Exploding pool!!!

[JasonLion]

Given the most recent information, I just can't see it being freeze related. The temperatures simply didn't get low enough and even if they did the freeze protection should have eliminated all of the risk. The only way there could have been any freeze damage, let alone something this dramatic, is if there were lower temperatures for longer and some section of the piping was closed off and didn't have any water flowing. So that seems ruled out in multiple ways.

By the by, I have had freeze damage in pipes that were not sealed off. A short section of the plumbing under the pump house used to be down below everything else and didn't always get blown out fully. It was open to pipe that was blown out at both ends, but still got cracked open in the winter if any water was left after winterizing.

Caretaker valves are quite capable of causing water hammer.
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Still, I can't imagine it getting up to the kind of pressures required to shatter the PVC. It should have caused a small crack at the weakest spot, not totally blown things apart. I can certainly imagine that kind of repeating stress damaging the filter housing over time, but blowing the pipes apart just doesn't seem plausible.

I'm leaning more and more towards a hydrogen explosion, despite the problems explaining the spark source. I know I'm reaching, but maybe the water hammer compressed a hydrogen bubble enough to heat it above the ignition point.

 

[Budman]

Your right, the damage looks more like a sledge hammer as Dave suggested than ice damage.

But How? Why? Although he does live at Lake Havasu. The partying can get pretty crazy there...

 

[Budman]

Sorry for not quoting individual replies.
Yes, the natural gas lines are wrong or at least the size. The Pentair rep came out to fix one of the heaters and he told the builder they were wrong.

As far as plumbing and loops, I don't know.
Everytime I have someone come out and fix something they ask, Why did they plumb it like that or the electrician asks why did they wire it like that?
it never ends.

The pool was beyond the builders capabilities and now we just deal with it. They aren't very responsive anymore so here I am.

I did find the intake leak to the main pump. I don't know the exact name but the large pot with the basket just before the inlet of the pump. At the bottom, water comes out when I shut down the pump. So it's either the pot is cracked or bad connection.
That's why bubbles would come out of the pop ups.

maybe too much air in the system at start up and it finally blew?

 

[swimcmp]

Also take note the OP said he has an in floor system and has just recently replaced the head of the unit. You are restricting water flow to an extreme and getting a lot of pressure jumps and surges. I have installed a couple of these systems and won't use them anymore after seeing the problems they cause. Usually they will cause the IC housing to split open first.

 

[mas985]

By the by, I have had freeze damage in pipes that were not sealed off. A short section of the plumbing under the pump house used to be down below everything else and didn't always get blown out fully. It was open to pipe that was blown out at both ends, but still got cracked open in the winter if any water was left after winterizing.

If the pipe was truly unblocked, then the water would have flowed out of the ends and would not break the pipe.

What can happen is an ice dam can form near the ends of the pipe first and then the remaining water expands to break the pipe. But theoretically, there is no way to break the pipe unless the expanding water is confined in some way. It is the water that breaks the pipe and not the ice. Once ice forms, it has already expanded. This shows that ice actually shrinks (density gets larger) as it get colder than 0C.

http://www.engineeringtoolbox.com/ice-t ... d_576.html

 

[Pool Clown]

Caretaker valves are quite capable of causing water hammer. Normally, with no air in the system you won't notice any hammering other than some pressure spikes on the gauge as the valve changes zones. However, given there is air getting into the system (which we know is happening) and given the high pressures that the system is running at, the hammer could be fairly dramatic and would repeat over and over again any time the system is running.

Large air bubbles are going to amplify any hammering,

I'm leaning more and more towards a hydrogen explosion, despite the problems explaining the spark source. I know I'm reaching, but maybe the water hammer compressed a hydrogen bubble enough to heat it above the ignition point.

I hate to step on toes, but i believe it is in the best interest of the OP to have accurate info on this subject, and not just to prove someone wrong.

With no air in the system is when you will get the most hammering effect. Air is going to compress, and give more of a cushion and less force exerted, the energy will be absorbed by the compression of the gas (air) . With no air, you get a hydraulic effect where the most force is exerted against the walls of the plumbing because water does not compress. While you can get "hammer" with a fluid or a gas, fluid hammering produces more force than gas.

Forgive my neanderthal explanation, you most certainly can get a better explanation than mine somewhere on the net.

 

[Budman]

Caretaker valves are quite capable of causing water hammer. Normally, with no air in the system you won't notice any hammering other than some pressure spikes on the gauge as the valve changes zones. However, given there is air getting into the system (which we know is happening) and given the high pressures that the system is running at, the hammer could be fairly dramatic and would repeat over and over again any time the system is running.

Large air bubbles are going to amplify any hammering,

I'm leaning more and more towards a hydrogen explosion, despite the problems explaining the spark source. I know I'm reaching, but maybe the water hammer compressed a hydrogen bubble enough to heat it above the ignition point.

I hate to step on toes, but i believe it is in the best interest of the OP to have accurate info on this subject, and not just to prove someone wrong.

With no air in the system is when you will get the most hammering effect. Air is going to compress, and give more of a cushion and less force exerted, the energy will be absorbed by the compression of the gas (air) . With no air, you get a hydraulic effect where the most force is exerted against the walls of the plumbing because water does not compress. While you can get "hammer" with a fluid or a gas, fluid hammering produces more force than gas.

Forgive my neanderthal explanation, you most certainly can get a better explanation than mine somewhere on the net.

Those were my thoughts also. Maybe the combination of air and water has harsher effects than just compressed air.
The odd thing, like someone else said, is to the location of the break. The valve was turned slightly so some water would always be going to the spa and the most of the water going to the pop ups. For it to shatter at the 3 way joint and valve is perplexing since it wouldn't be a total dead end in either direction.

I really do appreciate everyone's input. There aren't any wrong answers.
I just wish it was something I did wrong so everyone can say, "don't do that".

 

[JamesW]

I would suspect a spontaneous reaction between hydrogen gas and chlorine gas, which can be rather violent.

Cl₂ (g) + H₂ (g) ? 2 HCl(g)

chlorine gas + hydrogen gas --> hydrogen chloride.

It does not take much to initiate the reaction as shown here (and in other videos):

http://www.youtube.com/watch?v=NN82GoBG98s

Here is an example of a salt cell exploding, it is a clear cell and the explosion might have been ignited by UV light from the sun.

swg-cell-explosion-t51234.html

There is a clear lid on the poster's check valve. If the hydrogen and chlorine gas were to build up to include the check valve, then UV light might be the ignition source.

 

[JasonLion]

With no air in the system is when you will get the most hammering effect.

Agreed. My mistake.

 

[Pool Clown]

I might be more inclined to agree with the hydrogen gas theory, if it weren't for:
Intellichlor production stops when the unit experiences no flow or the flow switch opens.
" " " when the filter motor turns off (providing it is wired as instructed by the install guide)
" " " when the water temperature falls below the pre-described temp. I believe this has been satisfied.

I would believe that theory more if there was an on line tab feeder, those things never sleep...

 

[JasonLion]

I might be more inclined to agree with the hydrogen gas theory

Yea, I hear that.

Everything appears to be ruled out one way or another. The only thing in favor of a hydrogen explosion (of one kind or another) is that everything else appears to be even less likely.

 

[mas985]

Except for the sledge hammer. To me, that seems more likely. Vandalism?

 

[Budman]

Except for the sledge hammer. To me, that seems more likely. Vandalism?

I won't get into that but that was the first thing that came to everyone's mind.
Some issues in the developement.
But we had a house full of people. gates were locked.
I wouldn't rule anything out.
If none of the other issues I addressed hadn't happened, vandalism would be at the top of the list.

 

[Pool Clown]

Except for the sledge hammer. To me, that seems more likely. Vandalism?

Agreed, Do you aggravate your nieghbors with your parties er get togethers?

 

[Pool Clown]

Inspect the pieces, The force it would take to shatter that pipe would leave some kind of mark on it.

 

[Budman]

Except for the sledge hammer. To me, that seems more likely. Vandalism?

Agreed, Do you aggravate your nieghbors with your parties er get togethers?

No, nothing like that.
Some legal matters between homeowners and golf course and rv park might lead to some jackwagon retaliating in a childish way.
Equipment is fairly inaccessible unless someone wants to jump a 6' wall.

 

[JamesW]

How far did the pieces go? If any pieces went over a few feet, then I think that that would support the explosion hypothesis. If no pieces went very far, then I would think that that would not support the explosion hypothesis.

On a separate note, that is a beautiful pool!

 

[Budman]

How far did the pieces go? If any pieces went over a few feet, then I think that that would support the explosion hypothesis. If no pieces went very far, then I would think that that would not support the explosion hypothesis.

On a separate note, that is a beautiful pool!

Thanks
One piece blew over the wall about 20' away.

 

[Budman]

There are separate pumps/heaters/filters for spa and pool side and both were running freeze protection.
Yes, there was a pool vac running and occasionaly sucks air if it gets high on the wall.
But nothing seems blocked after as far as any of the returns.
Water is cold and I believe the salt generators are inactive. Although it did happen shortly after the morning start up. Maybe there was a buildup from the night before?
Spa was run for the weekend and pool was shut down so warm spa water wouldn't return back to pool.
Break occured when everything was left to turn back on normally the next day.
Water hammer would make sense if air pockets in lines.
Can anything be added to prevent this? I'm nervous about running it again until I can figure out the cause.
Everything looks normal as far as pressure for now but I shut it down.

Uh oh, just sinking in from all the replies.
While I was looking for the intake leak on the pool side, I noticed the SWG wasn't on when the pump was on.
When both pumps, spa and pool, are on everyday, both SWGs are on.
I turn the spa pump on and the SWG comes on to the pool side.
I believe the SWGs are reversed as to which pump is running.
That means that while I shut down the pool for the weekend and ran the spa, the SWG was on for the pool but the pump wasn't running.
When the pool kicked on normally after a couple days, a hydrogen gas explosion occured when the SWG kicked on.
Could that have ignited it?
Don't beat me up on this one.

 

[JamesW]

The distance traveled by the pieces supports the explosion theory. The flow switch should have prevented the cell from operating without flow, but there might be some sort of misconfiguration or damage that is allowing gasses to build up.