I don't know if this is a common knowledge or not, but it was news to me that solar panel placed on the pressure side of the pump can suck air in. But they for sure can.
My panels have been a bit nosy since I installed them 6 or so years ago - there was some quite gurgling and water rush heard thru them and some air in the returns (only when solar is on). I thought maybe vacuum breaker was to blame, but I didn't care too much about it.
Last year one panel developed a leak. It was coming from underside of the panel, so I couldn't see where exactly it was. It was very small, so I didn't bother with it. Two days ago I opened the pool and that leak was quite noticeably worse. I figured I will flip the panel, see where it is and fix it.
But then half a day later it disappeared. I thought maybe something plugged it. Later that day, I started hearing quite a low hissing from the same panel, but at the very top. Which later on I discovered was the same hole! But it switched form being a water leak to air suck. What changed? Filter pressure! Went from 10psi to 20psi.
When pressure was high enough, it was pushing water thru. When pressure dropped, it started sucking air in. The hole was right next where the pipe goes into the header. I'm not sure, but I think the speed difference between the water in the tube and in the header results in Bernoulli effect, that results in pressure drop in the tube to the point where it starts sucking air in.
Filter pressure got brought back to 10psi and started as a leak again, but now I knew the vicinity of it, so I located it and patched it. And now my panels are leak free and completely silent. If I put my ear against the header I could hear a nice laminar flow. Or at least no bubbles or rushing sounds. Very happy with it.
For reference, I have Aquasol panels and I successfully fixed 2 leaks in their 6 years. I cut a small piece of plastic from the panels, melt it with a lighter and let it drip on the leak. For this one, since it was in such an awkward, uneven spot, I just set piece of plastic of fire and stuck it against the place where the hole was and it seems like it worked at least for now. The first fix is holding on for 4 years now.
Speaking of pressure drop - I did not backwash my DE filter to bring the pressure down. My pool had some dead algae/old leaves very fine residue when I opened. It clouded the pool, but the chlorine drop didn't indicate it was live. But it clogged up the filter. The filter did it's job, the water is clear, the filter is clogged. But then overnight the pressure dropped back to normal. I think it happened to me in the past and it looked to me that high levels of chlorine ended up dissolving everything that was already dead and clogging the filter. Can this be the case?
I don't think I have a hole in my filter grids - when I had that in the past, I would end up with DE in my pool. Nothing of that sort happening.
As a bonus, here is a cool thermal pic of my panels filling with cold water.
My panels have been a bit nosy since I installed them 6 or so years ago - there was some quite gurgling and water rush heard thru them and some air in the returns (only when solar is on). I thought maybe vacuum breaker was to blame, but I didn't care too much about it.
Last year one panel developed a leak. It was coming from underside of the panel, so I couldn't see where exactly it was. It was very small, so I didn't bother with it. Two days ago I opened the pool and that leak was quite noticeably worse. I figured I will flip the panel, see where it is and fix it.
But then half a day later it disappeared. I thought maybe something plugged it. Later that day, I started hearing quite a low hissing from the same panel, but at the very top. Which later on I discovered was the same hole! But it switched form being a water leak to air suck. What changed? Filter pressure! Went from 10psi to 20psi.
When pressure was high enough, it was pushing water thru. When pressure dropped, it started sucking air in. The hole was right next where the pipe goes into the header. I'm not sure, but I think the speed difference between the water in the tube and in the header results in Bernoulli effect, that results in pressure drop in the tube to the point where it starts sucking air in.
Filter pressure got brought back to 10psi and started as a leak again, but now I knew the vicinity of it, so I located it and patched it. And now my panels are leak free and completely silent. If I put my ear against the header I could hear a nice laminar flow. Or at least no bubbles or rushing sounds. Very happy with it.
For reference, I have Aquasol panels and I successfully fixed 2 leaks in their 6 years. I cut a small piece of plastic from the panels, melt it with a lighter and let it drip on the leak. For this one, since it was in such an awkward, uneven spot, I just set piece of plastic of fire and stuck it against the place where the hole was and it seems like it worked at least for now. The first fix is holding on for 4 years now.
Speaking of pressure drop - I did not backwash my DE filter to bring the pressure down. My pool had some dead algae/old leaves very fine residue when I opened. It clouded the pool, but the chlorine drop didn't indicate it was live. But it clogged up the filter. The filter did it's job, the water is clear, the filter is clogged. But then overnight the pressure dropped back to normal. I think it happened to me in the past and it looked to me that high levels of chlorine ended up dissolving everything that was already dead and clogging the filter. Can this be the case?
I don't think I have a hole in my filter grids - when I had that in the past, I would end up with DE in my pool. Nothing of that sort happening.
As a bonus, here is a cool thermal pic of my panels filling with cold water.
