HELP NEEDED - Pentair manifold pops off stand pipe

[eostrike]

Hello,

It has been several years since I have had to post anything here. I have been having an issue for years that I have not been able to figure out. Since you do not clean the filter often it takes awhile until this reoccur. Leslies has never heard of it either. The issue does not happen every time but does happen often. It only happens after you clean the filter. If I get lucky and it did not pop off it will not pop off anymore until I take it apart again and then it is a 50/50 if it will stay on.

After I clean my filter and put it back together I turn the pool pump back on to get the filter full of water and flowing through the pipes. What is happening is once the filter fills it will sometimes pop the manifold off the standpipe which in return blows all the DE back in my pool. When this issue started a few years back I replaced the manifold and it did not fix the issue. I have replaced the o-ring on the standpipe a few times over the years and still no go. This baffles me as to why this is happening.

The only thing that I can think of is maybe when it is priming it is set to high. It has been set to 2500 (speed) for years. Just before writing this I had to take the top off the filter again, put the manifold back on the standpipe and this time I turned the prime down to 1250 (speed). I am not certain this is the cause or not as it does not happen every time.

I had to shock my pool several days ago due to an algae issue, it is not fully cured but I need to figure out the cause of this manifold issue.

When the filter has been cleaned I have always opened the valve at the top and kept it open until it starts shooting water out the spout. Then I will regulate it until all the air escapes. I always thought that is how I am supposed to do it. Maybe what could be happening as well is keeping it open during prime may be the issue. Could that cause the manifold to pop off once it starts shooting water out and I close the valve?

I really need someone's professional opinion as this is something I have not been able to figure out. And google has no mention of this happening to anyone else.

I attached a few pictures. One with what it looks like when the manifold pops off, one at the higher prime setting and lastly the lower prime setting I just did before posting this here.

Please help on this issue.

Thanks,

EricO

 

[proavia]

Is the air bleed assembly correctly installed?
Is the screen at the top of the air bleed intact and clean?

It's part #7 at this link...

Pentair FNS Plus D.E. Filter 24, 36, 48, 60 Parts - INYOPools.com

Pentair FNS Plus D.E. Filter 24, 36, 48, 60 - INYOpools.com has the largest selection of swimming pool and spa replacement parts with over 70,000 parts in stock. Order today and save!

www.inyopools.com

 

[eostrike]

Thanks for the reply. So the air bleed screen you are speaking of is built into this manifold, it is flat and does not stick up like the original Pentair one did. When this problem occurred years back I purchased a non-Pentair manifold in hopes this issue would stop. Changing to a different brand manifold did not do anything to resolve what was happening with the Pentair manifold. I suppose it could be possible it is the screen however this has happened many times after I change the filter and when I start putting the DE in the skimmer it just puts it all in the pool. That's when I open the filter and see the manifold off the standpipe.

 

[Jimrahbe]

E,

I have no idea what the problem is, but in the filter mode that stand pipe should have suction, and so it does not make a lot of sense that the manifold would pop off of the stand pipe..

Maybe some problem with the backwash valve???

Thanks,

Jim R.

 

[trivetman]

The pipe which is plumbed from the bottom of the backwash valve and runs underground….is that a waste line or does it return to the pool? I am wondering if your de filter is plumbed backwards like a sand filter.

But if that was the case, I would think the DE always ends up in the pool and it sounds like that doesn’t happen.

 

[wireform]

I think somehow you're deadheading the filter by having more pumping into it then what can get out and that will make it pop off. Perhaps one of the valves aren't open to full port which builds pressure in the filter.

 

[JamesW]

Usually, that points to the water going the wrong way, but it looks like the DE is on the outside of the grids like it should be.

Double check that the flow is correct.

 

[JamesW]

Is this still accurate?

 

[eostrike]

E,

I have no idea what the problem is, but in the filter mode that stand pipe should have suction, and so it does not make a lot of sense that the manifold would pop off of the stand pipe..

Maybe some problem with the backwash valve???

Thanks,

Jim R.

Thanks Jim. When the problem first occurred I replaced the o-rings and inspected the backwash valve as well. The pool is fairly new being completed in early 2016.

 

[eostrike]

Is this still accurate?

View attachment 458853

Only thing that changed in that picture is I have a 3rd automated valve at the lower right side of the picture.

 

[eostrike]

The pipe which is plumbed from the bottom of the backwash valve and runs underground….is that a waste line or does it return to the pool? I am wondering if your de filter is plumbed backwards like a sand filter.

But if that was the case, I would think the DE always ends up in the pool and it sounds like that doesn’t happen.

The pipe under the backwash valve goes to a drain which will flow to the street when I backwash.

 

[eostrike]

I think somehow you're deadheading the filter by having more pumping into it then what can get out and that will make it pop off. Perhaps one of the valves aren't open to full port which builds pressure in the filter.

Since my first post on this yesterday I have turned the prime feature on my Easytouch to 0 minutes. My pool equipment is approximately 15' from the pool (deep end). Maybe since the pool is so close to the equipment their is more pressure than if it had to travel say 50' away.

 

[eostrike]

I think somehow you're deadheading the filter by having more pumping into it then what can get out and that will make it pop off. Perhaps one of the valves aren't open to full port which builds pressure in the filter.

I will need to pay attention to this as when I turn the pump on the valves will move to their position based on what I turn on which is normally the pool. So with that said while the pump is priming the valves will move to their position. Appreciate the comment.

 

[eostrike]

Is this still accurate?

View attachment 458853

James, great find on my pool pic. Here are some current ones I just took.

 

[JamesW]

That looks correct.

Maybe the grids are filling with air and floating up?

https://www.c-m-p.com/wp-content/uploads/2014/02/25831-11x-750-Pentair-Slide-Valve-Instructions.pdf

 

[trivetman]

Looks like you have check valves plumbed jn. Maybe they are not working properly and restricting flow?

What does the filter pressure build to during the priming?

 

[eostrike]

That looks correct.

Maybe the grids are filling with air and floating up?


View attachment 458963

https://www.c-m-p.com/wp-content/uploads/2014/02/25831-11x-750-Pentair-Slide-Valve-Instructions.pdf

Those grids are less than a year old. I replaced them as they were around 6 years old and I was running out of options. New grids do the same as the old. And as mentioned in the beginning it does not happen all the time but does happen more than it should.

And I am pretty certain the backwash valve is working properly as if it was not I would imagine I would be losing water to the street.

 

[eostrike]

Looks like you have check valves plumbed jn. Maybe they are not working properly and restricting flow?

What does the filter pressure build to during the priming?

Yes I have 2 check valves. One for the spa returns and one going to the pool heater. I will check what it goes up to when priming on Saturday or Sunday when I clean the filter again. I turned prime off last night. Maybe I should put it back to where it was? The strange thing is for the first few years I never had that issue. Then out of nowhere there it came.

 

[trivetman]

I think somehow you're deadheading the filter by having more pumping into it then what can get out and that will make it pop off. Perhaps one of the valves aren't open to full port which builds pressure in the filter.

What if that check valve in front of the heater sometimes isn’t opening properly? Could that be deadheading the filter causing pressure buildup in the standpipe?

I am feeling very invested in this mystery!!

 

[wireform]

What if that check valve in front of the heater sometimes isn’t opening properly? Could that be deadheading the filter causing pressure buildup in the standpipe?

I am feeling very invested in this mystery!!

I think you can remove the innards of the check valve by removing all the screws on the cover. I'd temporarily remove it to see if anything changes.