Freedom Spas spa filter (C-4401)

Freedom Spas

Replacement numbers

Unicel C-4401, Pleatco PRB17.5SF-PAIR

Fits Freedom Spas.

Diameter 4-15/16" (125 mm)Length 4-5/8" (117 mm)35 sq ft1 model listed

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UnicelC-4401
PleatcoPRB17.5SF-PAIR (Unicel cross-reference PDF p.47: C-4401 = PRB17.5SF-JH-PAIR. Spec table prints PRB17.5SF-PAIR at 5" OD. Same cross as the Beachcomber row.)
FilburFC-2386
Top2-1/8" (54 mm) / open
Bottom2-1/8" (54 mm) / open
Ø 4-15/16" (125 mm)4-5/8" (117 mm)Side view · end views belowTopBottom
Top: 2-1/8" (54 mm) / open
Bottom: 2-1/8" (54 mm) / open
Drawn to scale from the listed diameter and length and open-end sizes. Handles, threads and closed ends are drawn as symbols, not to scale. 35 sq ft media.

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Freedom Spas is the group name on the Freedom Spas row C-4401 cartridge (Liberty). Match these numbers: Unicel C-4401; Pleatco PRB17.5SF-PAIR; Filbur FC-2386. 4-15/16" across, 4-5/8" long, top 2-1/8" / open, bottom 2-1/8" / open, 35 sq ft.

Catalog note for PRB17.5SF-PAIR: Unicel's Freedom list names Liberty only on this 35 sq ft row: 4-15/16" x 4-5/8", C-4401, 4 oz. The spec note says two cartridges per set with a stick handle. Filbur's Freedom section lists FC-2386 / C-4401 as Rainbow DSF 35, 2/set, and does not print Liberty. The same Unicel number is Beachcomber SKU 3005820. This row stays out of the search index because it has no Freedom OEM number and the model name is Unicel's alone.

C-4401 (OEM C-4401 cartridge (Liberty)), Pleatco side: Unicel cross-reference PDF p.47: C-4401 = PRB17.5SF-JH-PAIR. Spec table prints PRB17.5SF-PAIR at 5" OD. Same cross as the Beachcomber row..

PRB17.5SF-PAIR, Filbur note: Freedom Spas section PDF p.18 (printed p.35): FC-2386, Rainbow DSF 35, 2/set, PRB17.5SF-PAIR/JH, C-4401, 35 sq ft. Does not print Liberty..

Freedom Spas applications recorded for this cartridge: Liberty, no year range printed, listed by Unicel 2026 Replacement Guide (Unicel Freedom list only, on the 35 sq ft row. The following C-4405 row has no model name.).

Hold C-4401 next to 4CH-30 differs by Unicel 4CH-30, Pleatco PTL25P-4, Filbur FC-0141, 4-5/8" diameter, 11-7/8" long, top molded cone handle, bottom 1-1/2” male thread/MPT, 30 sq ft, note says Shown at 30 sq ft because that is Unicel's Freedom Spas line, Unicel's spec table (158 pleats, 4 oz), Filbur's size table and Aladdin 13005. Unicel's Sundance line prints the same 4CH-30 for OEM 6540-484 at 25 sq ft, and Filbur's Sundance line does too. Unicel names Franklin, Statesman and Revere. Aladdin's model field uses that same string and lists Freedom among many brands, including Dimension One and Sundance. Pleatco's Unicel cross-reference does not list 4CH-30; PTL25P-4 is Filbur's Pleatco cell.; C-4637 differs by Unicel C-4637, Pleatco PRB37-IN-4, Filbur FC-2380, 13-5/16" long, 37 sq ft, note says Unicel's Freedom list names Concord, Patriot, Ambassador and Executive on this row only: 4-15/16" x 13-5/16", C-4637, 37 sq ft, 4 oz. The spec table gives 158 pleats, 2-1/8" open ends, and calls 37 sq ft an upgrade of the 25 sq ft C-4326 and C-4625. The brands on that spec line are Rainbow, Waterway, Morgan, Leisure Bay and Custom Molded Products, not Freedom. Filbur's Freedom section calls FC-2380 Rainbow Dynamic 37 and does not print the Concord names. PRB37-IN-4 is Filbur's Pleatco cell..

Left blank on purpose: Liberty is Unicel's Freedom list only. Filbur says Rainbow DSF 35, two per set. No Freedom OEM number. Duplicate of the Beachcomber C-4401 body..

Pages checked for PRB17.5SF-PAIR: Unicel 2026 Replacement Guide on C-4401 (Freedom Spas line, PDF p.35 (printed p.31): Liberty = C-4401, 4-15/16" x 4-5/8", 35 sq ft, 4 oz; spec table PDF p.8 (printed p.4): two per set with stick handle). Pleatco 2023 Catalog on C-4401 (Unicel cross-reference PDF p.47: C-4401 = PRB17.5SF-JH-PAIR). Filbur Catalog & Reference Guide on C-4401 (Freedom Spas section PDF p.18 (printed p.35): FC-2386, Rainbow DSF 35, 2/set, C-4401. No Liberty name).

Hot tubs listed for this cartridge

The rest of the Freedom Spas model list is the Freedom Spas filter by model and year lookup.

Model / systemYearsListed by
Liberty (Unicel Freedom list only, on the 35 sq ft row. The following C-4405 row has no model name.)not givenUnicel 2026 Replacement Guide

Check the cartridge you removed

Measure diameter, length, and both ends, then compare them with the figures above. The steps are in the measuring guide. Why the bottom decides whether it seals: open-end vs threaded filters. Power, the retainer, and not running the spa empty: how to install a cartridge. Number formats: how Filbur, Unicel and Pleatco numbers compare.

The same C-4401 number is also on the Beachcomber page.

Other Freedom Spas cartridges

All 6 Freedom Spas spa filters

Every number on this row, on one screen: cross-reference lookup. Published clean and replace intervals for this cartridge, and a buy link for the numbers above: replacement schedule and reorder. The interval comparison by brand: calculator.

Cleaner and test strips

Hose rinse and soak steps are in how to clean a cartridge. Named cleaners and strips are in filter cleaners and test strips.

Filter cleaner and test strips

Sources

Not in sources: Liberty is Unicel's Freedom list only. Filbur says Rainbow DSF 35, two per set. No Freedom OEM number. Duplicate of the Beachcomber C-4401 body..