First of all, thanks a lot for your answer and attention to help me out. Well, i wanted to add the desire time to turn the valves on and off. Like a timer. I used the RTC to program a local time and then based on it input the time i want. As you can see, i compared hours and minutes to activate and deactivate them. Yes, the relay worked as expected before the code got "jammed". i have a 4 channel relay and i'm checking and updating the source code adding one - by - one. Before writing this message, it worked good again and after a while the RX led indicating transmission was not blinking anymore. This is very strange.