I am thinking about installing solar panels and have done a lot of reading on TFP. I have a question about how the panel works. When water is not pumped to the panels (say early morning when it's cold), do the panels drain because of the vacuum release valve? Then when water is diverted back to the solar panel, I should expect some bubble out of my return. Is this correct?
Or does water stay in the panels at all time?
Any recommendation on brand? I am leaning towards Solar Sun Pacific (who sells panels through eBay).