Solar plumbing questions

[nugimon]

Im putting up some new solar panels and found a spot for another 4x8 piece on a lower level of my roof. However I'm unsure where to tie in the lower panel to into the other 5 panels. I'm thinking "b" and put a relief valve where "a" is and another relief valve where "c" is. Does that sound correct for the water to drain properly?

Also on the return to the pool, there is a 14ft drop that currently has a 1 1/2" PVC from the old solar. My solar is half 1 1/2 (old) and half 2"(new) panels and all 2" pipes. I was told that I should keep the vertical return drop from my roof at 1 1/2 and then plump everything else with 2" because of "cavitation", I think that what the solar guy said, or maybe he meant the the bigger the pipe for the drop could cause the solar to colapse on themselves. Sounds improbable but just wanted to see what you guys thought since I want the best possible flow. I really want to change everything to 2" pipe. (my pipes to my pool are 1 1/2 underground. Everything above ground is now 2" since i've replumbed everything. Thanks.

 

[JasonLion]

Re: Solar plumbing questinos

There are two basic ways to set things up. You can either plumb the new panels as a separate loop from ground level with a valve that lets you adjust the amount of flow going to the new panels to balance the flow. Or you can try to balance the path lengths and max height, which means plumbing the output of the new panels up to the highest point in the system to join up with the flow from the existing panels.

It is important that you don't have pipe going up and then down and then up again, which is what the orange lines you have drawn in appear to do. Water needs to travel up until it gets to the top and then down from there on, or the panels won't drain properly.

 

[nugimon]

Re: Solar plumbing questinos

Thanks Jason,

Actually, I think you are misreading my poor outline. The blue line is the feed, pumping water into the bottom of the 4x8 panel. The orange lines are paths to the bottom and top of the existing panels, at no point does the pipes go up and down again, they are all traversing the roof pitch and rise. The only time when the water would go up is at "b" where I'll need to put 2 90's elbows to go into the bottom of the solar panel. The Red line obviously is the hot water return.

Any advise on the 1 1/2 pipe for the 14ft drop? Should I leave it alone or plumb with 2"?