You guys are great. This is what I love about HBT, ask a question and folks line up to help. Awesome! As I read more from the replies, I just realized that after I change the out flow to the top of the pump, I will be able to use the ball valve I normally use throttle the flow from the pump to control the bleed out of any air. Once that's done I just slap on the return line and start pumping. So I already got purge mechanism, just didn't know it! Keeps getting better.