Hi all - A blower related question - I have a Dayton 4C006 blower. The published ratings for it start at a static pressure of 1/2 in and go up to 1.2 in. there is a note in the 0 inch static pressure column which says - "overloaded, do not operate under .5 in SP" I've asked my friendly neighborhood Granger dealer why that is and they have no idea. Anybody know? Tnx Frank W2FCA