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Thread: Help plumbing Pentair FNS+ 48 filter... (Sightglass???)

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    Help plumbing Pentair FNS+ 48 filter... (Sightglass???)

    I just received my new Pentair FNS+ 48 D.E. filter in the mail, along with the high-flow MPV and a 'sightglass kit'.

    Problem is, this "sightglass" is basically a clear piece of plastic that has threads on one end, and a big hole at the other. I'm sure you veterans know exactly what I'm talking about, but that makes one of us.

    I've seen numerous sightglass before, but they were all small (maybe 1" diameter) and they screwed into the MPV, and they were closed (like a cup). This is closer to 2" diameter and wide open, if I screwed it into anything (which I don't even know where to put it, the MPV doesn't seem to have a place to screw it into) the water would just come rushing right out.

    So, any ideas?
    20' x 40' custom shape (modified kidney) inground (plaster?) pool w/built-in steps & seating area
    ~38,000 gallons / Pentair VSP Pump / Pentair FNS-Plus 48 Filter / RayPak Digital P-R266 Heater
    1.5" Pipes / Single Skimmer / 3 Returns / 1 Light

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    Re: Help plumbing Pentair FNS+ 48 filter... (Sightglass???)

    For example, this is what I expected...



    And this is what I received...



    Am I missing something?
    20' x 40' custom shape (modified kidney) inground (plaster?) pool w/built-in steps & seating area
    ~38,000 gallons / Pentair VSP Pump / Pentair FNS-Plus 48 Filter / RayPak Digital P-R266 Heater
    1.5" Pipes / Single Skimmer / 3 Returns / 1 Light

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    Join Date
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    Re: Help plumbing Pentair FNS+ 48 filter... (Sightglass???)

    I believe the idea with that is to plumb it into your waste line
    15,600 Gallon, 16' x 32' In-Ground Vinyl Pool
    Pentair VS 3050 pump, Quad DE 60 filter and SunTouch controller
    8 gallon Liquidator, Aquatherm EcoSun Solar Panels, 2 wheel ThePoolCleaner

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    JasonLion's Avatar
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    Re: Help plumbing Pentair FNS+ 48 filter... (Sightglass???)

    Some multi-port valves have a place where you screw in a sight glass like the one you have pictured. But for all the main valves that don't have that feature built in you need to use a section of transparent pipe on the backwash line instead.
    19K gal, vinyl, 1/2 HP WhisperFlo pump, 200 sqft cartridge filter, AutoPilot Digital SWG, Dolphin Dynamic cleaning robot
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    Re: Help plumbing Pentair FNS+ 48 filter... (Sightglass???)

    So carlscan26 is correct, somehow I need to find a way to plumb that into my waste line? Should I use a T and a screw-on cap?
    20' x 40' custom shape (modified kidney) inground (plaster?) pool w/built-in steps & seating area
    ~38,000 gallons / Pentair VSP Pump / Pentair FNS-Plus 48 Filter / RayPak Digital P-R266 Heater
    1.5" Pipes / Single Skimmer / 3 Returns / 1 Light

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    Mod Squad Bama Rambler's Avatar
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    Re: Help plumbing Pentair FNS+ 48 filter... (Sightglass???)

    How is your waste line plumbed now? Hard pipe, hose, etc?
    Dave J. TFP Moderator
    24' x 52" Round AGP. 2hp/¼hp SPL Power-Flo 2-speed pump. 200sqft Waterway Cartridge Filter. 45MHP2(3GPD) Stenner Peristaltic Pump
    Pool School ----- Pool Math ----- TF-Test Kit

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    Re: Help plumbing Pentair FNS+ 48 filter... (Sightglass???)

    Hard pipe...
    20' x 40' custom shape (modified kidney) inground (plaster?) pool w/built-in steps & seating area
    ~38,000 gallons / Pentair VSP Pump / Pentair FNS-Plus 48 Filter / RayPak Digital P-R266 Heater
    1.5" Pipes / Single Skimmer / 3 Returns / 1 Light

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    Mod Squad Bama Rambler's Avatar
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    Re: Help plumbing Pentair FNS+ 48 filter... (Sightglass???)

    You should be able to cut out a piece of the piping an thread that in the valve then glue a coupling on the smooth end of it. I'd use a union to make it easier to remove the valve if ever needed.
    Dave J. TFP Moderator
    24' x 52" Round AGP. 2hp/¼hp SPL Power-Flo 2-speed pump. 200sqft Waterway Cartridge Filter. 45MHP2(3GPD) Stenner Peristaltic Pump
    Pool School ----- Pool Math ----- TF-Test Kit

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    Re: Help plumbing Pentair FNS+ 48 filter... (Sightglass???)

    Not sure how its going to work yet, I still have about 1 foot of pipe left to plumb (from pipe to filter), but what I did is put a 2" cap on the smooth end, got a 2" female thread to pipe adapter for the other end, and then glued that into a T in the waste line so I can unscrew the sightglass and replace or clean it easily, or even take it out completely and just screw a 2" cap in it's place... I'll let you know how it goes..

    Thanks!
    20' x 40' custom shape (modified kidney) inground (plaster?) pool w/built-in steps & seating area
    ~38,000 gallons / Pentair VSP Pump / Pentair FNS-Plus 48 Filter / RayPak Digital P-R266 Heater
    1.5" Pipes / Single Skimmer / 3 Returns / 1 Light

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    Re: Help plumbing Pentair FNS+ 48 filter... (Sightglass???)

    Here is a pic of what I ended up with (all new pipes except for the ones in/out of the heater)...



    Hopefully this will work well.. The sightglass simply unscrews and I can put a cap in there, or clean/replace it easily.
    20' x 40' custom shape (modified kidney) inground (plaster?) pool w/built-in steps & seating area
    ~38,000 gallons / Pentair VSP Pump / Pentair FNS-Plus 48 Filter / RayPak Digital P-R266 Heater
    1.5" Pipes / Single Skimmer / 3 Returns / 1 Light

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    Mod Squad Bama Rambler's Avatar
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    Re: Help plumbing Pentair FNS+ 48 filter... (Sightglass???)

    That will work fine, but it is designed to go inline where you put the TEE. It would screw into the valve and a coupling would glue over the back of it.
    Dave J. TFP Moderator
    24' x 52" Round AGP. 2hp/¼hp SPL Power-Flo 2-speed pump. 200sqft Waterway Cartridge Filter. 45MHP2(3GPD) Stenner Peristaltic Pump
    Pool School ----- Pool Math ----- TF-Test Kit

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    Re: Help plumbing Pentair FNS+ 48 filter... (Sightglass???)

    Yeah, I gathered that.. I just thought my solution worked better. Now I have options... I like options.. It's easy to pull and clean, replace, get rid of, etc.
    20' x 40' custom shape (modified kidney) inground (plaster?) pool w/built-in steps & seating area
    ~38,000 gallons / Pentair VSP Pump / Pentair FNS-Plus 48 Filter / RayPak Digital P-R266 Heater
    1.5" Pipes / Single Skimmer / 3 Returns / 1 Light

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