O-ring pops out

Duard

New member
May 15, 2019
3
New York
Hi, I have a 3 year old Pentair FNS+4800 DE filter. I've had trouble with clamp issues, broke one overtightening it, learned a lot. Today, the clamp seems fine but I have o-ring problems. After running for a few hours the o-ring pops out of its channel and water flies in all directions. The lid does not blow off because the clamp holds. The clamp also catches the o-ring. so far I have backwashed and replaced the DE, thoroughly cleaned the channel where the o-ring goes on both top and bottom parts, replaced the o-ring with a new one in manufacturer's packaging, lubricated the o-ring being careful not to stretch it, made sure all returns are open and operative. Still no help. The clamp appears to be on all the way, plenty of hammering with a rubber mallet, tightened as directed until the spring coils touch each other. bolt makes screaming noises for the last couple of turns. If you don't have any suggestions I might have to convert my pool to be a big garden planter. Not really, but I am desperate.
 

setsailsoon

LifeTime Supporter
TFP Guide
Oct 25, 2015
1,131
Stuart/FL
D,

Welcome to TFP and sorry to hear about your o-ring problem. Sounds like you have more than the typical o-ring stretched issue. I'll also get you some expert assistance @Jimrahbe @Texas Splash . I'm sure one of these will be more familiar with your equipment and be able to help more than I can. While you're waiting can you please add more information to your signature and a photo or two? This will allow them to be more responsive.

I hope this helps and Good luck!

Chris
 

Jimrahbe

Mod Squad
TFP Expert
LifeTime Supporter
Jul 7, 2014
12,171
Bedford, TX
Duard,

It sounds to me like the clamp is just not tight enough... I know I would be scared to tighten it, if I had one that just broke..

Show us a couple of pics of the clamp and the band..

Are you sure the new band is the correct one?

Thanks,

Jim R.
 

Duard

New member
May 15, 2019
3
New York
It's possible that the problem is resolved. I thought about what was happening between when I would start the pump with a freshly cleaned and tightened down filter, and four hours later when the o-ring would blow, and what was in common between all of the instances was vacuuming. That's what you do first after the pump comes on, right? With the chanes to our climate we are having weird winters, where we previously would have had a couple feet of snow and ice, this winter we had three or four inched of murky mud everywhere. So I unpacked another new o-ring, lubricated it being careful to push, not pull it through the lubricant, backwashed, refilled with new DE (third time in two days, last year I used three charges of DE the whole summer), and checked the pressure. I usually get about 12-13 PSI after a backwash and I clean when it hits 24. I had 12 PSI, so far so good. I vacuumed about a third of the pool and noticed that the waterfall from the spa to the pool had stopped. Checked the pressure, it was 41. I never saw it that high, was probably a couple psi from blowing. Cut the power, and instead of backwashing or opening the filter to hose it out, I opened it and found everything coated in red clay. My guess is that clay-rich mud ran under the winter cover, got vacuumed up, and waterproofed the inside of the filter, so the water could not pass through and pressure just built until it blew the weakest part of the filter, which would be the o-ring. So I set it to backwash and finished vacuuming directly to waste, then opened the filter and seriously hosed everything out, closed up and thoroughly tightened, pump on and PSI=12. Ran a couple hours, PSI still 12. Getting dark, time to go in - At this time of year I would normally run the filter 24h/day for a few days but I'm afraid - if the o-ring blows while I'm sleeping I'm sure the results would be really unfortunate. Will start up the bromine feeder in the morning and see what develops.
 
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