Ok guys, I'm sure you can answer this lickedy split. Last year my solar install was temporary at best but I'm making it somewhat more "proper" this year. The panel is a single 4X20 Fafco, nothing fancy, but my experiences with it were very positive last year. It is mounted on an overhang on the back of our house which is almost a perfect fit for the panel.
I've read a lot about the need for vacuum breakers on solar panels, but here's my question. The panel sits width wise in it's location on about a 45 degree upward angle. The feed and return manifolds have plugs at both ends, look at it from a "top/bottom" perspective perhaps (so water can be fed from either top or bottom, simply remove the desired plug and plumb) although one is higher than the other. Last year I fed the water in from the bottom of the feed side manifold, and the return was from the top of the return manifold. This way the panel was always full of water and there would be no chance of drainback. I want this - The area where the panel is mounted is susceptible to extreme building-elevated (AKA, wind tunnel) high winds in storms and the extra weight of the water left in the panel is significant which without doubt helps keep it firmly in place.
So, if the panel is NOT having a vacuum drawn on it (if I had the return plumbed to the bottom/lower side of the return manifold), do I need to install a vacuum breaker anyways? It seems like it would be unnecessary as the way the panel is setup there's no way it can drain back on it's own.
At the end of the season I drain the panel manually, blow it out, and then roll it up and remove it from the roof, so I'm not worried about the fact it won't drain back automatically - it spends it's winters inside.
So, do I need one anyways installed at the top of the feed side manifold? (The highest point, basically the same height as the return however...)