Solar panels on east and west sides of roof. Design advice

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rhaas12321

rhaas12321

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Jul 22, 2012
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Sunny Southern Oregon
Good afternoon!

I have 6 4*12 used Heliocol panels to mount on my garage roof, 3 facing west and 3 facing east. The north side also has a small pitched roof. Below that is the 8' wall.
I apologize in advance for my graphics skills, but I hope you can understand the layout. :confused:
I intend to run up the side of the garage, over to each cold inlet. Then join the 2 hot outlets at the center peak, down the north roof, then down the wall to the pool return, all with 2" sched 40 pvc.

You can see where the vacuum relief valve and winter drains are planned. All this is subject to the knowledgeable people on this forum. All thoughts are greatly appreciated!

Thank you,
Robert
 

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With proper routing on the pipes to make sure you don't have any low spots and with that layout, you should not need the winter drains.
 
Wow! Thanks Mark! I put those in as a double check. The thought was to close the isolation valves in the pump room, blow in one and out the other. We get regular freezes here in the winter.I'm not the best plumber and figured better safe than sorry. It won't create any problems will it?
 
No. Just not needed. We freeze too but my system doesn't have nor need any drains. Many solar systems are built this way. You just need to make sure they are self draining without the possibility of trapping water which isn't all that hard to do.

One other thing is that it takes nearly a full pipe of water before there is any chance of damage so as long as you can be sure the pipes are mostly self draining, there should not be any issue. But you are the one that needs to sleep at night.
 
Well hold on. I said drains were not needed as long as the plumbing was designed properly so there is a caveat.
 
The solar panels were up and working last summer! A noticeable increase in the pool temperature!

The only problem was I had to close 1 of the 2 returns (inter-connected, I used a winter plug) in order to keep the panels fully primed. With both open I get consistent bubbles out of the returns and "gurgling" in the solar piping.
I will say that the 1 hp Hayward pump has a constant drip between the pump and the wet end. I have replaced all of the seals twice with no improvement. There must be a crack in the housing that I can't see (53 year old eyes :eek:) The solar is all 2" and the underground is all 1.5". 1 skimmer and 1 bottom drain, separate valves.

So the plan for this year is to open the season with a new pump and I am leaning towards the Pentair Whisperflo WFE-3. I only have 110 volts at the pad, the pump will always rum on high speed as it appears to be necessary for the solar (and the wife wants a hot tub temperature) and electricity is relatively inexpensive. It seems to push a little more volume at my "guess" of 50' of head than my existing Hayward. Maybe I should go up to the WFE-4?
I would like to be able to open the other return so the water circulates better.

I have read and tried to understand Hydraulics 1001 (101 isn't nearly enough), played a bunch with Pool Pump Tools (thanks Mark!) and studied pump curves till I can't see straight.

I would really appreciate and comments or recommendations before I spend the money. I want to do it right the first time.

Thank you TFP!

Robert
 
Where is the vacuum release valve (VRV) located? Shown as PRV in the pic above?

Also, I am not aware of a Hayward Super Flo pump. Is it a MaxFlo or a SuperPump?

What is the filter pressure when solar is engaged?

Do you get air out of the returns when the solar valve is off as well?
 
Thanks Poodv, I will take a look at the vs pump!

Mark, yes it is a MaxFlo. I guess I shouldn't write after midnight.

Yes the VRV is as shown as the PRV above. I even tried sealing it in plastic and got the same results.

It surprised me when the pressure really didn't change with the solar on. I evem went to the hardware store and bought a new 0-60 psi gauge. It runs between 18 - 19 psi.

When the solar is off, I get no bubbles with 1 or both returns open.

Thank you!
 

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Then you may have leak in the system. The pressure is more than enough to keep the vrv closed. Are you bypassing any flow with solar on?
 
No bypass. Full flow with 1 return closed to stop the bubbles.

Not to distract, but why does increasing the back pressure (closing a return) fix it? It is the only way I could stop the bubbles. I assumed it "forced" the solar the fill up with more flow in than out.

Sent from my SAMSUNG-SM-N915A using Tapatalk
 
Also, there is a pinhole leak in 1 panel. I hate getting on the roof even with safety gear. I see moisture on a couple tubes down a couple feet before it evaporates. I can't see water but the panel "looks" wet.

Sent from my SAMSUNG-SM-N915A using Tapatalk
 
You say you used 2 inch plumbing for all of it, my guess is the siphon column on that 2 inch return line flows faster than the pump supplies water to the panel, so it is causing the VRV valve to open and let air in. Sort of the way an auto siphon works, for examples of auto siphons check youtube
 
Can you post a picture of the pad equipment and solar installation?

It could be there is a piece of plumbing that is causing quite a bit of head loss between the filter and the VRV. If the pressure is too low at the VRV, it will let air in and closing one of the returns will increase the pressure at the VRV and it closes.

Also, have you backwashed the filter recently? That is another reason that the VRV may not be closing.
 
20160220_120538.jpg90's at the top to the outside then 90's to the roof.

Thanks Isaac, that is really what I thought the problem was (something like it anyway)

The left vertical pipe goes directly underground and splits to 2 returns.
The middle is not used (obviously) but goes to a return in the pool.
The right pipe goes out to the roof plumbing, which is exactly as pictured in my drawing, except no drains :p

I deep cleaned the filter before the 2015 season and backwash regularly.

But it has the same issue if I cover the VRV with a plastic bag and Ziploc it tight. (surprised it didn't suck in or blow up like balloon)

Thank you again for your time. I really appreciate it!
 

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It looks like the 3 ball valves are set for bypassing solar completely. Shouldn't they all be 90 deg from the setting in the picture?
 
Has this system ever worked without having bubbles? If not, then my guess would be that check valve right after the filter. Those types of check valves tend to have very high head loss so will lose much of the pressure. Your pressure right now is pretty high for that pump which indicates a large amount of head loss somewhere in the plumbing and since you said the pressure does not change with engaging solar, it is likely something between the filter and solar.
 
The check valve is a swing valve, not a spring valve and I installed it for the solar. Do some swing valves have a lot of head loss?

With the solar disengaged (and also before the solar) there are no bubbles, with either 1 or both of the returns open, so no problems at all.

With the solar engaged and both returns open, I get bubbles. Plug 1 return and the bubbles stop. This is with, or without, the VRV capped.

Isaac's idea of the siphon effect make sense but hydraulics aren't even in the realm of my specialties. Maybe I need to divert some water directly to the return instead of 100% to the solar. I think I tried that last summer but I can't remember for sure. This also plays into the question of getting a pump with a higher curve. I am less concerned with electric costs and more with warming the pool which keeps my wife happy.

Again I appreciate all of your time. It is the most valuable commodity.

Robert
 

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