Aloha all, I have a few odd problems with my DIY setup as described below: I am using a 1/8 hp pool pump for my 7800 gallon pool so I get very little or no pressure on the filter gauge, so it is hard to figure out how much water to divert to the solar heater. If I adjust much under 4 gpm I seem to get a lot of air burps every 10 seconds or so. I think it is that air is sucking back from the 2" return line to the pool. Am I asking too much from a 1/8 hp pump? The flow is really good going 8' up to the "panels" on the roof. (actually no degradation in water volume). It was sunny for 1/3 and overcast for 2/3 of today and the water was running at 6gpm to the panels (and 6gpm to the pool from filter) ranging from +1 degrees to +4 degrees depending if the sun was out. I raised the pool 3 degrees. Pool is covered with a white tarp roof and the most the ambient daily heat raised the temp before was 1-2 degrees, so I feel the heater boosted the temp by a solid 1 degree.
I put a valve on the return line to throttle down the flow a bit and it seems to help the water/air burps.
I am going to install an air relief port on both of the 2" headers (and elevate the headers on that end by an inch or so) as I think maybe air is getting trapped and the pump does not have enough "push" to expel the air. And some of the 33 tubes are hotter than others. Maybe some are running dry?
Anyone here had experience with this tuning phase?
Here is the heater setup
1: used 2 x 2" headers and 33 1/2" x 45' tubes
2: NO LEAKS !!!
3: I used a hole saw and drill press to drill out the 66 holes
4: Used a 1/2"x1/2" joiner coupling that I turned down on my lathe to tightly fit the 66 holes made above
5: Bought irrigation 1/2" compression fittings that glued into the couplings @ .22 each
Total cost about $150.00 parts
Labor intensive and probably not as good as the Ebay panels (2 x 4x20' ones are coming tomorrow so will be able to A/B test the effeciency. So better idea to buy store bought panels unless $ is a real issue.
I can adjust from 6gpm @ 2 degrees to 2gpm @ 6 degrees.