Jason, I agree, I don't think check valve 1 is necessary at all. It can just be removed since it's right next to a diverter that will be closed all the time. Seeing as they're 5x the price of a ball valve, I'm in! The link's diagram doesn't have one on the solar return. What's to keep the bypassed water from going up the solar panel return? Is it the fact that the motorized valve is closed on the other side? The air vent thingie doesn't mess that up? So the air vent goes on the low end of the panels, lets say bottom left in my case. Got it. I'm not sure I understand what it does then. My system is about 5' high on the back and 1' high on the front and 2' from the pool.
I'm thinking since the check valves came with a thread connector they have to be brought in during winter, is that right? Another negative for them.
[attachment=0:1m0q9hhl]Solar Panels 20100509b-1.jpg[/attachment:1m0q9hhl]