Solar Panel Installation *PIC*

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el_steak

el_steak

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LifeTime Supporter
Aug 15, 2007
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Ottawa, Canada
Finally got around to completing my solar panel installation. Everything went smoothly, although working 30 feet high on a 12/12 roof was a bit scarier than I expected...

The panels are 4' x 12' (Technosolis brand). All the piping is PVC and was painted black on the roof and brown on the walls using Krylon Fusion PVC paint.

We were 2 guys and we had appropriate scaffolding and used ladders to "walk" on the roof. It took us about 4 hours to install the 4 panels. A nice fun project if you are a DIYer and do your homework before the installation.

I completed the installation last week and we only got 1 real nice hot and sunny day. The water went from 64 to 74 on that day. Unfortunately its been cold and cloudy since then so we lost it all.

Here are the pics:

panel1.jpg



panel2.jpg
 
Nice work, neat, tiddy and I like the paint job too but doesn't the vacuum break usually go at the top of the panels instead of the bottom?
 
Nice job!

Our vacuum break is also on the bottom. I believe it may help keep the system going as the filter's pressure increases from dirt. When I hear a noise from the vacuum break, it is time to backwash the filter.
 
mas985 said:
Nice work, neat, tiddy and I like the paint job too but doesn't the vacuum break usually go at the top of the panels instead of the bottom?
Click to expand...

Thanks.

I also thought the vacuum break would go on top, but it appears that the recommended spot is on the bottom of the panels, on the opposite end of the input.

We discussed it here: http://www.troublefreepool.com/viewtopic.php?t=4859
 
Maybe I'm missing something but from what I read of that post, most are recommeding the highest point of the panels which would be logical so I'm not sure where you got that it should be on the bottom.

The problem with putting it at the bottom of the panels that that you run the risk of a vacuum lock in the panels and they won't drain completely when the pump is shut off. You need an air release at the top of panels so the water will run out.
 
A number of sources, including PowerMat, put the vacuum breaker at a local high point, not at the very top. My understanding is that the tilt of the pipes is the crucial issue, so air and/or water doesn't get trapped anywhere, not the specific location of the vacuum breaker.
 
Powermat does show that location for the vacumm break and I'm sure that it will probably work but IMHO, I would avoid it and here is why.

When the pump is shut off, the water will pull downwards with the full weight of the water in the pipes on both sides of the panels. Because the break is at the bottom of the panels, the water needs to be pulled backwards up the panels (as shown in the Powermat animation) to drain creating a local vacuum in the small tubing of the panels. This puts stress on the tubing and if the panels are hot and depending on the panel material, the tubing can collapse. For a steep roof, the vacuum is more so to avoid problems and if I had the choice, I would try and put the vacuum release on the top. I can't see any benefit in putting it at the bottom so why do it?
 
mas985 said:
Maybe I'm missing something but from what I read of that post, most are recommeding the highest point of the panels which would be logical so I'm not sure where you got that it should be on the bottom.
Click to expand...

There's a few different opinions in the thread.

1 person says all the way up (JohnT), 2 say on the opposite end of the input (JasonLion and JoenJ) and 2 others have the air relief even lower (Dschlic1 and TPhaggerty).

I also asked the retailer for the panels and he recommended the opposite end of the input as well so I went with the majority and installed it there.

I'm wondering though if I really need it at all. Is it just used to prevent damage from freezing? If so, since I start the pool only in May and close it in September, there aren't much risks.

The problem I have with it is that the air needs to be pushed out of the panels everytime water is sent to them. This air causes a lot of bubbling in the pool, setting of the alarm occasionaly (PoolGuard).
 
Mark, you are wrong in this case. The water in the panels drains back into the source side, it is not pulled up and through to the return side. That is why you have a "leaky" or drilled 3-way valve (you would be right ONLY if you had a solid 3-way, which is not recommended). The high point on your panels is like the top of a mountain, on one side, it drains back to the return line, on the other side, it drains back to the source line.

The breaker just lets air into the system so that this can happen. The air entering the system goes to the "top" anyway, thus relieving pressure to both the return and source lines. The breaker has to be high enough so that the "pull" pressure of the returning water is higher than the breaker setting, but that is all.

It isn't just Powermat that shows this. The installation manual for my Solar Industries panels (and another one for a different company that I pulled from the web) both show the first install postion for the breaker at the lower panel line. The next position to try is often the one you recommend, which is opposite the return at the top of the panels. Then, as in my case, if you still get air into the system when running, you often have to cut the return in at a lower point on the return line.
 

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el_steak said:
I'm wondering though if I really need it at all. Is it just used to prevent damage from freezing? If so, since I start the pool only in May and close it in September, there aren't much risks.

The problem I have with it is that the air needs to be pushed out of the panels everytime water is sent to them. This air causes a lot of bubbling in the pool, setting of the alarm occasionaly (PoolGuard).
Click to expand...

YES, you NEED it. Any water left in the panels can really stress your system and your roof in 3 ways! They are:

1) the water weight itself can be quite stressful on your roof and system
2) the pressure of the column of water left in your system can cause stress and fatigue wear in the panels and piping
3) WORST! The water left in the system can get very hot. Hot water expands. The pressure caused by the expansion can be enough to split your panels.

Bubbles also let you know the system is working.
 
tphaggerty said:
Mark, you are wrong in this case. The water in the panels drains back into the source side, it is not pulled up and through to the return side. That is why you have a "leaky" or drilled 3-way valve (you would be right ONLY if you had a solid 3-way, which is not recommended). The high point on your panels is like the top of a mountain, on one side, it drains back to the return line, on the other side, it drains back to the source line.

I disagree. When the pump stops, the break at the bottom of the panels opens and the source side pipe will drain out the source pipe which is what you said and I don't disagree with that part. However, air cannot get to the top of the panels unless it comes from the bottom where the break is. That is the only place where air can enter the system. Therefore, the water in the panels must be replaced by the air at the bottom of the panels and the only way to do that is if the water flows up the panels and drains out the return pipe. Air will not displace water in very small tubing so it must flow out and will usualy be sucked out by the water weight in the return side. You must remember that the return side is still full of water which will want to drain out of the return side and will create a vacuum at the top of the panels ([EDIT] 23 feet high creates -10 PSI) which in turn will draw the water out of the panels. Powermat shows this action correctly in their web site animation.

[EDIT] - Wanted to add that at the moment the vacuum breaker opens, the PSI at the bottom of the panels is about 0 PSI and the PSI at the top of the panels is at (a guess) about -10 PSI, water flows from higher to lower PSI so the water in the panels will travel upwards and drain out the return side.


The breaker just lets air into the system so that this can happen. The air entering the system goes to the "top" anyway, thus relieving pressure to both the return and source lines. The breaker has to be high enough so that the "pull" pressure of the returning water is higher than the breaker setting, but that is all.

It isn't just Powermat that shows this. The installation manual for my Solar Industries panels (and another one for a different company that I pulled from the web) both show the first install postion for the breaker at the lower panel line. The next position to try is often the one you recommend, which is opposite the return at the top of the panels. Then, as in my case, if you still get air into the system when running, you often have to cut the return in at a lower point on the return line.
Click to expand...

When I researched my panels, I saw more installation manuals which recommend the breaker at the top rather than the bottom. Unless, you can give me a good reason to put it at the bottom, I would say that the top is safer and works a bit better for both draining and priming.

The panels prime from bottom to top so when the breaker is at the bottom, it closes when water reaches it so both the panels and the return pipe must be purged through the return pipe. With the breaker on the top, only the return pipe needs to be purged of air since the breaker does not close until water reaches it at the top of the panel.

So far, no one has given me a very good reason to put it at the bottom and I think that I have given two reasonable reasons for putting it at the top.
 
mas985 said:
tphaggerty said:
Mark, you are wrong in this case. The water in the panels drains back into the source side, it is not pulled up and through to the return side. That is why you have a "leaky" or drilled 3-way valve (you would be right ONLY if you had a solid 3-way, which is not recommended). The high point on your panels is like the top of a mountain, on one side, it drains back to the return line, on the other side, it drains back to the source line.

I disagree. When the pump stops, the break at the bottom of the panels opens and the source side pipe will drain out the source pipe which is what you said and I don't disagree with that part. However, air cannot get to the top of the panels unless it comes from the bottom where the break is. That is the only place where air can enter the system. Therefore, the water in the panels must be replaced by the air at the bottom of the panels and the only way to do that is if the water flows up the panels and drains out the return pipe. Air will not displace water in very small tubing so it must flow out and will usualy be sucked out by the water weight in the return side. You must remember that the return side is still full of water which will want to drain out of the return side and will create a vacuum at the top of the panels ([EDIT] 23 feet high creates -10 PSI) which in turn will draw the water out of the panels. Powermat shows this action correctly in their web site animation.

[EDIT] - Wanted to add that at the moment the vacuum breaker opens, the PSI at the bottom of the panels is about 0 PSI and the PSI at the top of the panels is at (a guess) about -10 PSI, water flows from higher to lower PSI so the water in the panels will travel upwards and drain out the return side.


The breaker just lets air into the system so that this can happen. The air entering the system goes to the "top" anyway, thus relieving pressure to both the return and source lines. The breaker has to be high enough so that the "pull" pressure of the returning water is higher than the breaker setting, but that is all.

It isn't just Powermat that shows this. The installation manual for my Solar Industries panels (and another one for a different company that I pulled from the web) both show the first install postion for the breaker at the lower panel line. The next position to try is often the one you recommend, which is opposite the return at the top of the panels. Then, as in my case, if you still get air into the system when running, you often have to cut the return in at a lower point on the return line.
Click to expand...

When I researched my panels, I saw more installation manuals which recommend the breaker at the top rather than the bottom. Unless, you can give me a good reason to put it at the bottom, I would say that the top is safer and works a bit better for both draining and priming.

The panels prime from bottom to top so when the breaker is at the bottom, it closes when water reaches it so both the panels and the return pipe must be purged through the return pipe. With the breaker on the top, only the return pipe needs to be purged of air since the breaker does not close until water reaches it at the top of the panel.

So far, no one has given me a very good reason to put it at the bottom and I think that I have given two reasonable reasons for putting it at the top.
Click to expand...

Sorry, you are just wrong! The breaker is a check valve. It is ALWAYS closed unless pulled open by a vacuum. The pump doesn't "close" the breaker when it turns on, it is already closed. There is NO WAY that the water "above" the breaker on the source side is "pulled up to the return line" (unless you have a hard closed source line). It just isn't going to happen that way. Think of the breaker as a one-way hole in your pipe, it doesn't matter WHERE the hole is, if the water is under vacuum, air will flow into the pipe. The only difference that the location of the breaker makes is how easily it opens. The lower it is, the less vacuum pressure it is under when the pump stops, the "harder" it is to open. That is why moving the breaker DOWN the pipe can help if you are getting air in the system when it is running. I agree that it makes sense to locate the breaker high, but if doesn't have to be for the system to work correctly.

As for the air not being able to displace the water in the "very small pipes in the panel", they aren't that small, believe me. Most panels have panels have internal piping that is about 1/8 to 1/4 in diameter. About twice as big as a normal straw. Air will have no trouble rising up through the water in pipes that size to relieve the pressure.

Go back and look at the powermat site videos. When the pump stops, the water drains down from the top of the system, air is allowed into the system and allows both sides to drain. And your explaination of why the water flows up because the pressure is lower at the top of the system makes no sense when you are allowing AIR into the system. Put a tennis ball at the bottom of the pipe, sure, it will be sucked up as the water drains. But if you OPEN the bottom of the pipe (the equivalent of opening the breaker), do you really think the water is still going to flow up the pipe?
 
As a practical matter, it can be observed that many systems get built with the vacuum breaker noticeably below the top, and those systems do indeed work. For all we know, there may be small differences in the lifetime of the system depending on the location of the vacuum breaker, but nothing goes seriously wrong when it is low.

Further, vacuum breaker valves do not live up to the ideal of a true one way valve. It isn't frequent, but water has been known to come out of vacuum breaker valves, especially when there is insufficient pressure holding them closed. By placing the vacuum breaker lower you increase the pressure helping it close and significantly reduce the chances that it will fail open and let water out.

When a vacuum breaker fails open, the pool will drain onto the roof, a rather obvious and serious failure. This is to be compared to a hypothetical reduction in panel lifetime, which while plausible is observably not causing failures at a dramatic rate.
 
I really like the look of the techno-solis/vortex panels, and your install looks great. I've been looking around for some panels for some time and have narrowed it down to aquasol 4' x 12' which look very similar to a fafco sunsaver, or vortex 4' x 12' which I guess are the same as your techno-solis. The vortex panels are a little more expensive, but not a huge difference.

How do you like the flat surface extruded design compared to the typical ribbed design?

Do you find the panels to be heavier or more rigid than a ribbed design might be? I notice the vortex panels claim "commercial grade - 30% heavier." Wondering what the comparison is, and if this is a good thing?
 

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