Plumbing solar heat panels?

[J4S0N]

Hi everyone! Couple of questions around plumping a solar heat kit we got with our new pool kit.

The kit came with this diverter:

https://www.amazon.com/Smartpool-SK35-Replacement-SunHeater-Aboveground/dp/B00C4063TQ/

The instructions call for the two tee's to be connected with the valve in the middle. So the pipes running to the solar collectors would always be open, just a the bypass would be open to closed.



I will be mounting the panels on the roof, I'm guessing there shouldn't be much issue, but this seems different than what i see others doing on here. Any concerns here?

Assuming that's an ok way to control it, I'd like to think towards the future when I might want to automate this and add an actuator. I worried this valve won't be able to be automated (but I have no idea).

Should I switch it out for something now (if so, what?) or would this work with some type of actuator/automation?

Since all my other plumping is 1-1/2" I plan to just run the same size sch40 PVC from my pump area under ground to a barn about 35-40 feet away. the barn is a few feet down hill where I can add a drain to each side. I plan to just put two ball valves on a 90. Will that cause any issues pumping up to the roof?

I assumed I should pump the water in from the bottom of the bypass, something like this:



Or could I simplify this by pumping in from the top plump the panels to the bottom of the bypass?

I'm considering using flexible PVC tubing from the ground up to the panels on the roof (and connections to/from pool).

Would this work? Or so should I stick with rigid PVC? Is there other flex PVC I should consider?
https://www.amazon.com/gp/product/B01CB65924/

Look forward to hearing your feedback! and thanks for any advice you can share!!

 

[jblizzle]

Re: Plumbing solar heat panels?

You can't automate that type of valve. You would need to use pool valves, like the Jandy Neverlube or Pentair, so that an actuator could be mounted to them.

For that matter, I would not recommend the use of any PVC ball valves as they get stiff and break eventually.

I used a little bit of flex PVC on my roof and the AZ sun did a real number on it to the point I had to switch it out after it started leaking and just used rigid.

I am not really a fan of the way they are suggesting you plumb the solar. I would suggest something more like shown here: Plumbing and Controlling Solar Swimming Pool Heating Systems

Although even that is overly complex. I do not have any of there ball valves and I do not have a bypass, but that is because I want all the flow to go to the roof through the solar 3-way. If I did not, I could just not turn the 3-way all the way and it would allow some to bypass.

 

[Dirk]

Re: Plumbing solar heat panels?

I can answer some of those.

You shouldn't use ball valves anywhere. They freeze and leak. You'll be replacing them. This is the better way to plumb your drains:



A little hard to make out. Brass hose bibs into reducers into your pipes (or tees). They're more easily replaceable should they fail, and they'll last longer than a PVC valve.

While technically a bypass, that valve in your schematic is functioning more like a throttle. It isn't used to engage the solar system, but rather to allow some amount of water to bypass it. Used to tune a solar system that is being fed with a non-variable speed pump. Turning it on and off will not turn your solar system on and off. You'd need two more ball valves for it to work that way. And you're right, you can't actuate a PVC ball valve.

Forget all that. Scrap that valve and put in a proper three-way drain-down solar valve, and get the actuator now, along with a proper solar controller. You'll be doing so in a week or a month, just do it now. Going out to your pad each day, several times, to manually control your solar system, checking pool temp for when to turn it off, and air temp for when to turn it on, etc... uh uh.

Do it right. Do it once. Get this or something similar. Has everything you need, except the check valve, which you'll find lower on that same page in the "Frequently Bought Together" section. Set it and forget it. It'll even turn your solar system on and off on a partially cloudy day, dozens of times if it has to. You gunna do that? Or how many times will you forget and leave your system on all night to wake to a 65° pool!?

https://www.amazon.com/Pentair-Water-521592-System-Swimming/dp/B00E4QARU4/ref=asc_df_B00E4QARU4/?tag=hyprod-20&linkCode=df0&hvadid=167126811300&hvpos=1o1&hvnetw=g&hvrand=11000571809081797417&hvpone=&hvptwo=&hvqmt=&hvdev=c&hvdvcmdl=&hvlocint=&hvlocphy=9031745&hvtargid=pla-311235041184&psc=1

Your roof needs to be able to support the load of the water in your system. For most modern construction, that is a non-issue. For an old barn or shed... something to consider.

There might also be something to consider about the size of the pipe running that distance. I don't know enough about hydraulics to advise. Someone else here might. They might weigh in about the flex pipe too.

You'll also need a vacuum breaker, so your panels can drain each day when they're done producing.

I learned how to install my system from the google machine. This site was especially helpful. It's illustrations and animations helped me understand what to do, and how to plumb everything, and how it all works:

Plumbing and Controlling Solar Swimming Pool Heating Systems

Hint: Look for the part about how to tilt your panel array.

You can kinda make out how I did my pad setup from the photo above, too. I ran mine underground like you're planning to.

If you ignore my advice about putting in the controller now, at the very least run a four-conductor direct-burial wire underground along with the pipes you'll bury, with enough slack to reach your pad and your panels. You'll thank me later!

- - - Updated - - -

Dang it Jason, you stole my entire post!!! Right down to the link!!

Err, what I meant to say...

Yay! Great minds think alike!

(I gotta learn how to type faster!!)

 

[jblizzle]

Re: Plumbing solar heat panels?

You post is way better, mine is really a series of random thoughts

I was about to post the Solar Touch that included the valve and actuator ... and I see you have done it already

 

[Dirk]

Re: Plumbing solar heat panels?

Funny that we both ended up at that same website, at some point in our solar installation adventures. I like their animations.

 

[Dirk]

Re: Plumbing solar heat panels?

To the other J4SON (the OP), I've never used the SolarTouch I linked to. My solar system is controlled by my Pentair ET automation system. Which also controls my variable speed pump, etc. For solar, it's awesome.

Point was: do your research. Download the manual of whatever you might end up buying, to make sure it is compatible with your pump and your expectations. Maybe call Pentair to confirm if you're thinking of going with the SolarTouch.

Or if a full automation system is in your near future, then you wouldn't need a dedicated solar control like the SolarTouch. Just giving you things to consider before you plunk down any dough.

 

[J4S0N]

Re: Plumbing solar heat panels?

Thank you for the replies! Not going to lie... I'm a bit overwhelmed trying to plan all of this.

It looks like the actuator is 2", I'm assuming it's better to just run 2" underground as well. would it be ok to drop back to 1-1/2 from the ground to the roof?

I'm still thinking about using the flex pipe, unless someone tells me it's a horrible idea...

I've seen the h20tsun website referenced a lot and have read through it. They appear to be using vertical panels, where mine are horizontal. Does it make much difference?

Based on what I'm reading here, I should plump it like the link, minus the bypass and ball valves. (so the only valve in the system is the actuator). Does that sound right?

 

[Dirk]

Re: Plumbing solar heat panels?

My system is plumbed with one actuated 3-way solar drain-down valve* and one check valve. No PVC ball valves, no bypass valves. But I can control the amount of water going through the panels by adjusting the RPMs of my variable speed pump. Is your pump variable or one or two speed? If not variable, you might need a bypass valve to limit the amount of water running through the panels. They'll have a GPM specification that should be met to achieve the best, most efficient heat exchange (best heating capability). The manufacturer of the panels should supply the correct GPM flow rate. I dialed in the perfect GPM for my panels by using a FlowVis flow meter. If that is not in your budget, there are other ways to determine good flow for your panels (I just don't know what those are). A FlowVis flow meter doubles as a check valve (and you'll use at least one for your solar plumbing). So you could buy a FlowVis instead of the check valve. It's a bit overkill, but I've gotten good value out of mine, not only to fine tune my solar system, but for other things, too. Some here can do the math to figure out flow rate. Others feel the temperature of the panels, or the heated water, or both, to determine if the panels are getting good flow. My system was $3K, I figured for an extra $100, a FlowVis would assure me I'm using that $3K system to its fullest potential.

* You really should use the appropriate drain-down valve, specifically designed for solar installations. Be sure you understand what that is and buy the correct one.

The header manifolds on my panels are 1.5". I ran 2" pipe all the way to and from the panels, I didn't convert to 1.5" until the connection to the panels. If you're going to run 2", then you might as well maintain 2" all the way to the panels. I found the correct pipe size spec in my panel manufacturer's install instructions. Had to do with the number of panels connected together.

I found and used UV resistant black PVC pipe for my PVC running up to the roof. It makes for a cleaner look on my house. Painting "regular" PVC, to give it some UV protection, is always a good idea, especially on a roof, but it is usually a losing proposition, as it will tend to peel off in the hot sun. I did a great deal of research about the correct and best way to color or paint PVC. I was about to use a special MEK die I found, which would in essence melt its way into the PVC material (no peeling), but then found the black PVC and used that. It wasn't cheap. About $3 a foot, if I recall. So I just used that above ground. Do it right. Do it once, I say. I've read others just use white, unpainted PVC and take their chances. The theory being: 2" PVC is so thick that it'll do fine in the sun, and just leave it white, which will not look as nice at first, but will end up looking better than peeling PVC. I didn't go that route, so can't speak to how well that MO works. Others just paint it black and deal with that. Sanding the PVC first to give the paint something to grab might help. But, for me, sanding all that PVC, and then painting it with a couple coats made that $3 a foot a lot more affordable!

A poster above warned you about using flex (post #2).

I don't know much about mounting horizontal panels. I'd say follow the manufacturer's instructions for mounting. I took a lot of care in mounting my panels so that they would drain empty correctly and fill and flow correctly. The h20tsun site describes why this is important (and that's where I learned it). I would think having horizontal panels would increase the challenge of draining and filling correctly, but there must be a best way, so look for info about that. Call the panel manufacturer for advice if need be. They'd know.

Speaking of which: solar panels, and to some extent the PVC, on the roof will expand and contract, a good amount. Your mounting method should accommodate that. Nothing should be affixed to the roof in a way that doesn't allow for some movement. My Heliocol panels have a great mounting solution for that, which also accommodates the wind load stress panels must endure. Your panels' manufacturer hopefully has addressed those two issues with their hardware. Something to look out for. I also took great effort to make sure no part of my panels actually touch the roof. My roof is rough, concrete tiles, that would eventually saw their way through my panels if they were touching, because of the expansion/contraction movement. Something else to watch out for.

Don't forget to run that wire in the trench, between pad and panels. You'll need it for the temperature sender by the panels should you ever decide to use a controller or automation.

Take a few pictures of your pipes in the trench before you backfill. Never know when you might need to remember where they are.

Yes, it can be overwhelming, but the good news is: it's pretty much all re-doable if you get it wrong. Just cut and reglue! Leave yourself plenty of space between fittings to do just that. Try not to jam fittings and valves right up close to each other. Leave yourself a few inches of PVC, at least, between every component, so that if you have to cut things apart, you can, and glue them back together with PVC couplers. This is good practice with any PVC plumbing installation, if you have the room.

Good luck.

 

[pooldv]

Re: Plumbing solar heat panels?

Ive used the Solartouch for 6ish years and it is great. There are pics of my plumbing, etc in my pool thread, link in sig.

 

[Dirk]

Re: Plumbing solar heat panels?

Ive used the Solartouch for 6ish years and it is great. There are pics of my plumbing, etc in my pool thread, link in sig.

Does it run the pump? Can it control a VS pump and vary the RPMs when solar is on/off? Can it be used to cool a pool at night?

 

[J4S0N]

Re: Plumbing solar heat panels?

I think I'm going to bite the bullet and get the Pentair 521592 Solar System and rethinking where I'm going to put my pump. I think it might be easier to put the pump/filter next to the barn and run two 2" pipes underground to the pool about 35-40' away. I assume something like this could work, blue lines are 1-1/2" pipe, grey is 2":



All the connection in our setup are 1-1/2, will switching between pipe sizes cause many issues? Will the 1.5HP pump be able to handle this? Or would it be better to have the pump closer to the pool since it will be running more than the panels?

Should I add anything else?

 

[pooldv]

Re: Plumbing solar heat panels?

Does it run the pump? Can it control a VS pump and vary the RPMs when solar is on/off? Can it be used to cool a pool at night?

Yes, to all of the above. It does solar heat and solar cool. It is connected to my Intelliflo. The Intelliflo is wired to the breaker and turns on from its own internal timer to 1200 rpm. When solar heat (or cool) is available the Solartouch ramps the Intelliflo to External Control speed 2 and opens the solar valve. When solar turns off it closes the solar valve and reverts back to 1200 rpm.

All the connection in our setup are 1-1/2, will switching between pipe sizes cause many issues? Will the 1.5HP pump be able to handle this? Or would it be better to have the pump closer to the pool since it will be running more than the panels?*

Should I add anything else?

No issue switching pipe sizes
Yes, the pump is plenty.
Doesn't matter where the pump is, moving water horizontally doesn't impact flow rate much at all.

 

[Dirk]

Do you have a frost line where you live? Would you want to blow out the underground pipes come winter, but still run your pump and filter? Or would you winterize the whole plumbing system at the same time?

Put the pump where it makes the most sense for aesthetics, noise, the off season, etc. Where you would place it were there no solar. If that's before the 35' run underground, and closer to the pool, I'd do that. No sense pumping that extra 70', when the solar is not engaged, if you don't have to. As Pooldv points out, flow efficiency won't be affected based on pump location. But heat efficiency might be. By that I mean: picture a day where solar is kicking on and off due to air temp or partial clouds. It heats the pool for a while, then a cloud passes over and your panels get bypassed. You wouldn't want to continue to circulate the pool water through that extra 70' underground, which would just serve to cool the water down. But if it looks or sounds better to have your pad farther away from the pool, then the solar efficiency hit might be worth it.

Not sure how well I described that...

 

[J4S0N]

Thanks for the replies. We are in Ohio, so the I need to set this up to be easily winterized. The pool is a few feet up in evaluation from the barn so I'm planning to add drainable tees at the lowest point. While the 2" pipe will be underground 95% of the run to the pool I should be able to have a few inches near the pump to drain both pipes.

Is there a better solution then just slapping hose nozzle adapters on a tee for drainage? or would threaded caps be better?

 

[Dirk]

Well, hose bibs would be more convenient, for sure. Threaded caps would have to be tightened well, and you'd need to use teflon tape, and reuse tape each time, after removing the scrunched up tape each time. Probably need some channel locks. Not sure what advantage threaded caps would be... They'd probably be prone to leaking.

I see hose bibs plumbed in pad setups all the time, in pictures posted here. I think they're used to drain the pool? Threaded caps, not so much (actually, never, that I recall). Pretty sure hose bibs are the preferred thing to use.