Master Spas spa filter (4CH-949)

Master Spas Eco-Pur (5" OD)

Replacement numbers

Unicel 4CH-949, Pleatco PWW50L

Fits Master Spas Eco-Pur (5" OD).

Diameter 4-15/16" (125 mm)Length 13-1/2" (343 mm)50 sq ft

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Unicel4CH-949
PleatcoPWW50L
FilburFC-0172
Topv-groove semi-circular handle
Bottom2" female SAE thread
Ø 4-15/16" (125 mm)13-1/2" (343 mm)Side view · end views belowTopBottom
Top: v-groove semi-circular handle
Bottom: 2" female SAE thread
Drawn to scale from the listed diameter and length. Handles, threads and closed ends are drawn as symbols, not to scale. 50 sq ft media.

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For Master Spas, 4CH-949 cartridge sits in Master Spas Eco-Pur (5" OD). The cross-reference prints Unicel 4CH-949; Pleatco PWW50L; Filbur FC-0172. 4-15/16" across, 13-1/2" long, top v-groove semi-circular handle, bottom 2" female SAE thread, 50 sq ft.

Catalog note for PWW50L: Unicel: replacement for 5" OD Eco-Pur systems; must verify OAL.

Hold 4CH-949 next to 4CH-252 differs by Unicel 4CH-252, Pleatco PMA20-F2M, no Filbur number, 4-5/8" diameter, 8" long, top molded cone handle, bottom 2” male thread/MPT, 25 sq ft, OEM X268521, note says Unicel: Master Spas original has 4-3/4" OD; 6CH-402 differs by Unicel 6CH-402, Pleatco PMA40L-F2M, Filbur FC-0317, 6" diameter, 9-1/2" long, top semi-circular handle, bottom 2” male thread/MPT, 40 sq ft, OEM PMA40L-F2M, note says Unicel prints PMA40L-F2M (a Pleatco number) in its OEM column; Pleatco lists Master Spas Twilight OEM X268365 for PMA40L-F2M. Unicel: must remove black stand pipe.

Left blank on purpose: no model/model-year fitment in sources; Unicel lists no OEM part number for this brand entry.

Source locations for this Master Spas row: Unicel 2026 Replacement Guide on 4CH-949 (OEM cross reference (Master Spas section), PDF p.45 (printed p.41); spec table PDF p.9 (printed p.5)). Pleatco 2023 Catalog on 4CH-949 (Unicel-to-Pleatco cross reference, PDF p.47). Filbur Catalog & Reference Guide on 4CH-949 (Unicel-to-Filbur reverse cross reference, printed p.66 (PDF p.34)).

If you know the Master Spas model and not the part number, use the Master Spas filter by model and year lookup.

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. Brand notes: Master Spas Eco-Pur filters. Number formats: how Filbur, Unicel and Pleatco numbers compare.

The same 4CH-949 number is also on the PDC Spas, Waterway Plastics pages.

Other Master Spas cartridges

All 13 Master 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: no model/model-year fitment in sources; Unicel lists no OEM part number for this brand entry.