Sungrabber solar panel flow rate calculation

[mas985]

The reason I think it is high is because 20 PSI is about 49' of return head (adjusted for filter gauge height of 3') and if you assume another 5' of suction head, which is probably on the low side, results in 54' of total head loss. That pump puts out about 34 GPM @ 54' of head so the plumbing would be the equivalent of almost 800' of 1.5" pipe! To me it seems like a lot of head loss for such little flow rate. Also, the operating point is on the far left of the head curve which is far from optimum. If true, then there is something in the plumbing which is causing a lot of heat loss.

[TRHOD12]

20 PSI is really high for a 1 HP Superpump even with 1 1/2" plumbing. I would have expected much lower pressure. That is 50' of head for just the return side.

Are you sure the gauge is operating properly? Does it go to zero with the pump off?
Yes, the gauge is working. It goes to zero when pump is off, and I can see pressure changes when I back wash, turn on the solar panel lines, etc

Also, how long are the runs from pool to the equipment?

I'll try and give you my best guess estimate. The pool is 18X36. I have a skimmer line that I would say is 66-75', I have a wall drain I would say is 35'. My return line is a single line, and I would say it is 25-35'.

Anyway it sounds like the panels will not fully prime unless the bypass is closed so you may need to operate that way. You might try to slowly close the valve until you hear the panels starting to prime and air coming out of the returns. This would be the minimum required flow setting but it probably wouldn't hurt anything to have all the water going through the panels.

The panels DO prime. Actually, I have additional shut off valves going TO the solar panels, AND a shut off valve coming FROM the panels. When I open the shutoff valve TO the panels I can hear water moving thru the pipes and can see bubbles in the pool(air pushed out of panels before the water starts flowing), even before I turn the bypass valve on. So the panels are priming. As I start to turn the bypass valve, when I get it fully closed I will get a short bump in pressure from about 20-21 psi up to 25psi, the it rapidly returns to about 21-22psi.

Today we had a partly sunny day, and I saw a 4-5 degree raise in the pool temp. It seems to me that it is working, but is it working to its full potential.

One other side note that I can't figure out. When I start up the solar panels (open valves and flow water thru the panels) I have several glued joints that will leak. These are glued joints on the plumbing going TO the panels, and not the panels themselves) These are Drip leaks, not stream shooting leaks. When I go back out to the pool to shut the panels down at night, there are NO leaks and the concrete below the filter/pump, etc is dry.

Why would the plumbing leak upon startup, but stop leaking thru out the day as water, pressure, and heat are applied to these joints???? This one is blowing my mind. I would think the heat, pressure, and water would cause the leak to get worse. This has happend the last 2 days I have run the panels. (keep in mind these are the only 2 days I have had the panels installed to run them)

BLessings,

[mas985]

If the panels are only leaking when they are first turned on, then it could be the VRV. Sometimes they will let a bit of water through before shutting off. However, if you still see the water dripping after several hours of operation, then it is likely a very small leak somewhere. Just trace it back to it's origin to make sure.

As for priming the panels. After all the air as stopped coming out of the returns with the bypass open (i.e. bypassing water around the panels), if you then close the bypass, is there any more air that is forced out of the panels? If not, then they are probably fully priming even when the bypass is on. However, if you get more air out, then the panels may not be fully priming.

[TRHOD12]

The leak is NOT from the panels, it is from the plumbing (abs sch 40) glued fittings going TO the panels, but NOT the actual panels.

The glued fittings will leak when I start moving water thru the pipes, but as the day goes on, the leaks will stop. This doesn't make sense to me.

Why???

[mas985]

If the leak is small enough and the pipe heats up, it could be that it is expanding enough close off the leak. There is PVC epoxy that can be used on the outside to seal small leaks.

[TRHOD12]

Mark,

I'll look for that PCV epoxy.

Thanks for all your time on this and the other "winterizing solar panel" threads.


Blessings,