Poor return flow from new solar panel header

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whitedog4

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LifeTime Supporter
May 1, 2013
22
Lansing, MI
Well, it's finally done but I'm having an issue I can't seem to find an answer to. Pool fill was Sunday, 5/26, and plumbing was completed Monday, 5/27. With 20' of 1.5" PVC and 30+ glue joints, I had only one leak at a threaded teflon junction right at the pump outlet. This was fixed today along with install of a union fitting. My issue is that the solar panel return seems poor compared to the supply. There is no recognizable PSI difference when panel is engaged - the guage (brand new pump/filter) does react when I momentarily cut off the supply altogether. I thought that repairing the leak would boost the solar return but it didn't. The return does react slightly when the panel is disengaged/re-engaged and it did take some time when initially turned on for water to appear in the return (I used clear tubing). The panel supply tubing swells impressively, but no such luck for the return.
I plumbed the supply on the bottom, return on the top - was this incorrect? Should it be reversed?
The panel runs ever so slightly 'downhill' from the pool - perhaps 3" for every 12'. (the pad needed leveling) Do I need to raise the end of the pool rack to assist the pump?
The pressure going into the pool itself is impressive, especially compared to the previous 530gph wimpy pump.
Is there a baffle in-between the two sections of panel, in either or both ends of the panel? Should it be removed? Don't wanna blow up the panels!

Please help. Pics attached. In pic PanelReturn you can see the tube about 1/2 way filled, quite unliike the supply.

We've had a lot of rain the last few days and I was advised to start Dichlor ASAP. With leak fixed I did, after verifying PH of 7.8 and Chlorine of 0.5. Water looks cloudy and a bit green. Temp 58F, measured at the supply outlet. Added 3.5oz. of Dichlor, pump running.
 

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Sorry I have to ask but in the picture, the solar valve is in the wrong position to get flow through the panels. That is bypass mode. The handle should be opposite of the cross pipe to get flow. Also, are you sure the check valve is in the correct direction?
 
It looks like the handle for the diverter is pointed back towards the pump. Also most solar panel require opposite corner flow, unless they header had a blocking valve in the middle (don't see one) that allows same side connection like you show.


have to run now
Ike
 
Ike - the panel instructions call for same side supply/return unless multiple panels are being used.
Mark - you are correct that the pic shows the panel off (bypass mode). When I swing it 90 degrees counterclockwise so that the handle is in-line with the cross pipe that leads to the tee, the panel return reacts, but only slightly. If I swing it another 90 degrees counterclockwise (180 opposite of pic), it kills the return (in the pool) altogether. I cannot turn the handle anymore clockwise than its pictured position, putting the handle opposite of the cross pipe that leads to the tee. I'm thinking that I need to pop the pins on the top of the Pentair 3 Way in order to properly pressurize the panels (?). If that's the case I feel like a tremendous idiot.
The check valve is in between the solar return and the tee, with the flow arrow pointed towards the tee so when killing the panels they aren't pressurized with back flow (recommended placement by Jason).
 
Turning the handle opposite of the cross pipe is exactly what you need to do. Turning it aligned with the cross pipe allows flow in both directions. And since water takes the path of least resistance, no go! :(
 
I am not sure how your valve is configured, but most 3 way valves come from the factory set up to allow input on the base of the T and output allowed to either side, not in one side and out the base or the other side. That brand panels are these?

Ike
 
I will pop the pins, swing that sucker around slowly, and post results when I get home in a few hours. I've never done this before. I was soooo close! Next payday this site is getting another supporter. I never would've gotten this far without you all. Thank you.
Now, that Pentair better co-operate with its pins pulled! :?
 
With only one panel you probably don't want to send 100% of the water through the panel. The ideal setting is going to be with the valve fairly close to the 100% to the panel position, but not all the way there.
 
Ike -I will be sorely disappointed if that valve doesn't swing around as multiple designs I looked at (this one I posted here for pre-build opinions) reflect the configuration I built. The panels are literally a no-name brand I got off Ebay for $90 delivered.
If the valve doesn't swing with set pins popped, I'm looking at a re-build, which would be a real bummer. I spent the whole long weekend on this. In the rain.
 

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With the pins removed you should be able to swing the handle so it points to the top of the T allowing full flow to solar, but will not allow you to blend partial flow. Is there a blockage in the header that forces water to the far end then back for same end return? If not you will just get flow in one end of the header and back out the other with little or no heating.

Ike
 
Ike - I ordered one (1) 2'x20' panel and got four (4) 6"x20' sections that are paired in between the header and the end (pipe). As you can see in the header pic, there's a connnection that joins the two pairs of 6" panels together. There must be some blocker in there to force the water down to the far end, as it took a good 10 minutes for water to appear in the same-end return once the panel was engaged (albeit not at 100%). The instructions are all based upon pump HP. Anything above .5 they call for a diverter kit to shunt the flow. I have a .5, but wanted to isolate the panels so they don't radiate and to customize pressure/flow/temp. The only time the instructions call for different ends for supply/return is when 3 or more panels are being used with a pump = or < .5HP. All other variations call for same-end supply/return with no mention of addition or removal of a baffle. Now, these instructions were not written in this country... I'll put it that way.
 
Possible.. but if there were no blocker/baffle in there, why would it have taken so long to prime? I would imagine that if there were no blocker, I would have seen water in the return on top within seconds. I didn't - it took awhile...
 
As Jason said, you likely do not need to force all the water through the panels as that will lower your flow rate (as you found). If you put the off on the valve handle between the 2 outputs you can get some mix of flow, but this also causes a blockage in both outlets ... that is why it is always best to have the "common" pipe in the middle port of the valve.
 
As a newbie, I sure wish that suggestion had been made prior to the build. But, I may have enough room to replumb it if I really want to and when I fiddled with the valve with one hand and had the other in the pool over the return, I could feel the slightly lower flow water (partial solar on) was much warmer than the highest flow (solar off), even after the sun had been off of the panels for an hour. It's a small pool and if I can achieve what I'm after with the way it is, so be it.
 
The most heat transfer happens when the flow is high enough that the water coming out of the panels is just barely warmer than the pool water. Which may be against common sense, but is the truth, as your goal is not to make a small amount of water very hot, it is to make a lot of water a little warmer.
 
As Isaac said, the highest efficiency would be to force all the water through the panels, but that is bad for the panels if they become too pressurized ... thus likely the need to bypass some of the water.

As long as the panel feels cool to the touch, you should have enough flow through it.
 

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