MPV model for Pentair FNS Plus, 1.5' pre-plumbed or 2"?

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ShinDiors

Well-known member
Jul 16, 2021
233
Northern VA
Pool Size
20500
Surface
Plaster
Chlorine
Liquid Chlorine
Recently got a new Pentair FNS plus 48 to swap out the old PACFAB NS48 DE filter that starts to leak. Currently has a slide valve and it looks like there would be some replumbing needed. I'm wondering if you guys feel MPV is better if replumbing is needed. I understand the added functionalities of a mpv, but I'm also thinking the more complicated valve would have more places to go bad potentially.

Anyways, if MPV is to be had, which one is the correct model? I see some with 1.5inch pre-plumbed, some with 2inch pre-plumbed, is the only differences the size of pvc in the existing plumbing system? I would think we want to have 2inch compared to 1.5inch plumbing (if replumbing is needed)?

Thanks a lot.
 
Should be no difference between the two versions internally, it's just the port size for the plumbing. I would go with the 2" if possible. I'm seeing the Pentair 261152 as a proposed fit. Let me confirm with @JamesW to be sure. As for longevity of a plunger over a MPV, they each have their share of parts that ca wear, O-rings, gasket, springs, etc, but I would go with a MVP if I could.
 
The MPV will have slightly less flow restriction. The MPV will give more options, only valuable if you use them. The push/pull is easier to install and has served you well. You need to find out if the new valves will fit that old tank.
 
Texas Splash said:
Should be no difference between the two versions internally, it's just the port size for the plumbing. I would go with the 2" if possible. I'm seeing the Pentair 261152 as a proposed fit. Let me confirm with @JamesW to be sure. As for longevity of a plunger over a MPV, they each have their share of parts that ca wear, O-rings, gasket, springs, etc, but I would go with a MVP if I could.
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Saw a 1.5 inch pentair MPV on FB MP, asking for $115. Will I be able to make it work with 2“ plumbing? The 2" one seems to be $200+ on amazon.
 
@JamesW @Texas Splash I have a question regarding using cartridge filter vs DE filter. I bought this FNS plus thinking it would be the same physical size and almost identical plumbing config, that re-plumbing or any alteration would be minimal; plus I got it at 45% off msrp. However, it turned out that the new one was taller than my old PACFAB and require removing my equipment enclosure's roof to provide sufficient clearance, also the inlet/outlet configuration is different from PACFAB as well, which kinda beat the my initial intention.

I understand that cartridge filter is more DIY friendly and also the recommendation of "getting the largest capacity ones you can afford". In my case, what might be the recommended cartridge filter (size and model)? I want to see the cost and physical size for the cartridge filter to see if I can get away with tearing out the roof. The pool is 20k gal, I used 48sqft DE filter, the clearance I have for the equipment enclosure is 62 inch (the PACFAB requires 61 inch clearance to be able to remove the top and filter grid inside, but the new filter requires 74 inch clearance) Thanks a lot.
 
My current setup has a few problems.
1. The equipment is lower than pool water level. I had a nightmare last year when the return pipe had a joint leak, that it took 3 hours for the water to stop gushing out (plugged all returns, skimmers, maybe not sealed too well though). I initially thought a replumbing that lift the equipment might solve the problem, but now thinking back, unless I have turn off valves on return line, there is always a place along that pipe lower than water level.
2. The clearance and space is too tight for any further improvement, for example, larger filter or a SWCG?

I'm thinking if replumbing and removing the roof is inevitable, should I consider lifting up the equipment, adding more shut off valves and reroute the pipes altogether?
 

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1poolman1 said:
That's the danger of putting equipment under a structure that can't be lifted. Since a cartridge filter has to be opened for cleaning, you may want to move it out from under the deck. If you're not going to use the heater, put it there.
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The heater was leaking last year right after we renovated the pool, and it was bypassed since. I would stilll want to have a heater down the road and the gas line is already there. I was somewhat convinced that I would have to at least cut open that roof to make room for the new filter unless I can use a cartridge filter similar size to my old PACFAB.
 
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ShinDiors said:
I'm thinking if replumbing and removing the roof is inevitable, should I consider lifting up the equipment, adding more shut off valves and reroute the pipes altogether?
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Easy for us to say yes because it's not our money and effort :), but that may a reasonable option.
 
Back to this question, for a 20k gal pool, what is the proper size of cartridge filter? Will it be possible to use one that is similar size to the PACFAB NS48 (only needs 61 inch clearance) that I do not have to tear down the roof? I found CC plus 320 is similar clearance and faster turnover rate than my current PACFAB, not sure if that would be adequate.
 
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ShinDiors said:
Back to this question, for a 20k gal pool, what is the proper size of cartridge filter? Will it be possible to use one that is similar size to the PACFAB NS48 (only needs 61 inch clearance) that I do not have to tear down the roof? I found CC plus 320 is similar clearance and faster turnover rate than my current PACFAB, not sure if that would be adequate.
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There is no “proper size” for a cartridge filter. In Florida they use small 150 or 200 sq ft filters.

The smaller the cartridge filter the more often you may need to clean it.

If a 320 is the biggest filter that fits your space then go with it.
 
ajw22 said:
There is no “proper size” for a cartridge filter. In Florida they use small 150 or 200 sq ft filters.

The smaller the cartridge filter the more often you may need to clean it.

If a 320 is the biggest filter that fits your space then go with it.
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I must have seen the price of those single cartridge filter before and thinking they are way cheaper than the MSRP of a 48sqft DE filter. Now looking at it, CC320 would run 1000-1200 it looks like. I got the FNS Plus DE filter for about $500 brand new (still got some time that I can return it), guess I will need to factor in the necessity and cost of modifying that equipment enclosure (at least tearing part of the roof off) to make the comparison. Oh and another thing, if I want to eventually get a SWCG, would I need to switch to cartridge? I saw the label on this new FNS DE filter says for "freshwater pool only".

I do not like that cramped space but it does provide some weatherproof for the equipment. choice choice...
 
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A filter is the most weather resistant piece of equipment you have. There is no reason for it to be under an enclosure.
 
ajw22 said:
A filter is the most weather resistant piece of equipment you have. There is no reason for it to be under an enclosure.
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I was thinking more about the ones that needs electricity, pumps, electric panels etc. But again, a lot of equipment pads I saw here are entirely exposed, so that should not be too much of a problem.

Now the question is if a plumbing overhaul (rerouting, adding some shutoff valves) and re-arrange the equipment would be necessary for my future improvement (adding swcg, revitalize a heater at least). If the enclosure must go for the future plan, then I could use the new DE filter that I got for cheap. Right now not seeing anything below $1000 for the CCP320 (even more expensive for 420/520).
 
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