Not sure why you wouldn`t get results. For a specific search I use quotes around the word. "RED". it will pull up thread with just that word in it. Without quotes it will pull up any words with RED in the word. You can also refine the search by clicking on advanced search that is next to the search box. As far as why your search found zero results is beyond me, there are a number of words with red in that sequence that should result in a ton of results.
Edit: I just tried an experiment with the search box. From what I can tell it will not search on 3 letters as I tried a couple different searches.