- Jul 24, 2017
- 171
- Pool Size
- 8400
- Surface
- Plaster
- Chlorine
- Salt Water Generator
- SWG Type
- Pentair Intellichlor IC-40
I had a small DE leak earlier this year in our seven year old Pentair FNS Plus. Filter elements were all original. Several had small frame cracks. No obvious fabric rips, but they were 7 years old and the I could tell the plastic was cracking. Since I had a DE leak I replaced them all. I figured problem solved but within a couple days subtle DE streaks were visible. Frustrated, I took the filter apart again. I had checked the manifold last time and found no cracks, but this time I inspected it very carefully in direct sunlight. With the help of the sun, I found a very small, subtle crack where the air bleed tube slides in. I installed a new manifold and that did it, no more DE. High fives, time for an adult beverage.
The best price I could find on a new manifold was to buy a Pentair kit that included not just that new manifold, but also 8 OEM Pentair filter elements. I didn't need the elements at that moment but the price was great and I was happy to have them as spares. The new replacement elements I'd originally installed (before finding the manifold crack) had been third party product. Those looked okay but they were not as stout as the original Pentair elements had been. Since the original elements had been flawless for 7+ years, I installed all those new elements at the next filter cleaning, and washed off all the third party elements to store them as spares. All good, except a few days after doing that, I could see signs of another DE leak. It can't be the new OEM elements, can it? Hint: yes it can, but I was skeptical about that, so at first I replaced the stand pipe o-ring. That didn't solve the problem. My next suspect was the multiport valve, so I looked at that next and could see the seven year old spiker gasket was quite worn, so I replaced that too. The multiport operated easily again (yay), but the slow DE leak persisted.
So I took disassembled the filter again (what a fun job) and inspected all 8 of the brand new OEM Pentair filter elements carefully. Turns out that one of them had a seam sewing error. Not a big one, so I'd missed it on the too casual inspection I gave them all when I first installed them. But it was big enough to cause the leak -- about a half inch of that bottom seam on the "short" element that sits next to the stand pipe wasn't fully sealed. DE is tiny, we all know, so it doesn't take much of a gap to bleed through. I inspected all 8 the same way. Only one had a gap.
Here's what may be a helpful tip: My leaking seam was at the bottom of the filter element. In other words, at the end opposite of where the connection tube pops out that you slide into the manifold. If you have a new element "seam leak" that's probably a good place to start to start looking, and here's why. It looks like when those elements get fabricated, the top seam (where the connection tube pops out) and the two long side seams get stitched together first, likely on a sewing machine in the factory where all they're dealing with (so far) is just stitching together the fabric. Once that gets done, the now finished-on-three sides covers then get pulled over the plastic frame, with only that last "bottom" seam left to get sewn closed. But that's a trickier thing to stitch up, since now you've got this big pice of curved plastic inside the fabric. That makes sewing that final seam more difficult.
Another tell is that, on these Pentair elements, that bottom seam also had a different colored seam thread than the other three sides. It was black on the bottom seam and white on the other three sides. On all 8 of the new Pentair elements, the wonkiest looking seam stitching was on that bottom, black thread seam. Only one of the eight had an actual hole though. So I replaced that grid with one of my third-party spares, and boom, DE problem finally solved.
To find that kind of tear or hole on the seam, you will really have to clean them thoroughly and then "separate the fabric flaps" that stick out just beyond where they sew the seams. That was 100% the only way to see the small gap on mine. It wasn't visible otherwise. If that doesn't make sense right now, don't worry, it will once you have your filter elements in your hands. Try to do this close inspection on a sunny day if possible, good light makes it easier.
Anyway, I couldn't find a post like this and didn't know how to attack the problem. Hope this helps one of you. Enjoy your pools, stay safe and Happy New Year!
The best price I could find on a new manifold was to buy a Pentair kit that included not just that new manifold, but also 8 OEM Pentair filter elements. I didn't need the elements at that moment but the price was great and I was happy to have them as spares. The new replacement elements I'd originally installed (before finding the manifold crack) had been third party product. Those looked okay but they were not as stout as the original Pentair elements had been. Since the original elements had been flawless for 7+ years, I installed all those new elements at the next filter cleaning, and washed off all the third party elements to store them as spares. All good, except a few days after doing that, I could see signs of another DE leak. It can't be the new OEM elements, can it? Hint: yes it can, but I was skeptical about that, so at first I replaced the stand pipe o-ring. That didn't solve the problem. My next suspect was the multiport valve, so I looked at that next and could see the seven year old spiker gasket was quite worn, so I replaced that too. The multiport operated easily again (yay), but the slow DE leak persisted.
So I took disassembled the filter again (what a fun job) and inspected all 8 of the brand new OEM Pentair filter elements carefully. Turns out that one of them had a seam sewing error. Not a big one, so I'd missed it on the too casual inspection I gave them all when I first installed them. But it was big enough to cause the leak -- about a half inch of that bottom seam on the "short" element that sits next to the stand pipe wasn't fully sealed. DE is tiny, we all know, so it doesn't take much of a gap to bleed through. I inspected all 8 the same way. Only one had a gap.
Here's what may be a helpful tip: My leaking seam was at the bottom of the filter element. In other words, at the end opposite of where the connection tube pops out that you slide into the manifold. If you have a new element "seam leak" that's probably a good place to start to start looking, and here's why. It looks like when those elements get fabricated, the top seam (where the connection tube pops out) and the two long side seams get stitched together first, likely on a sewing machine in the factory where all they're dealing with (so far) is just stitching together the fabric. Once that gets done, the now finished-on-three sides covers then get pulled over the plastic frame, with only that last "bottom" seam left to get sewn closed. But that's a trickier thing to stitch up, since now you've got this big pice of curved plastic inside the fabric. That makes sewing that final seam more difficult.
Another tell is that, on these Pentair elements, that bottom seam also had a different colored seam thread than the other three sides. It was black on the bottom seam and white on the other three sides. On all 8 of the new Pentair elements, the wonkiest looking seam stitching was on that bottom, black thread seam. Only one of the eight had an actual hole though. So I replaced that grid with one of my third-party spares, and boom, DE problem finally solved.
To find that kind of tear or hole on the seam, you will really have to clean them thoroughly and then "separate the fabric flaps" that stick out just beyond where they sew the seams. That was 100% the only way to see the small gap on mine. It wasn't visible otherwise. If that doesn't make sense right now, don't worry, it will once you have your filter elements in your hands. Try to do this close inspection on a sunny day if possible, good light makes it easier.
Anyway, I couldn't find a post like this and didn't know how to attack the problem. Hope this helps one of you. Enjoy your pools, stay safe and Happy New Year!
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