Solar Panel plumbing question

[piezon50]

One last thing. In looking at those 2 links, they both have diagrams showing the relief valve installed at the lower end of the panel header opposite the input side and the return line simply coming out the top end & down the roof line. My instructions from the manufacturer call for the relief valve to be installed on the top header opposite the return end and it also shows that the return line should come out & go up the roof and then back across the entire length of the top header and then down the side of the panels next to the input line.
Is either install acceptable??

 

[Isaac-1]

On the topic of the vacuum breaker valve there are arguments for both top and bottom mounting, they sometimes require a little positive pressure to seal, which you KNOW you will have at the bottom of a panel thanks to the weight of water, or you might have at the top. The instructions for the brand of panels I ended up buying says to first try it at the top and if you have leaks move it to the bottom. As to the return, in most installations it is just that, a return to the pad, so will need to run back to a point near where the feed lines originate, it therefore tends to make sense that they parallel each other.

Ike

 

[cramar]

....why oh why did I start reading this thread
I did alot of reading last summer trying to dial in my own solar set up, it can get to be a deep field of study.

 

[JasonLion]

Is either install acceptable??

Yes. There are minor pros and cons to each approach but they are both fine.

 

[piezon50]

Just installed my five 4x12's on the roof this morning in under 2 hours. With 2 people, it's a rather easy job provided your roof isn't too steep. Will finish up the plumbing tomorrow and it will then be time to sit back & wait for the sun to shine (once I check for leaks).

 

[bobby1017]

Jason, I noticed in your signature that you have 500 sq. ft. of solar panels for a 20K pool and I just bought 240 sq. ft. of panels for a 30K pool because that's all i could fit on my deck roof. My feeling is that I usually get my pool to 85 in July/August without any panels so having my water run thru 5 4x12's that are in full sun for 8-9 hours per day has to give me much better results plus enhance my temps in June & Sept. as well. Hope i'm not wrong in my thinking process because I now have the panels ready to be installed.

I have a 20 x 40 with 350 sq foot of helicol panels and as of this am the pool is 81 deg, more would be better for april and november, but may thru october they will keep the pool above 80 no problem. The exposure of mine are due south with 8 - 9 hrs of full sun.

 

[piezon50]

you're in CA so your outside temp is probably warmer than mine is in PA this time of year. Are you keeping your solar cover on at night to maintain the temp?

 

[piezon50]

Can those with solar panels please let me know what you experienced with your PSI after running the water thru the panels? Mine went from 20 to 27 & I'm wondering if that's normal as I have a lot of 90 degree elbows between the filter & the panels vs. only a handful between the filter & the pool. The force coming out of the returns is still pretty good although not as powerful as when I bypass the panels. Thanks

 

[linen]

That is typical.

Is the 20 your clean pressure?

 

[jblizzle]

I don't think I get quite that much pressure rise. But depends on how many panels you have and how much water you are forcing through them.

Posted from my Droid with Tapatalk ... sorry if my response is short

 

[piezon50]

I have 5 panels (4x12's) with 1 1/2" headers & pipes. Perhaps that causes a bit more pressure than 2" headers/pipes. My clean pressure used to be 15-18 but I noticed that this year it's now about 22-23 but, when the pump is off, the gauge still reads 5, rather than zero,i so I'm hoping it's still around 15-18 when you subtract the starting reading of 5.
Either way, the reading is about 5-7 psi higher when the water is flowing thru the panels which sounds logical.
Thanks for your feedback.

 

[jblizzle]

I get a 4 psi rise through 50 feet of 1.5" PVC before putting up to 2" pipe and headers.

There is no way to know if your gauge just has an offset. Best and cheap too replace it.

Posted from my Droid with Tapatalk ... sorry if my response is short

 

[bobby1017]

you're in CA so your outside temp is probably warmer than mine is in PA this time of year. Are you keeping your solar cover on at night to maintain the temp?

Yea the auto cover is closed most of the time which helps at night but does keep the sun out during the day, with low wind it would probably be better open during the day but I have no fence so the cover is my safety device. Daytime air temps are around mid 70's so far with night times in the high 30's - low 40's.

Can those with solar panels please let me know what you experienced with your PSI after running the water thru the panels? Mine went from 20 to 27 & I'm wondering if that's normal as I have a lot of 90 degree elbows between the filter & the panels vs. only a handful between the filter & the pool. The force coming out of the returns is still pretty good although not as powerful as when I bypass the panels. Thanks

I get approx 6 psi rise from solar off to solar on.

 

[Isaac-1]

Are you forcing all of your water flow through the panels, or do you have a bypass valve to allow only partial flow through the panels?

 

[piezon50]

So far, I have the bypass valve closed so 100% is going up to the panels. I assume if I divert "some" back to the pool, the psi would drop a bit?

This question is for Bobby from CA. What was your water temp at the beginning of the season & how long did it take to get the temp to 81?? Thanks

 

[Isaac-1]

My guess is then your trying to force way too much water through the panels which is causing your pressure to spike. For most 4x8 to 4x12 panels optimal flow rate is around 5 gpm per panel, depending on amount of head restrictions a 1.5 HP pump should be able to flow up to about 120 gpm with no head, and somewhere in the 50-80 gpm range with reasonable head restriction.

You may want to read this page about overpressure in solar panels http://h2otsun.com/vahe.html

Ike

 

[bobby1017]

So far, I have the bypass valve closed so 100% is going up to the panels. I assume if I divert "some" back to the pool, the psi would drop a bit?

This question is for Bobby from CA. What was your water temp at the beginning of the season & how long did it take to get the temp to 81?? Thanks

The low was 49 deg back in January, but it was about 60 in late feburary when I turned my solar back on, by mid March it was 72 deg but then it was stuck in the low 70's untill April 8 when it reached 74. It finally made it over 80 on approx April 18th and peaked at 84 on April 21st. Last week had four days with windy 60 deg temps so dropped back to 79 on 4-26, but back to 82 deg yesterday afternoon. Hot week ahead here so it will be at 85, which is the max I want, by mid week.

I usually get about 4 deg increase per day but then loose about 2 1/2 / 3 deg at night so there is a little over 1 degree net gain on sunny days.

 

[piezon50]

Just changed out my pressure gauge and my psi with the solar off was 18 and went to 24 with the solar on @ 100%. I have a Kreepy Krauly pool cleaner that runs off the pool pump and thru the skimmer and, to my surprise, it's working just as well with the solar on as it does with the solar off. So, it looks like I should be good to go with my new solar system install.

 

[piezon50]

Re: Solar Panel update

Ok. So I just completed my 2nd full day of running the water thru my new solar panels. My water temp yesterday morning before i started was 60 and, after 8 hours, it was 64 without my blue solar cover on (the outside air temp hit 65 for a high). Put the solar cover on last night as the overnight temps dropped into the upper 40's here in PA. The water temp dropped to 62 overnight but I just looked after running the filter for 8 hours on day 2 and it was up to 67 with the solar cover on all day. The air temp got to 72 today with total sunshine. I'm thinking this is pretty good considering I only have five 4x12 panels due to space even though the calculations called for 8 panels. The next few days are supposed to be just like today so I'm now wondering if I'd be better off taking the solar cover off during the day so the suns rays can penetrate the water & assist the solar panels or is the vast majority of the temperature rise coming from the panels?
Hope to be swimming on the weekend in 75 plus water.

Any input would be appreicated. Thanks.

 

[linen]

When trying to raise the average temperature of my pool, I take my solar cover off during days when there is very little wind and the ambient temperature is a few degrees higher than the pool.