Pentair FNS plus has a small leak. Any ideas?

[cruzmisl]

Hi All,
I have a Pentair FNS plus 48 DE filter. It has a small leak around the separation between the upper and lower tank. I replaced the large o-ring last year. Any ideas how to stop it. IIRC I had the same leak last year but it wasn't nearly as bad. It was very slow. Even now it just seeps out but it annoying. I don't want to buy another o-ring if it could be another problem. Also I installed the o-ring dry. I didn't use any teflon lube. I'm not sure if that's correct or not.
Thanks for the help,
Joe

 

[jblizzle]

If it is like my Hayward, you are supposed to lube it up good when you install it. That is the likely cause of your leak. And should be a pretty cheap fix :-D

 

[Bama Rambler]

I agree you should lube it well. That large an o-ring needs to 'settle' into place and without lube it can't do that.

 

[maxepr1]

Lube the O-ring and adjust the band clamp and re-torque.

 

[jblizzle]

I also want to add that when I am tightening the band clamp I get it snug and then tap on it all the way around with a rubber mallet to seat the band some more. Then tighten and tap, tighten and tap, etc until the bolt/nut stays torqued to the correct spec after tapping.

 

[cruzmisl]

Thanks for the tips. Is there a torque value for the nut. I didn't see one listed in the manual.

 

[jblizzle]

On my Hayward you tighten until a spring is compressed and touching ... not sure about the Pentairs.

 

[maxepr1]

It says to compress the spring until the coils touch each other.

 

[cruzmisl]

meh, I did all of the above and still have some seepage. Any other ideas?

 

[boon4376]

meh, I did all of the above and still have some seepage. Any other ideas?

How much lube did you use?

This year when putting everything together, I cleaned all of the connecting surfaces of both tanks, and the o-ring. I put it back together forgetting to lube it up and it was leaking.

I took it apart, lubed up the o-ring real well and put it back together. Still leaking!

So I took it apart again and lubed the ring again, plus the lips on the top and lower tank. Put it back together, no more leaks.

It can take a lot of lube, especially if you are starting with None. My o-ring seems to absorb a lot of this stuff.

Also, I use something called o-ring lube that my pool supply store stocks, its nasty green stuff, but made specially for this application.