Added more solar panels and now the return flow is too low

pennywise

Member
Jun 26, 2009
23
Derry, ME
I added two more sungrabber solar panels to my semi-inground pool (with 1/2 HP self-priming superpump) and now the pressure in the filter is too high and the return flow is way too low. The directions for the panels says to add a tee and a valve to direct some of the flow away from the panels and back to the pool. But won't this reduce the heating affect of the panels? Is my only other option to buy a bigger pump? If so- how do I determine which one is right (3/4 hp, 1hp,...etc?)?
Thanks for the advise in advance...I should have just bought a propane heater!
 

PSW

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Feb 13, 2012
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Phoenix, AZ
Re: Added more solar panels and now the return flow is too l

Hello and welcome to TFP! :wave:

pennywise said:
The directions for the panels says to add a tee and a valve to direct some of the flow away from the panels and back to the pool. But won't this reduce the heating affect of the panels?
Yes, this will reduce the heating effect, but more importantly..it will help the flow of your system.

pennywise said:
Is my only other option to buy a bigger pump? If so- how do I determine which one is right (3/4 hp, 1hp,...etc?)?
Thanks for the advise in advance...I should have just bought a propane heater!
Yes, a new pump might solve your problem, but it is impossible to determine the best size for you. Can you please share more information about your pool and equipment? Adding this information to your signature box (in User Control Panel) will be helpful for future posts. The more information you give us, the better.
 

pennywise

Member
Jun 26, 2009
23
Derry, ME
Re: Added more solar panels and now the return flow is too l

Thanks. I have a 15x30 AGP with a Hayward EC50 DE filter and a 1/2HP super pump with 4- 2x20 solar panels mounted on the ground next to the pool (but a bit up hill from the pool). How can I determine what pump I need to get to increase flow? Would Hayward approve of outfitting my system with a bigger pump?
 

jblizzle

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May 19, 2010
43,260
Tucson, AZ
Re: Added more solar panels and now the return flow is too l

I find it surprising that you the pressure went up and the flow dropped so dramatically with a relatively small solar array on the ground (Someone here has a 1/2HP pump running solar on a 2 story house). How did you plumb the new panels together (add a picture?)? If you put them in series, then your results would be expected. But, if you put them in parallel, I would not expect you to have problems.
 

JasonLion

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May 7, 2007
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Silver Spring, MD
Re: Added more solar panels and now the return flow is too l

I suspect jblizzle has the answer. The panels need to be plumbed in parallel.
 

pennywise

Member
Jun 26, 2009
23
Derry, ME
Re: Added more solar panels and now the return flow is too l

They are in series. The directions that came with it definitely indicates they should be in series. Certainly re-arranging them in parallel will drop the pressure and increase the flow but I assume the manufacturer specifies series to maximize the amount of time the water is in contact with the panel?
 

jblizzle

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May 19, 2010
43,260
Tucson, AZ
Re: Added more solar panels and now the return flow is too l

Solar efficiency is higher as the flow rate goes up ... NOT the amount of time the water is in the panels. Seems odd to me that they would recommend series as it does not make sense for multiple reasons.

Many panels are only 10' long and your are 20' long so the water will be in the panels longer than many setups already. Do the ones you have flow down and back or just 1 direction?

In either case I would put them in parallel as almost all other manufacturers recommend.
 

pennywise

Member
Jun 26, 2009
23
Derry, ME
Re: Added more solar panels and now the return flow is too l

Seems reasonable to me that the flow rate is more important than contact time. I'm going to be contacting the manufacturer to find out why they recommend series. The ones I have are laid out in a 4-panel grid where the top panel flows to the right and then is connected to the next panel (which is below the first panel) and then the second panel flows to the left, and so on until the output of the forth panel returns to the pool.
 

jblizzle

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May 19, 2010
43,260
Tucson, AZ
Re: Added more solar panels and now the return flow is too l

The best option for you would be to connect all the panel headers on the Left and supply the water there. Then all the panels flow to the right. And then connect all the panel headers on the right and go back to the pool there. (EDIT: NOTE you should feed the bank and return from the bank to the pool at opposite corners so that the water always has to travel the same distance)

That puts all 4 in parallel. The other option is to leave your original 2 in series and then duplicate that setup with the new ones (also in series with each other) but have the new pair in parallel with the original pair.

Really the first option would be best and give you the highest flow rate and thus solar efficiency.
 

pennywise

Member
Jun 26, 2009
23
Derry, ME
Re: Added more solar panels and now the return flow is too l

That sounds a lot cheaper than buying a more powerful pump! Thanks for the suggestions. I think I'll go with all four in parallel. I just don't get why the directions doesn't say to do it that way. I can't wait for some sunny days to see how it all works!
 

linen

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Jul 30, 2010
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Twin Cities, MN
Re: Added more solar panels and now the return flow is too l

Your sungrabbers might have a disk in the middle of the inlet manifold that allows each panel an out and back flow...not a good way to run them IMO. Are yours marked inlet and outlet on one end (one manifold)? I have some that are marked and all 4 of those had the disks. I have two that were unmarked and they had the disks as well. I removed the disks from all of mine and have run them in some variation of parallel connection. Post your model number and we might be able to help with the disk question. The easiest way to know you have the disk is to look down the inside of the manifold.
 

pennywise

Member
Jun 26, 2009
23
Derry, ME
Re: Added more solar panels and now the return flow is too l

They are not marked inlet and outlet but I'll check to see if they have the disks you are referring to.
I see that you are in Minn. May I ask how much of a temp increase you get on a daily basis (since I too have 4 2x20 panels now)?