lots of air bubbles in pump basket when solar system shuts off or is not on.

aqua mango

Member
Jun 10, 2015
9
Waikoloa Hawaii
We have a problem with our pool plumbing system and would appreciate any ideas as to why it is happening.

We are on Hawaii Island and have a Pentair Intelliflo pump. Our system is connected to 12 solar water heater roof panels and the water flow comes in through the skimmer and floor drain, to a Jandy check valve to the pump then to the sand filter then up through a Jandy 3-way valve to the solar panels then down through a flow meter, then a Jandy truclear salt cell back to the pool.

The pump starts in the morning before the solar system activates, It primes and pumps well through the system and out to the pool with the solar system coming on shortly after. While the solar system is on the pump runs smoothly. If it is a cloudy day or later when the solar system turns off, there are mega air bubbles seen in the Jandy check valve located in the pipe before the pump and after where the skimmer and floor drain pipes converge bringing water to the pump. There are also mega airbubbles in the pump basket as well as coming out in the pool's return pipes into the pool . The flow rate drops below 40 gallons per minute and the pump sounds a bit starved for water. We replaced the o ring in the Jandy check valve before the pump and replaced the check valve after the sand filter that leads up to the solar system and it has had no impact. When the pump turns on the next morning, it runs well until the solar shuts off later in the day or if the solar doesn't come on due to cloudy weather. When ever the solar shuts off or doesn't come on and the pump is on the mega bubbles and low flow rate occur. I have used a soapy solution on all fittings between the pipes coming in from the pool through to and including the pump. I can attach photos of the plumbing if helpful. Thank you for any ideas.

Any Ideas on what to check.
 

Dirk

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Hi, and welcome to TFP! Sorry you’re having trouble with your system.

Do you know if the three-way valve that engages the solar panels is a true solar drain-down valve?

And do you know if your solar system includes a vacuum breaker? It might be visible from the ground, or it might be on the roof. It would be at least 6’ from the ground.

Has this always occurred? Or is this something that just started happening?
 

aqua mango

Member
Jun 10, 2015
9
Waikoloa Hawaii
Hi, and welcome to TFP! Sorry you’re having trouble with your system.

Do you know if the three-way valve that engages the solar panels is a true solar drain-down valve?

And do you know if your solar system includes a vacuum breaker? It might be visible from the ground, or it might be on the roof. It would be at least 6’ from the ground.

Has this always occurred? Or is this something that just started happening?
[/QUO
Try this:

thank you for posting this leak detection method. first I will go further with you regarding what is in our solar plumbing then possibly this. the unusual part of the mystery though is there are not air bubbles in the pump basket and the jandy valve before the pump basket when the solar system is on. It is only when the solar system is off. so I would think that rules out airleaks in the plumbing before the pump... is this correct thinking? Thank you
 

Dirk

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Not necessarily. Suction-side leaks (those that occur between the pool and the pump) can vary depending on flow rate and amount of suction. It may be that when solar is on the flow through the system is lower, and so suction is less. When solar turns off, the flow and suction increase and the leak reveals itself.

When the solar system comes on, does the RPM of the pump change? What is the RPM when the solar is on? What is it when the solar is off? Same for the pressure gauge on the filter? What does it read when solar is on, and then when solar is off? When was the last time you clean the filter?

We're just looking for clues at this point. Pictures of your plumbing might present a clue...
 

aqua mango

Member
Jun 10, 2015
9
Waikoloa Hawaii
Not necessarily. Suction-side leaks (those that occur between the pool and the pump) can vary depending on flow rate and amount of suction. It may be that when solar is on the flow through the system is lower, and so suction is less. When solar turns off, the flow and suction increase and the leak reveals itself.

When the solar system comes on, does the RPM of the pump change? What is the RPM when the solar is on? What is it when the solar is off? Same for the pressure gauge on the filter? What does it read when solar is on, and then when solar is off? When was the last time you clean the filter?

We're just looking for clues at this point. Pictures of your plumbing might present a clue...
Hi I have been gathering info and photos, so now I can answer your questions.
I have taken a photo of the 3 way valve and the pumping. Please see photos.
we do not have a vacuum breaker. We checked the roof besides the pipes going up to the roof. We don’t have a check valve on the return piping down from the solar. Also this problem has been going on for many years. We only lived in our house this past year so realize now how unusual it is.
Attached with the photos is the pump/ solar system data you requested.5C37B795-571F-490F-84AE-12A9530DC3F0.pngAC58AB81-090F-4912-8FE3-5745F6CFBA91.jpegC3C987D0-3E84-413C-8B99-47260B7D17CE.jpeg40E81DFC-B452-4992-9FAE-DF6760F46733.jpeg2C49EECF-70DF-4344-A2F2-AB1054B4D585.jpegDD740397-C14C-4E06-86CC-4F8358D79351.jpegF9AF5D41-9567-441F-A650-FCD6A8576A28.jpegAC58AB81-090F-4912-8FE3-5745F6CFBA91.jpeg
 

Dirk

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Well, it's a bit late, but I can muster a few comments, about some weirdness I'm seeing. I'm not a solar expert or installer, other than my own system. But we can try to sort this out together.

It's my understanding that you must have a vacuum breaker in a rooftop solar system, or risk damage to the panels and/or the plumbing, especially the hot plumbing on the roof. So either it's missing and that might be related to your bubble problem, or you just haven't found it yet. Sometimes they are obvious, and sometimes they are semi hidden in the end of one of the panel manifolds up on the roof. I think it's important that you know for sure you do or don't have one, which might require a trip to the roof to inspect the four corners of the panel array. It could look like any of these (and maybe something else, too):

Screen Shot 2021-02-02 at 10.04.27 PM.png

I see what looks like temperature gauges on both pipes to the roof. Someone was apparently interested in how much heat the panels were generating. That's fine, but not the best way to optimize your solar heater performance if that's what they were being used for. They're not standard, for sure. A properly tuned system would show a very small temp differential between those two locations, maybe 1 or 2 degrees. Which is likely well within the margin of error of either or both of those gauges. Which means you really don't know what the differential is, or if it's too much or too little. Contrary to logic, you don't want 5 or 10 degrees difference coming off the roof. That would indicate your system is not optimized and not heating your pool as well as it should, because the flow rate is too low (allowing the water to get too hot). The higher the flow rate the better, up to a certain point. You want a lot of slightly warmer water going into your pool, not a little of very hot water. The correct way to optimize your system is to first determine the optimal flow rate through the panels (as specified by their manufacturer) and then use a flow meter to dial in that optimal flow. I digress, we can come back to that if you're interested.

But the gauges are not the weird part. You have a check valve on the pipe leading to the roof. That serves no purpose that I know of, and it should be located on the pipe coming down from the roof. Let me correct that, that check valve might be serving to inhibit the way the system is supposed to work. Which is:

Solar panels are supposed to be empty when the pump is off. When the pump first turns on, the panels would still be empty. When the solar controller calls for heat and moves the solar valve to its "solar on" position, the panels fill with water. You'll should see a lot of bubbles of air coming out of the pool returns, almost like a jacuzzi. A lot of air! Once everything fills with water, the bubbles stop, and the solar system proceeds to heat your pool.

Say a cloud passes by, and the controller then turns off the system by operating the solar valve, because it senses there's not enough heat available, but the water would stay in the panels, ready for when the cloud goes away, the valve turns again, and water resumes flowing through the panels and heating your pool. With me so far?

But then at the end of the day, when the solar heater is done, and the main filter pump shuts off, the water must drain down from the roof. It exits the panels via two paths. A relatively small amount comes down the return pipe (in your system that's the one on the right). But most of it would come down the supply pipe (yours is on the left). The pipe on the right is always open to the pool. But the pipe on the left would run into the solar valve, which is not in its "solar off" position. A proper system utilizes a special three-way solar valve called a solar drain-down valve. It has a one-way component inside that opens when the main pump is off, that allows water to (you guessed it) "drain down" through the three-way valve. That water flows through the three-way and joins the water coming down the return line, on to the pool, until the panels are empty.

Now none of that draining can occur if air is not allowed into the system. Worse, the weight of the water trying to come down will suck on the panels and the pipes up on the roof, which might be very hot after a long day in the sun. And that suction can actually damage the panels and deform the pipes, sucking them in on themselves. Enter the vacuum breaker! That breaker "breaks the vacuum" and allows air into the panels and roof top plumbing (when it senses the pump is off), which allows all the water to drain down without stressing the system up top. That's how it's supposed to work.

But here's the rub. If you're missing the breaker, the system might try to draw in air from somewhere else. I can't quite wrap my head around the possibility, but that might have something to do with the air getting into the pump. As if it's sucking so hard on the plumbing? I can't be sure about that. But the first step is to find the breaker, or confirm it doesn't exist.

But that's not even the weirdest part. It's that check valve on the supply side of your solar plumbing. Remember, most of the water that needs to come down off the roof will exit through the supply side, and then through the solar drain down valve. But that check valve is not going to allow that. It is blocking the flow down that pipe! It only allows water to go up, not down. So I'm not sure what's going on with that, or why it's there.

It's possible that the plumber didn't want the water to come down for some reason. That the intention was to keep the panels full of water all the time. Which might explain the absence of a vacuum breaker, since if the panels never have to empty, there would be no need for one. But if that's the case, if that setup is a legit way to run a solar system, it is way beyond me, and not something I've ever seen described in all the research I did while building my system, nor in any of the schematic drawings I've viewed and used. Here's one that depicts a typical plumbing setup for solar. Note that your system is not this!

0c1bbe36d6af8e0477923a19d3d2f377.gif

Not shown is the vacuum breaker. It's typically on the feed line (supply line), at least 6' off the ground, or on the roof, or sticking out of one end of a solar array manifold.

It's not definitive that any of your weird plumbing is causing the bubbles in the pump. One possible approach would be to redo your solar plumbing to a more standard configuration (move the check valve to the correct pipe and install a vacuum breaker if it is in fact missing) and see if that solves your problem. We can talk about installing a flow meter at the same time, and how that can help you get the most heat from your system, if you're interested.

If that doesn't help with the pump issue, then at least you've ruled that out and will end up with a properly plumbed solar system. You can DIY if you're up for it, I can assist as best I can, or you can call a local solar installer and have them replumb your system for you. If the latter, maybe before they do they can explain why your system is plumbed the way it is... Which I'd very much like to understand, if it's not incorrect like I think it is.

Let me know what you think and how you want to proceed...
 

aqua mango

Member
Jun 10, 2015
9
Waikoloa Hawaii
Thanks for your very informative response. I went on the roof and it looks like there are two vacuum breakers. I am attaching photos of them. The roof solar panels are on the other side of peak of the roof from the solar feed and solar return pipes so the pipes go up and over the ridge. Could this be the reason for only one check valve and it is located on the solar feed after the three way valve. Also, why would there be a check valve on the return side? We do have a flow meter installed and get a flow of around 60 gpm when the system is operating with no air bubbles. The flow rate changes when the solar is shut off as noted in the datsolar on roof.pngvalve 1.jpgvalve 2.jpgvalve 3.jpga I sent.
 

Dirk

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Yep, I think you found the vacuum breakers. I'll have to stare at this for a while, but I gotta say this system is way beyond what I know about solar. It was either built by someone that really knew how to install it that way, and the weirdness I called out is all necessary because of the location of your panels, or this was built by someone that had no idea about how a solar system works. The temperature gauges are a clue that this was an amateur install. As I explained, those are not particularly useful, but might have been misunderstood as useful by someone making this up as they went along. I could very easily be wrong about that, I've just never seen it before.

In the research I did to learn how to build my system:
I never came across a system described or diagramed with two vacuum breakers.
I never saw a system described or diagramed with either pipe, let alone both, running over the top of the roof ridge.
I never saw a system described or diagramed with a check valve on the supply side of the pipes leading to the roof.

Your panels can't drain, that I can figure out, which leaves water in the panels and roof plumbing 24/365, which is also counter to everything I learned. I think now what I guessed before, that the supply side check valve is there to keep water trapped on the roof. Since water would stay trapped in the panels no matter what, without the supply-side check valve, the water would drain out of the supply pipe, from the ridge down. Then when the pump started the next day, the air in the supply pipe would have to push against all the water stuck in the panels, and work it's way through all that, which can't be good.

Something like that. Just guessing, basically I'm stumped.

On the other hand, it's Hawaii, where it never gets too cold at night, so maybe leaving water in the panels 24/365 is how it's done over there.

Like I said, I'll stare at it a bit, and see if I can make sense of it, but I wouldn't hold your breath. You might need a solar pro to come out and assess your system. See if he can make heads or tails out of it.

If it is all wonky, I don't think it would take much to straighten it out. They would have to reconfigure that plumbing a bit, and reroute how the pipes come off the roof (so they don't go over the ridge), but it's probably all doable.

I can't really answer the question if this could be the cause of your other issue, because, like I said, I'm not fully understanding how your system works.

Regarding why there would be a check valve on the return side: I've seen "normal" systems designed with and without that check valve. It's optional. Mine has one in that location. If you study the diagram I posted, and follow the path of the water, for both "solar on" mode and "solar off" mode, you'll see how in solar on mode, the check valve would allow water to come down off the roof and return to the pool. It can't go to the left, because the three-way is open to the roof, and closed off from the horizontal pipe that connects to the tee in the return line. Now flip the valve to solar off. The water can't go up onto the roof, but instead goes right, back to the pool. But it first hits that tee and would split, some going down, but some going up, too. The check valve would stop the flow of water from traveling up onto the roof, the wrong way though the panels. Without the check valve, it eventually would get stopped by the air or water in the panels, because it has no where to go, but it would still put pressure on the panels. With the check valve, the flow would stop at the check, and just go to the pool. Hope that makes sense. For your system, I'm not surprised it's not there, because your panels are never empty.

Sorry I couldn't be more help, but I just have no experience with your plumbing setup. Keep us posted about what you find out, if you call in a pro...
 

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Dirk

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My system has 2 rows of panels and each row has its own VRV. So I think that much is normal in this system.
One for each array? I see. The site I used to refer to had a great diagram of how to plumb two arrays, but I think that website got rid of it, I couldn't find it earlier. From what I remember that diagram showed one. I think it depends on how the two arrays are plumbed together. No matter, as long as they both work, I would think more than one is fine.
 

Dirk

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Found it. Wayback machine. Scary thing...

This is what I was thinking of. It's one way to plumb a second array (and only one VRV). aqua mango's system does not look to be done this way.

addabank.gif
 
Last edited:

Dirk

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Here's an alternate line of logic, since I can't offer anything else. It seems logical to assume the system worked at one point. It was built, and tested and used, we presume. If right after it first went on line, the pump started misbehaving as aqua mango describes, you'd think whoever built the system would have noticed a problem and addressed it. It's hard to imagine the pump acted up right away because of the solar plumbing installation, and then the home owner and/or solar installer just said "Oh well," and left it that way for all these years.

If that logic holds, then the system once worked as is and the pump was fine. Which points to some other cause of the pump bubbles issue. That train of thought does nothing to help solve the pump bubbles, sorry.

It still could be true that the extra flow through the system when the solar is disengaged is exacerbating some leak on the suction side. But it is odd that that doesn't happen before the solar first comes on, only after if goes off later on (if I have that right). It does seem to be solar system related. So it could have something to do with how the system first fills, and how it later drains water (or doesn't drain water) when the solar goes off for the day. Still stumped, sorry...

One possible troubleshooting step: Turn off the solar system using the solar controller so it doesn't come on at all. Be sure the solar valve is in the "solar off" position. This will in effect isolate the solar system, as much as possible. Let it be for overnight, even a full day. Then in the morning observe the pump. You say it acts normally when it first comes on, right? So instead of turning on the solar, try different RPM setting on your VS pump. Don't go crazy, just speed it up some, back it off some, like that. What were exploring is if you can recreate the bubbles in the check valve and pump without engaging the solar system. This might simulate how the flow rate is altered by the solar system, but without actually using the solar system to affect the flow. If you can use the pump RPMs to cause the bubbles while the solar system is isolated, then that would point to a suction-side leak that is only being aggravated by the presence of the solar system, not actually caused by it.

If that does nothing, you might next try to run your system without any solar system (isolated as described above) and with the normal RPM setting. Run that all day. See if the bubbles develop. That would be a clue, either way.

Just basic troubleshoot: try to eliminate things, one by one, to see which thing is causing the problem. It's not 100% fool proof, as sometimes it is a strange combination of things that cause a problem that isolating just one at a time won't reveal, but everything you try might provide a clue...
 

aqua mango

Member
Jun 10, 2015
9
Waikoloa Hawaii
Yep, I think you found the vacuum breakers. I'll have to stare at this for a while, but I gotta say this system is way beyond what I know about solar. It was either built by someone that really knew how to install it that way, and the weirdness I called out is all necessary because of the location of your panels, or this was built by someone that had no idea about how a solar system works. The temperature gauges are a clue that this was an amateur install. As I explained, those are not particularly useful, but might have been misunderstood as useful by someone making this up as they went along. I could very easily be wrong about that, I've just never seen it before.

In the research I did to learn how to build my system:
I never came across a system described or diagramed with two vacuum breakers.
I never saw a system described or diagramed with either pipe, let alone both, running over the top of the roof ridge.
I never saw a system described or diagramed with a check valve on the supply side of the pipes leading to the roof.

Your panels can't drain, that I can figure out, which leaves water in the panels and roof plumbing 24/365, which is also counter to everything I learned. I think now what I guessed before, that the supply side check valve is there to keep water trapped on the roof. Since water would stay trapped in the panels no matter what, without the supply-side check valve, the water would drain out of the supply pipe, from the ridge down. Then when the pump started the next day, the air in the supply pipe would have to push against all the water stuck in the panels, and work it's way through all that, which can't be good.

Something like that. Just guessing, basically I'm stumped.

On the other hand, it's Hawaii, where it never gets too cold at night, so maybe leaving water in the panels 24/365 is how it's done over there.

Like I said, I'll stare at it a bit, and see if I can make sense of it, but I wouldn't hold your breath. You might need a solar pro to come out and assess your system. See if he can make heads or tails out of it.

If it is all wonky, I don't think it would take much to straighten it out. They would have to reconfigure that plumbing a bit, and reroute how the pipes come off the roof (so they don't go over the ridge), but it's probably all doable.

I can't really answer the question if this could be the cause of your other issue, because, like I said, I'm not fully understanding how your system works.

Regarding why there would be a check valve on the return side: I've seen "normal" systems designed with and without that check valve. It's optional. Mine has one in that location. If you study the diagram I posted, and follow the path of the water, for both "solar on" mode and "solar off" mode, you'll see how in solar on mode, the check valve would allow water to come down off the roof and return to the pool. It can't go to the left, because the three-way is open to the roof, and closed off from the horizontal pipe that connects to the tee in the return line. Now flip the valve to solar off. The water can't go up onto the roof, but instead goes right, back to the pool. But it first hits that tee and would split, some going down, but some going up, too. The check valve would stop the flow of water from traveling up onto the roof, the wrong way though the panels. Without the check valve, it eventually would get stopped by the air or water in the panels, because it has no where to go, but it would still put pressure on the panels. With the check valve, the flow would stop at the check, and just go to the pool. Hope that makes sense. For your system, I'm not surprised it's not there, because your panels are never empty.

Sorry I couldn't be more help, but I just have no experience with your plumbing setup. Keep us posted about what you find out, if you call in a pro...
Thanks again for your analysis. The solar system was installed by a solar company but has changed hands. I will bring your comments to the new company owner when they come to service our domestic solar water heater.
 
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aqua mango

Member
Jun 10, 2015
9
Waikoloa Hawaii
Found it. Wayback machine. Scary thing...

This is what I was thinking of. It's one way to plumb a second array (and only one VRV). aqua mango's system does not look to be done this way.

View attachment 174772
Very interesting diagram. Thank you for hunting for it and yes you are correct our awareness before trying your next suggestions is that the wild bubbles in the pump basket and going into the pool only happens after the solar has been on and it turns off do to clouds.
 
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