I tried the link from the string of comments and it worked fine. Here it is again:
http://www.micromatic.com/category.php?cid=151. Place the blower in an area that is out of the way and can pick up tje coldest air. Route the flex tube from the blower outlet up into the tower behind the faucets. If your tower has a 3" column, this should be fine. The air will return into the kegerator through the 3" tower. Check this link out:
http://www.micromatic.com/product.php?pid=D4743T-PVD
Scott Zuhse, Instructor
Micro Matic Dispense Institute