Pentair FNS Plus Filter - Bulkhead O-ring Missing and Drain Plug Removal

[acpie360]

Yesterday I finally summoned up courage to clean the DE filter for the first time since we owned the house. I followed jblizzle's tutorial page and everything went smoothly. It did take me half a day though. Here is the before and after:

Anyway, during the cleaning process, I noticed two things:
1) The existing bulkhead seems to have gone through some kind of repair by the previous owner. A PVC pipe connector was put on the top and sanded down to fit the manifold. If there is no o-ring to seal the connection, what kind of "bad things" could happen?

2) My Pentair FNSP 60 DE Filter has the drain plug at the bottom of the tank. I couldn't get it to open by hand. Is there a special tool that is designed for the job?

 

[d103]

Have the same filter, for the bottom drain plug you can use a vise grip or open end wrench, just do not put too much force as the plastic tends to get crushed easily.

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[acpie360]

Thanks. I'll try that next time. It is really an awkward position to work on.

Regarding my first question - If the standpipe(#19) and the manifold(#6) can't joint very well and create a leak, would that cause DE to come back from the return? I think I have some kind leak causing DE to flow back in the return, but I am not sure where to look for the problem.

I have the kind of backwash valve that goes up and down.

To backwash, I need to turn the handle then pull it all the way up. Yesterday, I had trouble pushing the handle down after I put back the DE filter. The handle wouldn't go all the way down so I fiddled the backwash valve assembly and finally was able to get it to the normal operation position. Other that this I can't think of anything else...

 

[RedScare]

I use a shop vac to clean the water and DE from the bottom of the filter instead of using the drain plug. This way I do not risk strip the drain plug thread.

I replaced my O-ring while searching for the source of DE returning to my pool, but I do not think that is what caused it (likely source was a bad spider gasket).

 

[acpie360]

I use a shop vac to clean the water and DE from the bottom of the filter instead of using the drain plug. This way I do not risk strip the drain plug thread.

I replaced my O-ring while searching for the source of DE returning to my pool, but I do not think that is what caused it (likely source was a bad spider gasket).

That's what I did by using a shop vac to empty the tank. Since I have a two position slide valve as shown in the second picture of my last post, could a bad slide valve cause DE to shot back from the return? If I add a scoop of DE to the skimmer while pump is running, I can see "white stream" shooting out of the returns.

I have no DE residue seen in the skimmer port or the bottom of the pool drain port, can I assume I don't have air leak? I am trying to understand how the DE can come back in the return. Any comments?

 

[RedScare]

Well, I spent the better part of a week replacing parts and gaskets that I thought could be causing it. Obviously, you want to carefully inspect your filter grids for torn fabric or cracked plastic. Inspect the manifold on top for broken fittings. To be on the safe side, I replaced my O-rings. What finally solved my DE problem was replacing the spider gasket in my multiport. The interesting thin is that the spider gasket did not look that bad, but I replaced it anyway. For $28, it is worth replacing to see if that solves the problem.

 

[PoolguyinCT]

There is a proprietary wrench for the drain, but I usually have a mid size channel lock handy anyway.

You should treat yourself to a multi port valve, they offer so much more control than those old push pulls.

 

[acpie360]

There is a proprietary wrench for the drain, but I usually have a mid size channel lock handy anyway.

You should treat yourself to a multi port valve, they offer so much more control than those old push pulls.

I am thinking about the multi port valve. Not only that, I am thinking about doing away with the DE and go with a cartridge filter system.