So my pool tried to kill me yesterday...

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T

thothtp

0
May 15, 2008
18
Here is a puzzler for you guys.

For reference I have this filter http://www.poolcenter.com/parts_filters ... arPLUS.htm


Story starts a few weeks ago. It is still pretty cold up here in Rochester NY (but well above freezing) so we are still weeks away from opening the pool. However, I noticed that the pool had started turning green despite the cold. I took part of the cover off, reconnected all my equipment, and got the system up and running. Shocked the pool, killed the algae, everything was good. I would run the pump on and off whenever I thought of it, just to keep the circulation up, but otherwise I pretty much left it alone till I was ready to open fully.

Fast forward to a few days ago. I came home and noticed that the pump was not running, even though I had left it on when I went to work. Uh oh... I go outside, and I can see that the ground is soaked, and the top half of the filter is slightly cockeyed, with part of the rubber O ring pushed out the side. I go inside and notice that the breaker has tripped on my pump. Obviously, the pressure had overwhelmed the filter clamp, blown out the gasket, and the gushing water eventually flooded and short circuited the pump, causing the breaker to trip.

I immediately assumed that my filters had gotten too clogged from all the dead algae, and that I maybe hadn't tightened down the clamp on the filter as much as I should. Perhaps I hadn't been paying enough attention and it was slightly cockeyed when I put it on. So I cleaned out the carts, reset the breakers, and was very careful to set the clamp just right and tighten it down very securely.

I hit the pump, it primed, water filled the filter, bubbles poured out of the returns, everything was as it should be. Gauge climbed to around 15psi, right where it normally goes. Job well done, I fixed it.

Just as I was about to head inside.... KAAAABOOOOOOOOOM. The top half of the filter housing takes off like the space shuttle, rockets 10 feet up, smashes against the roof overhang, spirals through the air, and lands right in between me and my shocked Boston Terrier, not 2 feet away.

So after I changed my underwear, I started to try to figure out what the heck could have happened.

Way I figure there are two possible culprits, or perhaps both together.

For one, the automatic pressure relief valve at the top of the filter obviously didn't do its job, so I figure that must be broken.

The other possibility is a clog in the lines after my filter and before the jandy valve that directs the return flow to either my spa seat or the normal pool returns. There is a heater in between there. The mystery is how could anything possibly get clogged in that part of the system, after it had been through the skimmer basket, pump basket, pump impeller, and filter? Theoretically nothing smaller then 15 microns could get to that point, much less a dead squirrel or whatever is big enough to cause a clog. Incidentally, there is a very bad odor coming from somewhere near the pool equipment, that smells like something decomposing. It could just be stagnant water in the filter from before liftoff, or could be coincidence.

So, could this be that there is no clog at all, its just a failed pressure relief valve? Could the air relief tube in the filter itself be at fault? Anyone have any ideas how my pool could become so murderous?

Wish I had video, I bet it would get a lot of hits on youtube.

Thanks for the help guys.
 
Even if the pipe is completely blocked, the top should never blow off of the filter. The filter is designed to hold as much pressure as the pump can produce. The only way the top can blow off the filter is if some part of the clamp/attachment system is broken. Most likely something involved in holding the top on has been starting to break for some time and has only completely failed just now.

Personally, I would just replace the entire filter. Now that part of system that holds the top on has failed, several parts are probably damaged. Because the filter can "explode" and cause serious injuries, this isn't something that you want to try and patch and have fail again.
 
Wow. I'm glad you weren't watching the gauge closely when that happened.

I agree with Jason. Either something went wrong during reassembly of the band or something is bent/broken. If that were the case it wouldn't even take a blockage to pop it. 15 psi would be plenty.

Was there any freezing weather during this time? If the filter got clogged to the point of no water movement, then froze, that could pop the gasket out and warp everything to the point of insecurity.
 
Thats the thing though, the clamp is completely intact. Nothing wrong with it.

I found the manual for my filter here http://www.waterwarehouse.com/Pdfs/1876.pdf and it says repeatedly that air in the system can cause the top to blow off. I think that must be my issue, and the lid came off because I didn't tighten it down as much as possible I guess.

When I bought the house last year, the previous owner told me everything I needed to do with the filter, including that I should hand tighten the clamp till I couldn't tighten it anymore. What I did not use was a wrench, but after reading the manual it seems it requires a lot more pressure then hand tightening could ever provide. They also suggest a rubber mallet, which I obviously didn't use. Tightening it this way worked all last summer perfectly.

I am a little weary of clamping it on even harder though, as that will cause even more force if it were to let go. The issue must be either a clog or air or both.


edit: oh and no freezing weather, its been between 40 and 75 since i started.
 
Ah, I've never been able to hand-tighten one to the point of it not leaking. After it's as tight as you can get it by hand use the mallet to tap the band tighter, starting from the side opposite the nut. As you tap it you should be able to tighten it by hand further and further.

Try it out. Just stand back when you do! :-D
 
Yeah, lesson learned, don't listen to the guy selling you the house, he is probably doing everything wrong.

But still, there must be air getting stuck in the system, and if the first failure is an indication it builds up slowly till it eventually overpowers the clamp and explodes. Tightening the clamp down with a wrench and mallet scares the Crud out of me, because if the pressure continues to build and it overpowers the now much tighter clamp, it will do so with much more force. Is that possible with a properly clamped filter, or is it impossible for the pump to build that much pressure? and why did it work so perfectly all last year, when I was actually clamping it down less tightly? I am afraid to risk a catastrophic failure again, but I also don't want to spend $1000 on a new filter if this one is fine.
 
Even if there was an air leak, the filter should be able to hold what the pump can give it unless there's a warped or broken part. I've got lots of customers with cartridge filters and they've probably all had air in the system at one point or another, but I've never had one explode on me.
 

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I'll second (or third) the recommendation to get a new filter. What's the diameter of your filter? About 24"? At 15 psi, that's over 6700 lbs of total force on the lid of that filter. Don't take any chances.

Whether the pump is full of water or air, the pressure is the same, and the potential for a failure is the same. The only difference is the water is incompressible, and with a filter entirely full of water you won't get the violent "space shuttle" effect that occurred when your filter failed after filling with air. As others have pointed out, the filter will get air in it sooner or later, and you won't want to be near it again when it does.
 
thothtp said:
Thats the thing though, the clamp is completely intact. Nothing wrong with it.

I found the manual for my filter here http://www.waterwarehouse.com/Pdfs/1876.pdf and it says repeatedly that air in the system can cause the top to blow off. I think that must be my issue, and the lid came off because I didn't tighten it down as much as possible I guess.

When I bought the house last year, the previous owner told me everything I needed to do with the filter, including that I should hand tighten the clamp till I couldn't tighten it anymore. What I did not use was a wrench, but after reading the manual it seems it requires a lot more pressure then hand tightening could ever provide. They also suggest a rubber mallet, which I obviously didn't use. Tightening it this way worked all last summer perfectly.

I am a little weary of clamping it on even harder though, as that will cause even more force if it were to let go. The issue must be either a clog or air or both.


edit: oh and no freezing weather, its been between 40 and 75 since i started.
Click to expand...

I just noticed your comment about hand tightening the clamp. OMG!! I have a Pentair filter that is the same or very similar to yours. I use a 1/2" drive socket wrench and a rubber mallet to tighten the clamp, as directed in the manual. Hand tightening would NEVER be sufficient. You have to tighten the nut to the point where the coils of the spring (which is adjacent to the nut) are touching. You firmly tap the clamp all the way around the perimeter frequently as you tighten the nut. The mallet serves to distribute the force evenly around the clamp, preventing any localized binding. Now I can see why your lid went "space shuttle."

The whole system might still be ok if you tighten it properly, or the explosion may have permanently damaged it. If you decide to keep using it, I would be very careful.
 
I can't imagine NOT using a rubber mallet and wrench to cinch up my filter. There is an awful lot of play in that band that is eliminated by the alternating use of these two items. The mallet causes the lip on the clamp to fully engage the lips on the filter halves, which creates slack in the band. Then you tighten it some more, and the next round of malleting creates more slack. You don't stop banging, until the process has no more effect--that is, the nut and band are just as tight before as they are after. You can then run that pump to max pressure on a blocked output and that filter pump still won't blow the clamp.

The 'air relief' valve in these filters are usually NOT pressure relief or safety valves. They merely eliminate the air pocket at the top of the filter tank and they take a long time to do that. They have no effect on an overpressure condition when there is no air present, therefore you should not think it is defective if a filter explodes because it was improperly clamped. That said, even normal working pressure of 10-20 psi can cause a pretty dramatic 'explosion' if the clamp slips off.
 
socalsharky said:
I just noticed your comment about hand tightening the clamp. OMG!! I have a Pentair filter that is the same or very similar to yours. I use a 1/2" drive socket wrench and a rubber mallet to tighten the clamp, as directed in the manual. Hand tightening would NEVER be sufficient. You have to tighten the nut to the point where the coils of the spring (which is adacent to the nut) are touching. You firmly tap the clamp all the way around the perimter frequently as you tighten the nut. The mallet serves to distribute the force evenly around the clamp, preventing any localized binding. Now I can see why your lid went "space shuttle."

The whole system might still be ok if you tighten it properly, or the explosion may have permanently damaged it. If you decide to keep using it, I would be very careful.
Click to expand...


Yeah, that is obviously the issue. When I bought the house it came with no manuals, and the previous owner told me to hand crank it till you can't anymore. I assumed he knew what he was talking about, as it worked all last summer, even with pressures hitting 25psi on a dirty filter.

After all this happened I went and finally found some manuals online, and saw the part about compressing the spring. I was nowhere near that tight before.

Incidentally, he also told me the relief valve at the top was automatic. I am finding out now that that is also not the case, and should be open when the filter is filling.

Inspecting the filter, nothing is damaged at all, the clamp is completely intact and the dome is perfect. The only place it may be damaged is the gauge, considering it was the point of the missile when it hit my roof heh. It looks fine, but the internal parts could be damaged.

I will try again with proper tightening, and make sure I have a blast shield when I turn it on. Hopefully everything is fine, otherwise I will be buying a new filter.


Moral of the story, DO NOT TAKE THE PREVIOUS HOMEOWNERS WORD FOR IT. Even if everything works perfectly for a whole year, you are likely doing something wrong. Find the manuals.
 
Well I got everything put back together, and the filter seems to be fine. I gave the filters a thorough dish soap soaking as well, and that brought the pressure down to 10. Not sure the previous owner ever did that.

So with the filter set, the pump is now making me nervous. As I said earlier, it tripped the breakers and shut itself off both times the filter came apart. I am assuming the flood of water shorted it out, thats the only thing I can think of. Anyways, its up and running fine, except I noticed that it seems to be making a lot more noise now. Its got more of a whine noise to it now. I don't want to say grinding noise, as that sounds harsher then what it is, but it definitely sounds different. Should I be worried? Or should I just let it go and if it fails it fails? As long as it doesn't burn my house down heh.
 
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