Nautilus FNS 48 leaking DE into pool

[DavidTX]

So, i backwashed my filter for the first time last weekend on my own. Before the pool cleaning folks were taking care of it.

Once I backwashed and put more DE in I started to notice DE was being blown back into the pool and the Robot was picking it up over the next couple of days.

Today I took it apart and pulled the grid assembly and washed them off with the hose. They had very little DE on them but since its my first clean It's a guess.

After adding more DE I started to see lots of DE coming out of my return jet and the bottom of the pool has it all over now.

The grids looked okay with no visible tears from what I could see, but I did not dis-assemble as I was limited on time. The Manifold looks good except the air relief hose is missing the grid cover looks like it degraded away.

Wondering if I should order a set of grids or a full assembly to be safe. Previous owner had no info on maintenance or replacement date other than giving me a manual for the filter.

Few questions: what is difference between the FNS and FNS plus parts wise?
Was looking at this on Amazon but it says its for a plus
https://www.amazon.com/gp/product/B001E06892/ref=ox_sc_act_title_2?smid=ATVPDKIKX0DER&psc=1

I did find the original part number from manual for an assembly and it's about $400.

Thanks for the help on this.
-David

 

[crudsrus]

So, i backwashed my filter for the first time last weekend on my own. Before the pool cleaning folks were taking care of it.

Once I backwashed and put more DE in I started to notice DE was being blown back into the pool and the Robot was picking it up over the next couple of days.

Today I took it apart and pulled the grid assembly and washed them off with the hose. They had very little DE on them but since its my first clean It's a guess.

After adding more DE I started to see lots of DE coming out of my return jet and the bottom of the pool has it all over now.

The grids looked okay with no visible tears from what I could see, but I did not dis-assemble as I was limited on time. The Manifold looks good except the air relief hose is missing the grid cover looks like it degraded away.

Wondering if I should order a set of grids or a full assembly to be safe. Previous owner had no info on maintenance or replacement date other than giving me a manual for the filter.

Few questions: what is difference between the FNS and FNS plus parts wise?
Was looking at this on Amazon but it says its for a plus
https://www.amazon.com/gp/product/B001E06892/ref=ox_sc_act_title_2?smid=ATVPDKIKX0DER&psc=1

I did find the original part number from manual for an assembly and it's about $400.

Thanks for the help on this.
-David

"The Manifold looks good except the air relief hose is missing the grid cover looks like it degraded away."

The air relief hose needs replacement for sure. If you're missing the grid cover this will allow DE to return via return jets to pool.

If you open your filter to check for grid tears, do yourself a favor and disassemble the grids at least once a year. It's fairly simple and you can search YouTube for how to videos on this process.
Summary.... hopefully you only need to replace the air relief tube and it corrects the problem.

Good luck

 

[DavidTX]

Thanks for the info. I plan to take it apart again tomorrow and actually pull the grids out and inspect them further.

Really would be cool if it was the air relief cover missing that is letting that stuff through. I would guess I have about 2-3 scoops of de in the pool at the moment.


On a side note I see you have an FNS also when I opened mine it had no O-ring for the area were the two parts meet. Assuming its required based on the manual but its hard to tell were it would fit.

 

[crudsrus]

There should be an O-ring located on the standpipe. Please replace this O-ring along with air relief fittings. If you have any torn or week filter grids, do yourself a favor and replace as a complete set. Lots of options for complete set replacement for under $200.
There's also an option for manifold with build in air relief. I'll search and post link later.

 

[crudsrus]

Manifold for Pentair FNS Plus D.E. Filter V38-140
Search on Amazon. I'm currently using this manifold and I highly recommend it. It comes with built-in air relief, read the reviews and description.
Harry

 

[DavidTX]

Wow that does look like a really good option for a replacement manifold and you get rid of that air relief part that seems to go bad often.

I am going to take it apart in a few minutes before it gets to hot outside and see what I am dealing with grid wise.