New homeowner needs help understanding diy solar heater

[Kat-mac]

The house is about 40 years old, and the neighbors who are original say that a plumber who lived in the neighborhood had modified everyone's system with solar pool heaters. The pipes were still present when the previous owner moved in, but the solar system was gone. He installed a DIY solar heater using coiled black irrigation tubing.

I am a little confused about how this system works. There is a valve that I was told to leave about half-open. This didn't seem to be doing much, so I recently opened the valve all the way. This caused a lot of bubbles, which did subside. But, then the next time it turned on, there was a river of water running off the roof! I closed the valve and inspected it the next day. I did not see any obvious problems, and when I opened the valve again, the river did not return. However, now the pool sweep will not run when the solar heater valve is open. I think this is because of all the air in the system.

I guess my questions are:
1) Can you all help me understand this system? LMK what you need pics of. For example, where could that river have come from? Should the valve only be half-open? Why?
2) From other threads on this forum, it sounds like the bubbles are normal. If so, what is going on with the pool sweep and how do I fix that?

 

[mas985]

1) Wide view of the entire pad plumbing and the solar runs and panels.

2) The bubbles are only normal when priming the panels. After a few minutes, all the bubbles should be gone.

As for the cleaner, when you redirect all the water through the panels, the panels can reduce flow rates by quite a bit, especially DIY panels. The valve is there to fine tune the flow rate through the panels and keep the cleaner running. Also, redirecting all the water to the panels can create high pressures in the panels which may have forced them to leak. Back off on the valve is see if the cleaner runs.

 

[Kat-mac]

I watched more closely today and, there are still small occasional bubbles after even half an hour with the valve fully open. Will watch how sweep runs and what happens with bubbles with it partly closed.

Pictures attached.

 

[mas985]

I am not sure how big your pools is but I don't think those two small panels will be adding much heat. The amount of heat they can collect is directly proportional to the capture area of the panels which based upon the picture, is not very much.

Also the head loss in that type of configuration is going to be very high so you don't want to send much water to those panels. But because they are so small, they don't really need much water anyway. I would set the valve such that the filter pressure rise is no more than 4-5 PSI (off vs on). This should be sufficient flow to capture as much heat as possible.

Since you have a booster pump, that should run the cleaner no matter what the solar valve position may be. There is a small screen on the suction side of the booster that can get clogged so you might want to check that.