VRV on solar, adjustable?

[Dirk]

You said you had 8 panels but what is the area of each? 5 GPM would imply 12x4 panels? What is the panel tilt and the direction they are pointed?

I think they are 12.5' x 4'.
Panel tilt = This-much degrees.
Direction = Over-yonder.

Ha, ha, I don't know! The roof is what it is and the house sets how it sets!

But I'm hearing you. So many variables, but physics is physics and there are formulas to figure it all out. I just happened to approach it from the other end: can't change the angle or direction. Can't change the height above the pool. I maxed out available space of the roof. All I could really control was flow rate and runtime. Runtime is bracketed by SWG need and available sun. So really it just came down to flow rate. The $120 my Vis cost was cheaper than the time it would have taken me to learn any other way to get flow, so I went with the Vis. And I trusted Heliocol for the correct rate. I figured they'd know more about what their panels need than any other source.

So my pool gets as warm as it gets, which is some of the time warm enough! I've spent more time and effort learning from you and others here how to advise TFPers (none to well, as it turns out), than I ever spent learning what to do about my own system before I installed it. I'm convinced I've optimize my own system correctly, but it's clear that every install is unique, and needs its own unique optimizing MO.

 

[Dave95602]

Yes, its an Aqualink RS. It was set to prime for 3 minutes at 2850 rpm. I'm currently trying 5 minutes at 3000, which helps push surface debris towards the edge and into the trough (we don't have skimmers).

 

[Dirk]

Another related question - have you felt the need to increase your priming rpm to get all the air out of the array? My pump has been priming at 2850 rpm for 5 minutes, and kicking it up to 3000 seems to pull some more air from the array.

No, but I don't recall ever lowering it. My pump is still likely priming at 3500RPM.

But my panels sometimes fill well after the pump primes. So my pump will start for the day and prime, and then it can be an hour or two later that the solar controller calls for the solar heater for the first time that day. Before that happens, my pump is running at about 1550 (to satisfy my SWG). When the solar controller calls, the pump ramps up to 2210 while the solar valve is actuating. In other words, my pump will flush the air out of my panels at 2210. It might even lower, but I've never tried.

Then they stay full of water all day, so subsequent solar calls don't have to flush any air. Then, when the pump shuts off for the day, my panels drain.

 

[mas985]

With my controller and when solar is called for, it ramps up to priming speed for 3 minutes and then steps down to the solar speed setting. Mine is a fairly old controller (AquaLogic) and so I thought most controllers did this but perhaps they don't? It is a nice feature to have when running solar at lower speeds.

 

[Dirk]

With my controller and when solar is called for, it ramps up to priming speed for 3 minutes and then steps down to the solar speed setting.

At least I don't think mine does that. I'll have to check this summer, can't turn it on now to test it.