I just recently bought a used 25-pvd from a private seller (built 1998) , when i first installed it and fired it up I could feel the blower throwing the air out 5 feet or more. Now I've burned about 15 bags and really havnt paid much attention to it, but looked at it the other day and noticed the air is only blowing out about a foot or so. Whats wrong with it? I can still hear the blower starting and the blower setting on the side is set to 9 and does slow when I turn it down. my other setting are at 4-6-1. please help me out!