the problem. With their statements, the compiler worked perfectly!
I always worked with Intel processors family (51) and Atmel Asm with languages and Basic. So that almost do not know programming in C.
I want to slightly modify the original code to switch to adjustable steps of 1 ° C instead of steps of 5 ° C.