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Pentair Quad 80 DE Filter Correct Installation

Posted by mred111 (My Page) on
Wed, Apr 18, 12 at 16:49

I'm trying to figure out if my Pentair Quad 80 DE filter is plumbed incorrectly. It is installed with the appropriate P/N 261165 - 2" PVC Slide Valve Kit.

I was reading that it is supposed to be installed like a sand filter. It is installed like a DE filter so with the slide valve up, it backwashes out the bottom waste opening. I just replaced all my filters. One of them was blown up. Wondering if it is plumbed backwards. It is plumbed like a DE Filter with the bottom to waste and the slide valve down for filtering and up for backwashing. Think this is backwards according to the post on here which I copied at the bottom.Would attach pics but I guess they have to be linked to from another source. I can do that if someone wants to see the configuration.

Can't decipher the owner's manual as it seems vague with no diagram. Coudn't find pics of installed Quad DE filters so not sure what to do as I have a pool leak. Even checked "Pentair University" and they don't have installation instructions for this filter.

I have one of the first intelliflo pumps (2006) and some kind of pool leak so it won't prime (alarms out) and goes into feature 1 mode which I haven't figured out how to disable. Wondered if plumbed backwards and this could be my priming issue. Thanks so much!

Hi Pan,
It really sounds like you have it backwards.
Slide valve should be up in normal operation.
Valve should be down during backwash.
Yes the valve locks in either up or down position.
No it should not get sucked down unless it is plumbed wrong.
Here is a picture, hope it helps. (Picture not there)
The valve operates 2 ways, one for sand and one for DE.
The following is directly from the slide valve manual - SLIDE Valve For Pentair Sand and DE Filters #261165 2"
Sand Connection: Valve top connection - to waste, middle connection - from pump, bottom connection - return to pool
Sand operation: requires Handle up for filtering and handle down for back washing.
DE Connection: Valve top connection - return to pool, middle connection - from pump, bottom connection - to waste
DE Operation: requires handle down for filtering and handle up for back washing.


You are wrong on this filter.
This is not a normal DE filter, it is a QUAD DE. When you use a slide valve with a QUAD you plumb it like a SAND filter, not a DE. You must read the directions of the filter. When you plumb it as you have it, it will EXPLODE the $400 plus cartridges.
We have installed many of these, plus I have one in my own backyard.

Follow-Up Postings:

RE: Pentair Quad 80 DE Filter Correct Installation

If a filter was blown up, it was likely installed backwards. The valve used is, in fact, installed like a side mounted sand filter. Water enters the filter from the upper port on the filter and departs from the lower one. The slide valve on most DE filters is the opposite.


RE: Pentair Quad 80 DE Filter Correct Installation

Thanks. Scott! I replumbed the filter. My slide valve is sticking and hard to move.I finally got it all the way up and restarted but water shot out the bottom waste like it was backwashing. I did hear a pop sound so perhaps something blew inside the slide valve? It's the Pentair Model 261165. Do you advise taking it apart and trying to replace O rings etc and perhaps lubing the rod, replacing it or getting rid of it altogether? The slide valve is only for backwashing isn't it?I usually take the filters out to clean them so don't see a real need to have backwash capability.

Also, I have a Pentair 320 inline chlorinator. The feeder hose snapped off. I was advised to just remove it since it raises CYA. Have a pool leak so putting water in alot so until I can get that fixed, should I use it? Do I need a check valve on the pressure side before or after this 320?

Thanks, Ed

RE: Pentair Quad 80 DE Filter Correct Installation

Looks like I replumbed it wrong over the weekend.Unfortunately, can't attach pics here or link. I just reversed the input and output. Was told that it has to be plumbed like a "sand filter" with waste coming out the top instead of the bottom.

Heard the slide valve make a popping sound upon restart and I can hardly move the slider. I usually take out the cartridges to clean them anyway. The hose broke on the Pentair 320 inline chlorinator so should I just remove it? Heard they are not worth raising your CYA although my pool leaks now so replacing water.

Other Questions:

1. Can I eliminate slide valve and plumb directly?
2. If so, what plumbing do I need to attache to filter?
3. If not, should I just replace the whole valve?


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