I recently bought some Sungrabber panels on e-bay. They are 2' wide by 20' long. They claim that they should be installed in what I consider a very strange manner. At one end the right side of the header says inlet and the left side says outlet. While at the far end there are caps on both ends of the header. It says something about an integral disc being in the feed header such that water comes in from the right and flows down half the tubes and then returns up the other half the tubes. You then connect the outlet on the left of the top header to the inlet of the next pannel and the oulet goes to the pool. I did that and with about 6gpm of flow was getting a 4 degree temperature rise. But what I noticed was that standing at the header where water was going in and out the panel on the right (nearest feed) was very hot and the one on th left was cold. This seemed wrong.
So, I repiped it so water flows in the top of one panel and then out the other end. That end is then connected in series with the second pannel. Without adjusting valves my flow dropped to 4 gpm, but my temperature rise went from 4 up to 9 degrees. Thus, instead of getting 12,000 BTU/Hr I am now getting 18,000 BTU/Hr.
Does anyone know anything about these supposed integral discs? I assume I am better with this second setup, but let me know if you think otherwise.