Solar heat three way diverter question?

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uncledeadly

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May 19, 2009
57
Chilliwack, BC, Canada
I have a solar heat systgoldlineem on my pool. It's controlled by an aqua solar controller and uses a electric controlled goldline 3 way valve. I had read somewhere that this valve should be rendered "leaky"so that when the water was not going to the roof the water was able to drain out of the panels and not "hang"in the panels.
To accomplish this I removed the seal inside the valve. I think it bypassed too much water as it did not heat nearly as good as the year before when the seal was still in place. I still want to have the water return to the pool when not heating but don't need that much bypass. I'm thinking of reinstalling the seal and drilling a hole or two in the valve but.....what size hole(s) should I drill? Any experience on this anyone?
Thanks in advance
RR
 
If your panels up top have a relief valve and are properlly installed, as they should, then all the water in the panels will drain. The exception would be the water in the inlet pipe going to the roof. Being in Florida, I don't have a need to drain this water except on rare occasions when it might freeze, and then I just open the valve while the pump is off and let it drain out.

After thinking about that, if you still want to drill a hole, I'd start with a 1/8" and see how it works for you. You can always go larger, and if you decide to change your mind and plug the hole, it should be easy to do - just do it from the inside and don't protrude on the outside of the valve plate.
 
I actually was thinking of asking a related question. On a general roof solar panel, the water goes up the house and then from the bottom of the panel up and then returns to the pool from the top of the panel down the house and through a check valve. So, for the panel to drain, the water must go back down the up leg of the plumbing and then back through the 3-way valve (which I assumed did not let water pass).

Are the valves generally leaky enough to allow this to happen or in an installation is a hole added to the 3-way valve?

I am skeptical of the way previous owner install my current homemade ridiculously under-sized solar system after all the other things I have discovered in the house. I currently just have to turn the valve manually, so I always have a lot of air to clear. But, I want to add some automation, so I guess I may need to check and drill a hole in the valve. Correct?
 
jblauert said:
I actually was thinking of asking a related question. On a general roof solar panel, the water goes up the house and then from the bottom of the panel up and then returns to the pool from the top of the panel down the house and through a check valve. So, for the panel to drain, the water must go back down the up leg of the plumbing and then back through the 3-way valve (which I assumed did not let water pass).
Click to expand...

No. Water will drain from the panels through the outlet. The check valve on the outlet prevents water from going up that pipe to the panels, but allows flow down and out to the pool. The relief valve up top on the panels will open to allow air in and the water out. The only part that will stll have water is the up leg of the pvc. If your 3-way valve is only partially open, then water will drain from there too. But if it is fully open or closed, then this is when a small hole would allow water to drain from that pipe.
 
But isn't the outlet pvc connected to the top of the panel at the relief valve? Meaning that when the 3-way valve was closed, the water in the panel would somehow have to be drawn up the panel to then be able to go down the outlet plumbing back to the pool through the check valve?

That was my impression that the inlet plumbing connected to the bottom of the panel and then pushed the water up the panel to the outlet plumbing. So, I was assuming that gravity was pulling the water down the panel and back down the inlet plumbing requiring the relief valve to allow air in at the top. The only way I can start to imagine the "stagnant" water in the panel to be able to return to the pool through the outlet would be due to a siphoning affect, but the relief valve at the top would not make that possible.

What am I missing?
 
I'm struggling a bit with how the panels can drain without having a "leaky"valve. I agree with you that a belief is out htere that the panels will siphon out but...that depends on the location of the relief valve. Normally, I think, the relief valve is located on the opposite end of the top header pipe from the discharge line going back to the pool...I was having problems with that location as the relief valve was "chattering"so I moved it down to the bottom header pipe where the delivery pipe to the panels is located. I can see where the setup I have may siphon off but, like you say...if the relief valve is located on the top header pipe I can't see that the panels would siphon out.....I may be missing something, as well, though....lol
 
The relief valve should be on the inlet to the panels. When the pump turns off it lets air into the inlet which is drawn through the panels replacing the water which flows down the outlet back into the pool at the returns. There is usually a check valve after the filter to stop water flowing backwards through the filter pulling sand into the pool. All the water in the inlet pipe before the relief valve stays where it is unless you drill a small hole or have a leaky 3 way valve.
 
I just re-looked and see that some diagrams (h2otsun.com) show the relief valve on the bottom on the inlet piping as solarboy describes. So, the panels are supposed to empty via a siphoning effect. This also explains the previous mention of water remaining in the inlet pipe (unless the 3-way leaks).

However many of the other diagrams online (and some of the pictures I have seen in this forum) show the vacuum break on the top at the outlet ... which is the configuration that I can not picture how it works without a leaky 3-way. Thus my confusion. Is there a right way?
 

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There are various ways to do it. How the system drains all depends on where the vacuum breaker actually is. If the vacuum breaker is on the inlet pipe then the panels will drain down, or at least mostly drain down, even if the three way valve is sealed. How throughly the panels drain depends on several details of the plumbing and the positioning of the panels. If everything is done correctly they will drain fairly throughly, but there will still be water in the inlet pipe.

Other setups have the vacuum breaker at the high point of the system, which has a couple of minor advantages and disadvantages, including that the panels will not drain down unless the diverter is leaky, and that it takes more pump pressure to get the vacuum breaker to seal closed. On the plus side, having the vacuum breaker at the high point means much less air going through the system and back to the pool when the solar turns on.
 
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