How to replace Pentair FNS Plus Manifold

ag62

LifeTime Supporter
Jul 2, 2010
19
0
#1
Opened pool about a month ago and the water still have lots of small particles especially near return lines. I also see lots of sand (probably DE) on the floor. I decided to open the filter (never done this by myself before) and found that plastic on top of the grid has some cracks. I assume this is the top manifold and I believe the cause of my problem. I found replacement part, but can’t figure out how to do you replace it. Do I have to unscrew two plastic hex nuts and lift the grid out? Does anyone have instructions how to do it?

Thank you,
 

PoolGuyNJ

TFP Expert
May 20, 2007
3,192
0
57
South Central NJ
#2
Pull the grid first.

Unscrew the two nuts. Lift the manifold up.

I suggest taking the opportunity to hose off the panels too. Sounds like it hasn't been for some time. I also suggest a soaking for the panels after in a clean 32 gallon trash can, full of water and a 1/2 box of of cheap, powdered dishwasher detergent.Two hours right side up, two more upside down. Inspect them closely for hose and broken framework. Replace as needed.

Note where the 1 short panel is in the spiral. The others are all the same, larger size. This should be done annually, by the way.

Scott
 

ag62

LifeTime Supporter
Jul 2, 2010
19
0
#3
Took it apart and followed your advice. I’m now waiting for replacement manifold to arrive and I also found some grids with soft edges that are also being replaced. I found that one of the grids is partial size(looks like half) and unfortunately I didn’t notice where it was.
Is this the one that goes closest to the center of the template?
Thanks
 

ag62

LifeTime Supporter
Jul 2, 2010
19
0
#4
Never mind. I think I found how it works. The bottom template shows exactly how to put grids back. Duh!