Very good explanation Dale. And it is true that CFM's is what matters. More CFM, more recovery. From what I understand is that if you don't have variable speed on the motor, which is unlikely on your older dairy pumps...you can put the smallest pully you can find on the motor and that will slow it down considerably, therefore less heat generated...same cfm? Yes?
Bob- 4 x 12 Small Bros. Lightning w/raised flues-open pans
20 x 40 sugarhouse, all tubing-main line to sugarhouse
1400+- for 2011 & 100% vacuum
Polaris 500 HO w/Tatou 4s Tracks
1 Chocolate Lab from TEXAS