my relay is working as i mentioned. I used those millies to start counting time at the time exhaust fan starts, and if the time passed 10 minutes and the temperature is not less than 28 the exhaust has to be off and rest of the cooling job is to be carried to the cooler.. i wrote the sketch with this intention in mind.but i am not getting the result what is wanted .From that i under stood millies are not what i understand can you ease off my confusion.