Backwash Valve Replacement

poollizard

Active member
Jul 4, 2010
31
Apple Valley, California
My slider backwash valve is stuck. So stuck that I can't even turn the handle. So, I am planning on replacing it with a "Pentair 261152 Multiport Valve Kit 2in. Threaded" valve.

First, I want to know if this is the right valve for my DE filter:
261152 Pentair Multiport Valve Threaded.jpg - Shared with pCloud

My DE filter is an old PAC-FAB FNS 60.
20191125_115459.jpg - Shared with pCloud

Next, I'm just asking for some advice on how to properly do the job, and any helpful tips for doing the job correctly the first time. I am fairly good with hand tools and small DIY jobs around the home. I just don't want to screw this up.

Here's a link to other photos of my pool equipment:
Backwash Valve - Shared with pCloud (If this link doesn't work, please let me know.)

Thanks in advance for any help!

Jerry, the poollizard.
 

poollizard

Active member
Jul 4, 2010
31
Apple Valley, California
Well, I finally got the core out of the casing. What I did was, 1) First I drained the filter tank, 2) then I disconnected the tank from the backwash valve, 3) Then I sprayed some WD-40 into the valve's both ports, 4) I let that soak a while, while I cleaned the filter grids, 5) then I reconnected the tank to the valve to give it some stability, 6) then I tried one more time to get the core to turn, and by golly, it turned! So then I just kept pulling and turning and finally it popped out.

Here's a pic of the core plunger:
20191126-0412571409.jpg - Shared with pCloud

It looks to me like the lube I had put on it back on October 23rd, got all gummy and stiff. I used a well known store brand "Pool & Spa Lube".

What would you do? Would you just get a whole new valve, plunger and all? Or would you just clean up this one and use a different lube on the O rings? Maybe even get a new set of O rings.
 

poollizard

Active member
Jul 4, 2010
31
Apple Valley, California
Well, it's come to this. I'm either going to get a whole new valve, plunger, casing and all, or I'm just going to replace the core plunger.

This old plunger of mine has a few problems from when I replaced the O rings back in October. I bunged up the cotter pin getting the handle off of the shaft so I could replace that small o-ring that's just under the top plate.

So now the question is, should I replace the whole thing, or just the plunger?

I'm not real excited about redoing the plumbing for a whole new valve. I think I'm going to get a new plunger assembly.

But what lube should I use? I'm afraid to use the same lube that I already have, for fear of the same thing happening again.

I've already checked my local Home Depot and Lowe's, neither of them have ZerO lube.
 

ajw22

Gold Supporter
TFP Guide
Jul 21, 2013
11,315
Northern NJ
New O rings and the right lube should get it going.

Pool Lube is used to seal O rings and make them water tight. They are not good for a sliding O ring like here.
 

poollizard

Active member
Jul 4, 2010
31
Apple Valley, California
Well, as it turned out I had to replace the whole piston assembly. I must have cracked the original one, because even with new o-rings it leaked out the top. New one installed and working fine now.

Thanks to everyone who replied and left tips. It all helped.

Happy Thanksgiving to all!