Hw does the introduction go against conventional wisdom and signal to the reader that a different value system will be introduced?

From the very first line, the reader is aware that something is amiss. It opens with the line, "It was a pleasure to burn" -- and then soon after, the reader finds out that this is a fireman talking. He is burning something and then returning to the firehouse. This is backwards from how things are supposed to be because a fireman typically gets a signal and then goes to the fire, from the firehouse. Plus, Montag meets his neighbor, Clarisse, and she guesses he is a fireman because he smells like kerosene. A fireman would not smell like kerosene unless he was the one doing the burning, which, in this case, is true. As the story progresses, the reader soon realizes that the fireman is not putting out the fire, but starting the fire. A very different world is about to unfold, a scary world.