Tip & How-To about Pool & Spa

Changing from a Pentair FNS DE Filter To A Pentair FNS Plus DE Filter

If you are the proud owner of a Penatir FNS DE filter, it may be nearing the time when you will be upgrading to a new filter. Since your first filter has probably been a great performer, you will be considering keeping the same brand of filter.
Ironically, since Pentair is trying to do away with the FNS filter, you may find that the FNS Plus is actually more affordable, and with the minor changes that have been made, is a an even better filter.
So, how do you avoid costly plumbing expenditures in changing out this filter? The FNS actually has the bulkheads (the connections where the backwash valve union nuts) that sit 1/4" lower than the standard FNS filter. In order to avoid having to change the plumbing for the backwash valve (although it is always recommended you change the valve when you install a new filter), you need to bring the filter up that 1/4" to make the bulkhead fittings line up.
Pictured below is a filter and the two kinds of valves that are used with the filter. On the left, the two black "dots" on the front of the filter are the bulkheads. On the right, you will see the two connection ports that the valves use to connect to the filter. Either valve works with this filter (i.e. multiport (left valve) or standard push/pull (right valve).

When changing the filter you should need only a large pair of channel locks and some lube. The other important component is a 18" X 18" Ceramic tile. When you install the new filter, first lay down the ceramic tile. This will make up for that 1/4" difference on the bulkhead location and ensure that your filter lines up with your valve! Thats it...no additional plumbing required.
Always remember, before you attempt to do any installation on your own, with anything you are unfamilar with, do your best to find the people who have been doing this for awhile. These little tips and tricks will make the job much easier, and save some aggravation!
The Ugly Pool Guy www.WeFixUglyPools.com

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